Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

12 files changed, 12543 insertions, 0 deletions

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
new file mode 100644
index 0000000000..f7901cb4d2
--- /dev/null
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -0,0 +1,7161 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Kernel-based Virtual Machine driver for Linux
+ *
+ * This module enables machines with Intel VT-x extensions to run virtual
+ * machines without emulation or binary translation.
+ *
+ * MMU support
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ * Copyright 2010 Red Hat, Inc. and/or its affiliates.
+ *
+ * Authors:
+ *   Yaniv Kamay  <yaniv@qumranet.com>
+ *   Avi Kivity   <avi@qumranet.com>
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include "irq.h"
+#include "ioapic.h"
+#include "mmu.h"
+#include "mmu_internal.h"
+#include "tdp_mmu.h"
+#include "x86.h"
+#include "kvm_cache_regs.h"
+#include "smm.h"
+#include "kvm_emulate.h"
+#include "page_track.h"
+#include "cpuid.h"
+#include "spte.h"
+
+#include <linux/kvm_host.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/moduleparam.h>
+#include <linux/export.h>
+#include <linux/swap.h>
+#include <linux/hugetlb.h>
+#include <linux/compiler.h>
+#include <linux/srcu.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+#include <linux/uaccess.h>
+#include <linux/hash.h>
+#include <linux/kern_levels.h>
+#include <linux/kstrtox.h>
+#include <linux/kthread.h>
+
+#include <asm/page.h>
+#include <asm/memtype.h>
+#include <asm/cmpxchg.h>
+#include <asm/io.h>
+#include <asm/set_memory.h>
+#include <asm/vmx.h>
+
+#include "trace.h"
+
+extern bool itlb_multihit_kvm_mitigation;
+
+static bool nx_hugepage_mitigation_hard_disabled;
+
+int __read_mostly nx_huge_pages = -1;
+static uint __read_mostly nx_huge_pages_recovery_period_ms;
+#ifdef CONFIG_PREEMPT_RT
+/* Recovery can cause latency spikes, disable it for PREEMPT_RT.  */
+static uint __read_mostly nx_huge_pages_recovery_ratio = 0;
+#else
+static uint __read_mostly nx_huge_pages_recovery_ratio = 60;
+#endif
+
+static int get_nx_huge_pages(char *buffer, const struct kernel_param *kp);
+static int set_nx_huge_pages(const char *val, const struct kernel_param *kp);
+static int set_nx_huge_pages_recovery_param(const char *val, const struct kernel_param *kp);
+
+static const struct kernel_param_ops nx_huge_pages_ops = {
+	.set = set_nx_huge_pages,
+	.get = get_nx_huge_pages,
+};
+
+static const struct kernel_param_ops nx_huge_pages_recovery_param_ops = {
+	.set = set_nx_huge_pages_recovery_param,
+	.get = param_get_uint,
+};
+
+module_param_cb(nx_huge_pages, &nx_huge_pages_ops, &nx_huge_pages, 0644);
+__MODULE_PARM_TYPE(nx_huge_pages, "bool");
+module_param_cb(nx_huge_pages_recovery_ratio, &nx_huge_pages_recovery_param_ops,
+		&nx_huge_pages_recovery_ratio, 0644);
+__MODULE_PARM_TYPE(nx_huge_pages_recovery_ratio, "uint");
+module_param_cb(nx_huge_pages_recovery_period_ms, &nx_huge_pages_recovery_param_ops,
+		&nx_huge_pages_recovery_period_ms, 0644);
+__MODULE_PARM_TYPE(nx_huge_pages_recovery_period_ms, "uint");
+
+static bool __read_mostly force_flush_and_sync_on_reuse;
+module_param_named(flush_on_reuse, force_flush_and_sync_on_reuse, bool, 0644);
+
+/*
+ * When setting this variable to true it enables Two-Dimensional-Paging
+ * where the hardware walks 2 page tables:
+ * 1. the guest-virtual to guest-physical
+ * 2. while doing 1. it walks guest-physical to host-physical
+ * If the hardware supports that we don't need to do shadow paging.
+ */
+bool tdp_enabled = false;
+
+static bool __ro_after_init tdp_mmu_allowed;
+
+#ifdef CONFIG_X86_64
+bool __read_mostly tdp_mmu_enabled = true;
+module_param_named(tdp_mmu, tdp_mmu_enabled, bool, 0444);
+#endif
+
+static int max_huge_page_level __read_mostly;
+static int tdp_root_level __read_mostly;
+static int max_tdp_level __read_mostly;
+
+#define PTE_PREFETCH_NUM		8
+
+#include <trace/events/kvm.h>
+
+/* make pte_list_desc fit well in cache lines */
+#define PTE_LIST_EXT 14
+
+/*
+ * struct pte_list_desc is the core data structure used to implement a custom
+ * list for tracking a set of related SPTEs, e.g. all the SPTEs that map a
+ * given GFN when used in the context of rmaps.  Using a custom list allows KVM
+ * to optimize for the common case where many GFNs will have at most a handful
+ * of SPTEs pointing at them, i.e. allows packing multiple SPTEs into a small
+ * memory footprint, which in turn improves runtime performance by exploiting
+ * cache locality.
+ *
+ * A list is comprised of one or more pte_list_desc objects (descriptors).
+ * Each individual descriptor stores up to PTE_LIST_EXT SPTEs.  If a descriptor
+ * is full and a new SPTEs needs to be added, a new descriptor is allocated and
+ * becomes the head of the list.  This means that by definitions, all tail
+ * descriptors are full.
+ *
+ * Note, the meta data fields are deliberately placed at the start of the
+ * structure to optimize the cacheline layout; accessing the descriptor will
+ * touch only a single cacheline so long as @spte_count<=6 (or if only the
+ * descriptors metadata is accessed).
+ */
+struct pte_list_desc {
+	struct pte_list_desc *more;
+	/* The number of PTEs stored in _this_ descriptor. */
+	u32 spte_count;
+	/* The number of PTEs stored in all tails of this descriptor. */
+	u32 tail_count;
+	u64 *sptes[PTE_LIST_EXT];
+};
+
+struct kvm_shadow_walk_iterator {
+	u64 addr;
+	hpa_t shadow_addr;
+	u64 *sptep;
+	int level;
+	unsigned index;
+};
+
+#define for_each_shadow_entry_using_root(_vcpu, _root, _addr, _walker)     \
+	for (shadow_walk_init_using_root(&(_walker), (_vcpu),              \
+					 (_root), (_addr));                \
+	     shadow_walk_okay(&(_walker));			           \
+	     shadow_walk_next(&(_walker)))
+
+#define for_each_shadow_entry(_vcpu, _addr, _walker)            \
+	for (shadow_walk_init(&(_walker), _vcpu, _addr);	\
+	     shadow_walk_okay(&(_walker));			\
+	     shadow_walk_next(&(_walker)))
+
+#define for_each_shadow_entry_lockless(_vcpu, _addr, _walker, spte)	\
+	for (shadow_walk_init(&(_walker), _vcpu, _addr);		\
+	     shadow_walk_okay(&(_walker)) &&				\
+		({ spte = mmu_spte_get_lockless(_walker.sptep); 1; });	\
+	     __shadow_walk_next(&(_walker), spte))
+
+static struct kmem_cache *pte_list_desc_cache;
+struct kmem_cache *mmu_page_header_cache;
+static struct percpu_counter kvm_total_used_mmu_pages;
+
+static void mmu_spte_set(u64 *sptep, u64 spte);
+
+struct kvm_mmu_role_regs {
+	const unsigned long cr0;
+	const unsigned long cr4;
+	const u64 efer;
+};
+
+#define CREATE_TRACE_POINTS
+#include "mmutrace.h"
+
+/*
+ * Yes, lot's of underscores.  They're a hint that you probably shouldn't be
+ * reading from the role_regs.  Once the root_role is constructed, it becomes
+ * the single source of truth for the MMU's state.
+ */
+#define BUILD_MMU_ROLE_REGS_ACCESSOR(reg, name, flag)			\
+static inline bool __maybe_unused					\
+____is_##reg##_##name(const struct kvm_mmu_role_regs *regs)		\
+{									\
+	return !!(regs->reg & flag);					\
+}
+BUILD_MMU_ROLE_REGS_ACCESSOR(cr0, pg, X86_CR0_PG);
+BUILD_MMU_ROLE_REGS_ACCESSOR(cr0, wp, X86_CR0_WP);
+BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, pse, X86_CR4_PSE);
+BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, pae, X86_CR4_PAE);
+BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, smep, X86_CR4_SMEP);
+BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, smap, X86_CR4_SMAP);
+BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, pke, X86_CR4_PKE);
+BUILD_MMU_ROLE_REGS_ACCESSOR(cr4, la57, X86_CR4_LA57);
+BUILD_MMU_ROLE_REGS_ACCESSOR(efer, nx, EFER_NX);
+BUILD_MMU_ROLE_REGS_ACCESSOR(efer, lma, EFER_LMA);
+
+/*
+ * The MMU itself (with a valid role) is the single source of truth for the
+ * MMU.  Do not use the regs used to build the MMU/role, nor the vCPU.  The
+ * regs don't account for dependencies, e.g. clearing CR4 bits if CR0.PG=1,
+ * and the vCPU may be incorrect/irrelevant.
+ */
+#define BUILD_MMU_ROLE_ACCESSOR(base_or_ext, reg, name)		\
+static inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu)	\
+{								\
+	return !!(mmu->cpu_role. base_or_ext . reg##_##name);	\
+}
+BUILD_MMU_ROLE_ACCESSOR(base, cr0, wp);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pse);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smep);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smap);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pke);
+BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, la57);
+BUILD_MMU_ROLE_ACCESSOR(base, efer, nx);
+BUILD_MMU_ROLE_ACCESSOR(ext,  efer, lma);
+
+static inline bool is_cr0_pg(struct kvm_mmu *mmu)
+{
+        return mmu->cpu_role.base.level > 0;
+}
+
+static inline bool is_cr4_pae(struct kvm_mmu *mmu)
+{
+        return !mmu->cpu_role.base.has_4_byte_gpte;
+}
+
+static struct kvm_mmu_role_regs vcpu_to_role_regs(struct kvm_vcpu *vcpu)
+{
+	struct kvm_mmu_role_regs regs = {
+		.cr0 = kvm_read_cr0_bits(vcpu, KVM_MMU_CR0_ROLE_BITS),
+		.cr4 = kvm_read_cr4_bits(vcpu, KVM_MMU_CR4_ROLE_BITS),
+		.efer = vcpu->arch.efer,
+	};
+
+	return regs;
+}
+
+static unsigned long get_guest_cr3(struct kvm_vcpu *vcpu)
+{
+	return kvm_read_cr3(vcpu);
+}
+
+static inline unsigned long kvm_mmu_get_guest_pgd(struct kvm_vcpu *vcpu,
+						  struct kvm_mmu *mmu)
+{
+	if (IS_ENABLED(CONFIG_RETPOLINE) && mmu->get_guest_pgd == get_guest_cr3)
+		return kvm_read_cr3(vcpu);
+
+	return mmu->get_guest_pgd(vcpu);
+}
+
+static inline bool kvm_available_flush_remote_tlbs_range(void)
+{
+	return kvm_x86_ops.flush_remote_tlbs_range;
+}
+
+int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages)
+{
+	if (!kvm_x86_ops.flush_remote_tlbs_range)
+		return -EOPNOTSUPP;
+
+	return static_call(kvm_x86_flush_remote_tlbs_range)(kvm, gfn, nr_pages);
+}
+
+static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index);
+
+/* Flush the range of guest memory mapped by the given SPTE. */
+static void kvm_flush_remote_tlbs_sptep(struct kvm *kvm, u64 *sptep)
+{
+	struct kvm_mmu_page *sp = sptep_to_sp(sptep);
+	gfn_t gfn = kvm_mmu_page_get_gfn(sp, spte_index(sptep));
+
+	kvm_flush_remote_tlbs_gfn(kvm, gfn, sp->role.level);
+}
+
+static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
+			   unsigned int access)
+{
+	u64 spte = make_mmio_spte(vcpu, gfn, access);
+
+	trace_mark_mmio_spte(sptep, gfn, spte);
+	mmu_spte_set(sptep, spte);
+}
+
+static gfn_t get_mmio_spte_gfn(u64 spte)
+{
+	u64 gpa = spte & shadow_nonpresent_or_rsvd_lower_gfn_mask;
+
+	gpa |= (spte >> SHADOW_NONPRESENT_OR_RSVD_MASK_LEN)
+	       & shadow_nonpresent_or_rsvd_mask;
+
+	return gpa >> PAGE_SHIFT;
+}
+
+static unsigned get_mmio_spte_access(u64 spte)
+{
+	return spte & shadow_mmio_access_mask;
+}
+
+static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
+{
+	u64 kvm_gen, spte_gen, gen;
+
+	gen = kvm_vcpu_memslots(vcpu)->generation;
+	if (unlikely(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS))
+		return false;
+
+	kvm_gen = gen & MMIO_SPTE_GEN_MASK;
+	spte_gen = get_mmio_spte_generation(spte);
+
+	trace_check_mmio_spte(spte, kvm_gen, spte_gen);
+	return likely(kvm_gen == spte_gen);
+}
+
+static int is_cpuid_PSE36(void)
+{
+	return 1;
+}
+
+#ifdef CONFIG_X86_64
+static void __set_spte(u64 *sptep, u64 spte)
+{
+	WRITE_ONCE(*sptep, spte);
+}
+
+static void __update_clear_spte_fast(u64 *sptep, u64 spte)
+{
+	WRITE_ONCE(*sptep, spte);
+}
+
+static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
+{
+	return xchg(sptep, spte);
+}
+
+static u64 __get_spte_lockless(u64 *sptep)
+{
+	return READ_ONCE(*sptep);
+}
+#else
+union split_spte {
+	struct {
+		u32 spte_low;
+		u32 spte_high;
+	};
+	u64 spte;
+};
+
+static void count_spte_clear(u64 *sptep, u64 spte)
+{
+	struct kvm_mmu_page *sp =  sptep_to_sp(sptep);
+
+	if (is_shadow_present_pte(spte))
+		return;
+
+	/* Ensure the spte is completely set before we increase the count */
+	smp_wmb();
+	sp->clear_spte_count++;
+}
+
+static void __set_spte(u64 *sptep, u64 spte)
+{
+	union split_spte *ssptep, sspte;
+
+	ssptep = (union split_spte *)sptep;
+	sspte = (union split_spte)spte;
+
+	ssptep->spte_high = sspte.spte_high;
+
+	/*
+	 * If we map the spte from nonpresent to present, We should store
+	 * the high bits firstly, then set present bit, so cpu can not
+	 * fetch this spte while we are setting the spte.
+	 */
+	smp_wmb();
+
+	WRITE_ONCE(ssptep->spte_low, sspte.spte_low);
+}
+
+static void __update_clear_spte_fast(u64 *sptep, u64 spte)
+{
+	union split_spte *ssptep, sspte;
+
+	ssptep = (union split_spte *)sptep;
+	sspte = (union split_spte)spte;
+
+	WRITE_ONCE(ssptep->spte_low, sspte.spte_low);
+
+	/*
+	 * If we map the spte from present to nonpresent, we should clear
+	 * present bit firstly to avoid vcpu fetch the old high bits.
+	 */
+	smp_wmb();
+
+	ssptep->spte_high = sspte.spte_high;
+	count_spte_clear(sptep, spte);
+}
+
+static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
+{
+	union split_spte *ssptep, sspte, orig;
+
+	ssptep = (union split_spte *)sptep;
+	sspte = (union split_spte)spte;
+
+	/* xchg acts as a barrier before the setting of the high bits */
+	orig.spte_low = xchg(&ssptep->spte_low, sspte.spte_low);
+	orig.spte_high = ssptep->spte_high;
+	ssptep->spte_high = sspte.spte_high;
+	count_spte_clear(sptep, spte);
+
+	return orig.spte;
+}
+
+/*
+ * The idea using the light way get the spte on x86_32 guest is from
+ * gup_get_pte (mm/gup.c).
+ *
+ * An spte tlb flush may be pending, because kvm_set_pte_rmap
+ * coalesces them and we are running out of the MMU lock.  Therefore
+ * we need to protect against in-progress updates of the spte.
+ *
+ * Reading the spte while an update is in progress may get the old value
+ * for the high part of the spte.  The race is fine for a present->non-present
+ * change (because the high part of the spte is ignored for non-present spte),
+ * but for a present->present change we must reread the spte.
+ *
+ * All such changes are done in two steps (present->non-present and
+ * non-present->present), hence it is enough to count the number of
+ * present->non-present updates: if it changed while reading the spte,
+ * we might have hit the race.  This is done using clear_spte_count.
+ */
+static u64 __get_spte_lockless(u64 *sptep)
+{
+	struct kvm_mmu_page *sp =  sptep_to_sp(sptep);
+	union split_spte spte, *orig = (union split_spte *)sptep;
+	int count;
+
+retry:
+	count = sp->clear_spte_count;
+	smp_rmb();
+
+	spte.spte_low = orig->spte_low;
+	smp_rmb();
+
+	spte.spte_high = orig->spte_high;
+	smp_rmb();
+
+	if (unlikely(spte.spte_low != orig->spte_low ||
+	      count != sp->clear_spte_count))
+		goto retry;
+
+	return spte.spte;
+}
+#endif
+
+/* Rules for using mmu_spte_set:
+ * Set the sptep from nonpresent to present.
+ * Note: the sptep being assigned *must* be either not present
+ * or in a state where the hardware will not attempt to update
+ * the spte.
+ */
+static void mmu_spte_set(u64 *sptep, u64 new_spte)
+{
+	WARN_ON_ONCE(is_shadow_present_pte(*sptep));
+	__set_spte(sptep, new_spte);
+}
+
+/*
+ * Update the SPTE (excluding the PFN), but do not track changes in its
+ * accessed/dirty status.
+ */
+static u64 mmu_spte_update_no_track(u64 *sptep, u64 new_spte)
+{
+	u64 old_spte = *sptep;
+
+	WARN_ON_ONCE(!is_shadow_present_pte(new_spte));
+	check_spte_writable_invariants(new_spte);
+
+	if (!is_shadow_present_pte(old_spte)) {
+		mmu_spte_set(sptep, new_spte);
+		return old_spte;
+	}
+
+	if (!spte_has_volatile_bits(old_spte))
+		__update_clear_spte_fast(sptep, new_spte);
+	else
+		old_spte = __update_clear_spte_slow(sptep, new_spte);
+
+	WARN_ON_ONCE(spte_to_pfn(old_spte) != spte_to_pfn(new_spte));
+
+	return old_spte;
+}
+
+/* Rules for using mmu_spte_update:
+ * Update the state bits, it means the mapped pfn is not changed.
+ *
+ * Whenever an MMU-writable SPTE is overwritten with a read-only SPTE, remote
+ * TLBs must be flushed. Otherwise rmap_write_protect will find a read-only
+ * spte, even though the writable spte might be cached on a CPU's TLB.
+ *
+ * Returns true if the TLB needs to be flushed
+ */
+static bool mmu_spte_update(u64 *sptep, u64 new_spte)
+{
+	bool flush = false;
+	u64 old_spte = mmu_spte_update_no_track(sptep, new_spte);
+
+	if (!is_shadow_present_pte(old_spte))
+		return false;
+
+	/*
+	 * For the spte updated out of mmu-lock is safe, since
+	 * we always atomically update it, see the comments in
+	 * spte_has_volatile_bits().
+	 */
+	if (is_mmu_writable_spte(old_spte) &&
+	      !is_writable_pte(new_spte))
+		flush = true;
+
+	/*
+	 * Flush TLB when accessed/dirty states are changed in the page tables,
+	 * to guarantee consistency between TLB and page tables.
+	 */
+
+	if (is_accessed_spte(old_spte) && !is_accessed_spte(new_spte)) {
+		flush = true;
+		kvm_set_pfn_accessed(spte_to_pfn(old_spte));
+	}
+
+	if (is_dirty_spte(old_spte) && !is_dirty_spte(new_spte)) {
+		flush = true;
+		kvm_set_pfn_dirty(spte_to_pfn(old_spte));
+	}
+
+	return flush;
+}
+
+/*
+ * Rules for using mmu_spte_clear_track_bits:
+ * It sets the sptep from present to nonpresent, and track the
+ * state bits, it is used to clear the last level sptep.
+ * Returns the old PTE.
+ */
+static u64 mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep)
+{
+	kvm_pfn_t pfn;
+	u64 old_spte = *sptep;
+	int level = sptep_to_sp(sptep)->role.level;
+	struct page *page;
+
+	if (!is_shadow_present_pte(old_spte) ||
+	    !spte_has_volatile_bits(old_spte))
+		__update_clear_spte_fast(sptep, 0ull);
+	else
+		old_spte = __update_clear_spte_slow(sptep, 0ull);
+
+	if (!is_shadow_present_pte(old_spte))
+		return old_spte;
+
+	kvm_update_page_stats(kvm, level, -1);
+
+	pfn = spte_to_pfn(old_spte);
+
+	/*
+	 * KVM doesn't hold a reference to any pages mapped into the guest, and
+	 * instead uses the mmu_notifier to ensure that KVM unmaps any pages
+	 * before they are reclaimed.  Sanity check that, if the pfn is backed
+	 * by a refcounted page, the refcount is elevated.
+	 */
+	page = kvm_pfn_to_refcounted_page(pfn);
+	WARN_ON_ONCE(page && !page_count(page));
+
+	if (is_accessed_spte(old_spte))
+		kvm_set_pfn_accessed(pfn);
+
+	if (is_dirty_spte(old_spte))
+		kvm_set_pfn_dirty(pfn);
+
+	return old_spte;
+}
+
+/*
+ * Rules for using mmu_spte_clear_no_track:
+ * Directly clear spte without caring the state bits of sptep,
+ * it is used to set the upper level spte.
+ */
+static void mmu_spte_clear_no_track(u64 *sptep)
+{
+	__update_clear_spte_fast(sptep, 0ull);
+}
+
+static u64 mmu_spte_get_lockless(u64 *sptep)
+{
+	return __get_spte_lockless(sptep);
+}
+
+/* Returns the Accessed status of the PTE and resets it at the same time. */
+static bool mmu_spte_age(u64 *sptep)
+{
+	u64 spte = mmu_spte_get_lockless(sptep);
+
+	if (!is_accessed_spte(spte))
+		return false;
+
+	if (spte_ad_enabled(spte)) {
+		clear_bit((ffs(shadow_accessed_mask) - 1),
+			  (unsigned long *)sptep);
+	} else {
+		/*
+		 * Capture the dirty status of the page, so that it doesn't get
+		 * lost when the SPTE is marked for access tracking.
+		 */
+		if (is_writable_pte(spte))
+			kvm_set_pfn_dirty(spte_to_pfn(spte));
+
+		spte = mark_spte_for_access_track(spte);
+		mmu_spte_update_no_track(sptep, spte);
+	}
+
+	return true;
+}
+
+static inline bool is_tdp_mmu_active(struct kvm_vcpu *vcpu)
+{
+	return tdp_mmu_enabled && vcpu->arch.mmu->root_role.direct;
+}
+
+static void walk_shadow_page_lockless_begin(struct kvm_vcpu *vcpu)
+{
+	if (is_tdp_mmu_active(vcpu)) {
+		kvm_tdp_mmu_walk_lockless_begin();
+	} else {
+		/*
+		 * Prevent page table teardown by making any free-er wait during
+		 * kvm_flush_remote_tlbs() IPI to all active vcpus.
+		 */
+		local_irq_disable();
+
+		/*
+		 * Make sure a following spte read is not reordered ahead of the write
+		 * to vcpu->mode.
+		 */
+		smp_store_mb(vcpu->mode, READING_SHADOW_PAGE_TABLES);
+	}
+}
+
+static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
+{
+	if (is_tdp_mmu_active(vcpu)) {
+		kvm_tdp_mmu_walk_lockless_end();
+	} else {
+		/*
+		 * Make sure the write to vcpu->mode is not reordered in front of
+		 * reads to sptes.  If it does, kvm_mmu_commit_zap_page() can see us
+		 * OUTSIDE_GUEST_MODE and proceed to free the shadow page table.
+		 */
+		smp_store_release(&vcpu->mode, OUTSIDE_GUEST_MODE);
+		local_irq_enable();
+	}
+}
+
+static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect)
+{
+	int r;
+
+	/* 1 rmap, 1 parent PTE per level, and the prefetched rmaps. */
+	r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
+				       1 + PT64_ROOT_MAX_LEVEL + PTE_PREFETCH_NUM);
+	if (r)
+		return r;
+	r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_shadow_page_cache,
+				       PT64_ROOT_MAX_LEVEL);
+	if (r)
+		return r;
+	if (maybe_indirect) {
+		r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_shadowed_info_cache,
+					       PT64_ROOT_MAX_LEVEL);
+		if (r)
+			return r;
+	}
+	return kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
+					  PT64_ROOT_MAX_LEVEL);
+}
+
+static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
+{
+	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache);
+	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_shadow_page_cache);
+	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_shadowed_info_cache);
+	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
+}
+
+static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
+{
+	kmem_cache_free(pte_list_desc_cache, pte_list_desc);
+}
+
+static bool sp_has_gptes(struct kvm_mmu_page *sp);
+
+static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
+{
+	if (sp->role.passthrough)
+		return sp->gfn;
+
+	if (!sp->role.direct)
+		return sp->shadowed_translation[index] >> PAGE_SHIFT;
+
+	return sp->gfn + (index << ((sp->role.level - 1) * SPTE_LEVEL_BITS));
+}
+
+/*
+ * For leaf SPTEs, fetch the *guest* access permissions being shadowed. Note
+ * that the SPTE itself may have a more constrained access permissions that
+ * what the guest enforces. For example, a guest may create an executable
+ * huge PTE but KVM may disallow execution to mitigate iTLB multihit.
+ */
+static u32 kvm_mmu_page_get_access(struct kvm_mmu_page *sp, int index)
+{
+	if (sp_has_gptes(sp))
+		return sp->shadowed_translation[index] & ACC_ALL;
+
+	/*
+	 * For direct MMUs (e.g. TDP or non-paging guests) or passthrough SPs,
+	 * KVM is not shadowing any guest page tables, so the "guest access
+	 * permissions" are just ACC_ALL.
+	 *
+	 * For direct SPs in indirect MMUs (shadow paging), i.e. when KVM
+	 * is shadowing a guest huge page with small pages, the guest access
+	 * permissions being shadowed are the access permissions of the huge
+	 * page.
+	 *
+	 * In both cases, sp->role.access contains the correct access bits.
+	 */
+	return sp->role.access;
+}
+
+static void kvm_mmu_page_set_translation(struct kvm_mmu_page *sp, int index,
+					 gfn_t gfn, unsigned int access)
+{
+	if (sp_has_gptes(sp)) {
+		sp->shadowed_translation[index] = (gfn << PAGE_SHIFT) | access;
+		return;
+	}
+
+	WARN_ONCE(access != kvm_mmu_page_get_access(sp, index),
+	          "access mismatch under %s page %llx (expected %u, got %u)\n",
+	          sp->role.passthrough ? "passthrough" : "direct",
+	          sp->gfn, kvm_mmu_page_get_access(sp, index), access);
+
+	WARN_ONCE(gfn != kvm_mmu_page_get_gfn(sp, index),
+	          "gfn mismatch under %s page %llx (expected %llx, got %llx)\n",
+	          sp->role.passthrough ? "passthrough" : "direct",
+	          sp->gfn, kvm_mmu_page_get_gfn(sp, index), gfn);
+}
+
+static void kvm_mmu_page_set_access(struct kvm_mmu_page *sp, int index,
+				    unsigned int access)
+{
+	gfn_t gfn = kvm_mmu_page_get_gfn(sp, index);
+
+	kvm_mmu_page_set_translation(sp, index, gfn, access);
+}
+
+/*
+ * Return the pointer to the large page information for a given gfn,
+ * handling slots that are not large page aligned.
+ */
+static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn,
+		const struct kvm_memory_slot *slot, int level)
+{
+	unsigned long idx;
+
+	idx = gfn_to_index(gfn, slot->base_gfn, level);
+	return &slot->arch.lpage_info[level - 2][idx];
+}
+
+static void update_gfn_disallow_lpage_count(const struct kvm_memory_slot *slot,
+					    gfn_t gfn, int count)
+{
+	struct kvm_lpage_info *linfo;
+	int i;
+
+	for (i = PG_LEVEL_2M; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) {
+		linfo = lpage_info_slot(gfn, slot, i);
+		linfo->disallow_lpage += count;
+		WARN_ON_ONCE(linfo->disallow_lpage < 0);
+	}
+}
+
+void kvm_mmu_gfn_disallow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn)
+{
+	update_gfn_disallow_lpage_count(slot, gfn, 1);
+}
+
+void kvm_mmu_gfn_allow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn)
+{
+	update_gfn_disallow_lpage_count(slot, gfn, -1);
+}
+
+static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *slot;
+	gfn_t gfn;
+
+	kvm->arch.indirect_shadow_pages++;
+	gfn = sp->gfn;
+	slots = kvm_memslots_for_spte_role(kvm, sp->role);
+	slot = __gfn_to_memslot(slots, gfn);
+
+	/* the non-leaf shadow pages are keeping readonly. */
+	if (sp->role.level > PG_LEVEL_4K)
+		return __kvm_write_track_add_gfn(kvm, slot, gfn);
+
+	kvm_mmu_gfn_disallow_lpage(slot, gfn);
+
+	if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K))
+		kvm_flush_remote_tlbs_gfn(kvm, gfn, PG_LEVEL_4K);
+}
+
+void track_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	/*
+	 * If it's possible to replace the shadow page with an NX huge page,
+	 * i.e. if the shadow page is the only thing currently preventing KVM
+	 * from using a huge page, add the shadow page to the list of "to be
+	 * zapped for NX recovery" pages.  Note, the shadow page can already be
+	 * on the list if KVM is reusing an existing shadow page, i.e. if KVM
+	 * links a shadow page at multiple points.
+	 */
+	if (!list_empty(&sp->possible_nx_huge_page_link))
+		return;
+
+	++kvm->stat.nx_lpage_splits;
+	list_add_tail(&sp->possible_nx_huge_page_link,
+		      &kvm->arch.possible_nx_huge_pages);
+}
+
+static void account_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp,
+				 bool nx_huge_page_possible)
+{
+	sp->nx_huge_page_disallowed = true;
+
+	if (nx_huge_page_possible)
+		track_possible_nx_huge_page(kvm, sp);
+}
+
+static void unaccount_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *slot;
+	gfn_t gfn;
+
+	kvm->arch.indirect_shadow_pages--;
+	gfn = sp->gfn;
+	slots = kvm_memslots_for_spte_role(kvm, sp->role);
+	slot = __gfn_to_memslot(slots, gfn);
+	if (sp->role.level > PG_LEVEL_4K)
+		return __kvm_write_track_remove_gfn(kvm, slot, gfn);
+
+	kvm_mmu_gfn_allow_lpage(slot, gfn);
+}
+
+void untrack_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	if (list_empty(&sp->possible_nx_huge_page_link))
+		return;
+
+	--kvm->stat.nx_lpage_splits;
+	list_del_init(&sp->possible_nx_huge_page_link);
+}
+
+static void unaccount_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	sp->nx_huge_page_disallowed = false;
+
+	untrack_possible_nx_huge_page(kvm, sp);
+}
+
+static struct kvm_memory_slot *gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu,
+							   gfn_t gfn,
+							   bool no_dirty_log)
+{
+	struct kvm_memory_slot *slot;
+
+	slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+	if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
+		return NULL;
+	if (no_dirty_log && kvm_slot_dirty_track_enabled(slot))
+		return NULL;
+
+	return slot;
+}
+
+/*
+ * About rmap_head encoding:
+ *
+ * If the bit zero of rmap_head->val is clear, then it points to the only spte
+ * in this rmap chain. Otherwise, (rmap_head->val & ~1) points to a struct
+ * pte_list_desc containing more mappings.
+ */
+
+/*
+ * Returns the number of pointers in the rmap chain, not counting the new one.
+ */
+static int pte_list_add(struct kvm_mmu_memory_cache *cache, u64 *spte,
+			struct kvm_rmap_head *rmap_head)
+{
+	struct pte_list_desc *desc;
+	int count = 0;
+
+	if (!rmap_head->val) {
+		rmap_head->val = (unsigned long)spte;
+	} else if (!(rmap_head->val & 1)) {
+		desc = kvm_mmu_memory_cache_alloc(cache);
+		desc->sptes[0] = (u64 *)rmap_head->val;
+		desc->sptes[1] = spte;
+		desc->spte_count = 2;
+		desc->tail_count = 0;
+		rmap_head->val = (unsigned long)desc | 1;
+		++count;
+	} else {
+		desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+		count = desc->tail_count + desc->spte_count;
+
+		/*
+		 * If the previous head is full, allocate a new head descriptor
+		 * as tail descriptors are always kept full.
+		 */
+		if (desc->spte_count == PTE_LIST_EXT) {
+			desc = kvm_mmu_memory_cache_alloc(cache);
+			desc->more = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+			desc->spte_count = 0;
+			desc->tail_count = count;
+			rmap_head->val = (unsigned long)desc | 1;
+		}
+		desc->sptes[desc->spte_count++] = spte;
+	}
+	return count;
+}
+
+static void pte_list_desc_remove_entry(struct kvm *kvm,
+				       struct kvm_rmap_head *rmap_head,
+				       struct pte_list_desc *desc, int i)
+{
+	struct pte_list_desc *head_desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+	int j = head_desc->spte_count - 1;
+
+	/*
+	 * The head descriptor should never be empty.  A new head is added only
+	 * when adding an entry and the previous head is full, and heads are
+	 * removed (this flow) when they become empty.
+	 */
+	KVM_BUG_ON_DATA_CORRUPTION(j < 0, kvm);
+
+	/*
+	 * Replace the to-be-freed SPTE with the last valid entry from the head
+	 * descriptor to ensure that tail descriptors are full at all times.
+	 * Note, this also means that tail_count is stable for each descriptor.
+	 */
+	desc->sptes[i] = head_desc->sptes[j];
+	head_desc->sptes[j] = NULL;
+	head_desc->spte_count--;
+	if (head_desc->spte_count)
+		return;
+
+	/*
+	 * The head descriptor is empty.  If there are no tail descriptors,
+	 * nullify the rmap head to mark the list as emtpy, else point the rmap
+	 * head at the next descriptor, i.e. the new head.
+	 */
+	if (!head_desc->more)
+		rmap_head->val = 0;
+	else
+		rmap_head->val = (unsigned long)head_desc->more | 1;
+	mmu_free_pte_list_desc(head_desc);
+}
+
+static void pte_list_remove(struct kvm *kvm, u64 *spte,
+			    struct kvm_rmap_head *rmap_head)
+{
+	struct pte_list_desc *desc;
+	int i;
+
+	if (KVM_BUG_ON_DATA_CORRUPTION(!rmap_head->val, kvm))
+		return;
+
+	if (!(rmap_head->val & 1)) {
+		if (KVM_BUG_ON_DATA_CORRUPTION((u64 *)rmap_head->val != spte, kvm))
+			return;
+
+		rmap_head->val = 0;
+	} else {
+		desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+		while (desc) {
+			for (i = 0; i < desc->spte_count; ++i) {
+				if (desc->sptes[i] == spte) {
+					pte_list_desc_remove_entry(kvm, rmap_head,
+								   desc, i);
+					return;
+				}
+			}
+			desc = desc->more;
+		}
+
+		KVM_BUG_ON_DATA_CORRUPTION(true, kvm);
+	}
+}
+
+static void kvm_zap_one_rmap_spte(struct kvm *kvm,
+				  struct kvm_rmap_head *rmap_head, u64 *sptep)
+{
+	mmu_spte_clear_track_bits(kvm, sptep);
+	pte_list_remove(kvm, sptep, rmap_head);
+}
+
+/* Return true if at least one SPTE was zapped, false otherwise */
+static bool kvm_zap_all_rmap_sptes(struct kvm *kvm,
+				   struct kvm_rmap_head *rmap_head)
+{
+	struct pte_list_desc *desc, *next;
+	int i;
+
+	if (!rmap_head->val)
+		return false;
+
+	if (!(rmap_head->val & 1)) {
+		mmu_spte_clear_track_bits(kvm, (u64 *)rmap_head->val);
+		goto out;
+	}
+
+	desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+
+	for (; desc; desc = next) {
+		for (i = 0; i < desc->spte_count; i++)
+			mmu_spte_clear_track_bits(kvm, desc->sptes[i]);
+		next = desc->more;
+		mmu_free_pte_list_desc(desc);
+	}
+out:
+	/* rmap_head is meaningless now, remember to reset it */
+	rmap_head->val = 0;
+	return true;
+}
+
+unsigned int pte_list_count(struct kvm_rmap_head *rmap_head)
+{
+	struct pte_list_desc *desc;
+
+	if (!rmap_head->val)
+		return 0;
+	else if (!(rmap_head->val & 1))
+		return 1;
+
+	desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+	return desc->tail_count + desc->spte_count;
+}
+
+static struct kvm_rmap_head *gfn_to_rmap(gfn_t gfn, int level,
+					 const struct kvm_memory_slot *slot)
+{
+	unsigned long idx;
+
+	idx = gfn_to_index(gfn, slot->base_gfn, level);
+	return &slot->arch.rmap[level - PG_LEVEL_4K][idx];
+}
+
+static void rmap_remove(struct kvm *kvm, u64 *spte)
+{
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *slot;
+	struct kvm_mmu_page *sp;
+	gfn_t gfn;
+	struct kvm_rmap_head *rmap_head;
+
+	sp = sptep_to_sp(spte);
+	gfn = kvm_mmu_page_get_gfn(sp, spte_index(spte));
+
+	/*
+	 * Unlike rmap_add, rmap_remove does not run in the context of a vCPU
+	 * so we have to determine which memslots to use based on context
+	 * information in sp->role.
+	 */
+	slots = kvm_memslots_for_spte_role(kvm, sp->role);
+
+	slot = __gfn_to_memslot(slots, gfn);
+	rmap_head = gfn_to_rmap(gfn, sp->role.level, slot);
+
+	pte_list_remove(kvm, spte, rmap_head);
+}
+
+/*
+ * Used by the following functions to iterate through the sptes linked by a
+ * rmap.  All fields are private and not assumed to be used outside.
+ */
+struct rmap_iterator {
+	/* private fields */
+	struct pte_list_desc *desc;	/* holds the sptep if not NULL */
+	int pos;			/* index of the sptep */
+};
+
+/*
+ * Iteration must be started by this function.  This should also be used after
+ * removing/dropping sptes from the rmap link because in such cases the
+ * information in the iterator may not be valid.
+ *
+ * Returns sptep if found, NULL otherwise.
+ */
+static u64 *rmap_get_first(struct kvm_rmap_head *rmap_head,
+			   struct rmap_iterator *iter)
+{
+	u64 *sptep;
+
+	if (!rmap_head->val)
+		return NULL;
+
+	if (!(rmap_head->val & 1)) {
+		iter->desc = NULL;
+		sptep = (u64 *)rmap_head->val;
+		goto out;
+	}
+
+	iter->desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
+	iter->pos = 0;
+	sptep = iter->desc->sptes[iter->pos];
+out:
+	BUG_ON(!is_shadow_present_pte(*sptep));
+	return sptep;
+}
+
+/*
+ * Must be used with a valid iterator: e.g. after rmap_get_first().
+ *
+ * Returns sptep if found, NULL otherwise.
+ */
+static u64 *rmap_get_next(struct rmap_iterator *iter)
+{
+	u64 *sptep;
+
+	if (iter->desc) {
+		if (iter->pos < PTE_LIST_EXT - 1) {
+			++iter->pos;
+			sptep = iter->desc->sptes[iter->pos];
+			if (sptep)
+				goto out;
+		}
+
+		iter->desc = iter->desc->more;
+
+		if (iter->desc) {
+			iter->pos = 0;
+			/* desc->sptes[0] cannot be NULL */
+			sptep = iter->desc->sptes[iter->pos];
+			goto out;
+		}
+	}
+
+	return NULL;
+out:
+	BUG_ON(!is_shadow_present_pte(*sptep));
+	return sptep;
+}
+
+#define for_each_rmap_spte(_rmap_head_, _iter_, _spte_)			\
+	for (_spte_ = rmap_get_first(_rmap_head_, _iter_);		\
+	     _spte_; _spte_ = rmap_get_next(_iter_))
+
+static void drop_spte(struct kvm *kvm, u64 *sptep)
+{
+	u64 old_spte = mmu_spte_clear_track_bits(kvm, sptep);
+
+	if (is_shadow_present_pte(old_spte))
+		rmap_remove(kvm, sptep);
+}
+
+static void drop_large_spte(struct kvm *kvm, u64 *sptep, bool flush)
+{
+	struct kvm_mmu_page *sp;
+
+	sp = sptep_to_sp(sptep);
+	WARN_ON_ONCE(sp->role.level == PG_LEVEL_4K);
+
+	drop_spte(kvm, sptep);
+
+	if (flush)
+		kvm_flush_remote_tlbs_sptep(kvm, sptep);
+}
+
+/*
+ * Write-protect on the specified @sptep, @pt_protect indicates whether
+ * spte write-protection is caused by protecting shadow page table.
+ *
+ * Note: write protection is difference between dirty logging and spte
+ * protection:
+ * - for dirty logging, the spte can be set to writable at anytime if
+ *   its dirty bitmap is properly set.
+ * - for spte protection, the spte can be writable only after unsync-ing
+ *   shadow page.
+ *
+ * Return true if tlb need be flushed.
+ */
+static bool spte_write_protect(u64 *sptep, bool pt_protect)
+{
+	u64 spte = *sptep;
+
+	if (!is_writable_pte(spte) &&
+	    !(pt_protect && is_mmu_writable_spte(spte)))
+		return false;
+
+	if (pt_protect)
+		spte &= ~shadow_mmu_writable_mask;
+	spte = spte & ~PT_WRITABLE_MASK;
+
+	return mmu_spte_update(sptep, spte);
+}
+
+static bool rmap_write_protect(struct kvm_rmap_head *rmap_head,
+			       bool pt_protect)
+{
+	u64 *sptep;
+	struct rmap_iterator iter;
+	bool flush = false;
+
+	for_each_rmap_spte(rmap_head, &iter, sptep)
+		flush |= spte_write_protect(sptep, pt_protect);
+
+	return flush;
+}
+
+static bool spte_clear_dirty(u64 *sptep)
+{
+	u64 spte = *sptep;
+
+	KVM_MMU_WARN_ON(!spte_ad_enabled(spte));
+	spte &= ~shadow_dirty_mask;
+	return mmu_spte_update(sptep, spte);
+}
+
+static bool spte_wrprot_for_clear_dirty(u64 *sptep)
+{
+	bool was_writable = test_and_clear_bit(PT_WRITABLE_SHIFT,
+					       (unsigned long *)sptep);
+	if (was_writable && !spte_ad_enabled(*sptep))
+		kvm_set_pfn_dirty(spte_to_pfn(*sptep));
+
+	return was_writable;
+}
+
+/*
+ * Gets the GFN ready for another round of dirty logging by clearing the
+ *	- D bit on ad-enabled SPTEs, and
+ *	- W bit on ad-disabled SPTEs.
+ * Returns true iff any D or W bits were cleared.
+ */
+static bool __rmap_clear_dirty(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+			       const struct kvm_memory_slot *slot)
+{
+	u64 *sptep;
+	struct rmap_iterator iter;
+	bool flush = false;
+
+	for_each_rmap_spte(rmap_head, &iter, sptep)
+		if (spte_ad_need_write_protect(*sptep))
+			flush |= spte_wrprot_for_clear_dirty(sptep);
+		else
+			flush |= spte_clear_dirty(sptep);
+
+	return flush;
+}
+
+/**
+ * kvm_mmu_write_protect_pt_masked - write protect selected PT level pages
+ * @kvm: kvm instance
+ * @slot: slot to protect
+ * @gfn_offset: start of the BITS_PER_LONG pages we care about
+ * @mask: indicates which pages we should protect
+ *
+ * Used when we do not need to care about huge page mappings.
+ */
+static void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
+				     struct kvm_memory_slot *slot,
+				     gfn_t gfn_offset, unsigned long mask)
+{
+	struct kvm_rmap_head *rmap_head;
+
+	if (tdp_mmu_enabled)
+		kvm_tdp_mmu_clear_dirty_pt_masked(kvm, slot,
+				slot->base_gfn + gfn_offset, mask, true);
+
+	if (!kvm_memslots_have_rmaps(kvm))
+		return;
+
+	while (mask) {
+		rmap_head = gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
+					PG_LEVEL_4K, slot);
+		rmap_write_protect(rmap_head, false);
+
+		/* clear the first set bit */
+		mask &= mask - 1;
+	}
+}
+
+/**
+ * kvm_mmu_clear_dirty_pt_masked - clear MMU D-bit for PT level pages, or write
+ * protect the page if the D-bit isn't supported.
+ * @kvm: kvm instance
+ * @slot: slot to clear D-bit
+ * @gfn_offset: start of the BITS_PER_LONG pages we care about
+ * @mask: indicates which pages we should clear D-bit
+ *
+ * Used for PML to re-log the dirty GPAs after userspace querying dirty_bitmap.
+ */
+static void kvm_mmu_clear_dirty_pt_masked(struct kvm *kvm,
+					 struct kvm_memory_slot *slot,
+					 gfn_t gfn_offset, unsigned long mask)
+{
+	struct kvm_rmap_head *rmap_head;
+
+	if (tdp_mmu_enabled)
+		kvm_tdp_mmu_clear_dirty_pt_masked(kvm, slot,
+				slot->base_gfn + gfn_offset, mask, false);
+
+	if (!kvm_memslots_have_rmaps(kvm))
+		return;
+
+	while (mask) {
+		rmap_head = gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
+					PG_LEVEL_4K, slot);
+		__rmap_clear_dirty(kvm, rmap_head, slot);
+
+		/* clear the first set bit */
+		mask &= mask - 1;
+	}
+}
+
+/**
+ * kvm_arch_mmu_enable_log_dirty_pt_masked - enable dirty logging for selected
+ * PT level pages.
+ *
+ * It calls kvm_mmu_write_protect_pt_masked to write protect selected pages to
+ * enable dirty logging for them.
+ *
+ * We need to care about huge page mappings: e.g. during dirty logging we may
+ * have such mappings.
+ */
+void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
+				struct kvm_memory_slot *slot,
+				gfn_t gfn_offset, unsigned long mask)
+{
+	/*
+	 * Huge pages are NOT write protected when we start dirty logging in
+	 * initially-all-set mode; must write protect them here so that they
+	 * are split to 4K on the first write.
+	 *
+	 * The gfn_offset is guaranteed to be aligned to 64, but the base_gfn
+	 * of memslot has no such restriction, so the range can cross two large
+	 * pages.
+	 */
+	if (kvm_dirty_log_manual_protect_and_init_set(kvm)) {
+		gfn_t start = slot->base_gfn + gfn_offset + __ffs(mask);
+		gfn_t end = slot->base_gfn + gfn_offset + __fls(mask);
+
+		if (READ_ONCE(eager_page_split))
+			kvm_mmu_try_split_huge_pages(kvm, slot, start, end, PG_LEVEL_4K);
+
+		kvm_mmu_slot_gfn_write_protect(kvm, slot, start, PG_LEVEL_2M);
+
+		/* Cross two large pages? */
+		if (ALIGN(start << PAGE_SHIFT, PMD_SIZE) !=
+		    ALIGN(end << PAGE_SHIFT, PMD_SIZE))
+			kvm_mmu_slot_gfn_write_protect(kvm, slot, end,
+						       PG_LEVEL_2M);
+	}
+
+	/* Now handle 4K PTEs.  */
+	if (kvm_x86_ops.cpu_dirty_log_size)
+		kvm_mmu_clear_dirty_pt_masked(kvm, slot, gfn_offset, mask);
+	else
+		kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
+}
+
+int kvm_cpu_dirty_log_size(void)
+{
+	return kvm_x86_ops.cpu_dirty_log_size;
+}
+
+bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
+				    struct kvm_memory_slot *slot, u64 gfn,
+				    int min_level)
+{
+	struct kvm_rmap_head *rmap_head;
+	int i;
+	bool write_protected = false;
+
+	if (kvm_memslots_have_rmaps(kvm)) {
+		for (i = min_level; i <= KVM_MAX_HUGEPAGE_LEVEL; ++i) {
+			rmap_head = gfn_to_rmap(gfn, i, slot);
+			write_protected |= rmap_write_protect(rmap_head, true);
+		}
+	}
+
+	if (tdp_mmu_enabled)
+		write_protected |=
+			kvm_tdp_mmu_write_protect_gfn(kvm, slot, gfn, min_level);
+
+	return write_protected;
+}
+
+static bool kvm_vcpu_write_protect_gfn(struct kvm_vcpu *vcpu, u64 gfn)
+{
+	struct kvm_memory_slot *slot;
+
+	slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+	return kvm_mmu_slot_gfn_write_protect(vcpu->kvm, slot, gfn, PG_LEVEL_4K);
+}
+
+static bool __kvm_zap_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+			   const struct kvm_memory_slot *slot)
+{
+	return kvm_zap_all_rmap_sptes(kvm, rmap_head);
+}
+
+static bool kvm_zap_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+			 struct kvm_memory_slot *slot, gfn_t gfn, int level,
+			 pte_t unused)
+{
+	return __kvm_zap_rmap(kvm, rmap_head, slot);
+}
+
+static bool kvm_set_pte_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+			     struct kvm_memory_slot *slot, gfn_t gfn, int level,
+			     pte_t pte)
+{
+	u64 *sptep;
+	struct rmap_iterator iter;
+	bool need_flush = false;
+	u64 new_spte;
+	kvm_pfn_t new_pfn;
+
+	WARN_ON_ONCE(pte_huge(pte));
+	new_pfn = pte_pfn(pte);
+
+restart:
+	for_each_rmap_spte(rmap_head, &iter, sptep) {
+		need_flush = true;
+
+		if (pte_write(pte)) {
+			kvm_zap_one_rmap_spte(kvm, rmap_head, sptep);
+			goto restart;
+		} else {
+			new_spte = kvm_mmu_changed_pte_notifier_make_spte(
+					*sptep, new_pfn);
+
+			mmu_spte_clear_track_bits(kvm, sptep);
+			mmu_spte_set(sptep, new_spte);
+		}
+	}
+
+	if (need_flush && kvm_available_flush_remote_tlbs_range()) {
+		kvm_flush_remote_tlbs_gfn(kvm, gfn, level);
+		return false;
+	}
+
+	return need_flush;
+}
+
+struct slot_rmap_walk_iterator {
+	/* input fields. */
+	const struct kvm_memory_slot *slot;
+	gfn_t start_gfn;
+	gfn_t end_gfn;
+	int start_level;
+	int end_level;
+
+	/* output fields. */
+	gfn_t gfn;
+	struct kvm_rmap_head *rmap;
+	int level;
+
+	/* private field. */
+	struct kvm_rmap_head *end_rmap;
+};
+
+static void rmap_walk_init_level(struct slot_rmap_walk_iterator *iterator,
+				 int level)
+{
+	iterator->level = level;
+	iterator->gfn = iterator->start_gfn;
+	iterator->rmap = gfn_to_rmap(iterator->gfn, level, iterator->slot);
+	iterator->end_rmap = gfn_to_rmap(iterator->end_gfn, level, iterator->slot);
+}
+
+static void slot_rmap_walk_init(struct slot_rmap_walk_iterator *iterator,
+				const struct kvm_memory_slot *slot,
+				int start_level, int end_level,
+				gfn_t start_gfn, gfn_t end_gfn)
+{
+	iterator->slot = slot;
+	iterator->start_level = start_level;
+	iterator->end_level = end_level;
+	iterator->start_gfn = start_gfn;
+	iterator->end_gfn = end_gfn;
+
+	rmap_walk_init_level(iterator, iterator->start_level);
+}
+
+static bool slot_rmap_walk_okay(struct slot_rmap_walk_iterator *iterator)
+{
+	return !!iterator->rmap;
+}
+
+static void slot_rmap_walk_next(struct slot_rmap_walk_iterator *iterator)
+{
+	while (++iterator->rmap <= iterator->end_rmap) {
+		iterator->gfn += (1UL << KVM_HPAGE_GFN_SHIFT(iterator->level));
+
+		if (iterator->rmap->val)
+			return;
+	}
+
+	if (++iterator->level > iterator->end_level) {
+		iterator->rmap = NULL;
+		return;
+	}
+
+	rmap_walk_init_level(iterator, iterator->level);
+}
+
+#define for_each_slot_rmap_range(_slot_, _start_level_, _end_level_,	\
+	   _start_gfn, _end_gfn, _iter_)				\
+	for (slot_rmap_walk_init(_iter_, _slot_, _start_level_,		\
+				 _end_level_, _start_gfn, _end_gfn);	\
+	     slot_rmap_walk_okay(_iter_);				\
+	     slot_rmap_walk_next(_iter_))
+
+typedef bool (*rmap_handler_t)(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+			       struct kvm_memory_slot *slot, gfn_t gfn,
+			       int level, pte_t pte);
+
+static __always_inline bool kvm_handle_gfn_range(struct kvm *kvm,
+						 struct kvm_gfn_range *range,
+						 rmap_handler_t handler)
+{
+	struct slot_rmap_walk_iterator iterator;
+	bool ret = false;
+
+	for_each_slot_rmap_range(range->slot, PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL,
+				 range->start, range->end - 1, &iterator)
+		ret |= handler(kvm, iterator.rmap, range->slot, iterator.gfn,
+			       iterator.level, range->arg.pte);
+
+	return ret;
+}
+
+bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	bool flush = false;
+
+	if (kvm_memslots_have_rmaps(kvm))
+		flush = kvm_handle_gfn_range(kvm, range, kvm_zap_rmap);
+
+	if (tdp_mmu_enabled)
+		flush = kvm_tdp_mmu_unmap_gfn_range(kvm, range, flush);
+
+	if (kvm_x86_ops.set_apic_access_page_addr &&
+	    range->slot->id == APIC_ACCESS_PAGE_PRIVATE_MEMSLOT)
+		kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
+
+	return flush;
+}
+
+bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	bool flush = false;
+
+	if (kvm_memslots_have_rmaps(kvm))
+		flush = kvm_handle_gfn_range(kvm, range, kvm_set_pte_rmap);
+
+	if (tdp_mmu_enabled)
+		flush |= kvm_tdp_mmu_set_spte_gfn(kvm, range);
+
+	return flush;
+}
+
+static bool kvm_age_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+			 struct kvm_memory_slot *slot, gfn_t gfn, int level,
+			 pte_t unused)
+{
+	u64 *sptep;
+	struct rmap_iterator iter;
+	int young = 0;
+
+	for_each_rmap_spte(rmap_head, &iter, sptep)
+		young |= mmu_spte_age(sptep);
+
+	return young;
+}
+
+static bool kvm_test_age_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
+			      struct kvm_memory_slot *slot, gfn_t gfn,
+			      int level, pte_t unused)
+{
+	u64 *sptep;
+	struct rmap_iterator iter;
+
+	for_each_rmap_spte(rmap_head, &iter, sptep)
+		if (is_accessed_spte(*sptep))
+			return true;
+	return false;
+}
+
+#define RMAP_RECYCLE_THRESHOLD 1000
+
+static void __rmap_add(struct kvm *kvm,
+		       struct kvm_mmu_memory_cache *cache,
+		       const struct kvm_memory_slot *slot,
+		       u64 *spte, gfn_t gfn, unsigned int access)
+{
+	struct kvm_mmu_page *sp;
+	struct kvm_rmap_head *rmap_head;
+	int rmap_count;
+
+	sp = sptep_to_sp(spte);
+	kvm_mmu_page_set_translation(sp, spte_index(spte), gfn, access);
+	kvm_update_page_stats(kvm, sp->role.level, 1);
+
+	rmap_head = gfn_to_rmap(gfn, sp->role.level, slot);
+	rmap_count = pte_list_add(cache, spte, rmap_head);
+
+	if (rmap_count > kvm->stat.max_mmu_rmap_size)
+		kvm->stat.max_mmu_rmap_size = rmap_count;
+	if (rmap_count > RMAP_RECYCLE_THRESHOLD) {
+		kvm_zap_all_rmap_sptes(kvm, rmap_head);
+		kvm_flush_remote_tlbs_gfn(kvm, gfn, sp->role.level);
+	}
+}
+
+static void rmap_add(struct kvm_vcpu *vcpu, const struct kvm_memory_slot *slot,
+		     u64 *spte, gfn_t gfn, unsigned int access)
+{
+	struct kvm_mmu_memory_cache *cache = &vcpu->arch.mmu_pte_list_desc_cache;
+
+	__rmap_add(vcpu->kvm, cache, slot, spte, gfn, access);
+}
+
+bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	bool young = false;
+
+	if (kvm_memslots_have_rmaps(kvm))
+		young = kvm_handle_gfn_range(kvm, range, kvm_age_rmap);
+
+	if (tdp_mmu_enabled)
+		young |= kvm_tdp_mmu_age_gfn_range(kvm, range);
+
+	return young;
+}
+
+bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	bool young = false;
+
+	if (kvm_memslots_have_rmaps(kvm))
+		young = kvm_handle_gfn_range(kvm, range, kvm_test_age_rmap);
+
+	if (tdp_mmu_enabled)
+		young |= kvm_tdp_mmu_test_age_gfn(kvm, range);
+
+	return young;
+}
+
+static void kvm_mmu_check_sptes_at_free(struct kvm_mmu_page *sp)
+{
+#ifdef CONFIG_KVM_PROVE_MMU
+	int i;
+
+	for (i = 0; i < SPTE_ENT_PER_PAGE; i++) {
+		if (KVM_MMU_WARN_ON(is_shadow_present_pte(sp->spt[i])))
+			pr_err_ratelimited("SPTE %llx (@ %p) for gfn %llx shadow-present at free",
+					   sp->spt[i], &sp->spt[i],
+					   kvm_mmu_page_get_gfn(sp, i));
+	}
+#endif
+}
+
+/*
+ * This value is the sum of all of the kvm instances's
+ * kvm->arch.n_used_mmu_pages values.  We need a global,
+ * aggregate version in order to make the slab shrinker
+ * faster
+ */
+static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, long nr)
+{
+	kvm->arch.n_used_mmu_pages += nr;
+	percpu_counter_add(&kvm_total_used_mmu_pages, nr);
+}
+
+static void kvm_account_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	kvm_mod_used_mmu_pages(kvm, +1);
+	kvm_account_pgtable_pages((void *)sp->spt, +1);
+}
+
+static void kvm_unaccount_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	kvm_mod_used_mmu_pages(kvm, -1);
+	kvm_account_pgtable_pages((void *)sp->spt, -1);
+}
+
+static void kvm_mmu_free_shadow_page(struct kvm_mmu_page *sp)
+{
+	kvm_mmu_check_sptes_at_free(sp);
+
+	hlist_del(&sp->hash_link);
+	list_del(&sp->link);
+	free_page((unsigned long)sp->spt);
+	if (!sp->role.direct)
+		free_page((unsigned long)sp->shadowed_translation);
+	kmem_cache_free(mmu_page_header_cache, sp);
+}
+
+static unsigned kvm_page_table_hashfn(gfn_t gfn)
+{
+	return hash_64(gfn, KVM_MMU_HASH_SHIFT);
+}
+
+static void mmu_page_add_parent_pte(struct kvm_mmu_memory_cache *cache,
+				    struct kvm_mmu_page *sp, u64 *parent_pte)
+{
+	if (!parent_pte)
+		return;
+
+	pte_list_add(cache, parent_pte, &sp->parent_ptes);
+}
+
+static void mmu_page_remove_parent_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
+				       u64 *parent_pte)
+{
+	pte_list_remove(kvm, parent_pte, &sp->parent_ptes);
+}
+
+static void drop_parent_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
+			    u64 *parent_pte)
+{
+	mmu_page_remove_parent_pte(kvm, sp, parent_pte);
+	mmu_spte_clear_no_track(parent_pte);
+}
+
+static void mark_unsync(u64 *spte);
+static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
+{
+	u64 *sptep;
+	struct rmap_iterator iter;
+
+	for_each_rmap_spte(&sp->parent_ptes, &iter, sptep) {
+		mark_unsync(sptep);
+	}
+}
+
+static void mark_unsync(u64 *spte)
+{
+	struct kvm_mmu_page *sp;
+
+	sp = sptep_to_sp(spte);
+	if (__test_and_set_bit(spte_index(spte), sp->unsync_child_bitmap))
+		return;
+	if (sp->unsync_children++)
+		return;
+	kvm_mmu_mark_parents_unsync(sp);
+}
+
+#define KVM_PAGE_ARRAY_NR 16
+
+struct kvm_mmu_pages {
+	struct mmu_page_and_offset {
+		struct kvm_mmu_page *sp;
+		unsigned int idx;
+	} page[KVM_PAGE_ARRAY_NR];
+	unsigned int nr;
+};
+
+static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
+			 int idx)
+{
+	int i;
+
+	if (sp->unsync)
+		for (i=0; i < pvec->nr; i++)
+			if (pvec->page[i].sp == sp)
+				return 0;
+
+	pvec->page[pvec->nr].sp = sp;
+	pvec->page[pvec->nr].idx = idx;
+	pvec->nr++;
+	return (pvec->nr == KVM_PAGE_ARRAY_NR);
+}
+
+static inline void clear_unsync_child_bit(struct kvm_mmu_page *sp, int idx)
+{
+	--sp->unsync_children;
+	WARN_ON_ONCE((int)sp->unsync_children < 0);
+	__clear_bit(idx, sp->unsync_child_bitmap);
+}
+
+static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
+			   struct kvm_mmu_pages *pvec)
+{
+	int i, ret, nr_unsync_leaf = 0;
+
+	for_each_set_bit(i, sp->unsync_child_bitmap, 512) {
+		struct kvm_mmu_page *child;
+		u64 ent = sp->spt[i];
+
+		if (!is_shadow_present_pte(ent) || is_large_pte(ent)) {
+			clear_unsync_child_bit(sp, i);
+			continue;
+		}
+
+		child = spte_to_child_sp(ent);
+
+		if (child->unsync_children) {
+			if (mmu_pages_add(pvec, child, i))
+				return -ENOSPC;
+
+			ret = __mmu_unsync_walk(child, pvec);
+			if (!ret) {
+				clear_unsync_child_bit(sp, i);
+				continue;
+			} else if (ret > 0) {
+				nr_unsync_leaf += ret;
+			} else
+				return ret;
+		} else if (child->unsync) {
+			nr_unsync_leaf++;
+			if (mmu_pages_add(pvec, child, i))
+				return -ENOSPC;
+		} else
+			clear_unsync_child_bit(sp, i);
+	}
+
+	return nr_unsync_leaf;
+}
+
+#define INVALID_INDEX (-1)
+
+static int mmu_unsync_walk(struct kvm_mmu_page *sp,
+			   struct kvm_mmu_pages *pvec)
+{
+	pvec->nr = 0;
+	if (!sp->unsync_children)
+		return 0;
+
+	mmu_pages_add(pvec, sp, INVALID_INDEX);
+	return __mmu_unsync_walk(sp, pvec);
+}
+
+static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	WARN_ON_ONCE(!sp->unsync);
+	trace_kvm_mmu_sync_page(sp);
+	sp->unsync = 0;
+	--kvm->stat.mmu_unsync;
+}
+
+static bool kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
+				     struct list_head *invalid_list);
+static void kvm_mmu_commit_zap_page(struct kvm *kvm,
+				    struct list_head *invalid_list);
+
+static bool sp_has_gptes(struct kvm_mmu_page *sp)
+{
+	if (sp->role.direct)
+		return false;
+
+	if (sp->role.passthrough)
+		return false;
+
+	return true;
+}
+
+#define for_each_valid_sp(_kvm, _sp, _list)				\
+	hlist_for_each_entry(_sp, _list, hash_link)			\
+		if (is_obsolete_sp((_kvm), (_sp))) {			\
+		} else
+
+#define for_each_gfn_valid_sp_with_gptes(_kvm, _sp, _gfn)		\
+	for_each_valid_sp(_kvm, _sp,					\
+	  &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)])	\
+		if ((_sp)->gfn != (_gfn) || !sp_has_gptes(_sp)) {} else
+
+static bool kvm_sync_page_check(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+	union kvm_mmu_page_role root_role = vcpu->arch.mmu->root_role;
+
+	/*
+	 * Ignore various flags when verifying that it's safe to sync a shadow
+	 * page using the current MMU context.
+	 *
+	 *  - level: not part of the overall MMU role and will never match as the MMU's
+	 *           level tracks the root level
+	 *  - access: updated based on the new guest PTE
+	 *  - quadrant: not part of the overall MMU role (similar to level)
+	 */
+	const union kvm_mmu_page_role sync_role_ign = {
+		.level = 0xf,
+		.access = 0x7,
+		.quadrant = 0x3,
+		.passthrough = 0x1,
+	};
+
+	/*
+	 * Direct pages can never be unsync, and KVM should never attempt to
+	 * sync a shadow page for a different MMU context, e.g. if the role
+	 * differs then the memslot lookup (SMM vs. non-SMM) will be bogus, the
+	 * reserved bits checks will be wrong, etc...
+	 */
+	if (WARN_ON_ONCE(sp->role.direct || !vcpu->arch.mmu->sync_spte ||
+			 (sp->role.word ^ root_role.word) & ~sync_role_ign.word))
+		return false;
+
+	return true;
+}
+
+static int kvm_sync_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int i)
+{
+	if (!sp->spt[i])
+		return 0;
+
+	return vcpu->arch.mmu->sync_spte(vcpu, sp, i);
+}
+
+static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+	int flush = 0;
+	int i;
+
+	if (!kvm_sync_page_check(vcpu, sp))
+		return -1;
+
+	for (i = 0; i < SPTE_ENT_PER_PAGE; i++) {
+		int ret = kvm_sync_spte(vcpu, sp, i);
+
+		if (ret < -1)
+			return -1;
+		flush |= ret;
+	}
+
+	/*
+	 * Note, any flush is purely for KVM's correctness, e.g. when dropping
+	 * an existing SPTE or clearing W/A/D bits to ensure an mmu_notifier
+	 * unmap or dirty logging event doesn't fail to flush.  The guest is
+	 * responsible for flushing the TLB to ensure any changes in protection
+	 * bits are recognized, i.e. until the guest flushes or page faults on
+	 * a relevant address, KVM is architecturally allowed to let vCPUs use
+	 * cached translations with the old protection bits.
+	 */
+	return flush;
+}
+
+static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+			 struct list_head *invalid_list)
+{
+	int ret = __kvm_sync_page(vcpu, sp);
+
+	if (ret < 0)
+		kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
+	return ret;
+}
+
+static bool kvm_mmu_remote_flush_or_zap(struct kvm *kvm,
+					struct list_head *invalid_list,
+					bool remote_flush)
+{
+	if (!remote_flush && list_empty(invalid_list))
+		return false;
+
+	if (!list_empty(invalid_list))
+		kvm_mmu_commit_zap_page(kvm, invalid_list);
+	else
+		kvm_flush_remote_tlbs(kvm);
+	return true;
+}
+
+static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	if (sp->role.invalid)
+		return true;
+
+	/* TDP MMU pages do not use the MMU generation. */
+	return !is_tdp_mmu_page(sp) &&
+	       unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);
+}
+
+struct mmu_page_path {
+	struct kvm_mmu_page *parent[PT64_ROOT_MAX_LEVEL];
+	unsigned int idx[PT64_ROOT_MAX_LEVEL];
+};
+
+#define for_each_sp(pvec, sp, parents, i)			\
+		for (i = mmu_pages_first(&pvec, &parents);	\
+			i < pvec.nr && ({ sp = pvec.page[i].sp; 1;});	\
+			i = mmu_pages_next(&pvec, &parents, i))
+
+static int mmu_pages_next(struct kvm_mmu_pages *pvec,
+			  struct mmu_page_path *parents,
+			  int i)
+{
+	int n;
+
+	for (n = i+1; n < pvec->nr; n++) {
+		struct kvm_mmu_page *sp = pvec->page[n].sp;
+		unsigned idx = pvec->page[n].idx;
+		int level = sp->role.level;
+
+		parents->idx[level-1] = idx;
+		if (level == PG_LEVEL_4K)
+			break;
+
+		parents->parent[level-2] = sp;
+	}
+
+	return n;
+}
+
+static int mmu_pages_first(struct kvm_mmu_pages *pvec,
+			   struct mmu_page_path *parents)
+{
+	struct kvm_mmu_page *sp;
+	int level;
+
+	if (pvec->nr == 0)
+		return 0;
+
+	WARN_ON_ONCE(pvec->page[0].idx != INVALID_INDEX);
+
+	sp = pvec->page[0].sp;
+	level = sp->role.level;
+	WARN_ON_ONCE(level == PG_LEVEL_4K);
+
+	parents->parent[level-2] = sp;
+
+	/* Also set up a sentinel.  Further entries in pvec are all
+	 * children of sp, so this element is never overwritten.
+	 */
+	parents->parent[level-1] = NULL;
+	return mmu_pages_next(pvec, parents, 0);
+}
+
+static void mmu_pages_clear_parents(struct mmu_page_path *parents)
+{
+	struct kvm_mmu_page *sp;
+	unsigned int level = 0;
+
+	do {
+		unsigned int idx = parents->idx[level];
+		sp = parents->parent[level];
+		if (!sp)
+			return;
+
+		WARN_ON_ONCE(idx == INVALID_INDEX);
+		clear_unsync_child_bit(sp, idx);
+		level++;
+	} while (!sp->unsync_children);
+}
+
+static int mmu_sync_children(struct kvm_vcpu *vcpu,
+			     struct kvm_mmu_page *parent, bool can_yield)
+{
+	int i;
+	struct kvm_mmu_page *sp;
+	struct mmu_page_path parents;
+	struct kvm_mmu_pages pages;
+	LIST_HEAD(invalid_list);
+	bool flush = false;
+
+	while (mmu_unsync_walk(parent, &pages)) {
+		bool protected = false;
+
+		for_each_sp(pages, sp, parents, i)
+			protected |= kvm_vcpu_write_protect_gfn(vcpu, sp->gfn);
+
+		if (protected) {
+			kvm_mmu_remote_flush_or_zap(vcpu->kvm, &invalid_list, true);
+			flush = false;
+		}
+
+		for_each_sp(pages, sp, parents, i) {
+			kvm_unlink_unsync_page(vcpu->kvm, sp);
+			flush |= kvm_sync_page(vcpu, sp, &invalid_list) > 0;
+			mmu_pages_clear_parents(&parents);
+		}
+		if (need_resched() || rwlock_needbreak(&vcpu->kvm->mmu_lock)) {
+			kvm_mmu_remote_flush_or_zap(vcpu->kvm, &invalid_list, flush);
+			if (!can_yield) {
+				kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
+				return -EINTR;
+			}
+
+			cond_resched_rwlock_write(&vcpu->kvm->mmu_lock);
+			flush = false;
+		}
+	}
+
+	kvm_mmu_remote_flush_or_zap(vcpu->kvm, &invalid_list, flush);
+	return 0;
+}
+
+static void __clear_sp_write_flooding_count(struct kvm_mmu_page *sp)
+{
+	atomic_set(&sp->write_flooding_count,  0);
+}
+
+static void clear_sp_write_flooding_count(u64 *spte)
+{
+	__clear_sp_write_flooding_count(sptep_to_sp(spte));
+}
+
+/*
+ * The vCPU is required when finding indirect shadow pages; the shadow
+ * page may already exist and syncing it needs the vCPU pointer in
+ * order to read guest page tables.  Direct shadow pages are never
+ * unsync, thus @vcpu can be NULL if @role.direct is true.
+ */
+static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm *kvm,
+						     struct kvm_vcpu *vcpu,
+						     gfn_t gfn,
+						     struct hlist_head *sp_list,
+						     union kvm_mmu_page_role role)
+{
+	struct kvm_mmu_page *sp;
+	int ret;
+	int collisions = 0;
+	LIST_HEAD(invalid_list);
+
+	for_each_valid_sp(kvm, sp, sp_list) {
+		if (sp->gfn != gfn) {
+			collisions++;
+			continue;
+		}
+
+		if (sp->role.word != role.word) {
+			/*
+			 * If the guest is creating an upper-level page, zap
+			 * unsync pages for the same gfn.  While it's possible
+			 * the guest is using recursive page tables, in all
+			 * likelihood the guest has stopped using the unsync
+			 * page and is installing a completely unrelated page.
+			 * Unsync pages must not be left as is, because the new
+			 * upper-level page will be write-protected.
+			 */
+			if (role.level > PG_LEVEL_4K && sp->unsync)
+				kvm_mmu_prepare_zap_page(kvm, sp,
+							 &invalid_list);
+			continue;
+		}
+
+		/* unsync and write-flooding only apply to indirect SPs. */
+		if (sp->role.direct)
+			goto out;
+
+		if (sp->unsync) {
+			if (KVM_BUG_ON(!vcpu, kvm))
+				break;
+
+			/*
+			 * The page is good, but is stale.  kvm_sync_page does
+			 * get the latest guest state, but (unlike mmu_unsync_children)
+			 * it doesn't write-protect the page or mark it synchronized!
+			 * This way the validity of the mapping is ensured, but the
+			 * overhead of write protection is not incurred until the
+			 * guest invalidates the TLB mapping.  This allows multiple
+			 * SPs for a single gfn to be unsync.
+			 *
+			 * If the sync fails, the page is zapped.  If so, break
+			 * in order to rebuild it.
+			 */
+			ret = kvm_sync_page(vcpu, sp, &invalid_list);
+			if (ret < 0)
+				break;
+
+			WARN_ON_ONCE(!list_empty(&invalid_list));
+			if (ret > 0)
+				kvm_flush_remote_tlbs(kvm);
+		}
+
+		__clear_sp_write_flooding_count(sp);
+
+		goto out;
+	}
+
+	sp = NULL;
+	++kvm->stat.mmu_cache_miss;
+
+out:
+	kvm_mmu_commit_zap_page(kvm, &invalid_list);
+
+	if (collisions > kvm->stat.max_mmu_page_hash_collisions)
+		kvm->stat.max_mmu_page_hash_collisions = collisions;
+	return sp;
+}
+
+/* Caches used when allocating a new shadow page. */
+struct shadow_page_caches {
+	struct kvm_mmu_memory_cache *page_header_cache;
+	struct kvm_mmu_memory_cache *shadow_page_cache;
+	struct kvm_mmu_memory_cache *shadowed_info_cache;
+};
+
+static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm *kvm,
+						      struct shadow_page_caches *caches,
+						      gfn_t gfn,
+						      struct hlist_head *sp_list,
+						      union kvm_mmu_page_role role)
+{
+	struct kvm_mmu_page *sp;
+
+	sp = kvm_mmu_memory_cache_alloc(caches->page_header_cache);
+	sp->spt = kvm_mmu_memory_cache_alloc(caches->shadow_page_cache);
+	if (!role.direct)
+		sp->shadowed_translation = kvm_mmu_memory_cache_alloc(caches->shadowed_info_cache);
+
+	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
+
+	INIT_LIST_HEAD(&sp->possible_nx_huge_page_link);
+
+	/*
+	 * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages()
+	 * depends on valid pages being added to the head of the list.  See
+	 * comments in kvm_zap_obsolete_pages().
+	 */
+	sp->mmu_valid_gen = kvm->arch.mmu_valid_gen;
+	list_add(&sp->link, &kvm->arch.active_mmu_pages);
+	kvm_account_mmu_page(kvm, sp);
+
+	sp->gfn = gfn;
+	sp->role = role;
+	hlist_add_head(&sp->hash_link, sp_list);
+	if (sp_has_gptes(sp))
+		account_shadowed(kvm, sp);
+
+	return sp;
+}
+
+/* Note, @vcpu may be NULL if @role.direct is true; see kvm_mmu_find_shadow_page. */
+static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm *kvm,
+						      struct kvm_vcpu *vcpu,
+						      struct shadow_page_caches *caches,
+						      gfn_t gfn,
+						      union kvm_mmu_page_role role)
+{
+	struct hlist_head *sp_list;
+	struct kvm_mmu_page *sp;
+	bool created = false;
+
+	sp_list = &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)];
+
+	sp = kvm_mmu_find_shadow_page(kvm, vcpu, gfn, sp_list, role);
+	if (!sp) {
+		created = true;
+		sp = kvm_mmu_alloc_shadow_page(kvm, caches, gfn, sp_list, role);
+	}
+
+	trace_kvm_mmu_get_page(sp, created);
+	return sp;
+}
+
+static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu,
+						    gfn_t gfn,
+						    union kvm_mmu_page_role role)
+{
+	struct shadow_page_caches caches = {
+		.page_header_cache = &vcpu->arch.mmu_page_header_cache,
+		.shadow_page_cache = &vcpu->arch.mmu_shadow_page_cache,
+		.shadowed_info_cache = &vcpu->arch.mmu_shadowed_info_cache,
+	};
+
+	return __kvm_mmu_get_shadow_page(vcpu->kvm, vcpu, &caches, gfn, role);
+}
+
+static union kvm_mmu_page_role kvm_mmu_child_role(u64 *sptep, bool direct,
+						  unsigned int access)
+{
+	struct kvm_mmu_page *parent_sp = sptep_to_sp(sptep);
+	union kvm_mmu_page_role role;
+
+	role = parent_sp->role;
+	role.level--;
+	role.access = access;
+	role.direct = direct;
+	role.passthrough = 0;
+
+	/*
+	 * If the guest has 4-byte PTEs then that means it's using 32-bit,
+	 * 2-level, non-PAE paging. KVM shadows such guests with PAE paging
+	 * (i.e. 8-byte PTEs). The difference in PTE size means that KVM must
+	 * shadow each guest page table with multiple shadow page tables, which
+	 * requires extra bookkeeping in the role.
+	 *
+	 * Specifically, to shadow the guest's page directory (which covers a
+	 * 4GiB address space), KVM uses 4 PAE page directories, each mapping
+	 * 1GiB of the address space. @role.quadrant encodes which quarter of
+	 * the address space each maps.
+	 *
+	 * To shadow the guest's page tables (which each map a 4MiB region), KVM
+	 * uses 2 PAE page tables, each mapping a 2MiB region. For these,
+	 * @role.quadrant encodes which half of the region they map.
+	 *
+	 * Concretely, a 4-byte PDE consumes bits 31:22, while an 8-byte PDE
+	 * consumes bits 29:21.  To consume bits 31:30, KVM's uses 4 shadow
+	 * PDPTEs; those 4 PAE page directories are pre-allocated and their
+	 * quadrant is assigned in mmu_alloc_root().   A 4-byte PTE consumes
+	 * bits 21:12, while an 8-byte PTE consumes bits 20:12.  To consume
+	 * bit 21 in the PTE (the child here), KVM propagates that bit to the
+	 * quadrant, i.e. sets quadrant to '0' or '1'.  The parent 8-byte PDE
+	 * covers bit 21 (see above), thus the quadrant is calculated from the
+	 * _least_ significant bit of the PDE index.
+	 */
+	if (role.has_4_byte_gpte) {
+		WARN_ON_ONCE(role.level != PG_LEVEL_4K);
+		role.quadrant = spte_index(sptep) & 1;
+	}
+
+	return role;
+}
+
+static struct kvm_mmu_page *kvm_mmu_get_child_sp(struct kvm_vcpu *vcpu,
+						 u64 *sptep, gfn_t gfn,
+						 bool direct, unsigned int access)
+{
+	union kvm_mmu_page_role role;
+
+	if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep))
+		return ERR_PTR(-EEXIST);
+
+	role = kvm_mmu_child_role(sptep, direct, access);
+	return kvm_mmu_get_shadow_page(vcpu, gfn, role);
+}
+
+static void shadow_walk_init_using_root(struct kvm_shadow_walk_iterator *iterator,
+					struct kvm_vcpu *vcpu, hpa_t root,
+					u64 addr)
+{
+	iterator->addr = addr;
+	iterator->shadow_addr = root;
+	iterator->level = vcpu->arch.mmu->root_role.level;
+
+	if (iterator->level >= PT64_ROOT_4LEVEL &&
+	    vcpu->arch.mmu->cpu_role.base.level < PT64_ROOT_4LEVEL &&
+	    !vcpu->arch.mmu->root_role.direct)
+		iterator->level = PT32E_ROOT_LEVEL;
+
+	if (iterator->level == PT32E_ROOT_LEVEL) {
+		/*
+		 * prev_root is currently only used for 64-bit hosts. So only
+		 * the active root_hpa is valid here.
+		 */
+		BUG_ON(root != vcpu->arch.mmu->root.hpa);
+
+		iterator->shadow_addr
+			= vcpu->arch.mmu->pae_root[(addr >> 30) & 3];
+		iterator->shadow_addr &= SPTE_BASE_ADDR_MASK;
+		--iterator->level;
+		if (!iterator->shadow_addr)
+			iterator->level = 0;
+	}
+}
+
+static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
+			     struct kvm_vcpu *vcpu, u64 addr)
+{
+	shadow_walk_init_using_root(iterator, vcpu, vcpu->arch.mmu->root.hpa,
+				    addr);
+}
+
+static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
+{
+	if (iterator->level < PG_LEVEL_4K)
+		return false;
+
+	iterator->index = SPTE_INDEX(iterator->addr, iterator->level);
+	iterator->sptep	= ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
+	return true;
+}
+
+static void __shadow_walk_next(struct kvm_shadow_walk_iterator *iterator,
+			       u64 spte)
+{
+	if (!is_shadow_present_pte(spte) || is_last_spte(spte, iterator->level)) {
+		iterator->level = 0;
+		return;
+	}
+
+	iterator->shadow_addr = spte & SPTE_BASE_ADDR_MASK;
+	--iterator->level;
+}
+
+static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
+{
+	__shadow_walk_next(iterator, *iterator->sptep);
+}
+
+static void __link_shadow_page(struct kvm *kvm,
+			       struct kvm_mmu_memory_cache *cache, u64 *sptep,
+			       struct kvm_mmu_page *sp, bool flush)
+{
+	u64 spte;
+
+	BUILD_BUG_ON(VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK);
+
+	/*
+	 * If an SPTE is present already, it must be a leaf and therefore
+	 * a large one.  Drop it, and flush the TLB if needed, before
+	 * installing sp.
+	 */
+	if (is_shadow_present_pte(*sptep))
+		drop_large_spte(kvm, sptep, flush);
+
+	spte = make_nonleaf_spte(sp->spt, sp_ad_disabled(sp));
+
+	mmu_spte_set(sptep, spte);
+
+	mmu_page_add_parent_pte(cache, sp, sptep);
+
+	/*
+	 * The non-direct sub-pagetable must be updated before linking.  For
+	 * L1 sp, the pagetable is updated via kvm_sync_page() in
+	 * kvm_mmu_find_shadow_page() without write-protecting the gfn,
+	 * so sp->unsync can be true or false.  For higher level non-direct
+	 * sp, the pagetable is updated/synced via mmu_sync_children() in
+	 * FNAME(fetch)(), so sp->unsync_children can only be false.
+	 * WARN_ON_ONCE() if anything happens unexpectedly.
+	 */
+	if (WARN_ON_ONCE(sp->unsync_children) || sp->unsync)
+		mark_unsync(sptep);
+}
+
+static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep,
+			     struct kvm_mmu_page *sp)
+{
+	__link_shadow_page(vcpu->kvm, &vcpu->arch.mmu_pte_list_desc_cache, sptep, sp, true);
+}
+
+static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
+				   unsigned direct_access)
+{
+	if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) {
+		struct kvm_mmu_page *child;
+
+		/*
+		 * For the direct sp, if the guest pte's dirty bit
+		 * changed form clean to dirty, it will corrupt the
+		 * sp's access: allow writable in the read-only sp,
+		 * so we should update the spte at this point to get
+		 * a new sp with the correct access.
+		 */
+		child = spte_to_child_sp(*sptep);
+		if (child->role.access == direct_access)
+			return;
+
+		drop_parent_pte(vcpu->kvm, child, sptep);
+		kvm_flush_remote_tlbs_sptep(vcpu->kvm, sptep);
+	}
+}
+
+/* Returns the number of zapped non-leaf child shadow pages. */
+static int mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
+			    u64 *spte, struct list_head *invalid_list)
+{
+	u64 pte;
+	struct kvm_mmu_page *child;
+
+	pte = *spte;
+	if (is_shadow_present_pte(pte)) {
+		if (is_last_spte(pte, sp->role.level)) {
+			drop_spte(kvm, spte);
+		} else {
+			child = spte_to_child_sp(pte);
+			drop_parent_pte(kvm, child, spte);
+
+			/*
+			 * Recursively zap nested TDP SPs, parentless SPs are
+			 * unlikely to be used again in the near future.  This
+			 * avoids retaining a large number of stale nested SPs.
+			 */
+			if (tdp_enabled && invalid_list &&
+			    child->role.guest_mode && !child->parent_ptes.val)
+				return kvm_mmu_prepare_zap_page(kvm, child,
+								invalid_list);
+		}
+	} else if (is_mmio_spte(pte)) {
+		mmu_spte_clear_no_track(spte);
+	}
+	return 0;
+}
+
+static int kvm_mmu_page_unlink_children(struct kvm *kvm,
+					struct kvm_mmu_page *sp,
+					struct list_head *invalid_list)
+{
+	int zapped = 0;
+	unsigned i;
+
+	for (i = 0; i < SPTE_ENT_PER_PAGE; ++i)
+		zapped += mmu_page_zap_pte(kvm, sp, sp->spt + i, invalid_list);
+
+	return zapped;
+}
+
+static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	u64 *sptep;
+	struct rmap_iterator iter;
+
+	while ((sptep = rmap_get_first(&sp->parent_ptes, &iter)))
+		drop_parent_pte(kvm, sp, sptep);
+}
+
+static int mmu_zap_unsync_children(struct kvm *kvm,
+				   struct kvm_mmu_page *parent,
+				   struct list_head *invalid_list)
+{
+	int i, zapped = 0;
+	struct mmu_page_path parents;
+	struct kvm_mmu_pages pages;
+
+	if (parent->role.level == PG_LEVEL_4K)
+		return 0;
+
+	while (mmu_unsync_walk(parent, &pages)) {
+		struct kvm_mmu_page *sp;
+
+		for_each_sp(pages, sp, parents, i) {
+			kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
+			mmu_pages_clear_parents(&parents);
+			zapped++;
+		}
+	}
+
+	return zapped;
+}
+
+static bool __kvm_mmu_prepare_zap_page(struct kvm *kvm,
+				       struct kvm_mmu_page *sp,
+				       struct list_head *invalid_list,
+				       int *nr_zapped)
+{
+	bool list_unstable, zapped_root = false;
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+	trace_kvm_mmu_prepare_zap_page(sp);
+	++kvm->stat.mmu_shadow_zapped;
+	*nr_zapped = mmu_zap_unsync_children(kvm, sp, invalid_list);
+	*nr_zapped += kvm_mmu_page_unlink_children(kvm, sp, invalid_list);
+	kvm_mmu_unlink_parents(kvm, sp);
+
+	/* Zapping children means active_mmu_pages has become unstable. */
+	list_unstable = *nr_zapped;
+
+	if (!sp->role.invalid && sp_has_gptes(sp))
+		unaccount_shadowed(kvm, sp);
+
+	if (sp->unsync)
+		kvm_unlink_unsync_page(kvm, sp);
+	if (!sp->root_count) {
+		/* Count self */
+		(*nr_zapped)++;
+
+		/*
+		 * Already invalid pages (previously active roots) are not on
+		 * the active page list.  See list_del() in the "else" case of
+		 * !sp->root_count.
+		 */
+		if (sp->role.invalid)
+			list_add(&sp->link, invalid_list);
+		else
+			list_move(&sp->link, invalid_list);
+		kvm_unaccount_mmu_page(kvm, sp);
+	} else {
+		/*
+		 * Remove the active root from the active page list, the root
+		 * will be explicitly freed when the root_count hits zero.
+		 */
+		list_del(&sp->link);
+
+		/*
+		 * Obsolete pages cannot be used on any vCPUs, see the comment
+		 * in kvm_mmu_zap_all_fast().  Note, is_obsolete_sp() also
+		 * treats invalid shadow pages as being obsolete.
+		 */
+		zapped_root = !is_obsolete_sp(kvm, sp);
+	}
+
+	if (sp->nx_huge_page_disallowed)
+		unaccount_nx_huge_page(kvm, sp);
+
+	sp->role.invalid = 1;
+
+	/*
+	 * Make the request to free obsolete roots after marking the root
+	 * invalid, otherwise other vCPUs may not see it as invalid.
+	 */
+	if (zapped_root)
+		kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_FREE_OBSOLETE_ROOTS);
+	return list_unstable;
+}
+
+static bool kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
+				     struct list_head *invalid_list)
+{
+	int nr_zapped;
+
+	__kvm_mmu_prepare_zap_page(kvm, sp, invalid_list, &nr_zapped);
+	return nr_zapped;
+}
+
+static void kvm_mmu_commit_zap_page(struct kvm *kvm,
+				    struct list_head *invalid_list)
+{
+	struct kvm_mmu_page *sp, *nsp;
+
+	if (list_empty(invalid_list))
+		return;
+
+	/*
+	 * We need to make sure everyone sees our modifications to
+	 * the page tables and see changes to vcpu->mode here. The barrier
+	 * in the kvm_flush_remote_tlbs() achieves this. This pairs
+	 * with vcpu_enter_guest and walk_shadow_page_lockless_begin/end.
+	 *
+	 * In addition, kvm_flush_remote_tlbs waits for all vcpus to exit
+	 * guest mode and/or lockless shadow page table walks.
+	 */
+	kvm_flush_remote_tlbs(kvm);
+
+	list_for_each_entry_safe(sp, nsp, invalid_list, link) {
+		WARN_ON_ONCE(!sp->role.invalid || sp->root_count);
+		kvm_mmu_free_shadow_page(sp);
+	}
+}
+
+static unsigned long kvm_mmu_zap_oldest_mmu_pages(struct kvm *kvm,
+						  unsigned long nr_to_zap)
+{
+	unsigned long total_zapped = 0;
+	struct kvm_mmu_page *sp, *tmp;
+	LIST_HEAD(invalid_list);
+	bool unstable;
+	int nr_zapped;
+
+	if (list_empty(&kvm->arch.active_mmu_pages))
+		return 0;
+
+restart:
+	list_for_each_entry_safe_reverse(sp, tmp, &kvm->arch.active_mmu_pages, link) {
+		/*
+		 * Don't zap active root pages, the page itself can't be freed
+		 * and zapping it will just force vCPUs to realloc and reload.
+		 */
+		if (sp->root_count)
+			continue;
+
+		unstable = __kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list,
+						      &nr_zapped);
+		total_zapped += nr_zapped;
+		if (total_zapped >= nr_to_zap)
+			break;
+
+		if (unstable)
+			goto restart;
+	}
+
+	kvm_mmu_commit_zap_page(kvm, &invalid_list);
+
+	kvm->stat.mmu_recycled += total_zapped;
+	return total_zapped;
+}
+
+static inline unsigned long kvm_mmu_available_pages(struct kvm *kvm)
+{
+	if (kvm->arch.n_max_mmu_pages > kvm->arch.n_used_mmu_pages)
+		return kvm->arch.n_max_mmu_pages -
+			kvm->arch.n_used_mmu_pages;
+
+	return 0;
+}
+
+static int make_mmu_pages_available(struct kvm_vcpu *vcpu)
+{
+	unsigned long avail = kvm_mmu_available_pages(vcpu->kvm);
+
+	if (likely(avail >= KVM_MIN_FREE_MMU_PAGES))
+		return 0;
+
+	kvm_mmu_zap_oldest_mmu_pages(vcpu->kvm, KVM_REFILL_PAGES - avail);
+
+	/*
+	 * Note, this check is intentionally soft, it only guarantees that one
+	 * page is available, while the caller may end up allocating as many as
+	 * four pages, e.g. for PAE roots or for 5-level paging.  Temporarily
+	 * exceeding the (arbitrary by default) limit will not harm the host,
+	 * being too aggressive may unnecessarily kill the guest, and getting an
+	 * exact count is far more trouble than it's worth, especially in the
+	 * page fault paths.
+	 */
+	if (!kvm_mmu_available_pages(vcpu->kvm))
+		return -ENOSPC;
+	return 0;
+}
+
+/*
+ * Changing the number of mmu pages allocated to the vm
+ * Note: if goal_nr_mmu_pages is too small, you will get dead lock
+ */
+void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long goal_nr_mmu_pages)
+{
+	write_lock(&kvm->mmu_lock);
+
+	if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
+		kvm_mmu_zap_oldest_mmu_pages(kvm, kvm->arch.n_used_mmu_pages -
+						  goal_nr_mmu_pages);
+
+		goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
+	}
+
+	kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
+
+	write_unlock(&kvm->mmu_lock);
+}
+
+int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
+{
+	struct kvm_mmu_page *sp;
+	LIST_HEAD(invalid_list);
+	int r;
+
+	r = 0;
+	write_lock(&kvm->mmu_lock);
+	for_each_gfn_valid_sp_with_gptes(kvm, sp, gfn) {
+		r = 1;
+		kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
+	}
+	kvm_mmu_commit_zap_page(kvm, &invalid_list);
+	write_unlock(&kvm->mmu_lock);
+
+	return r;
+}
+
+static int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
+{
+	gpa_t gpa;
+	int r;
+
+	if (vcpu->arch.mmu->root_role.direct)
+		return 0;
+
+	gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
+
+	r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
+
+	return r;
+}
+
+static void kvm_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	trace_kvm_mmu_unsync_page(sp);
+	++kvm->stat.mmu_unsync;
+	sp->unsync = 1;
+
+	kvm_mmu_mark_parents_unsync(sp);
+}
+
+/*
+ * Attempt to unsync any shadow pages that can be reached by the specified gfn,
+ * KVM is creating a writable mapping for said gfn.  Returns 0 if all pages
+ * were marked unsync (or if there is no shadow page), -EPERM if the SPTE must
+ * be write-protected.
+ */
+int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot,
+			    gfn_t gfn, bool can_unsync, bool prefetch)
+{
+	struct kvm_mmu_page *sp;
+	bool locked = false;
+
+	/*
+	 * Force write-protection if the page is being tracked.  Note, the page
+	 * track machinery is used to write-protect upper-level shadow pages,
+	 * i.e. this guards the role.level == 4K assertion below!
+	 */
+	if (kvm_gfn_is_write_tracked(kvm, slot, gfn))
+		return -EPERM;
+
+	/*
+	 * The page is not write-tracked, mark existing shadow pages unsync
+	 * unless KVM is synchronizing an unsync SP (can_unsync = false).  In
+	 * that case, KVM must complete emulation of the guest TLB flush before
+	 * allowing shadow pages to become unsync (writable by the guest).
+	 */
+	for_each_gfn_valid_sp_with_gptes(kvm, sp, gfn) {
+		if (!can_unsync)
+			return -EPERM;
+
+		if (sp->unsync)
+			continue;
+
+		if (prefetch)
+			return -EEXIST;
+
+		/*
+		 * TDP MMU page faults require an additional spinlock as they
+		 * run with mmu_lock held for read, not write, and the unsync
+		 * logic is not thread safe.  Take the spinklock regardless of
+		 * the MMU type to avoid extra conditionals/parameters, there's
+		 * no meaningful penalty if mmu_lock is held for write.
+		 */
+		if (!locked) {
+			locked = true;
+			spin_lock(&kvm->arch.mmu_unsync_pages_lock);
+
+			/*
+			 * Recheck after taking the spinlock, a different vCPU
+			 * may have since marked the page unsync.  A false
+			 * positive on the unprotected check above is not
+			 * possible as clearing sp->unsync _must_ hold mmu_lock
+			 * for write, i.e. unsync cannot transition from 0->1
+			 * while this CPU holds mmu_lock for read (or write).
+			 */
+			if (READ_ONCE(sp->unsync))
+				continue;
+		}
+
+		WARN_ON_ONCE(sp->role.level != PG_LEVEL_4K);
+		kvm_unsync_page(kvm, sp);
+	}
+	if (locked)
+		spin_unlock(&kvm->arch.mmu_unsync_pages_lock);
+
+	/*
+	 * We need to ensure that the marking of unsync pages is visible
+	 * before the SPTE is updated to allow writes because
+	 * kvm_mmu_sync_roots() checks the unsync flags without holding
+	 * the MMU lock and so can race with this. If the SPTE was updated
+	 * before the page had been marked as unsync-ed, something like the
+	 * following could happen:
+	 *
+	 * CPU 1                    CPU 2
+	 * ---------------------------------------------------------------------
+	 * 1.2 Host updates SPTE
+	 *     to be writable
+	 *                      2.1 Guest writes a GPTE for GVA X.
+	 *                          (GPTE being in the guest page table shadowed
+	 *                           by the SP from CPU 1.)
+	 *                          This reads SPTE during the page table walk.
+	 *                          Since SPTE.W is read as 1, there is no
+	 *                          fault.
+	 *
+	 *                      2.2 Guest issues TLB flush.
+	 *                          That causes a VM Exit.
+	 *
+	 *                      2.3 Walking of unsync pages sees sp->unsync is
+	 *                          false and skips the page.
+	 *
+	 *                      2.4 Guest accesses GVA X.
+	 *                          Since the mapping in the SP was not updated,
+	 *                          so the old mapping for GVA X incorrectly
+	 *                          gets used.
+	 * 1.1 Host marks SP
+	 *     as unsync
+	 *     (sp->unsync = true)
+	 *
+	 * The write barrier below ensures that 1.1 happens before 1.2 and thus
+	 * the situation in 2.4 does not arise.  It pairs with the read barrier
+	 * in is_unsync_root(), placed between 2.1's load of SPTE.W and 2.3.
+	 */
+	smp_wmb();
+
+	return 0;
+}
+
+static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot,
+			u64 *sptep, unsigned int pte_access, gfn_t gfn,
+			kvm_pfn_t pfn, struct kvm_page_fault *fault)
+{
+	struct kvm_mmu_page *sp = sptep_to_sp(sptep);
+	int level = sp->role.level;
+	int was_rmapped = 0;
+	int ret = RET_PF_FIXED;
+	bool flush = false;
+	bool wrprot;
+	u64 spte;
+
+	/* Prefetching always gets a writable pfn.  */
+	bool host_writable = !fault || fault->map_writable;
+	bool prefetch = !fault || fault->prefetch;
+	bool write_fault = fault && fault->write;
+
+	if (unlikely(is_noslot_pfn(pfn))) {
+		vcpu->stat.pf_mmio_spte_created++;
+		mark_mmio_spte(vcpu, sptep, gfn, pte_access);
+		return RET_PF_EMULATE;
+	}
+
+	if (is_shadow_present_pte(*sptep)) {
+		/*
+		 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
+		 * the parent of the now unreachable PTE.
+		 */
+		if (level > PG_LEVEL_4K && !is_large_pte(*sptep)) {
+			struct kvm_mmu_page *child;
+			u64 pte = *sptep;
+
+			child = spte_to_child_sp(pte);
+			drop_parent_pte(vcpu->kvm, child, sptep);
+			flush = true;
+		} else if (pfn != spte_to_pfn(*sptep)) {
+			drop_spte(vcpu->kvm, sptep);
+			flush = true;
+		} else
+			was_rmapped = 1;
+	}
+
+	wrprot = make_spte(vcpu, sp, slot, pte_access, gfn, pfn, *sptep, prefetch,
+			   true, host_writable, &spte);
+
+	if (*sptep == spte) {
+		ret = RET_PF_SPURIOUS;
+	} else {
+		flush |= mmu_spte_update(sptep, spte);
+		trace_kvm_mmu_set_spte(level, gfn, sptep);
+	}
+
+	if (wrprot) {
+		if (write_fault)
+			ret = RET_PF_EMULATE;
+	}
+
+	if (flush)
+		kvm_flush_remote_tlbs_gfn(vcpu->kvm, gfn, level);
+
+	if (!was_rmapped) {
+		WARN_ON_ONCE(ret == RET_PF_SPURIOUS);
+		rmap_add(vcpu, slot, sptep, gfn, pte_access);
+	} else {
+		/* Already rmapped but the pte_access bits may have changed. */
+		kvm_mmu_page_set_access(sp, spte_index(sptep), pte_access);
+	}
+
+	return ret;
+}
+
+static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
+				    struct kvm_mmu_page *sp,
+				    u64 *start, u64 *end)
+{
+	struct page *pages[PTE_PREFETCH_NUM];
+	struct kvm_memory_slot *slot;
+	unsigned int access = sp->role.access;
+	int i, ret;
+	gfn_t gfn;
+
+	gfn = kvm_mmu_page_get_gfn(sp, spte_index(start));
+	slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, access & ACC_WRITE_MASK);
+	if (!slot)
+		return -1;
+
+	ret = gfn_to_page_many_atomic(slot, gfn, pages, end - start);
+	if (ret <= 0)
+		return -1;
+
+	for (i = 0; i < ret; i++, gfn++, start++) {
+		mmu_set_spte(vcpu, slot, start, access, gfn,
+			     page_to_pfn(pages[i]), NULL);
+		put_page(pages[i]);
+	}
+
+	return 0;
+}
+
+static void __direct_pte_prefetch(struct kvm_vcpu *vcpu,
+				  struct kvm_mmu_page *sp, u64 *sptep)
+{
+	u64 *spte, *start = NULL;
+	int i;
+
+	WARN_ON_ONCE(!sp->role.direct);
+
+	i = spte_index(sptep) & ~(PTE_PREFETCH_NUM - 1);
+	spte = sp->spt + i;
+
+	for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
+		if (is_shadow_present_pte(*spte) || spte == sptep) {
+			if (!start)
+				continue;
+			if (direct_pte_prefetch_many(vcpu, sp, start, spte) < 0)
+				return;
+			start = NULL;
+		} else if (!start)
+			start = spte;
+	}
+	if (start)
+		direct_pte_prefetch_many(vcpu, sp, start, spte);
+}
+
+static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
+{
+	struct kvm_mmu_page *sp;
+
+	sp = sptep_to_sp(sptep);
+
+	/*
+	 * Without accessed bits, there's no way to distinguish between
+	 * actually accessed translations and prefetched, so disable pte
+	 * prefetch if accessed bits aren't available.
+	 */
+	if (sp_ad_disabled(sp))
+		return;
+
+	if (sp->role.level > PG_LEVEL_4K)
+		return;
+
+	/*
+	 * If addresses are being invalidated, skip prefetching to avoid
+	 * accidentally prefetching those addresses.
+	 */
+	if (unlikely(vcpu->kvm->mmu_invalidate_in_progress))
+		return;
+
+	__direct_pte_prefetch(vcpu, sp, sptep);
+}
+
+/*
+ * Lookup the mapping level for @gfn in the current mm.
+ *
+ * WARNING!  Use of host_pfn_mapping_level() requires the caller and the end
+ * consumer to be tied into KVM's handlers for MMU notifier events!
+ *
+ * There are several ways to safely use this helper:
+ *
+ * - Check mmu_invalidate_retry_hva() after grabbing the mapping level, before
+ *   consuming it.  In this case, mmu_lock doesn't need to be held during the
+ *   lookup, but it does need to be held while checking the MMU notifier.
+ *
+ * - Hold mmu_lock AND ensure there is no in-progress MMU notifier invalidation
+ *   event for the hva.  This can be done by explicit checking the MMU notifier
+ *   or by ensuring that KVM already has a valid mapping that covers the hva.
+ *
+ * - Do not use the result to install new mappings, e.g. use the host mapping
+ *   level only to decide whether or not to zap an entry.  In this case, it's
+ *   not required to hold mmu_lock (though it's highly likely the caller will
+ *   want to hold mmu_lock anyways, e.g. to modify SPTEs).
+ *
+ * Note!  The lookup can still race with modifications to host page tables, but
+ * the above "rules" ensure KVM will not _consume_ the result of the walk if a
+ * race with the primary MMU occurs.
+ */
+static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn,
+				  const struct kvm_memory_slot *slot)
+{
+	int level = PG_LEVEL_4K;
+	unsigned long hva;
+	unsigned long flags;
+	pgd_t pgd;
+	p4d_t p4d;
+	pud_t pud;
+	pmd_t pmd;
+
+	/*
+	 * Note, using the already-retrieved memslot and __gfn_to_hva_memslot()
+	 * is not solely for performance, it's also necessary to avoid the
+	 * "writable" check in __gfn_to_hva_many(), which will always fail on
+	 * read-only memslots due to gfn_to_hva() assuming writes.  Earlier
+	 * page fault steps have already verified the guest isn't writing a
+	 * read-only memslot.
+	 */
+	hva = __gfn_to_hva_memslot(slot, gfn);
+
+	/*
+	 * Disable IRQs to prevent concurrent tear down of host page tables,
+	 * e.g. if the primary MMU promotes a P*D to a huge page and then frees
+	 * the original page table.
+	 */
+	local_irq_save(flags);
+
+	/*
+	 * Read each entry once.  As above, a non-leaf entry can be promoted to
+	 * a huge page _during_ this walk.  Re-reading the entry could send the
+	 * walk into the weeks, e.g. p*d_large() returns false (sees the old
+	 * value) and then p*d_offset() walks into the target huge page instead
+	 * of the old page table (sees the new value).
+	 */
+	pgd = READ_ONCE(*pgd_offset(kvm->mm, hva));
+	if (pgd_none(pgd))
+		goto out;
+
+	p4d = READ_ONCE(*p4d_offset(&pgd, hva));
+	if (p4d_none(p4d) || !p4d_present(p4d))
+		goto out;
+
+	pud = READ_ONCE(*pud_offset(&p4d, hva));
+	if (pud_none(pud) || !pud_present(pud))
+		goto out;
+
+	if (pud_large(pud)) {
+		level = PG_LEVEL_1G;
+		goto out;
+	}
+
+	pmd = READ_ONCE(*pmd_offset(&pud, hva));
+	if (pmd_none(pmd) || !pmd_present(pmd))
+		goto out;
+
+	if (pmd_large(pmd))
+		level = PG_LEVEL_2M;
+
+out:
+	local_irq_restore(flags);
+	return level;
+}
+
+int kvm_mmu_max_mapping_level(struct kvm *kvm,
+			      const struct kvm_memory_slot *slot, gfn_t gfn,
+			      int max_level)
+{
+	struct kvm_lpage_info *linfo;
+	int host_level;
+
+	max_level = min(max_level, max_huge_page_level);
+	for ( ; max_level > PG_LEVEL_4K; max_level--) {
+		linfo = lpage_info_slot(gfn, slot, max_level);
+		if (!linfo->disallow_lpage)
+			break;
+	}
+
+	if (max_level == PG_LEVEL_4K)
+		return PG_LEVEL_4K;
+
+	host_level = host_pfn_mapping_level(kvm, gfn, slot);
+	return min(host_level, max_level);
+}
+
+void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+	struct kvm_memory_slot *slot = fault->slot;
+	kvm_pfn_t mask;
+
+	fault->huge_page_disallowed = fault->exec && fault->nx_huge_page_workaround_enabled;
+
+	if (unlikely(fault->max_level == PG_LEVEL_4K))
+		return;
+
+	if (is_error_noslot_pfn(fault->pfn))
+		return;
+
+	if (kvm_slot_dirty_track_enabled(slot))
+		return;
+
+	/*
+	 * Enforce the iTLB multihit workaround after capturing the requested
+	 * level, which will be used to do precise, accurate accounting.
+	 */
+	fault->req_level = kvm_mmu_max_mapping_level(vcpu->kvm, slot,
+						     fault->gfn, fault->max_level);
+	if (fault->req_level == PG_LEVEL_4K || fault->huge_page_disallowed)
+		return;
+
+	/*
+	 * mmu_invalidate_retry() was successful and mmu_lock is held, so
+	 * the pmd can't be split from under us.
+	 */
+	fault->goal_level = fault->req_level;
+	mask = KVM_PAGES_PER_HPAGE(fault->goal_level) - 1;
+	VM_BUG_ON((fault->gfn & mask) != (fault->pfn & mask));
+	fault->pfn &= ~mask;
+}
+
+void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level)
+{
+	if (cur_level > PG_LEVEL_4K &&
+	    cur_level == fault->goal_level &&
+	    is_shadow_present_pte(spte) &&
+	    !is_large_pte(spte) &&
+	    spte_to_child_sp(spte)->nx_huge_page_disallowed) {
+		/*
+		 * A small SPTE exists for this pfn, but FNAME(fetch),
+		 * direct_map(), or kvm_tdp_mmu_map() would like to create a
+		 * large PTE instead: just force them to go down another level,
+		 * patching back for them into pfn the next 9 bits of the
+		 * address.
+		 */
+		u64 page_mask = KVM_PAGES_PER_HPAGE(cur_level) -
+				KVM_PAGES_PER_HPAGE(cur_level - 1);
+		fault->pfn |= fault->gfn & page_mask;
+		fault->goal_level--;
+	}
+}
+
+static int direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+	struct kvm_shadow_walk_iterator it;
+	struct kvm_mmu_page *sp;
+	int ret;
+	gfn_t base_gfn = fault->gfn;
+
+	kvm_mmu_hugepage_adjust(vcpu, fault);
+
+	trace_kvm_mmu_spte_requested(fault);
+	for_each_shadow_entry(vcpu, fault->addr, it) {
+		/*
+		 * We cannot overwrite existing page tables with an NX
+		 * large page, as the leaf could be executable.
+		 */
+		if (fault->nx_huge_page_workaround_enabled)
+			disallowed_hugepage_adjust(fault, *it.sptep, it.level);
+
+		base_gfn = gfn_round_for_level(fault->gfn, it.level);
+		if (it.level == fault->goal_level)
+			break;
+
+		sp = kvm_mmu_get_child_sp(vcpu, it.sptep, base_gfn, true, ACC_ALL);
+		if (sp == ERR_PTR(-EEXIST))
+			continue;
+
+		link_shadow_page(vcpu, it.sptep, sp);
+		if (fault->huge_page_disallowed)
+			account_nx_huge_page(vcpu->kvm, sp,
+					     fault->req_level >= it.level);
+	}
+
+	if (WARN_ON_ONCE(it.level != fault->goal_level))
+		return -EFAULT;
+
+	ret = mmu_set_spte(vcpu, fault->slot, it.sptep, ACC_ALL,
+			   base_gfn, fault->pfn, fault);
+	if (ret == RET_PF_SPURIOUS)
+		return ret;
+
+	direct_pte_prefetch(vcpu, it.sptep);
+	return ret;
+}
+
+static void kvm_send_hwpoison_signal(struct kvm_memory_slot *slot, gfn_t gfn)
+{
+	unsigned long hva = gfn_to_hva_memslot(slot, gfn);
+
+	send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva, PAGE_SHIFT, current);
+}
+
+static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+	if (is_sigpending_pfn(fault->pfn)) {
+		kvm_handle_signal_exit(vcpu);
+		return -EINTR;
+	}
+
+	/*
+	 * Do not cache the mmio info caused by writing the readonly gfn
+	 * into the spte otherwise read access on readonly gfn also can
+	 * caused mmio page fault and treat it as mmio access.
+	 */
+	if (fault->pfn == KVM_PFN_ERR_RO_FAULT)
+		return RET_PF_EMULATE;
+
+	if (fault->pfn == KVM_PFN_ERR_HWPOISON) {
+		kvm_send_hwpoison_signal(fault->slot, fault->gfn);
+		return RET_PF_RETRY;
+	}
+
+	return -EFAULT;
+}
+
+static int kvm_handle_noslot_fault(struct kvm_vcpu *vcpu,
+				   struct kvm_page_fault *fault,
+				   unsigned int access)
+{
+	gva_t gva = fault->is_tdp ? 0 : fault->addr;
+
+	vcpu_cache_mmio_info(vcpu, gva, fault->gfn,
+			     access & shadow_mmio_access_mask);
+
+	/*
+	 * If MMIO caching is disabled, emulate immediately without
+	 * touching the shadow page tables as attempting to install an
+	 * MMIO SPTE will just be an expensive nop.
+	 */
+	if (unlikely(!enable_mmio_caching))
+		return RET_PF_EMULATE;
+
+	/*
+	 * Do not create an MMIO SPTE for a gfn greater than host.MAXPHYADDR,
+	 * any guest that generates such gfns is running nested and is being
+	 * tricked by L0 userspace (you can observe gfn > L1.MAXPHYADDR if and
+	 * only if L1's MAXPHYADDR is inaccurate with respect to the
+	 * hardware's).
+	 */
+	if (unlikely(fault->gfn > kvm_mmu_max_gfn()))
+		return RET_PF_EMULATE;
+
+	return RET_PF_CONTINUE;
+}
+
+static bool page_fault_can_be_fast(struct kvm_page_fault *fault)
+{
+	/*
+	 * Page faults with reserved bits set, i.e. faults on MMIO SPTEs, only
+	 * reach the common page fault handler if the SPTE has an invalid MMIO
+	 * generation number.  Refreshing the MMIO generation needs to go down
+	 * the slow path.  Note, EPT Misconfigs do NOT set the PRESENT flag!
+	 */
+	if (fault->rsvd)
+		return false;
+
+	/*
+	 * #PF can be fast if:
+	 *
+	 * 1. The shadow page table entry is not present and A/D bits are
+	 *    disabled _by KVM_, which could mean that the fault is potentially
+	 *    caused by access tracking (if enabled).  If A/D bits are enabled
+	 *    by KVM, but disabled by L1 for L2, KVM is forced to disable A/D
+	 *    bits for L2 and employ access tracking, but the fast page fault
+	 *    mechanism only supports direct MMUs.
+	 * 2. The shadow page table entry is present, the access is a write,
+	 *    and no reserved bits are set (MMIO SPTEs cannot be "fixed"), i.e.
+	 *    the fault was caused by a write-protection violation.  If the
+	 *    SPTE is MMU-writable (determined later), the fault can be fixed
+	 *    by setting the Writable bit, which can be done out of mmu_lock.
+	 */
+	if (!fault->present)
+		return !kvm_ad_enabled();
+
+	/*
+	 * Note, instruction fetches and writes are mutually exclusive, ignore
+	 * the "exec" flag.
+	 */
+	return fault->write;
+}
+
+/*
+ * Returns true if the SPTE was fixed successfully. Otherwise,
+ * someone else modified the SPTE from its original value.
+ */
+static bool fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu,
+				    struct kvm_page_fault *fault,
+				    u64 *sptep, u64 old_spte, u64 new_spte)
+{
+	/*
+	 * Theoretically we could also set dirty bit (and flush TLB) here in
+	 * order to eliminate unnecessary PML logging. See comments in
+	 * set_spte. But fast_page_fault is very unlikely to happen with PML
+	 * enabled, so we do not do this. This might result in the same GPA
+	 * to be logged in PML buffer again when the write really happens, and
+	 * eventually to be called by mark_page_dirty twice. But it's also no
+	 * harm. This also avoids the TLB flush needed after setting dirty bit
+	 * so non-PML cases won't be impacted.
+	 *
+	 * Compare with set_spte where instead shadow_dirty_mask is set.
+	 */
+	if (!try_cmpxchg64(sptep, &old_spte, new_spte))
+		return false;
+
+	if (is_writable_pte(new_spte) && !is_writable_pte(old_spte))
+		mark_page_dirty_in_slot(vcpu->kvm, fault->slot, fault->gfn);
+
+	return true;
+}
+
+static bool is_access_allowed(struct kvm_page_fault *fault, u64 spte)
+{
+	if (fault->exec)
+		return is_executable_pte(spte);
+
+	if (fault->write)
+		return is_writable_pte(spte);
+
+	/* Fault was on Read access */
+	return spte & PT_PRESENT_MASK;
+}
+
+/*
+ * Returns the last level spte pointer of the shadow page walk for the given
+ * gpa, and sets *spte to the spte value. This spte may be non-preset. If no
+ * walk could be performed, returns NULL and *spte does not contain valid data.
+ *
+ * Contract:
+ *  - Must be called between walk_shadow_page_lockless_{begin,end}.
+ *  - The returned sptep must not be used after walk_shadow_page_lockless_end.
+ */
+static u64 *fast_pf_get_last_sptep(struct kvm_vcpu *vcpu, gpa_t gpa, u64 *spte)
+{
+	struct kvm_shadow_walk_iterator iterator;
+	u64 old_spte;
+	u64 *sptep = NULL;
+
+	for_each_shadow_entry_lockless(vcpu, gpa, iterator, old_spte) {
+		sptep = iterator.sptep;
+		*spte = old_spte;
+	}
+
+	return sptep;
+}
+
+/*
+ * Returns one of RET_PF_INVALID, RET_PF_FIXED or RET_PF_SPURIOUS.
+ */
+static int fast_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+	struct kvm_mmu_page *sp;
+	int ret = RET_PF_INVALID;
+	u64 spte = 0ull;
+	u64 *sptep = NULL;
+	uint retry_count = 0;
+
+	if (!page_fault_can_be_fast(fault))
+		return ret;
+
+	walk_shadow_page_lockless_begin(vcpu);
+
+	do {
+		u64 new_spte;
+
+		if (tdp_mmu_enabled)
+			sptep = kvm_tdp_mmu_fast_pf_get_last_sptep(vcpu, fault->addr, &spte);
+		else
+			sptep = fast_pf_get_last_sptep(vcpu, fault->addr, &spte);
+
+		if (!is_shadow_present_pte(spte))
+			break;
+
+		sp = sptep_to_sp(sptep);
+		if (!is_last_spte(spte, sp->role.level))
+			break;
+
+		/*
+		 * Check whether the memory access that caused the fault would
+		 * still cause it if it were to be performed right now. If not,
+		 * then this is a spurious fault caused by TLB lazily flushed,
+		 * or some other CPU has already fixed the PTE after the
+		 * current CPU took the fault.
+		 *
+		 * Need not check the access of upper level table entries since
+		 * they are always ACC_ALL.
+		 */
+		if (is_access_allowed(fault, spte)) {
+			ret = RET_PF_SPURIOUS;
+			break;
+		}
+
+		new_spte = spte;
+
+		/*
+		 * KVM only supports fixing page faults outside of MMU lock for
+		 * direct MMUs, nested MMUs are always indirect, and KVM always
+		 * uses A/D bits for non-nested MMUs.  Thus, if A/D bits are
+		 * enabled, the SPTE can't be an access-tracked SPTE.
+		 */
+		if (unlikely(!kvm_ad_enabled()) && is_access_track_spte(spte))
+			new_spte = restore_acc_track_spte(new_spte);
+
+		/*
+		 * To keep things simple, only SPTEs that are MMU-writable can
+		 * be made fully writable outside of mmu_lock, e.g. only SPTEs
+		 * that were write-protected for dirty-logging or access
+		 * tracking are handled here.  Don't bother checking if the
+		 * SPTE is writable to prioritize running with A/D bits enabled.
+		 * The is_access_allowed() check above handles the common case
+		 * of the fault being spurious, and the SPTE is known to be
+		 * shadow-present, i.e. except for access tracking restoration
+		 * making the new SPTE writable, the check is wasteful.
+		 */
+		if (fault->write && is_mmu_writable_spte(spte)) {
+			new_spte |= PT_WRITABLE_MASK;
+
+			/*
+			 * Do not fix write-permission on the large spte when
+			 * dirty logging is enabled. Since we only dirty the
+			 * first page into the dirty-bitmap in
+			 * fast_pf_fix_direct_spte(), other pages are missed
+			 * if its slot has dirty logging enabled.
+			 *
+			 * Instead, we let the slow page fault path create a
+			 * normal spte to fix the access.
+			 */
+			if (sp->role.level > PG_LEVEL_4K &&
+			    kvm_slot_dirty_track_enabled(fault->slot))
+				break;
+		}
+
+		/* Verify that the fault can be handled in the fast path */
+		if (new_spte == spte ||
+		    !is_access_allowed(fault, new_spte))
+			break;
+
+		/*
+		 * Currently, fast page fault only works for direct mapping
+		 * since the gfn is not stable for indirect shadow page. See
+		 * Documentation/virt/kvm/locking.rst to get more detail.
+		 */
+		if (fast_pf_fix_direct_spte(vcpu, fault, sptep, spte, new_spte)) {
+			ret = RET_PF_FIXED;
+			break;
+		}
+
+		if (++retry_count > 4) {
+			pr_warn_once("Fast #PF retrying more than 4 times.\n");
+			break;
+		}
+
+	} while (true);
+
+	trace_fast_page_fault(vcpu, fault, sptep, spte, ret);
+	walk_shadow_page_lockless_end(vcpu);
+
+	if (ret != RET_PF_INVALID)
+		vcpu->stat.pf_fast++;
+
+	return ret;
+}
+
+static void mmu_free_root_page(struct kvm *kvm, hpa_t *root_hpa,
+			       struct list_head *invalid_list)
+{
+	struct kvm_mmu_page *sp;
+
+	if (!VALID_PAGE(*root_hpa))
+		return;
+
+	sp = root_to_sp(*root_hpa);
+	if (WARN_ON_ONCE(!sp))
+		return;
+
+	if (is_tdp_mmu_page(sp))
+		kvm_tdp_mmu_put_root(kvm, sp, false);
+	else if (!--sp->root_count && sp->role.invalid)
+		kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
+
+	*root_hpa = INVALID_PAGE;
+}
+
+/* roots_to_free must be some combination of the KVM_MMU_ROOT_* flags */
+void kvm_mmu_free_roots(struct kvm *kvm, struct kvm_mmu *mmu,
+			ulong roots_to_free)
+{
+	int i;
+	LIST_HEAD(invalid_list);
+	bool free_active_root;
+
+	WARN_ON_ONCE(roots_to_free & ~KVM_MMU_ROOTS_ALL);
+
+	BUILD_BUG_ON(KVM_MMU_NUM_PREV_ROOTS >= BITS_PER_LONG);
+
+	/* Before acquiring the MMU lock, see if we need to do any real work. */
+	free_active_root = (roots_to_free & KVM_MMU_ROOT_CURRENT)
+		&& VALID_PAGE(mmu->root.hpa);
+
+	if (!free_active_root) {
+		for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
+			if ((roots_to_free & KVM_MMU_ROOT_PREVIOUS(i)) &&
+			    VALID_PAGE(mmu->prev_roots[i].hpa))
+				break;
+
+		if (i == KVM_MMU_NUM_PREV_ROOTS)
+			return;
+	}
+
+	write_lock(&kvm->mmu_lock);
+
+	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
+		if (roots_to_free & KVM_MMU_ROOT_PREVIOUS(i))
+			mmu_free_root_page(kvm, &mmu->prev_roots[i].hpa,
+					   &invalid_list);
+
+	if (free_active_root) {
+		if (kvm_mmu_is_dummy_root(mmu->root.hpa)) {
+			/* Nothing to cleanup for dummy roots. */
+		} else if (root_to_sp(mmu->root.hpa)) {
+			mmu_free_root_page(kvm, &mmu->root.hpa, &invalid_list);
+		} else if (mmu->pae_root) {
+			for (i = 0; i < 4; ++i) {
+				if (!IS_VALID_PAE_ROOT(mmu->pae_root[i]))
+					continue;
+
+				mmu_free_root_page(kvm, &mmu->pae_root[i],
+						   &invalid_list);
+				mmu->pae_root[i] = INVALID_PAE_ROOT;
+			}
+		}
+		mmu->root.hpa = INVALID_PAGE;
+		mmu->root.pgd = 0;
+	}
+
+	kvm_mmu_commit_zap_page(kvm, &invalid_list);
+	write_unlock(&kvm->mmu_lock);
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_free_roots);
+
+void kvm_mmu_free_guest_mode_roots(struct kvm *kvm, struct kvm_mmu *mmu)
+{
+	unsigned long roots_to_free = 0;
+	struct kvm_mmu_page *sp;
+	hpa_t root_hpa;
+	int i;
+
+	/*
+	 * This should not be called while L2 is active, L2 can't invalidate
+	 * _only_ its own roots, e.g. INVVPID unconditionally exits.
+	 */
+	WARN_ON_ONCE(mmu->root_role.guest_mode);
+
+	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
+		root_hpa = mmu->prev_roots[i].hpa;
+		if (!VALID_PAGE(root_hpa))
+			continue;
+
+		sp = root_to_sp(root_hpa);
+		if (!sp || sp->role.guest_mode)
+			roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
+	}
+
+	kvm_mmu_free_roots(kvm, mmu, roots_to_free);
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_free_guest_mode_roots);
+
+static hpa_t mmu_alloc_root(struct kvm_vcpu *vcpu, gfn_t gfn, int quadrant,
+			    u8 level)
+{
+	union kvm_mmu_page_role role = vcpu->arch.mmu->root_role;
+	struct kvm_mmu_page *sp;
+
+	role.level = level;
+	role.quadrant = quadrant;
+
+	WARN_ON_ONCE(quadrant && !role.has_4_byte_gpte);
+	WARN_ON_ONCE(role.direct && role.has_4_byte_gpte);
+
+	sp = kvm_mmu_get_shadow_page(vcpu, gfn, role);
+	++sp->root_count;
+
+	return __pa(sp->spt);
+}
+
+static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
+{
+	struct kvm_mmu *mmu = vcpu->arch.mmu;
+	u8 shadow_root_level = mmu->root_role.level;
+	hpa_t root;
+	unsigned i;
+	int r;
+
+	write_lock(&vcpu->kvm->mmu_lock);
+	r = make_mmu_pages_available(vcpu);
+	if (r < 0)
+		goto out_unlock;
+
+	if (tdp_mmu_enabled) {
+		root = kvm_tdp_mmu_get_vcpu_root_hpa(vcpu);
+		mmu->root.hpa = root;
+	} else if (shadow_root_level >= PT64_ROOT_4LEVEL) {
+		root = mmu_alloc_root(vcpu, 0, 0, shadow_root_level);
+		mmu->root.hpa = root;
+	} else if (shadow_root_level == PT32E_ROOT_LEVEL) {
+		if (WARN_ON_ONCE(!mmu->pae_root)) {
+			r = -EIO;
+			goto out_unlock;
+		}
+
+		for (i = 0; i < 4; ++i) {
+			WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i]));
+
+			root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT), 0,
+					      PT32_ROOT_LEVEL);
+			mmu->pae_root[i] = root | PT_PRESENT_MASK |
+					   shadow_me_value;
+		}
+		mmu->root.hpa = __pa(mmu->pae_root);
+	} else {
+		WARN_ONCE(1, "Bad TDP root level = %d\n", shadow_root_level);
+		r = -EIO;
+		goto out_unlock;
+	}
+
+	/* root.pgd is ignored for direct MMUs. */
+	mmu->root.pgd = 0;
+out_unlock:
+	write_unlock(&vcpu->kvm->mmu_lock);
+	return r;
+}
+
+static int mmu_first_shadow_root_alloc(struct kvm *kvm)
+{
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *slot;
+	int r = 0, i, bkt;
+
+	/*
+	 * Check if this is the first shadow root being allocated before
+	 * taking the lock.
+	 */
+	if (kvm_shadow_root_allocated(kvm))
+		return 0;
+
+	mutex_lock(&kvm->slots_arch_lock);
+
+	/* Recheck, under the lock, whether this is the first shadow root. */
+	if (kvm_shadow_root_allocated(kvm))
+		goto out_unlock;
+
+	/*
+	 * Check if anything actually needs to be allocated, e.g. all metadata
+	 * will be allocated upfront if TDP is disabled.
+	 */
+	if (kvm_memslots_have_rmaps(kvm) &&
+	    kvm_page_track_write_tracking_enabled(kvm))
+		goto out_success;
+
+	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+		slots = __kvm_memslots(kvm, i);
+		kvm_for_each_memslot(slot, bkt, slots) {
+			/*
+			 * Both of these functions are no-ops if the target is
+			 * already allocated, so unconditionally calling both
+			 * is safe.  Intentionally do NOT free allocations on
+			 * failure to avoid having to track which allocations
+			 * were made now versus when the memslot was created.
+			 * The metadata is guaranteed to be freed when the slot
+			 * is freed, and will be kept/used if userspace retries
+			 * KVM_RUN instead of killing the VM.
+			 */
+			r = memslot_rmap_alloc(slot, slot->npages);
+			if (r)
+				goto out_unlock;
+			r = kvm_page_track_write_tracking_alloc(slot);
+			if (r)
+				goto out_unlock;
+		}
+	}
+
+	/*
+	 * Ensure that shadow_root_allocated becomes true strictly after
+	 * all the related pointers are set.
+	 */
+out_success:
+	smp_store_release(&kvm->arch.shadow_root_allocated, true);
+
+out_unlock:
+	mutex_unlock(&kvm->slots_arch_lock);
+	return r;
+}
+
+static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
+{
+	struct kvm_mmu *mmu = vcpu->arch.mmu;
+	u64 pdptrs[4], pm_mask;
+	gfn_t root_gfn, root_pgd;
+	int quadrant, i, r;
+	hpa_t root;
+
+	root_pgd = kvm_mmu_get_guest_pgd(vcpu, mmu);
+	root_gfn = root_pgd >> PAGE_SHIFT;
+
+	if (!kvm_vcpu_is_visible_gfn(vcpu, root_gfn)) {
+		mmu->root.hpa = kvm_mmu_get_dummy_root();
+		return 0;
+	}
+
+	/*
+	 * On SVM, reading PDPTRs might access guest memory, which might fault
+	 * and thus might sleep.  Grab the PDPTRs before acquiring mmu_lock.
+	 */
+	if (mmu->cpu_role.base.level == PT32E_ROOT_LEVEL) {
+		for (i = 0; i < 4; ++i) {
+			pdptrs[i] = mmu->get_pdptr(vcpu, i);
+			if (!(pdptrs[i] & PT_PRESENT_MASK))
+				continue;
+
+			if (!kvm_vcpu_is_visible_gfn(vcpu, pdptrs[i] >> PAGE_SHIFT))
+				pdptrs[i] = 0;
+		}
+	}
+
+	r = mmu_first_shadow_root_alloc(vcpu->kvm);
+	if (r)
+		return r;
+
+	write_lock(&vcpu->kvm->mmu_lock);
+	r = make_mmu_pages_available(vcpu);
+	if (r < 0)
+		goto out_unlock;
+
+	/*
+	 * Do we shadow a long mode page table? If so we need to
+	 * write-protect the guests page table root.
+	 */
+	if (mmu->cpu_role.base.level >= PT64_ROOT_4LEVEL) {
+		root = mmu_alloc_root(vcpu, root_gfn, 0,
+				      mmu->root_role.level);
+		mmu->root.hpa = root;
+		goto set_root_pgd;
+	}
+
+	if (WARN_ON_ONCE(!mmu->pae_root)) {
+		r = -EIO;
+		goto out_unlock;
+	}
+
+	/*
+	 * We shadow a 32 bit page table. This may be a legacy 2-level
+	 * or a PAE 3-level page table. In either case we need to be aware that
+	 * the shadow page table may be a PAE or a long mode page table.
+	 */
+	pm_mask = PT_PRESENT_MASK | shadow_me_value;
+	if (mmu->root_role.level >= PT64_ROOT_4LEVEL) {
+		pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK;
+
+		if (WARN_ON_ONCE(!mmu->pml4_root)) {
+			r = -EIO;
+			goto out_unlock;
+		}
+		mmu->pml4_root[0] = __pa(mmu->pae_root) | pm_mask;
+
+		if (mmu->root_role.level == PT64_ROOT_5LEVEL) {
+			if (WARN_ON_ONCE(!mmu->pml5_root)) {
+				r = -EIO;
+				goto out_unlock;
+			}
+			mmu->pml5_root[0] = __pa(mmu->pml4_root) | pm_mask;
+		}
+	}
+
+	for (i = 0; i < 4; ++i) {
+		WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i]));
+
+		if (mmu->cpu_role.base.level == PT32E_ROOT_LEVEL) {
+			if (!(pdptrs[i] & PT_PRESENT_MASK)) {
+				mmu->pae_root[i] = INVALID_PAE_ROOT;
+				continue;
+			}
+			root_gfn = pdptrs[i] >> PAGE_SHIFT;
+		}
+
+		/*
+		 * If shadowing 32-bit non-PAE page tables, each PAE page
+		 * directory maps one quarter of the guest's non-PAE page
+		 * directory. Othwerise each PAE page direct shadows one guest
+		 * PAE page directory so that quadrant should be 0.
+		 */
+		quadrant = (mmu->cpu_role.base.level == PT32_ROOT_LEVEL) ? i : 0;
+
+		root = mmu_alloc_root(vcpu, root_gfn, quadrant, PT32_ROOT_LEVEL);
+		mmu->pae_root[i] = root | pm_mask;
+	}
+
+	if (mmu->root_role.level == PT64_ROOT_5LEVEL)
+		mmu->root.hpa = __pa(mmu->pml5_root);
+	else if (mmu->root_role.level == PT64_ROOT_4LEVEL)
+		mmu->root.hpa = __pa(mmu->pml4_root);
+	else
+		mmu->root.hpa = __pa(mmu->pae_root);
+
+set_root_pgd:
+	mmu->root.pgd = root_pgd;
+out_unlock:
+	write_unlock(&vcpu->kvm->mmu_lock);
+
+	return r;
+}
+
+static int mmu_alloc_special_roots(struct kvm_vcpu *vcpu)
+{
+	struct kvm_mmu *mmu = vcpu->arch.mmu;
+	bool need_pml5 = mmu->root_role.level > PT64_ROOT_4LEVEL;
+	u64 *pml5_root = NULL;
+	u64 *pml4_root = NULL;
+	u64 *pae_root;
+
+	/*
+	 * When shadowing 32-bit or PAE NPT with 64-bit NPT, the PML4 and PDP
+	 * tables are allocated and initialized at root creation as there is no
+	 * equivalent level in the guest's NPT to shadow.  Allocate the tables
+	 * on demand, as running a 32-bit L1 VMM on 64-bit KVM is very rare.
+	 */
+	if (mmu->root_role.direct ||
+	    mmu->cpu_role.base.level >= PT64_ROOT_4LEVEL ||
+	    mmu->root_role.level < PT64_ROOT_4LEVEL)
+		return 0;
+
+	/*
+	 * NPT, the only paging mode that uses this horror, uses a fixed number
+	 * of levels for the shadow page tables, e.g. all MMUs are 4-level or
+	 * all MMus are 5-level.  Thus, this can safely require that pml5_root
+	 * is allocated if the other roots are valid and pml5 is needed, as any
+	 * prior MMU would also have required pml5.
+	 */
+	if (mmu->pae_root && mmu->pml4_root && (!need_pml5 || mmu->pml5_root))
+		return 0;
+
+	/*
+	 * The special roots should always be allocated in concert.  Yell and
+	 * bail if KVM ends up in a state where only one of the roots is valid.
+	 */
+	if (WARN_ON_ONCE(!tdp_enabled || mmu->pae_root || mmu->pml4_root ||
+			 (need_pml5 && mmu->pml5_root)))
+		return -EIO;
+
+	/*
+	 * Unlike 32-bit NPT, the PDP table doesn't need to be in low mem, and
+	 * doesn't need to be decrypted.
+	 */
+	pae_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
+	if (!pae_root)
+		return -ENOMEM;
+
+#ifdef CONFIG_X86_64
+	pml4_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
+	if (!pml4_root)
+		goto err_pml4;
+
+	if (need_pml5) {
+		pml5_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
+		if (!pml5_root)
+			goto err_pml5;
+	}
+#endif
+
+	mmu->pae_root = pae_root;
+	mmu->pml4_root = pml4_root;
+	mmu->pml5_root = pml5_root;
+
+	return 0;
+
+#ifdef CONFIG_X86_64
+err_pml5:
+	free_page((unsigned long)pml4_root);
+err_pml4:
+	free_page((unsigned long)pae_root);
+	return -ENOMEM;
+#endif
+}
+
+static bool is_unsync_root(hpa_t root)
+{
+	struct kvm_mmu_page *sp;
+
+	if (!VALID_PAGE(root) || kvm_mmu_is_dummy_root(root))
+		return false;
+
+	/*
+	 * The read barrier orders the CPU's read of SPTE.W during the page table
+	 * walk before the reads of sp->unsync/sp->unsync_children here.
+	 *
+	 * Even if another CPU was marking the SP as unsync-ed simultaneously,
+	 * any guest page table changes are not guaranteed to be visible anyway
+	 * until this VCPU issues a TLB flush strictly after those changes are
+	 * made.  We only need to ensure that the other CPU sets these flags
+	 * before any actual changes to the page tables are made.  The comments
+	 * in mmu_try_to_unsync_pages() describe what could go wrong if this
+	 * requirement isn't satisfied.
+	 */
+	smp_rmb();
+	sp = root_to_sp(root);
+
+	/*
+	 * PAE roots (somewhat arbitrarily) aren't backed by shadow pages, the
+	 * PDPTEs for a given PAE root need to be synchronized individually.
+	 */
+	if (WARN_ON_ONCE(!sp))
+		return false;
+
+	if (sp->unsync || sp->unsync_children)
+		return true;
+
+	return false;
+}
+
+void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
+{
+	int i;
+	struct kvm_mmu_page *sp;
+
+	if (vcpu->arch.mmu->root_role.direct)
+		return;
+
+	if (!VALID_PAGE(vcpu->arch.mmu->root.hpa))
+		return;
+
+	vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
+
+	if (vcpu->arch.mmu->cpu_role.base.level >= PT64_ROOT_4LEVEL) {
+		hpa_t root = vcpu->arch.mmu->root.hpa;
+
+		if (!is_unsync_root(root))
+			return;
+
+		sp = root_to_sp(root);
+
+		write_lock(&vcpu->kvm->mmu_lock);
+		mmu_sync_children(vcpu, sp, true);
+		write_unlock(&vcpu->kvm->mmu_lock);
+		return;
+	}
+
+	write_lock(&vcpu->kvm->mmu_lock);
+
+	for (i = 0; i < 4; ++i) {
+		hpa_t root = vcpu->arch.mmu->pae_root[i];
+
+		if (IS_VALID_PAE_ROOT(root)) {
+			sp = spte_to_child_sp(root);
+			mmu_sync_children(vcpu, sp, true);
+		}
+	}
+
+	write_unlock(&vcpu->kvm->mmu_lock);
+}
+
+void kvm_mmu_sync_prev_roots(struct kvm_vcpu *vcpu)
+{
+	unsigned long roots_to_free = 0;
+	int i;
+
+	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
+		if (is_unsync_root(vcpu->arch.mmu->prev_roots[i].hpa))
+			roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
+
+	/* sync prev_roots by simply freeing them */
+	kvm_mmu_free_roots(vcpu->kvm, vcpu->arch.mmu, roots_to_free);
+}
+
+static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+				  gpa_t vaddr, u64 access,
+				  struct x86_exception *exception)
+{
+	if (exception)
+		exception->error_code = 0;
+	return kvm_translate_gpa(vcpu, mmu, vaddr, access, exception);
+}
+
+static bool mmio_info_in_cache(struct kvm_vcpu *vcpu, u64 addr, bool direct)
+{
+	/*
+	 * A nested guest cannot use the MMIO cache if it is using nested
+	 * page tables, because cr2 is a nGPA while the cache stores GPAs.
+	 */
+	if (mmu_is_nested(vcpu))
+		return false;
+
+	if (direct)
+		return vcpu_match_mmio_gpa(vcpu, addr);
+
+	return vcpu_match_mmio_gva(vcpu, addr);
+}
+
+/*
+ * Return the level of the lowest level SPTE added to sptes.
+ * That SPTE may be non-present.
+ *
+ * Must be called between walk_shadow_page_lockless_{begin,end}.
+ */
+static int get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes, int *root_level)
+{
+	struct kvm_shadow_walk_iterator iterator;
+	int leaf = -1;
+	u64 spte;
+
+	for (shadow_walk_init(&iterator, vcpu, addr),
+	     *root_level = iterator.level;
+	     shadow_walk_okay(&iterator);
+	     __shadow_walk_next(&iterator, spte)) {
+		leaf = iterator.level;
+		spte = mmu_spte_get_lockless(iterator.sptep);
+
+		sptes[leaf] = spte;
+	}
+
+	return leaf;
+}
+
+/* return true if reserved bit(s) are detected on a valid, non-MMIO SPTE. */
+static bool get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr, u64 *sptep)
+{
+	u64 sptes[PT64_ROOT_MAX_LEVEL + 1];
+	struct rsvd_bits_validate *rsvd_check;
+	int root, leaf, level;
+	bool reserved = false;
+
+	walk_shadow_page_lockless_begin(vcpu);
+
+	if (is_tdp_mmu_active(vcpu))
+		leaf = kvm_tdp_mmu_get_walk(vcpu, addr, sptes, &root);
+	else
+		leaf = get_walk(vcpu, addr, sptes, &root);
+
+	walk_shadow_page_lockless_end(vcpu);
+
+	if (unlikely(leaf < 0)) {
+		*sptep = 0ull;
+		return reserved;
+	}
+
+	*sptep = sptes[leaf];
+
+	/*
+	 * Skip reserved bits checks on the terminal leaf if it's not a valid
+	 * SPTE.  Note, this also (intentionally) skips MMIO SPTEs, which, by
+	 * design, always have reserved bits set.  The purpose of the checks is
+	 * to detect reserved bits on non-MMIO SPTEs. i.e. buggy SPTEs.
+	 */
+	if (!is_shadow_present_pte(sptes[leaf]))
+		leaf++;
+
+	rsvd_check = &vcpu->arch.mmu->shadow_zero_check;
+
+	for (level = root; level >= leaf; level--)
+		reserved |= is_rsvd_spte(rsvd_check, sptes[level], level);
+
+	if (reserved) {
+		pr_err("%s: reserved bits set on MMU-present spte, addr 0x%llx, hierarchy:\n",
+		       __func__, addr);
+		for (level = root; level >= leaf; level--)
+			pr_err("------ spte = 0x%llx level = %d, rsvd bits = 0x%llx",
+			       sptes[level], level,
+			       get_rsvd_bits(rsvd_check, sptes[level], level));
+	}
+
+	return reserved;
+}
+
+static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct)
+{
+	u64 spte;
+	bool reserved;
+
+	if (mmio_info_in_cache(vcpu, addr, direct))
+		return RET_PF_EMULATE;
+
+	reserved = get_mmio_spte(vcpu, addr, &spte);
+	if (WARN_ON_ONCE(reserved))
+		return -EINVAL;
+
+	if (is_mmio_spte(spte)) {
+		gfn_t gfn = get_mmio_spte_gfn(spte);
+		unsigned int access = get_mmio_spte_access(spte);
+
+		if (!check_mmio_spte(vcpu, spte))
+			return RET_PF_INVALID;
+
+		if (direct)
+			addr = 0;
+
+		trace_handle_mmio_page_fault(addr, gfn, access);
+		vcpu_cache_mmio_info(vcpu, addr, gfn, access);
+		return RET_PF_EMULATE;
+	}
+
+	/*
+	 * If the page table is zapped by other cpus, let CPU fault again on
+	 * the address.
+	 */
+	return RET_PF_RETRY;
+}
+
+static bool page_fault_handle_page_track(struct kvm_vcpu *vcpu,
+					 struct kvm_page_fault *fault)
+{
+	if (unlikely(fault->rsvd))
+		return false;
+
+	if (!fault->present || !fault->write)
+		return false;
+
+	/*
+	 * guest is writing the page which is write tracked which can
+	 * not be fixed by page fault handler.
+	 */
+	if (kvm_gfn_is_write_tracked(vcpu->kvm, fault->slot, fault->gfn))
+		return true;
+
+	return false;
+}
+
+static void shadow_page_table_clear_flood(struct kvm_vcpu *vcpu, gva_t addr)
+{
+	struct kvm_shadow_walk_iterator iterator;
+	u64 spte;
+
+	walk_shadow_page_lockless_begin(vcpu);
+	for_each_shadow_entry_lockless(vcpu, addr, iterator, spte)
+		clear_sp_write_flooding_count(iterator.sptep);
+	walk_shadow_page_lockless_end(vcpu);
+}
+
+static u32 alloc_apf_token(struct kvm_vcpu *vcpu)
+{
+	/* make sure the token value is not 0 */
+	u32 id = vcpu->arch.apf.id;
+
+	if (id << 12 == 0)
+		vcpu->arch.apf.id = 1;
+
+	return (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
+}
+
+static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
+				    gfn_t gfn)
+{
+	struct kvm_arch_async_pf arch;
+
+	arch.token = alloc_apf_token(vcpu);
+	arch.gfn = gfn;
+	arch.direct_map = vcpu->arch.mmu->root_role.direct;
+	arch.cr3 = kvm_mmu_get_guest_pgd(vcpu, vcpu->arch.mmu);
+
+	return kvm_setup_async_pf(vcpu, cr2_or_gpa,
+				  kvm_vcpu_gfn_to_hva(vcpu, gfn), &arch);
+}
+
+void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
+{
+	int r;
+
+	if ((vcpu->arch.mmu->root_role.direct != work->arch.direct_map) ||
+	      work->wakeup_all)
+		return;
+
+	r = kvm_mmu_reload(vcpu);
+	if (unlikely(r))
+		return;
+
+	if (!vcpu->arch.mmu->root_role.direct &&
+	      work->arch.cr3 != kvm_mmu_get_guest_pgd(vcpu, vcpu->arch.mmu))
+		return;
+
+	kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, 0, true, NULL);
+}
+
+static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+	struct kvm_memory_slot *slot = fault->slot;
+	bool async;
+
+	/*
+	 * Retry the page fault if the gfn hit a memslot that is being deleted
+	 * or moved.  This ensures any existing SPTEs for the old memslot will
+	 * be zapped before KVM inserts a new MMIO SPTE for the gfn.
+	 */
+	if (slot && (slot->flags & KVM_MEMSLOT_INVALID))
+		return RET_PF_RETRY;
+
+	if (!kvm_is_visible_memslot(slot)) {
+		/* Don't expose private memslots to L2. */
+		if (is_guest_mode(vcpu)) {
+			fault->slot = NULL;
+			fault->pfn = KVM_PFN_NOSLOT;
+			fault->map_writable = false;
+			return RET_PF_CONTINUE;
+		}
+		/*
+		 * If the APIC access page exists but is disabled, go directly
+		 * to emulation without caching the MMIO access or creating a
+		 * MMIO SPTE.  That way the cache doesn't need to be purged
+		 * when the AVIC is re-enabled.
+		 */
+		if (slot && slot->id == APIC_ACCESS_PAGE_PRIVATE_MEMSLOT &&
+		    !kvm_apicv_activated(vcpu->kvm))
+			return RET_PF_EMULATE;
+	}
+
+	async = false;
+	fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, false, &async,
+					  fault->write, &fault->map_writable,
+					  &fault->hva);
+	if (!async)
+		return RET_PF_CONTINUE; /* *pfn has correct page already */
+
+	if (!fault->prefetch && kvm_can_do_async_pf(vcpu)) {
+		trace_kvm_try_async_get_page(fault->addr, fault->gfn);
+		if (kvm_find_async_pf_gfn(vcpu, fault->gfn)) {
+			trace_kvm_async_pf_repeated_fault(fault->addr, fault->gfn);
+			kvm_make_request(KVM_REQ_APF_HALT, vcpu);
+			return RET_PF_RETRY;
+		} else if (kvm_arch_setup_async_pf(vcpu, fault->addr, fault->gfn)) {
+			return RET_PF_RETRY;
+		}
+	}
+
+	/*
+	 * Allow gup to bail on pending non-fatal signals when it's also allowed
+	 * to wait for IO.  Note, gup always bails if it is unable to quickly
+	 * get a page and a fatal signal, i.e. SIGKILL, is pending.
+	 */
+	fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, true, NULL,
+					  fault->write, &fault->map_writable,
+					  &fault->hva);
+	return RET_PF_CONTINUE;
+}
+
+static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
+			   unsigned int access)
+{
+	int ret;
+
+	fault->mmu_seq = vcpu->kvm->mmu_invalidate_seq;
+	smp_rmb();
+
+	ret = __kvm_faultin_pfn(vcpu, fault);
+	if (ret != RET_PF_CONTINUE)
+		return ret;
+
+	if (unlikely(is_error_pfn(fault->pfn)))
+		return kvm_handle_error_pfn(vcpu, fault);
+
+	if (unlikely(!fault->slot))
+		return kvm_handle_noslot_fault(vcpu, fault, access);
+
+	return RET_PF_CONTINUE;
+}
+
+/*
+ * Returns true if the page fault is stale and needs to be retried, i.e. if the
+ * root was invalidated by a memslot update or a relevant mmu_notifier fired.
+ */
+static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
+				struct kvm_page_fault *fault)
+{
+	struct kvm_mmu_page *sp = root_to_sp(vcpu->arch.mmu->root.hpa);
+
+	/* Special roots, e.g. pae_root, are not backed by shadow pages. */
+	if (sp && is_obsolete_sp(vcpu->kvm, sp))
+		return true;
+
+	/*
+	 * Roots without an associated shadow page are considered invalid if
+	 * there is a pending request to free obsolete roots.  The request is
+	 * only a hint that the current root _may_ be obsolete and needs to be
+	 * reloaded, e.g. if the guest frees a PGD that KVM is tracking as a
+	 * previous root, then __kvm_mmu_prepare_zap_page() signals all vCPUs
+	 * to reload even if no vCPU is actively using the root.
+	 */
+	if (!sp && kvm_test_request(KVM_REQ_MMU_FREE_OBSOLETE_ROOTS, vcpu))
+		return true;
+
+	return fault->slot &&
+	       mmu_invalidate_retry_hva(vcpu->kvm, fault->mmu_seq, fault->hva);
+}
+
+static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+	int r;
+
+	/* Dummy roots are used only for shadowing bad guest roots. */
+	if (WARN_ON_ONCE(kvm_mmu_is_dummy_root(vcpu->arch.mmu->root.hpa)))
+		return RET_PF_RETRY;
+
+	if (page_fault_handle_page_track(vcpu, fault))
+		return RET_PF_EMULATE;
+
+	r = fast_page_fault(vcpu, fault);
+	if (r != RET_PF_INVALID)
+		return r;
+
+	r = mmu_topup_memory_caches(vcpu, false);
+	if (r)
+		return r;
+
+	r = kvm_faultin_pfn(vcpu, fault, ACC_ALL);
+	if (r != RET_PF_CONTINUE)
+		return r;
+
+	r = RET_PF_RETRY;
+	write_lock(&vcpu->kvm->mmu_lock);
+
+	if (is_page_fault_stale(vcpu, fault))
+		goto out_unlock;
+
+	r = make_mmu_pages_available(vcpu);
+	if (r)
+		goto out_unlock;
+
+	r = direct_map(vcpu, fault);
+
+out_unlock:
+	write_unlock(&vcpu->kvm->mmu_lock);
+	kvm_release_pfn_clean(fault->pfn);
+	return r;
+}
+
+static int nonpaging_page_fault(struct kvm_vcpu *vcpu,
+				struct kvm_page_fault *fault)
+{
+	/* This path builds a PAE pagetable, we can map 2mb pages at maximum. */
+	fault->max_level = PG_LEVEL_2M;
+	return direct_page_fault(vcpu, fault);
+}
+
+int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
+				u64 fault_address, char *insn, int insn_len)
+{
+	int r = 1;
+	u32 flags = vcpu->arch.apf.host_apf_flags;
+
+#ifndef CONFIG_X86_64
+	/* A 64-bit CR2 should be impossible on 32-bit KVM. */
+	if (WARN_ON_ONCE(fault_address >> 32))
+		return -EFAULT;
+#endif
+
+	vcpu->arch.l1tf_flush_l1d = true;
+	if (!flags) {
+		trace_kvm_page_fault(vcpu, fault_address, error_code);
+
+		if (kvm_event_needs_reinjection(vcpu))
+			kvm_mmu_unprotect_page_virt(vcpu, fault_address);
+		r = kvm_mmu_page_fault(vcpu, fault_address, error_code, insn,
+				insn_len);
+	} else if (flags & KVM_PV_REASON_PAGE_NOT_PRESENT) {
+		vcpu->arch.apf.host_apf_flags = 0;
+		local_irq_disable();
+		kvm_async_pf_task_wait_schedule(fault_address);
+		local_irq_enable();
+	} else {
+		WARN_ONCE(1, "Unexpected host async PF flags: %x\n", flags);
+	}
+
+	return r;
+}
+EXPORT_SYMBOL_GPL(kvm_handle_page_fault);
+
+#ifdef CONFIG_X86_64
+static int kvm_tdp_mmu_page_fault(struct kvm_vcpu *vcpu,
+				  struct kvm_page_fault *fault)
+{
+	int r;
+
+	if (page_fault_handle_page_track(vcpu, fault))
+		return RET_PF_EMULATE;
+
+	r = fast_page_fault(vcpu, fault);
+	if (r != RET_PF_INVALID)
+		return r;
+
+	r = mmu_topup_memory_caches(vcpu, false);
+	if (r)
+		return r;
+
+	r = kvm_faultin_pfn(vcpu, fault, ACC_ALL);
+	if (r != RET_PF_CONTINUE)
+		return r;
+
+	r = RET_PF_RETRY;
+	read_lock(&vcpu->kvm->mmu_lock);
+
+	if (is_page_fault_stale(vcpu, fault))
+		goto out_unlock;
+
+	r = kvm_tdp_mmu_map(vcpu, fault);
+
+out_unlock:
+	read_unlock(&vcpu->kvm->mmu_lock);
+	kvm_release_pfn_clean(fault->pfn);
+	return r;
+}
+#endif
+
+int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+	/*
+	 * If the guest's MTRRs may be used to compute the "real" memtype,
+	 * restrict the mapping level to ensure KVM uses a consistent memtype
+	 * across the entire mapping.  If the host MTRRs are ignored by TDP
+	 * (shadow_memtype_mask is non-zero), and the VM has non-coherent DMA
+	 * (DMA doesn't snoop CPU caches), KVM's ABI is to honor the memtype
+	 * from the guest's MTRRs so that guest accesses to memory that is
+	 * DMA'd aren't cached against the guest's wishes.
+	 *
+	 * Note, KVM may still ultimately ignore guest MTRRs for certain PFNs,
+	 * e.g. KVM will force UC memtype for host MMIO.
+	 */
+	if (shadow_memtype_mask && kvm_arch_has_noncoherent_dma(vcpu->kvm)) {
+		for ( ; fault->max_level > PG_LEVEL_4K; --fault->max_level) {
+			int page_num = KVM_PAGES_PER_HPAGE(fault->max_level);
+			gfn_t base = gfn_round_for_level(fault->gfn,
+							 fault->max_level);
+
+			if (kvm_mtrr_check_gfn_range_consistency(vcpu, base, page_num))
+				break;
+		}
+	}
+
+#ifdef CONFIG_X86_64
+	if (tdp_mmu_enabled)
+		return kvm_tdp_mmu_page_fault(vcpu, fault);
+#endif
+
+	return direct_page_fault(vcpu, fault);
+}
+
+static void nonpaging_init_context(struct kvm_mmu *context)
+{
+	context->page_fault = nonpaging_page_fault;
+	context->gva_to_gpa = nonpaging_gva_to_gpa;
+	context->sync_spte = NULL;
+}
+
+static inline bool is_root_usable(struct kvm_mmu_root_info *root, gpa_t pgd,
+				  union kvm_mmu_page_role role)
+{
+	struct kvm_mmu_page *sp;
+
+	if (!VALID_PAGE(root->hpa))
+		return false;
+
+	if (!role.direct && pgd != root->pgd)
+		return false;
+
+	sp = root_to_sp(root->hpa);
+	if (WARN_ON_ONCE(!sp))
+		return false;
+
+	return role.word == sp->role.word;
+}
+
+/*
+ * Find out if a previously cached root matching the new pgd/role is available,
+ * and insert the current root as the MRU in the cache.
+ * If a matching root is found, it is assigned to kvm_mmu->root and
+ * true is returned.
+ * If no match is found, kvm_mmu->root is left invalid, the LRU root is
+ * evicted to make room for the current root, and false is returned.
+ */
+static bool cached_root_find_and_keep_current(struct kvm *kvm, struct kvm_mmu *mmu,
+					      gpa_t new_pgd,
+					      union kvm_mmu_page_role new_role)
+{
+	uint i;
+
+	if (is_root_usable(&mmu->root, new_pgd, new_role))
+		return true;
+
+	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
+		/*
+		 * The swaps end up rotating the cache like this:
+		 *   C   0 1 2 3   (on entry to the function)
+		 *   0   C 1 2 3
+		 *   1   C 0 2 3
+		 *   2   C 0 1 3
+		 *   3   C 0 1 2   (on exit from the loop)
+		 */
+		swap(mmu->root, mmu->prev_roots[i]);
+		if (is_root_usable(&mmu->root, new_pgd, new_role))
+			return true;
+	}
+
+	kvm_mmu_free_roots(kvm, mmu, KVM_MMU_ROOT_CURRENT);
+	return false;
+}
+
+/*
+ * Find out if a previously cached root matching the new pgd/role is available.
+ * On entry, mmu->root is invalid.
+ * If a matching root is found, it is assigned to kvm_mmu->root, the LRU entry
+ * of the cache becomes invalid, and true is returned.
+ * If no match is found, kvm_mmu->root is left invalid and false is returned.
+ */
+static bool cached_root_find_without_current(struct kvm *kvm, struct kvm_mmu *mmu,
+					     gpa_t new_pgd,
+					     union kvm_mmu_page_role new_role)
+{
+	uint i;
+
+	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
+		if (is_root_usable(&mmu->prev_roots[i], new_pgd, new_role))
+			goto hit;
+
+	return false;
+
+hit:
+	swap(mmu->root, mmu->prev_roots[i]);
+	/* Bubble up the remaining roots.  */
+	for (; i < KVM_MMU_NUM_PREV_ROOTS - 1; i++)
+		mmu->prev_roots[i] = mmu->prev_roots[i + 1];
+	mmu->prev_roots[i].hpa = INVALID_PAGE;
+	return true;
+}
+
+static bool fast_pgd_switch(struct kvm *kvm, struct kvm_mmu *mmu,
+			    gpa_t new_pgd, union kvm_mmu_page_role new_role)
+{
+	/*
+	 * Limit reuse to 64-bit hosts+VMs without "special" roots in order to
+	 * avoid having to deal with PDPTEs and other complexities.
+	 */
+	if (VALID_PAGE(mmu->root.hpa) && !root_to_sp(mmu->root.hpa))
+		kvm_mmu_free_roots(kvm, mmu, KVM_MMU_ROOT_CURRENT);
+
+	if (VALID_PAGE(mmu->root.hpa))
+		return cached_root_find_and_keep_current(kvm, mmu, new_pgd, new_role);
+	else
+		return cached_root_find_without_current(kvm, mmu, new_pgd, new_role);
+}
+
+void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd)
+{
+	struct kvm_mmu *mmu = vcpu->arch.mmu;
+	union kvm_mmu_page_role new_role = mmu->root_role;
+
+	/*
+	 * Return immediately if no usable root was found, kvm_mmu_reload()
+	 * will establish a valid root prior to the next VM-Enter.
+	 */
+	if (!fast_pgd_switch(vcpu->kvm, mmu, new_pgd, new_role))
+		return;
+
+	/*
+	 * It's possible that the cached previous root page is obsolete because
+	 * of a change in the MMU generation number. However, changing the
+	 * generation number is accompanied by KVM_REQ_MMU_FREE_OBSOLETE_ROOTS,
+	 * which will free the root set here and allocate a new one.
+	 */
+	kvm_make_request(KVM_REQ_LOAD_MMU_PGD, vcpu);
+
+	if (force_flush_and_sync_on_reuse) {
+		kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
+		kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
+	}
+
+	/*
+	 * The last MMIO access's GVA and GPA are cached in the VCPU. When
+	 * switching to a new CR3, that GVA->GPA mapping may no longer be
+	 * valid. So clear any cached MMIO info even when we don't need to sync
+	 * the shadow page tables.
+	 */
+	vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
+
+	/*
+	 * If this is a direct root page, it doesn't have a write flooding
+	 * count. Otherwise, clear the write flooding count.
+	 */
+	if (!new_role.direct) {
+		struct kvm_mmu_page *sp = root_to_sp(vcpu->arch.mmu->root.hpa);
+
+		if (!WARN_ON_ONCE(!sp))
+			__clear_sp_write_flooding_count(sp);
+	}
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_new_pgd);
+
+static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn,
+			   unsigned int access)
+{
+	if (unlikely(is_mmio_spte(*sptep))) {
+		if (gfn != get_mmio_spte_gfn(*sptep)) {
+			mmu_spte_clear_no_track(sptep);
+			return true;
+		}
+
+		mark_mmio_spte(vcpu, sptep, gfn, access);
+		return true;
+	}
+
+	return false;
+}
+
+#define PTTYPE_EPT 18 /* arbitrary */
+#define PTTYPE PTTYPE_EPT
+#include "paging_tmpl.h"
+#undef PTTYPE
+
+#define PTTYPE 64
+#include "paging_tmpl.h"
+#undef PTTYPE
+
+#define PTTYPE 32
+#include "paging_tmpl.h"
+#undef PTTYPE
+
+static void __reset_rsvds_bits_mask(struct rsvd_bits_validate *rsvd_check,
+				    u64 pa_bits_rsvd, int level, bool nx,
+				    bool gbpages, bool pse, bool amd)
+{
+	u64 gbpages_bit_rsvd = 0;
+	u64 nonleaf_bit8_rsvd = 0;
+	u64 high_bits_rsvd;
+
+	rsvd_check->bad_mt_xwr = 0;
+
+	if (!gbpages)
+		gbpages_bit_rsvd = rsvd_bits(7, 7);
+
+	if (level == PT32E_ROOT_LEVEL)
+		high_bits_rsvd = pa_bits_rsvd & rsvd_bits(0, 62);
+	else
+		high_bits_rsvd = pa_bits_rsvd & rsvd_bits(0, 51);
+
+	/* Note, NX doesn't exist in PDPTEs, this is handled below. */
+	if (!nx)
+		high_bits_rsvd |= rsvd_bits(63, 63);
+
+	/*
+	 * Non-leaf PML4Es and PDPEs reserve bit 8 (which would be the G bit for
+	 * leaf entries) on AMD CPUs only.
+	 */
+	if (amd)
+		nonleaf_bit8_rsvd = rsvd_bits(8, 8);
+
+	switch (level) {
+	case PT32_ROOT_LEVEL:
+		/* no rsvd bits for 2 level 4K page table entries */
+		rsvd_check->rsvd_bits_mask[0][1] = 0;
+		rsvd_check->rsvd_bits_mask[0][0] = 0;
+		rsvd_check->rsvd_bits_mask[1][0] =
+			rsvd_check->rsvd_bits_mask[0][0];
+
+		if (!pse) {
+			rsvd_check->rsvd_bits_mask[1][1] = 0;
+			break;
+		}
+
+		if (is_cpuid_PSE36())
+			/* 36bits PSE 4MB page */
+			rsvd_check->rsvd_bits_mask[1][1] = rsvd_bits(17, 21);
+		else
+			/* 32 bits PSE 4MB page */
+			rsvd_check->rsvd_bits_mask[1][1] = rsvd_bits(13, 21);
+		break;
+	case PT32E_ROOT_LEVEL:
+		rsvd_check->rsvd_bits_mask[0][2] = rsvd_bits(63, 63) |
+						   high_bits_rsvd |
+						   rsvd_bits(5, 8) |
+						   rsvd_bits(1, 2);	/* PDPTE */
+		rsvd_check->rsvd_bits_mask[0][1] = high_bits_rsvd;	/* PDE */
+		rsvd_check->rsvd_bits_mask[0][0] = high_bits_rsvd;	/* PTE */
+		rsvd_check->rsvd_bits_mask[1][1] = high_bits_rsvd |
+						   rsvd_bits(13, 20);	/* large page */
+		rsvd_check->rsvd_bits_mask[1][0] =
+			rsvd_check->rsvd_bits_mask[0][0];
+		break;
+	case PT64_ROOT_5LEVEL:
+		rsvd_check->rsvd_bits_mask[0][4] = high_bits_rsvd |
+						   nonleaf_bit8_rsvd |
+						   rsvd_bits(7, 7);
+		rsvd_check->rsvd_bits_mask[1][4] =
+			rsvd_check->rsvd_bits_mask[0][4];
+		fallthrough;
+	case PT64_ROOT_4LEVEL:
+		rsvd_check->rsvd_bits_mask[0][3] = high_bits_rsvd |
+						   nonleaf_bit8_rsvd |
+						   rsvd_bits(7, 7);
+		rsvd_check->rsvd_bits_mask[0][2] = high_bits_rsvd |
+						   gbpages_bit_rsvd;
+		rsvd_check->rsvd_bits_mask[0][1] = high_bits_rsvd;
+		rsvd_check->rsvd_bits_mask[0][0] = high_bits_rsvd;
+		rsvd_check->rsvd_bits_mask[1][3] =
+			rsvd_check->rsvd_bits_mask[0][3];
+		rsvd_check->rsvd_bits_mask[1][2] = high_bits_rsvd |
+						   gbpages_bit_rsvd |
+						   rsvd_bits(13, 29);
+		rsvd_check->rsvd_bits_mask[1][1] = high_bits_rsvd |
+						   rsvd_bits(13, 20); /* large page */
+		rsvd_check->rsvd_bits_mask[1][0] =
+			rsvd_check->rsvd_bits_mask[0][0];
+		break;
+	}
+}
+
+static void reset_guest_rsvds_bits_mask(struct kvm_vcpu *vcpu,
+					struct kvm_mmu *context)
+{
+	__reset_rsvds_bits_mask(&context->guest_rsvd_check,
+				vcpu->arch.reserved_gpa_bits,
+				context->cpu_role.base.level, is_efer_nx(context),
+				guest_can_use(vcpu, X86_FEATURE_GBPAGES),
+				is_cr4_pse(context),
+				guest_cpuid_is_amd_or_hygon(vcpu));
+}
+
+static void __reset_rsvds_bits_mask_ept(struct rsvd_bits_validate *rsvd_check,
+					u64 pa_bits_rsvd, bool execonly,
+					int huge_page_level)
+{
+	u64 high_bits_rsvd = pa_bits_rsvd & rsvd_bits(0, 51);
+	u64 large_1g_rsvd = 0, large_2m_rsvd = 0;
+	u64 bad_mt_xwr;
+
+	if (huge_page_level < PG_LEVEL_1G)
+		large_1g_rsvd = rsvd_bits(7, 7);
+	if (huge_page_level < PG_LEVEL_2M)
+		large_2m_rsvd = rsvd_bits(7, 7);
+
+	rsvd_check->rsvd_bits_mask[0][4] = high_bits_rsvd | rsvd_bits(3, 7);
+	rsvd_check->rsvd_bits_mask[0][3] = high_bits_rsvd | rsvd_bits(3, 7);
+	rsvd_check->rsvd_bits_mask[0][2] = high_bits_rsvd | rsvd_bits(3, 6) | large_1g_rsvd;
+	rsvd_check->rsvd_bits_mask[0][1] = high_bits_rsvd | rsvd_bits(3, 6) | large_2m_rsvd;
+	rsvd_check->rsvd_bits_mask[0][0] = high_bits_rsvd;
+
+	/* large page */
+	rsvd_check->rsvd_bits_mask[1][4] = rsvd_check->rsvd_bits_mask[0][4];
+	rsvd_check->rsvd_bits_mask[1][3] = rsvd_check->rsvd_bits_mask[0][3];
+	rsvd_check->rsvd_bits_mask[1][2] = high_bits_rsvd | rsvd_bits(12, 29) | large_1g_rsvd;
+	rsvd_check->rsvd_bits_mask[1][1] = high_bits_rsvd | rsvd_bits(12, 20) | large_2m_rsvd;
+	rsvd_check->rsvd_bits_mask[1][0] = rsvd_check->rsvd_bits_mask[0][0];
+
+	bad_mt_xwr = 0xFFull << (2 * 8);	/* bits 3..5 must not be 2 */
+	bad_mt_xwr |= 0xFFull << (3 * 8);	/* bits 3..5 must not be 3 */
+	bad_mt_xwr |= 0xFFull << (7 * 8);	/* bits 3..5 must not be 7 */
+	bad_mt_xwr |= REPEAT_BYTE(1ull << 2);	/* bits 0..2 must not be 010 */
+	bad_mt_xwr |= REPEAT_BYTE(1ull << 6);	/* bits 0..2 must not be 110 */
+	if (!execonly) {
+		/* bits 0..2 must not be 100 unless VMX capabilities allow it */
+		bad_mt_xwr |= REPEAT_BYTE(1ull << 4);
+	}
+	rsvd_check->bad_mt_xwr = bad_mt_xwr;
+}
+
+static void reset_rsvds_bits_mask_ept(struct kvm_vcpu *vcpu,
+		struct kvm_mmu *context, bool execonly, int huge_page_level)
+{
+	__reset_rsvds_bits_mask_ept(&context->guest_rsvd_check,
+				    vcpu->arch.reserved_gpa_bits, execonly,
+				    huge_page_level);
+}
+
+static inline u64 reserved_hpa_bits(void)
+{
+	return rsvd_bits(shadow_phys_bits, 63);
+}
+
+/*
+ * the page table on host is the shadow page table for the page
+ * table in guest or amd nested guest, its mmu features completely
+ * follow the features in guest.
+ */
+static void reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
+					struct kvm_mmu *context)
+{
+	/* @amd adds a check on bit of SPTEs, which KVM shouldn't use anyways. */
+	bool is_amd = true;
+	/* KVM doesn't use 2-level page tables for the shadow MMU. */
+	bool is_pse = false;
+	struct rsvd_bits_validate *shadow_zero_check;
+	int i;
+
+	WARN_ON_ONCE(context->root_role.level < PT32E_ROOT_LEVEL);
+
+	shadow_zero_check = &context->shadow_zero_check;
+	__reset_rsvds_bits_mask(shadow_zero_check, reserved_hpa_bits(),
+				context->root_role.level,
+				context->root_role.efer_nx,
+				guest_can_use(vcpu, X86_FEATURE_GBPAGES),
+				is_pse, is_amd);
+
+	if (!shadow_me_mask)
+		return;
+
+	for (i = context->root_role.level; --i >= 0;) {
+		/*
+		 * So far shadow_me_value is a constant during KVM's life
+		 * time.  Bits in shadow_me_value are allowed to be set.
+		 * Bits in shadow_me_mask but not in shadow_me_value are
+		 * not allowed to be set.
+		 */
+		shadow_zero_check->rsvd_bits_mask[0][i] |= shadow_me_mask;
+		shadow_zero_check->rsvd_bits_mask[1][i] |= shadow_me_mask;
+		shadow_zero_check->rsvd_bits_mask[0][i] &= ~shadow_me_value;
+		shadow_zero_check->rsvd_bits_mask[1][i] &= ~shadow_me_value;
+	}
+
+}
+
+static inline bool boot_cpu_is_amd(void)
+{
+	WARN_ON_ONCE(!tdp_enabled);
+	return shadow_x_mask == 0;
+}
+
+/*
+ * the direct page table on host, use as much mmu features as
+ * possible, however, kvm currently does not do execution-protection.
+ */
+static void reset_tdp_shadow_zero_bits_mask(struct kvm_mmu *context)
+{
+	struct rsvd_bits_validate *shadow_zero_check;
+	int i;
+
+	shadow_zero_check = &context->shadow_zero_check;
+
+	if (boot_cpu_is_amd())
+		__reset_rsvds_bits_mask(shadow_zero_check, reserved_hpa_bits(),
+					context->root_role.level, true,
+					boot_cpu_has(X86_FEATURE_GBPAGES),
+					false, true);
+	else
+		__reset_rsvds_bits_mask_ept(shadow_zero_check,
+					    reserved_hpa_bits(), false,
+					    max_huge_page_level);
+
+	if (!shadow_me_mask)
+		return;
+
+	for (i = context->root_role.level; --i >= 0;) {
+		shadow_zero_check->rsvd_bits_mask[0][i] &= ~shadow_me_mask;
+		shadow_zero_check->rsvd_bits_mask[1][i] &= ~shadow_me_mask;
+	}
+}
+
+/*
+ * as the comments in reset_shadow_zero_bits_mask() except it
+ * is the shadow page table for intel nested guest.
+ */
+static void
+reset_ept_shadow_zero_bits_mask(struct kvm_mmu *context, bool execonly)
+{
+	__reset_rsvds_bits_mask_ept(&context->shadow_zero_check,
+				    reserved_hpa_bits(), execonly,
+				    max_huge_page_level);
+}
+
+#define BYTE_MASK(access) \
+	((1 & (access) ? 2 : 0) | \
+	 (2 & (access) ? 4 : 0) | \
+	 (3 & (access) ? 8 : 0) | \
+	 (4 & (access) ? 16 : 0) | \
+	 (5 & (access) ? 32 : 0) | \
+	 (6 & (access) ? 64 : 0) | \
+	 (7 & (access) ? 128 : 0))
+
+
+static void update_permission_bitmask(struct kvm_mmu *mmu, bool ept)
+{
+	unsigned byte;
+
+	const u8 x = BYTE_MASK(ACC_EXEC_MASK);
+	const u8 w = BYTE_MASK(ACC_WRITE_MASK);
+	const u8 u = BYTE_MASK(ACC_USER_MASK);
+
+	bool cr4_smep = is_cr4_smep(mmu);
+	bool cr4_smap = is_cr4_smap(mmu);
+	bool cr0_wp = is_cr0_wp(mmu);
+	bool efer_nx = is_efer_nx(mmu);
+
+	for (byte = 0; byte < ARRAY_SIZE(mmu->permissions); ++byte) {
+		unsigned pfec = byte << 1;
+
+		/*
+		 * Each "*f" variable has a 1 bit for each UWX value
+		 * that causes a fault with the given PFEC.
+		 */
+
+		/* Faults from writes to non-writable pages */
+		u8 wf = (pfec & PFERR_WRITE_MASK) ? (u8)~w : 0;
+		/* Faults from user mode accesses to supervisor pages */
+		u8 uf = (pfec & PFERR_USER_MASK) ? (u8)~u : 0;
+		/* Faults from fetches of non-executable pages*/
+		u8 ff = (pfec & PFERR_FETCH_MASK) ? (u8)~x : 0;
+		/* Faults from kernel mode fetches of user pages */
+		u8 smepf = 0;
+		/* Faults from kernel mode accesses of user pages */
+		u8 smapf = 0;
+
+		if (!ept) {
+			/* Faults from kernel mode accesses to user pages */
+			u8 kf = (pfec & PFERR_USER_MASK) ? 0 : u;
+
+			/* Not really needed: !nx will cause pte.nx to fault */
+			if (!efer_nx)
+				ff = 0;
+
+			/* Allow supervisor writes if !cr0.wp */
+			if (!cr0_wp)
+				wf = (pfec & PFERR_USER_MASK) ? wf : 0;
+
+			/* Disallow supervisor fetches of user code if cr4.smep */
+			if (cr4_smep)
+				smepf = (pfec & PFERR_FETCH_MASK) ? kf : 0;
+
+			/*
+			 * SMAP:kernel-mode data accesses from user-mode
+			 * mappings should fault. A fault is considered
+			 * as a SMAP violation if all of the following
+			 * conditions are true:
+			 *   - X86_CR4_SMAP is set in CR4
+			 *   - A user page is accessed
+			 *   - The access is not a fetch
+			 *   - The access is supervisor mode
+			 *   - If implicit supervisor access or X86_EFLAGS_AC is clear
+			 *
+			 * Here, we cover the first four conditions.
+			 * The fifth is computed dynamically in permission_fault();
+			 * PFERR_RSVD_MASK bit will be set in PFEC if the access is
+			 * *not* subject to SMAP restrictions.
+			 */
+			if (cr4_smap)
+				smapf = (pfec & (PFERR_RSVD_MASK|PFERR_FETCH_MASK)) ? 0 : kf;
+		}
+
+		mmu->permissions[byte] = ff | uf | wf | smepf | smapf;
+	}
+}
+
+/*
+* PKU is an additional mechanism by which the paging controls access to
+* user-mode addresses based on the value in the PKRU register.  Protection
+* key violations are reported through a bit in the page fault error code.
+* Unlike other bits of the error code, the PK bit is not known at the
+* call site of e.g. gva_to_gpa; it must be computed directly in
+* permission_fault based on two bits of PKRU, on some machine state (CR4,
+* CR0, EFER, CPL), and on other bits of the error code and the page tables.
+*
+* In particular the following conditions come from the error code, the
+* page tables and the machine state:
+* - PK is always zero unless CR4.PKE=1 and EFER.LMA=1
+* - PK is always zero if RSVD=1 (reserved bit set) or F=1 (instruction fetch)
+* - PK is always zero if U=0 in the page tables
+* - PKRU.WD is ignored if CR0.WP=0 and the access is a supervisor access.
+*
+* The PKRU bitmask caches the result of these four conditions.  The error
+* code (minus the P bit) and the page table's U bit form an index into the
+* PKRU bitmask.  Two bits of the PKRU bitmask are then extracted and ANDed
+* with the two bits of the PKRU register corresponding to the protection key.
+* For the first three conditions above the bits will be 00, thus masking
+* away both AD and WD.  For all reads or if the last condition holds, WD
+* only will be masked away.
+*/
+static void update_pkru_bitmask(struct kvm_mmu *mmu)
+{
+	unsigned bit;
+	bool wp;
+
+	mmu->pkru_mask = 0;
+
+	if (!is_cr4_pke(mmu))
+		return;
+
+	wp = is_cr0_wp(mmu);
+
+	for (bit = 0; bit < ARRAY_SIZE(mmu->permissions); ++bit) {
+		unsigned pfec, pkey_bits;
+		bool check_pkey, check_write, ff, uf, wf, pte_user;
+
+		pfec = bit << 1;
+		ff = pfec & PFERR_FETCH_MASK;
+		uf = pfec & PFERR_USER_MASK;
+		wf = pfec & PFERR_WRITE_MASK;
+
+		/* PFEC.RSVD is replaced by ACC_USER_MASK. */
+		pte_user = pfec & PFERR_RSVD_MASK;
+
+		/*
+		 * Only need to check the access which is not an
+		 * instruction fetch and is to a user page.
+		 */
+		check_pkey = (!ff && pte_user);
+		/*
+		 * write access is controlled by PKRU if it is a
+		 * user access or CR0.WP = 1.
+		 */
+		check_write = check_pkey && wf && (uf || wp);
+
+		/* PKRU.AD stops both read and write access. */
+		pkey_bits = !!check_pkey;
+		/* PKRU.WD stops write access. */
+		pkey_bits |= (!!check_write) << 1;
+
+		mmu->pkru_mask |= (pkey_bits & 3) << pfec;
+	}
+}
+
+static void reset_guest_paging_metadata(struct kvm_vcpu *vcpu,
+					struct kvm_mmu *mmu)
+{
+	if (!is_cr0_pg(mmu))
+		return;
+
+	reset_guest_rsvds_bits_mask(vcpu, mmu);
+	update_permission_bitmask(mmu, false);
+	update_pkru_bitmask(mmu);
+}
+
+static void paging64_init_context(struct kvm_mmu *context)
+{
+	context->page_fault = paging64_page_fault;
+	context->gva_to_gpa = paging64_gva_to_gpa;
+	context->sync_spte = paging64_sync_spte;
+}
+
+static void paging32_init_context(struct kvm_mmu *context)
+{
+	context->page_fault = paging32_page_fault;
+	context->gva_to_gpa = paging32_gva_to_gpa;
+	context->sync_spte = paging32_sync_spte;
+}
+
+static union kvm_cpu_role kvm_calc_cpu_role(struct kvm_vcpu *vcpu,
+					    const struct kvm_mmu_role_regs *regs)
+{
+	union kvm_cpu_role role = {0};
+
+	role.base.access = ACC_ALL;
+	role.base.smm = is_smm(vcpu);
+	role.base.guest_mode = is_guest_mode(vcpu);
+	role.ext.valid = 1;
+
+	if (!____is_cr0_pg(regs)) {
+		role.base.direct = 1;
+		return role;
+	}
+
+	role.base.efer_nx = ____is_efer_nx(regs);
+	role.base.cr0_wp = ____is_cr0_wp(regs);
+	role.base.smep_andnot_wp = ____is_cr4_smep(regs) && !____is_cr0_wp(regs);
+	role.base.smap_andnot_wp = ____is_cr4_smap(regs) && !____is_cr0_wp(regs);
+	role.base.has_4_byte_gpte = !____is_cr4_pae(regs);
+
+	if (____is_efer_lma(regs))
+		role.base.level = ____is_cr4_la57(regs) ? PT64_ROOT_5LEVEL
+							: PT64_ROOT_4LEVEL;
+	else if (____is_cr4_pae(regs))
+		role.base.level = PT32E_ROOT_LEVEL;
+	else
+		role.base.level = PT32_ROOT_LEVEL;
+
+	role.ext.cr4_smep = ____is_cr4_smep(regs);
+	role.ext.cr4_smap = ____is_cr4_smap(regs);
+	role.ext.cr4_pse = ____is_cr4_pse(regs);
+
+	/* PKEY and LA57 are active iff long mode is active. */
+	role.ext.cr4_pke = ____is_efer_lma(regs) && ____is_cr4_pke(regs);
+	role.ext.cr4_la57 = ____is_efer_lma(regs) && ____is_cr4_la57(regs);
+	role.ext.efer_lma = ____is_efer_lma(regs);
+	return role;
+}
+
+void __kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu,
+					struct kvm_mmu *mmu)
+{
+	const bool cr0_wp = kvm_is_cr0_bit_set(vcpu, X86_CR0_WP);
+
+	BUILD_BUG_ON((KVM_MMU_CR0_ROLE_BITS & KVM_POSSIBLE_CR0_GUEST_BITS) != X86_CR0_WP);
+	BUILD_BUG_ON((KVM_MMU_CR4_ROLE_BITS & KVM_POSSIBLE_CR4_GUEST_BITS));
+
+	if (is_cr0_wp(mmu) == cr0_wp)
+		return;
+
+	mmu->cpu_role.base.cr0_wp = cr0_wp;
+	reset_guest_paging_metadata(vcpu, mmu);
+}
+
+static inline int kvm_mmu_get_tdp_level(struct kvm_vcpu *vcpu)
+{
+	/* tdp_root_level is architecture forced level, use it if nonzero */
+	if (tdp_root_level)
+		return tdp_root_level;
+
+	/* Use 5-level TDP if and only if it's useful/necessary. */
+	if (max_tdp_level == 5 && cpuid_maxphyaddr(vcpu) <= 48)
+		return 4;
+
+	return max_tdp_level;
+}
+
+static union kvm_mmu_page_role
+kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu,
+				union kvm_cpu_role cpu_role)
+{
+	union kvm_mmu_page_role role = {0};
+
+	role.access = ACC_ALL;
+	role.cr0_wp = true;
+	role.efer_nx = true;
+	role.smm = cpu_role.base.smm;
+	role.guest_mode = cpu_role.base.guest_mode;
+	role.ad_disabled = !kvm_ad_enabled();
+	role.level = kvm_mmu_get_tdp_level(vcpu);
+	role.direct = true;
+	role.has_4_byte_gpte = false;
+
+	return role;
+}
+
+static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu,
+			     union kvm_cpu_role cpu_role)
+{
+	struct kvm_mmu *context = &vcpu->arch.root_mmu;
+	union kvm_mmu_page_role root_role = kvm_calc_tdp_mmu_root_page_role(vcpu, cpu_role);
+
+	if (cpu_role.as_u64 == context->cpu_role.as_u64 &&
+	    root_role.word == context->root_role.word)
+		return;
+
+	context->cpu_role.as_u64 = cpu_role.as_u64;
+	context->root_role.word = root_role.word;
+	context->page_fault = kvm_tdp_page_fault;
+	context->sync_spte = NULL;
+	context->get_guest_pgd = get_guest_cr3;
+	context->get_pdptr = kvm_pdptr_read;
+	context->inject_page_fault = kvm_inject_page_fault;
+
+	if (!is_cr0_pg(context))
+		context->gva_to_gpa = nonpaging_gva_to_gpa;
+	else if (is_cr4_pae(context))
+		context->gva_to_gpa = paging64_gva_to_gpa;
+	else
+		context->gva_to_gpa = paging32_gva_to_gpa;
+
+	reset_guest_paging_metadata(vcpu, context);
+	reset_tdp_shadow_zero_bits_mask(context);
+}
+
+static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
+				    union kvm_cpu_role cpu_role,
+				    union kvm_mmu_page_role root_role)
+{
+	if (cpu_role.as_u64 == context->cpu_role.as_u64 &&
+	    root_role.word == context->root_role.word)
+		return;
+
+	context->cpu_role.as_u64 = cpu_role.as_u64;
+	context->root_role.word = root_role.word;
+
+	if (!is_cr0_pg(context))
+		nonpaging_init_context(context);
+	else if (is_cr4_pae(context))
+		paging64_init_context(context);
+	else
+		paging32_init_context(context);
+
+	reset_guest_paging_metadata(vcpu, context);
+	reset_shadow_zero_bits_mask(vcpu, context);
+}
+
+static void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu,
+				union kvm_cpu_role cpu_role)
+{
+	struct kvm_mmu *context = &vcpu->arch.root_mmu;
+	union kvm_mmu_page_role root_role;
+
+	root_role = cpu_role.base;
+
+	/* KVM uses PAE paging whenever the guest isn't using 64-bit paging. */
+	root_role.level = max_t(u32, root_role.level, PT32E_ROOT_LEVEL);
+
+	/*
+	 * KVM forces EFER.NX=1 when TDP is disabled, reflect it in the MMU role.
+	 * KVM uses NX when TDP is disabled to handle a variety of scenarios,
+	 * notably for huge SPTEs if iTLB multi-hit mitigation is enabled and
+	 * to generate correct permissions for CR0.WP=0/CR4.SMEP=1/EFER.NX=0.
+	 * The iTLB multi-hit workaround can be toggled at any time, so assume
+	 * NX can be used by any non-nested shadow MMU to avoid having to reset
+	 * MMU contexts.
+	 */
+	root_role.efer_nx = true;
+
+	shadow_mmu_init_context(vcpu, context, cpu_role, root_role);
+}
+
+void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
+			     unsigned long cr4, u64 efer, gpa_t nested_cr3)
+{
+	struct kvm_mmu *context = &vcpu->arch.guest_mmu;
+	struct kvm_mmu_role_regs regs = {
+		.cr0 = cr0,
+		.cr4 = cr4 & ~X86_CR4_PKE,
+		.efer = efer,
+	};
+	union kvm_cpu_role cpu_role = kvm_calc_cpu_role(vcpu, &regs);
+	union kvm_mmu_page_role root_role;
+
+	/* NPT requires CR0.PG=1. */
+	WARN_ON_ONCE(cpu_role.base.direct);
+
+	root_role = cpu_role.base;
+	root_role.level = kvm_mmu_get_tdp_level(vcpu);
+	if (root_role.level == PT64_ROOT_5LEVEL &&
+	    cpu_role.base.level == PT64_ROOT_4LEVEL)
+		root_role.passthrough = 1;
+
+	shadow_mmu_init_context(vcpu, context, cpu_role, root_role);
+	kvm_mmu_new_pgd(vcpu, nested_cr3);
+}
+EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);
+
+static union kvm_cpu_role
+kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty,
+				   bool execonly, u8 level)
+{
+	union kvm_cpu_role role = {0};
+
+	/*
+	 * KVM does not support SMM transfer monitors, and consequently does not
+	 * support the "entry to SMM" control either.  role.base.smm is always 0.
+	 */
+	WARN_ON_ONCE(is_smm(vcpu));
+	role.base.level = level;
+	role.base.has_4_byte_gpte = false;
+	role.base.direct = false;
+	role.base.ad_disabled = !accessed_dirty;
+	role.base.guest_mode = true;
+	role.base.access = ACC_ALL;
+
+	role.ext.word = 0;
+	role.ext.execonly = execonly;
+	role.ext.valid = 1;
+
+	return role;
+}
+
+void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
+			     int huge_page_level, bool accessed_dirty,
+			     gpa_t new_eptp)
+{
+	struct kvm_mmu *context = &vcpu->arch.guest_mmu;
+	u8 level = vmx_eptp_page_walk_level(new_eptp);
+	union kvm_cpu_role new_mode =
+		kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty,
+						   execonly, level);
+
+	if (new_mode.as_u64 != context->cpu_role.as_u64) {
+		/* EPT, and thus nested EPT, does not consume CR0, CR4, nor EFER. */
+		context->cpu_role.as_u64 = new_mode.as_u64;
+		context->root_role.word = new_mode.base.word;
+
+		context->page_fault = ept_page_fault;
+		context->gva_to_gpa = ept_gva_to_gpa;
+		context->sync_spte = ept_sync_spte;
+
+		update_permission_bitmask(context, true);
+		context->pkru_mask = 0;
+		reset_rsvds_bits_mask_ept(vcpu, context, execonly, huge_page_level);
+		reset_ept_shadow_zero_bits_mask(context, execonly);
+	}
+
+	kvm_mmu_new_pgd(vcpu, new_eptp);
+}
+EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);
+
+static void init_kvm_softmmu(struct kvm_vcpu *vcpu,
+			     union kvm_cpu_role cpu_role)
+{
+	struct kvm_mmu *context = &vcpu->arch.root_mmu;
+
+	kvm_init_shadow_mmu(vcpu, cpu_role);
+
+	context->get_guest_pgd     = get_guest_cr3;
+	context->get_pdptr         = kvm_pdptr_read;
+	context->inject_page_fault = kvm_inject_page_fault;
+}
+
+static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu,
+				union kvm_cpu_role new_mode)
+{
+	struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;
+
+	if (new_mode.as_u64 == g_context->cpu_role.as_u64)
+		return;
+
+	g_context->cpu_role.as_u64   = new_mode.as_u64;
+	g_context->get_guest_pgd     = get_guest_cr3;
+	g_context->get_pdptr         = kvm_pdptr_read;
+	g_context->inject_page_fault = kvm_inject_page_fault;
+
+	/*
+	 * L2 page tables are never shadowed, so there is no need to sync
+	 * SPTEs.
+	 */
+	g_context->sync_spte         = NULL;
+
+	/*
+	 * Note that arch.mmu->gva_to_gpa translates l2_gpa to l1_gpa using
+	 * L1's nested page tables (e.g. EPT12). The nested translation
+	 * of l2_gva to l1_gpa is done by arch.nested_mmu.gva_to_gpa using
+	 * L2's page tables as the first level of translation and L1's
+	 * nested page tables as the second level of translation. Basically
+	 * the gva_to_gpa functions between mmu and nested_mmu are swapped.
+	 */
+	if (!is_paging(vcpu))
+		g_context->gva_to_gpa = nonpaging_gva_to_gpa;
+	else if (is_long_mode(vcpu))
+		g_context->gva_to_gpa = paging64_gva_to_gpa;
+	else if (is_pae(vcpu))
+		g_context->gva_to_gpa = paging64_gva_to_gpa;
+	else
+		g_context->gva_to_gpa = paging32_gva_to_gpa;
+
+	reset_guest_paging_metadata(vcpu, g_context);
+}
+
+void kvm_init_mmu(struct kvm_vcpu *vcpu)
+{
+	struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
+	union kvm_cpu_role cpu_role = kvm_calc_cpu_role(vcpu, &regs);
+
+	if (mmu_is_nested(vcpu))
+		init_kvm_nested_mmu(vcpu, cpu_role);
+	else if (tdp_enabled)
+		init_kvm_tdp_mmu(vcpu, cpu_role);
+	else
+		init_kvm_softmmu(vcpu, cpu_role);
+}
+EXPORT_SYMBOL_GPL(kvm_init_mmu);
+
+void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * Invalidate all MMU roles to force them to reinitialize as CPUID
+	 * information is factored into reserved bit calculations.
+	 *
+	 * Correctly handling multiple vCPU models with respect to paging and
+	 * physical address properties) in a single VM would require tracking
+	 * all relevant CPUID information in kvm_mmu_page_role. That is very
+	 * undesirable as it would increase the memory requirements for
+	 * gfn_write_track (see struct kvm_mmu_page_role comments).  For now
+	 * that problem is swept under the rug; KVM's CPUID API is horrific and
+	 * it's all but impossible to solve it without introducing a new API.
+	 */
+	vcpu->arch.root_mmu.root_role.word = 0;
+	vcpu->arch.guest_mmu.root_role.word = 0;
+	vcpu->arch.nested_mmu.root_role.word = 0;
+	vcpu->arch.root_mmu.cpu_role.ext.valid = 0;
+	vcpu->arch.guest_mmu.cpu_role.ext.valid = 0;
+	vcpu->arch.nested_mmu.cpu_role.ext.valid = 0;
+	kvm_mmu_reset_context(vcpu);
+
+	/*
+	 * Changing guest CPUID after KVM_RUN is forbidden, see the comment in
+	 * kvm_arch_vcpu_ioctl().
+	 */
+	KVM_BUG_ON(kvm_vcpu_has_run(vcpu), vcpu->kvm);
+}
+
+void kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
+{
+	kvm_mmu_unload(vcpu);
+	kvm_init_mmu(vcpu);
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
+
+int kvm_mmu_load(struct kvm_vcpu *vcpu)
+{
+	int r;
+
+	r = mmu_topup_memory_caches(vcpu, !vcpu->arch.mmu->root_role.direct);
+	if (r)
+		goto out;
+	r = mmu_alloc_special_roots(vcpu);
+	if (r)
+		goto out;
+	if (vcpu->arch.mmu->root_role.direct)
+		r = mmu_alloc_direct_roots(vcpu);
+	else
+		r = mmu_alloc_shadow_roots(vcpu);
+	if (r)
+		goto out;
+
+	kvm_mmu_sync_roots(vcpu);
+
+	kvm_mmu_load_pgd(vcpu);
+
+	/*
+	 * Flush any TLB entries for the new root, the provenance of the root
+	 * is unknown.  Even if KVM ensures there are no stale TLB entries
+	 * for a freed root, in theory another hypervisor could have left
+	 * stale entries.  Flushing on alloc also allows KVM to skip the TLB
+	 * flush when freeing a root (see kvm_tdp_mmu_put_root()).
+	 */
+	static_call(kvm_x86_flush_tlb_current)(vcpu);
+out:
+	return r;
+}
+
+void kvm_mmu_unload(struct kvm_vcpu *vcpu)
+{
+	struct kvm *kvm = vcpu->kvm;
+
+	kvm_mmu_free_roots(kvm, &vcpu->arch.root_mmu, KVM_MMU_ROOTS_ALL);
+	WARN_ON_ONCE(VALID_PAGE(vcpu->arch.root_mmu.root.hpa));
+	kvm_mmu_free_roots(kvm, &vcpu->arch.guest_mmu, KVM_MMU_ROOTS_ALL);
+	WARN_ON_ONCE(VALID_PAGE(vcpu->arch.guest_mmu.root.hpa));
+	vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
+}
+
+static bool is_obsolete_root(struct kvm *kvm, hpa_t root_hpa)
+{
+	struct kvm_mmu_page *sp;
+
+	if (!VALID_PAGE(root_hpa))
+		return false;
+
+	/*
+	 * When freeing obsolete roots, treat roots as obsolete if they don't
+	 * have an associated shadow page, as it's impossible to determine if
+	 * such roots are fresh or stale.  This does mean KVM will get false
+	 * positives and free roots that don't strictly need to be freed, but
+	 * such false positives are relatively rare:
+	 *
+	 *  (a) only PAE paging and nested NPT have roots without shadow pages
+	 *      (or any shadow paging flavor with a dummy root, see note below)
+	 *  (b) remote reloads due to a memslot update obsoletes _all_ roots
+	 *  (c) KVM doesn't track previous roots for PAE paging, and the guest
+	 *      is unlikely to zap an in-use PGD.
+	 *
+	 * Note!  Dummy roots are unique in that they are obsoleted by memslot
+	 * _creation_!  See also FNAME(fetch).
+	 */
+	sp = root_to_sp(root_hpa);
+	return !sp || is_obsolete_sp(kvm, sp);
+}
+
+static void __kvm_mmu_free_obsolete_roots(struct kvm *kvm, struct kvm_mmu *mmu)
+{
+	unsigned long roots_to_free = 0;
+	int i;
+
+	if (is_obsolete_root(kvm, mmu->root.hpa))
+		roots_to_free |= KVM_MMU_ROOT_CURRENT;
+
+	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
+		if (is_obsolete_root(kvm, mmu->prev_roots[i].hpa))
+			roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
+	}
+
+	if (roots_to_free)
+		kvm_mmu_free_roots(kvm, mmu, roots_to_free);
+}
+
+void kvm_mmu_free_obsolete_roots(struct kvm_vcpu *vcpu)
+{
+	__kvm_mmu_free_obsolete_roots(vcpu->kvm, &vcpu->arch.root_mmu);
+	__kvm_mmu_free_obsolete_roots(vcpu->kvm, &vcpu->arch.guest_mmu);
+}
+
+static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
+				    int *bytes)
+{
+	u64 gentry = 0;
+	int r;
+
+	/*
+	 * Assume that the pte write on a page table of the same type
+	 * as the current vcpu paging mode since we update the sptes only
+	 * when they have the same mode.
+	 */
+	if (is_pae(vcpu) && *bytes == 4) {
+		/* Handle a 32-bit guest writing two halves of a 64-bit gpte */
+		*gpa &= ~(gpa_t)7;
+		*bytes = 8;
+	}
+
+	if (*bytes == 4 || *bytes == 8) {
+		r = kvm_vcpu_read_guest_atomic(vcpu, *gpa, &gentry, *bytes);
+		if (r)
+			gentry = 0;
+	}
+
+	return gentry;
+}
+
+/*
+ * If we're seeing too many writes to a page, it may no longer be a page table,
+ * or we may be forking, in which case it is better to unmap the page.
+ */
+static bool detect_write_flooding(struct kvm_mmu_page *sp)
+{
+	/*
+	 * Skip write-flooding detected for the sp whose level is 1, because
+	 * it can become unsync, then the guest page is not write-protected.
+	 */
+	if (sp->role.level == PG_LEVEL_4K)
+		return false;
+
+	atomic_inc(&sp->write_flooding_count);
+	return atomic_read(&sp->write_flooding_count) >= 3;
+}
+
+/*
+ * Misaligned accesses are too much trouble to fix up; also, they usually
+ * indicate a page is not used as a page table.
+ */
+static bool detect_write_misaligned(struct kvm_mmu_page *sp, gpa_t gpa,
+				    int bytes)
+{
+	unsigned offset, pte_size, misaligned;
+
+	offset = offset_in_page(gpa);
+	pte_size = sp->role.has_4_byte_gpte ? 4 : 8;
+
+	/*
+	 * Sometimes, the OS only writes the last one bytes to update status
+	 * bits, for example, in linux, andb instruction is used in clear_bit().
+	 */
+	if (!(offset & (pte_size - 1)) && bytes == 1)
+		return false;
+
+	misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
+	misaligned |= bytes < 4;
+
+	return misaligned;
+}
+
+static u64 *get_written_sptes(struct kvm_mmu_page *sp, gpa_t gpa, int *nspte)
+{
+	unsigned page_offset, quadrant;
+	u64 *spte;
+	int level;
+
+	page_offset = offset_in_page(gpa);
+	level = sp->role.level;
+	*nspte = 1;
+	if (sp->role.has_4_byte_gpte) {
+		page_offset <<= 1;	/* 32->64 */
+		/*
+		 * A 32-bit pde maps 4MB while the shadow pdes map
+		 * only 2MB.  So we need to double the offset again
+		 * and zap two pdes instead of one.
+		 */
+		if (level == PT32_ROOT_LEVEL) {
+			page_offset &= ~7; /* kill rounding error */
+			page_offset <<= 1;
+			*nspte = 2;
+		}
+		quadrant = page_offset >> PAGE_SHIFT;
+		page_offset &= ~PAGE_MASK;
+		if (quadrant != sp->role.quadrant)
+			return NULL;
+	}
+
+	spte = &sp->spt[page_offset / sizeof(*spte)];
+	return spte;
+}
+
+void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
+			 int bytes)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	struct kvm_mmu_page *sp;
+	LIST_HEAD(invalid_list);
+	u64 entry, gentry, *spte;
+	int npte;
+	bool flush = false;
+
+	/*
+	 * If we don't have indirect shadow pages, it means no page is
+	 * write-protected, so we can exit simply.
+	 */
+	if (!READ_ONCE(vcpu->kvm->arch.indirect_shadow_pages))
+		return;
+
+	write_lock(&vcpu->kvm->mmu_lock);
+
+	gentry = mmu_pte_write_fetch_gpte(vcpu, &gpa, &bytes);
+
+	++vcpu->kvm->stat.mmu_pte_write;
+
+	for_each_gfn_valid_sp_with_gptes(vcpu->kvm, sp, gfn) {
+		if (detect_write_misaligned(sp, gpa, bytes) ||
+		      detect_write_flooding(sp)) {
+			kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
+			++vcpu->kvm->stat.mmu_flooded;
+			continue;
+		}
+
+		spte = get_written_sptes(sp, gpa, &npte);
+		if (!spte)
+			continue;
+
+		while (npte--) {
+			entry = *spte;
+			mmu_page_zap_pte(vcpu->kvm, sp, spte, NULL);
+			if (gentry && sp->role.level != PG_LEVEL_4K)
+				++vcpu->kvm->stat.mmu_pde_zapped;
+			if (is_shadow_present_pte(entry))
+				flush = true;
+			++spte;
+		}
+	}
+	kvm_mmu_remote_flush_or_zap(vcpu->kvm, &invalid_list, flush);
+	write_unlock(&vcpu->kvm->mmu_lock);
+}
+
+int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code,
+		       void *insn, int insn_len)
+{
+	int r, emulation_type = EMULTYPE_PF;
+	bool direct = vcpu->arch.mmu->root_role.direct;
+
+	/*
+	 * IMPLICIT_ACCESS is a KVM-defined flag used to correctly perform SMAP
+	 * checks when emulating instructions that triggers implicit access.
+	 * WARN if hardware generates a fault with an error code that collides
+	 * with the KVM-defined value.  Clear the flag and continue on, i.e.
+	 * don't terminate the VM, as KVM can't possibly be relying on a flag
+	 * that KVM doesn't know about.
+	 */
+	if (WARN_ON_ONCE(error_code & PFERR_IMPLICIT_ACCESS))
+		error_code &= ~PFERR_IMPLICIT_ACCESS;
+
+	if (WARN_ON_ONCE(!VALID_PAGE(vcpu->arch.mmu->root.hpa)))
+		return RET_PF_RETRY;
+
+	r = RET_PF_INVALID;
+	if (unlikely(error_code & PFERR_RSVD_MASK)) {
+		r = handle_mmio_page_fault(vcpu, cr2_or_gpa, direct);
+		if (r == RET_PF_EMULATE)
+			goto emulate;
+	}
+
+	if (r == RET_PF_INVALID) {
+		r = kvm_mmu_do_page_fault(vcpu, cr2_or_gpa,
+					  lower_32_bits(error_code), false,
+					  &emulation_type);
+		if (KVM_BUG_ON(r == RET_PF_INVALID, vcpu->kvm))
+			return -EIO;
+	}
+
+	if (r < 0)
+		return r;
+	if (r != RET_PF_EMULATE)
+		return 1;
+
+	/*
+	 * Before emulating the instruction, check if the error code
+	 * was due to a RO violation while translating the guest page.
+	 * This can occur when using nested virtualization with nested
+	 * paging in both guests. If true, we simply unprotect the page
+	 * and resume the guest.
+	 */
+	if (vcpu->arch.mmu->root_role.direct &&
+	    (error_code & PFERR_NESTED_GUEST_PAGE) == PFERR_NESTED_GUEST_PAGE) {
+		kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(cr2_or_gpa));
+		return 1;
+	}
+
+	/*
+	 * vcpu->arch.mmu.page_fault returned RET_PF_EMULATE, but we can still
+	 * optimistically try to just unprotect the page and let the processor
+	 * re-execute the instruction that caused the page fault.  Do not allow
+	 * retrying MMIO emulation, as it's not only pointless but could also
+	 * cause us to enter an infinite loop because the processor will keep
+	 * faulting on the non-existent MMIO address.  Retrying an instruction
+	 * from a nested guest is also pointless and dangerous as we are only
+	 * explicitly shadowing L1's page tables, i.e. unprotecting something
+	 * for L1 isn't going to magically fix whatever issue cause L2 to fail.
+	 */
+	if (!mmio_info_in_cache(vcpu, cr2_or_gpa, direct) && !is_guest_mode(vcpu))
+		emulation_type |= EMULTYPE_ALLOW_RETRY_PF;
+emulate:
+	return x86_emulate_instruction(vcpu, cr2_or_gpa, emulation_type, insn,
+				       insn_len);
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
+
+static void __kvm_mmu_invalidate_addr(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+				      u64 addr, hpa_t root_hpa)
+{
+	struct kvm_shadow_walk_iterator iterator;
+
+	vcpu_clear_mmio_info(vcpu, addr);
+
+	/*
+	 * Walking and synchronizing SPTEs both assume they are operating in
+	 * the context of the current MMU, and would need to be reworked if
+	 * this is ever used to sync the guest_mmu, e.g. to emulate INVEPT.
+	 */
+	if (WARN_ON_ONCE(mmu != vcpu->arch.mmu))
+		return;
+
+	if (!VALID_PAGE(root_hpa))
+		return;
+
+	write_lock(&vcpu->kvm->mmu_lock);
+	for_each_shadow_entry_using_root(vcpu, root_hpa, addr, iterator) {
+		struct kvm_mmu_page *sp = sptep_to_sp(iterator.sptep);
+
+		if (sp->unsync) {
+			int ret = kvm_sync_spte(vcpu, sp, iterator.index);
+
+			if (ret < 0)
+				mmu_page_zap_pte(vcpu->kvm, sp, iterator.sptep, NULL);
+			if (ret)
+				kvm_flush_remote_tlbs_sptep(vcpu->kvm, iterator.sptep);
+		}
+
+		if (!sp->unsync_children)
+			break;
+	}
+	write_unlock(&vcpu->kvm->mmu_lock);
+}
+
+void kvm_mmu_invalidate_addr(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+			     u64 addr, unsigned long roots)
+{
+	int i;
+
+	WARN_ON_ONCE(roots & ~KVM_MMU_ROOTS_ALL);
+
+	/* It's actually a GPA for vcpu->arch.guest_mmu.  */
+	if (mmu != &vcpu->arch.guest_mmu) {
+		/* INVLPG on a non-canonical address is a NOP according to the SDM.  */
+		if (is_noncanonical_address(addr, vcpu))
+			return;
+
+		static_call(kvm_x86_flush_tlb_gva)(vcpu, addr);
+	}
+
+	if (!mmu->sync_spte)
+		return;
+
+	if (roots & KVM_MMU_ROOT_CURRENT)
+		__kvm_mmu_invalidate_addr(vcpu, mmu, addr, mmu->root.hpa);
+
+	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
+		if (roots & KVM_MMU_ROOT_PREVIOUS(i))
+			__kvm_mmu_invalidate_addr(vcpu, mmu, addr, mmu->prev_roots[i].hpa);
+	}
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_invalidate_addr);
+
+void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
+{
+	/*
+	 * INVLPG is required to invalidate any global mappings for the VA,
+	 * irrespective of PCID.  Blindly sync all roots as it would take
+	 * roughly the same amount of work/time to determine whether any of the
+	 * previous roots have a global mapping.
+	 *
+	 * Mappings not reachable via the current or previous cached roots will
+	 * be synced when switching to that new cr3, so nothing needs to be
+	 * done here for them.
+	 */
+	kvm_mmu_invalidate_addr(vcpu, vcpu->arch.walk_mmu, gva, KVM_MMU_ROOTS_ALL);
+	++vcpu->stat.invlpg;
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
+
+
+void kvm_mmu_invpcid_gva(struct kvm_vcpu *vcpu, gva_t gva, unsigned long pcid)
+{
+	struct kvm_mmu *mmu = vcpu->arch.mmu;
+	unsigned long roots = 0;
+	uint i;
+
+	if (pcid == kvm_get_active_pcid(vcpu))
+		roots |= KVM_MMU_ROOT_CURRENT;
+
+	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
+		if (VALID_PAGE(mmu->prev_roots[i].hpa) &&
+		    pcid == kvm_get_pcid(vcpu, mmu->prev_roots[i].pgd))
+			roots |= KVM_MMU_ROOT_PREVIOUS(i);
+	}
+
+	if (roots)
+		kvm_mmu_invalidate_addr(vcpu, mmu, gva, roots);
+	++vcpu->stat.invlpg;
+
+	/*
+	 * Mappings not reachable via the current cr3 or the prev_roots will be
+	 * synced when switching to that cr3, so nothing needs to be done here
+	 * for them.
+	 */
+}
+
+void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level,
+		       int tdp_max_root_level, int tdp_huge_page_level)
+{
+	tdp_enabled = enable_tdp;
+	tdp_root_level = tdp_forced_root_level;
+	max_tdp_level = tdp_max_root_level;
+
+#ifdef CONFIG_X86_64
+	tdp_mmu_enabled = tdp_mmu_allowed && tdp_enabled;
+#endif
+	/*
+	 * max_huge_page_level reflects KVM's MMU capabilities irrespective
+	 * of kernel support, e.g. KVM may be capable of using 1GB pages when
+	 * the kernel is not.  But, KVM never creates a page size greater than
+	 * what is used by the kernel for any given HVA, i.e. the kernel's
+	 * capabilities are ultimately consulted by kvm_mmu_hugepage_adjust().
+	 */
+	if (tdp_enabled)
+		max_huge_page_level = tdp_huge_page_level;
+	else if (boot_cpu_has(X86_FEATURE_GBPAGES))
+		max_huge_page_level = PG_LEVEL_1G;
+	else
+		max_huge_page_level = PG_LEVEL_2M;
+}
+EXPORT_SYMBOL_GPL(kvm_configure_mmu);
+
+/* The return value indicates if tlb flush on all vcpus is needed. */
+typedef bool (*slot_rmaps_handler) (struct kvm *kvm,
+				    struct kvm_rmap_head *rmap_head,
+				    const struct kvm_memory_slot *slot);
+
+static __always_inline bool __walk_slot_rmaps(struct kvm *kvm,
+					      const struct kvm_memory_slot *slot,
+					      slot_rmaps_handler fn,
+					      int start_level, int end_level,
+					      gfn_t start_gfn, gfn_t end_gfn,
+					      bool flush_on_yield, bool flush)
+{
+	struct slot_rmap_walk_iterator iterator;
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+
+	for_each_slot_rmap_range(slot, start_level, end_level, start_gfn,
+			end_gfn, &iterator) {
+		if (iterator.rmap)
+			flush |= fn(kvm, iterator.rmap, slot);
+
+		if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
+			if (flush && flush_on_yield) {
+				kvm_flush_remote_tlbs_range(kvm, start_gfn,
+							    iterator.gfn - start_gfn + 1);
+				flush = false;
+			}
+			cond_resched_rwlock_write(&kvm->mmu_lock);
+		}
+	}
+
+	return flush;
+}
+
+static __always_inline bool walk_slot_rmaps(struct kvm *kvm,
+					    const struct kvm_memory_slot *slot,
+					    slot_rmaps_handler fn,
+					    int start_level, int end_level,
+					    bool flush_on_yield)
+{
+	return __walk_slot_rmaps(kvm, slot, fn, start_level, end_level,
+				 slot->base_gfn, slot->base_gfn + slot->npages - 1,
+				 flush_on_yield, false);
+}
+
+static __always_inline bool walk_slot_rmaps_4k(struct kvm *kvm,
+					       const struct kvm_memory_slot *slot,
+					       slot_rmaps_handler fn,
+					       bool flush_on_yield)
+{
+	return walk_slot_rmaps(kvm, slot, fn, PG_LEVEL_4K, PG_LEVEL_4K, flush_on_yield);
+}
+
+static void free_mmu_pages(struct kvm_mmu *mmu)
+{
+	if (!tdp_enabled && mmu->pae_root)
+		set_memory_encrypted((unsigned long)mmu->pae_root, 1);
+	free_page((unsigned long)mmu->pae_root);
+	free_page((unsigned long)mmu->pml4_root);
+	free_page((unsigned long)mmu->pml5_root);
+}
+
+static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
+{
+	struct page *page;
+	int i;
+
+	mmu->root.hpa = INVALID_PAGE;
+	mmu->root.pgd = 0;
+	for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
+		mmu->prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID;
+
+	/* vcpu->arch.guest_mmu isn't used when !tdp_enabled. */
+	if (!tdp_enabled && mmu == &vcpu->arch.guest_mmu)
+		return 0;
+
+	/*
+	 * When using PAE paging, the four PDPTEs are treated as 'root' pages,
+	 * while the PDP table is a per-vCPU construct that's allocated at MMU
+	 * creation.  When emulating 32-bit mode, cr3 is only 32 bits even on
+	 * x86_64.  Therefore we need to allocate the PDP table in the first
+	 * 4GB of memory, which happens to fit the DMA32 zone.  TDP paging
+	 * generally doesn't use PAE paging and can skip allocating the PDP
+	 * table.  The main exception, handled here, is SVM's 32-bit NPT.  The
+	 * other exception is for shadowing L1's 32-bit or PAE NPT on 64-bit
+	 * KVM; that horror is handled on-demand by mmu_alloc_special_roots().
+	 */
+	if (tdp_enabled && kvm_mmu_get_tdp_level(vcpu) > PT32E_ROOT_LEVEL)
+		return 0;
+
+	page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_DMA32);
+	if (!page)
+		return -ENOMEM;
+
+	mmu->pae_root = page_address(page);
+
+	/*
+	 * CR3 is only 32 bits when PAE paging is used, thus it's impossible to
+	 * get the CPU to treat the PDPTEs as encrypted.  Decrypt the page so
+	 * that KVM's writes and the CPU's reads get along.  Note, this is
+	 * only necessary when using shadow paging, as 64-bit NPT can get at
+	 * the C-bit even when shadowing 32-bit NPT, and SME isn't supported
+	 * by 32-bit kernels (when KVM itself uses 32-bit NPT).
+	 */
+	if (!tdp_enabled)
+		set_memory_decrypted((unsigned long)mmu->pae_root, 1);
+	else
+		WARN_ON_ONCE(shadow_me_value);
+
+	for (i = 0; i < 4; ++i)
+		mmu->pae_root[i] = INVALID_PAE_ROOT;
+
+	return 0;
+}
+
+int kvm_mmu_create(struct kvm_vcpu *vcpu)
+{
+	int ret;
+
+	vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache;
+	vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO;
+
+	vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
+	vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO;
+
+	vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO;
+
+	vcpu->arch.mmu = &vcpu->arch.root_mmu;
+	vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
+
+	ret = __kvm_mmu_create(vcpu, &vcpu->arch.guest_mmu);
+	if (ret)
+		return ret;
+
+	ret = __kvm_mmu_create(vcpu, &vcpu->arch.root_mmu);
+	if (ret)
+		goto fail_allocate_root;
+
+	return ret;
+ fail_allocate_root:
+	free_mmu_pages(&vcpu->arch.guest_mmu);
+	return ret;
+}
+
+#define BATCH_ZAP_PAGES	10
+static void kvm_zap_obsolete_pages(struct kvm *kvm)
+{
+	struct kvm_mmu_page *sp, *node;
+	int nr_zapped, batch = 0;
+	bool unstable;
+
+restart:
+	list_for_each_entry_safe_reverse(sp, node,
+	      &kvm->arch.active_mmu_pages, link) {
+		/*
+		 * No obsolete valid page exists before a newly created page
+		 * since active_mmu_pages is a FIFO list.
+		 */
+		if (!is_obsolete_sp(kvm, sp))
+			break;
+
+		/*
+		 * Invalid pages should never land back on the list of active
+		 * pages.  Skip the bogus page, otherwise we'll get stuck in an
+		 * infinite loop if the page gets put back on the list (again).
+		 */
+		if (WARN_ON_ONCE(sp->role.invalid))
+			continue;
+
+		/*
+		 * No need to flush the TLB since we're only zapping shadow
+		 * pages with an obsolete generation number and all vCPUS have
+		 * loaded a new root, i.e. the shadow pages being zapped cannot
+		 * be in active use by the guest.
+		 */
+		if (batch >= BATCH_ZAP_PAGES &&
+		    cond_resched_rwlock_write(&kvm->mmu_lock)) {
+			batch = 0;
+			goto restart;
+		}
+
+		unstable = __kvm_mmu_prepare_zap_page(kvm, sp,
+				&kvm->arch.zapped_obsolete_pages, &nr_zapped);
+		batch += nr_zapped;
+
+		if (unstable)
+			goto restart;
+	}
+
+	/*
+	 * Kick all vCPUs (via remote TLB flush) before freeing the page tables
+	 * to ensure KVM is not in the middle of a lockless shadow page table
+	 * walk, which may reference the pages.  The remote TLB flush itself is
+	 * not required and is simply a convenient way to kick vCPUs as needed.
+	 * KVM performs a local TLB flush when allocating a new root (see
+	 * kvm_mmu_load()), and the reload in the caller ensure no vCPUs are
+	 * running with an obsolete MMU.
+	 */
+	kvm_mmu_commit_zap_page(kvm, &kvm->arch.zapped_obsolete_pages);
+}
+
+/*
+ * Fast invalidate all shadow pages and use lock-break technique
+ * to zap obsolete pages.
+ *
+ * It's required when memslot is being deleted or VM is being
+ * destroyed, in these cases, we should ensure that KVM MMU does
+ * not use any resource of the being-deleted slot or all slots
+ * after calling the function.
+ */
+static void kvm_mmu_zap_all_fast(struct kvm *kvm)
+{
+	lockdep_assert_held(&kvm->slots_lock);
+
+	write_lock(&kvm->mmu_lock);
+	trace_kvm_mmu_zap_all_fast(kvm);
+
+	/*
+	 * Toggle mmu_valid_gen between '0' and '1'.  Because slots_lock is
+	 * held for the entire duration of zapping obsolete pages, it's
+	 * impossible for there to be multiple invalid generations associated
+	 * with *valid* shadow pages at any given time, i.e. there is exactly
+	 * one valid generation and (at most) one invalid generation.
+	 */
+	kvm->arch.mmu_valid_gen = kvm->arch.mmu_valid_gen ? 0 : 1;
+
+	/*
+	 * In order to ensure all vCPUs drop their soon-to-be invalid roots,
+	 * invalidating TDP MMU roots must be done while holding mmu_lock for
+	 * write and in the same critical section as making the reload request,
+	 * e.g. before kvm_zap_obsolete_pages() could drop mmu_lock and yield.
+	 */
+	if (tdp_mmu_enabled)
+		kvm_tdp_mmu_invalidate_all_roots(kvm);
+
+	/*
+	 * Notify all vcpus to reload its shadow page table and flush TLB.
+	 * Then all vcpus will switch to new shadow page table with the new
+	 * mmu_valid_gen.
+	 *
+	 * Note: we need to do this under the protection of mmu_lock,
+	 * otherwise, vcpu would purge shadow page but miss tlb flush.
+	 */
+	kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_FREE_OBSOLETE_ROOTS);
+
+	kvm_zap_obsolete_pages(kvm);
+
+	write_unlock(&kvm->mmu_lock);
+
+	/*
+	 * Zap the invalidated TDP MMU roots, all SPTEs must be dropped before
+	 * returning to the caller, e.g. if the zap is in response to a memslot
+	 * deletion, mmu_notifier callbacks will be unable to reach the SPTEs
+	 * associated with the deleted memslot once the update completes, and
+	 * Deferring the zap until the final reference to the root is put would
+	 * lead to use-after-free.
+	 */
+	if (tdp_mmu_enabled)
+		kvm_tdp_mmu_zap_invalidated_roots(kvm);
+}
+
+static bool kvm_has_zapped_obsolete_pages(struct kvm *kvm)
+{
+	return unlikely(!list_empty_careful(&kvm->arch.zapped_obsolete_pages));
+}
+
+void kvm_mmu_init_vm(struct kvm *kvm)
+{
+	INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
+	INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages);
+	INIT_LIST_HEAD(&kvm->arch.possible_nx_huge_pages);
+	spin_lock_init(&kvm->arch.mmu_unsync_pages_lock);
+
+	if (tdp_mmu_enabled)
+		kvm_mmu_init_tdp_mmu(kvm);
+
+	kvm->arch.split_page_header_cache.kmem_cache = mmu_page_header_cache;
+	kvm->arch.split_page_header_cache.gfp_zero = __GFP_ZERO;
+
+	kvm->arch.split_shadow_page_cache.gfp_zero = __GFP_ZERO;
+
+	kvm->arch.split_desc_cache.kmem_cache = pte_list_desc_cache;
+	kvm->arch.split_desc_cache.gfp_zero = __GFP_ZERO;
+}
+
+static void mmu_free_vm_memory_caches(struct kvm *kvm)
+{
+	kvm_mmu_free_memory_cache(&kvm->arch.split_desc_cache);
+	kvm_mmu_free_memory_cache(&kvm->arch.split_page_header_cache);
+	kvm_mmu_free_memory_cache(&kvm->arch.split_shadow_page_cache);
+}
+
+void kvm_mmu_uninit_vm(struct kvm *kvm)
+{
+	if (tdp_mmu_enabled)
+		kvm_mmu_uninit_tdp_mmu(kvm);
+
+	mmu_free_vm_memory_caches(kvm);
+}
+
+static bool kvm_rmap_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
+{
+	const struct kvm_memory_slot *memslot;
+	struct kvm_memslots *slots;
+	struct kvm_memslot_iter iter;
+	bool flush = false;
+	gfn_t start, end;
+	int i;
+
+	if (!kvm_memslots_have_rmaps(kvm))
+		return flush;
+
+	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+		slots = __kvm_memslots(kvm, i);
+
+		kvm_for_each_memslot_in_gfn_range(&iter, slots, gfn_start, gfn_end) {
+			memslot = iter.slot;
+			start = max(gfn_start, memslot->base_gfn);
+			end = min(gfn_end, memslot->base_gfn + memslot->npages);
+			if (WARN_ON_ONCE(start >= end))
+				continue;
+
+			flush = __walk_slot_rmaps(kvm, memslot, __kvm_zap_rmap,
+						  PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL,
+						  start, end - 1, true, flush);
+		}
+	}
+
+	return flush;
+}
+
+/*
+ * Invalidate (zap) SPTEs that cover GFNs from gfn_start and up to gfn_end
+ * (not including it)
+ */
+void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
+{
+	bool flush;
+
+	if (WARN_ON_ONCE(gfn_end <= gfn_start))
+		return;
+
+	write_lock(&kvm->mmu_lock);
+
+	kvm_mmu_invalidate_begin(kvm, 0, -1ul);
+
+	flush = kvm_rmap_zap_gfn_range(kvm, gfn_start, gfn_end);
+
+	if (tdp_mmu_enabled)
+		flush = kvm_tdp_mmu_zap_leafs(kvm, gfn_start, gfn_end, flush);
+
+	if (flush)
+		kvm_flush_remote_tlbs_range(kvm, gfn_start, gfn_end - gfn_start);
+
+	kvm_mmu_invalidate_end(kvm, 0, -1ul);
+
+	write_unlock(&kvm->mmu_lock);
+}
+
+static bool slot_rmap_write_protect(struct kvm *kvm,
+				    struct kvm_rmap_head *rmap_head,
+				    const struct kvm_memory_slot *slot)
+{
+	return rmap_write_protect(rmap_head, false);
+}
+
+void kvm_mmu_slot_remove_write_access(struct kvm *kvm,
+				      const struct kvm_memory_slot *memslot,
+				      int start_level)
+{
+	if (kvm_memslots_have_rmaps(kvm)) {
+		write_lock(&kvm->mmu_lock);
+		walk_slot_rmaps(kvm, memslot, slot_rmap_write_protect,
+				start_level, KVM_MAX_HUGEPAGE_LEVEL, false);
+		write_unlock(&kvm->mmu_lock);
+	}
+
+	if (tdp_mmu_enabled) {
+		read_lock(&kvm->mmu_lock);
+		kvm_tdp_mmu_wrprot_slot(kvm, memslot, start_level);
+		read_unlock(&kvm->mmu_lock);
+	}
+}
+
+static inline bool need_topup(struct kvm_mmu_memory_cache *cache, int min)
+{
+	return kvm_mmu_memory_cache_nr_free_objects(cache) < min;
+}
+
+static bool need_topup_split_caches_or_resched(struct kvm *kvm)
+{
+	if (need_resched() || rwlock_needbreak(&kvm->mmu_lock))
+		return true;
+
+	/*
+	 * In the worst case, SPLIT_DESC_CACHE_MIN_NR_OBJECTS descriptors are needed
+	 * to split a single huge page. Calculating how many are actually needed
+	 * is possible but not worth the complexity.
+	 */
+	return need_topup(&kvm->arch.split_desc_cache, SPLIT_DESC_CACHE_MIN_NR_OBJECTS) ||
+	       need_topup(&kvm->arch.split_page_header_cache, 1) ||
+	       need_topup(&kvm->arch.split_shadow_page_cache, 1);
+}
+
+static int topup_split_caches(struct kvm *kvm)
+{
+	/*
+	 * Allocating rmap list entries when splitting huge pages for nested
+	 * MMUs is uncommon as KVM needs to use a list if and only if there is
+	 * more than one rmap entry for a gfn, i.e. requires an L1 gfn to be
+	 * aliased by multiple L2 gfns and/or from multiple nested roots with
+	 * different roles.  Aliasing gfns when using TDP is atypical for VMMs;
+	 * a few gfns are often aliased during boot, e.g. when remapping BIOS,
+	 * but aliasing rarely occurs post-boot or for many gfns.  If there is
+	 * only one rmap entry, rmap->val points directly at that one entry and
+	 * doesn't need to allocate a list.  Buffer the cache by the default
+	 * capacity so that KVM doesn't have to drop mmu_lock to topup if KVM
+	 * encounters an aliased gfn or two.
+	 */
+	const int capacity = SPLIT_DESC_CACHE_MIN_NR_OBJECTS +
+			     KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE;
+	int r;
+
+	lockdep_assert_held(&kvm->slots_lock);
+
+	r = __kvm_mmu_topup_memory_cache(&kvm->arch.split_desc_cache, capacity,
+					 SPLIT_DESC_CACHE_MIN_NR_OBJECTS);
+	if (r)
+		return r;
+
+	r = kvm_mmu_topup_memory_cache(&kvm->arch.split_page_header_cache, 1);
+	if (r)
+		return r;
+
+	return kvm_mmu_topup_memory_cache(&kvm->arch.split_shadow_page_cache, 1);
+}
+
+static struct kvm_mmu_page *shadow_mmu_get_sp_for_split(struct kvm *kvm, u64 *huge_sptep)
+{
+	struct kvm_mmu_page *huge_sp = sptep_to_sp(huge_sptep);
+	struct shadow_page_caches caches = {};
+	union kvm_mmu_page_role role;
+	unsigned int access;
+	gfn_t gfn;
+
+	gfn = kvm_mmu_page_get_gfn(huge_sp, spte_index(huge_sptep));
+	access = kvm_mmu_page_get_access(huge_sp, spte_index(huge_sptep));
+
+	/*
+	 * Note, huge page splitting always uses direct shadow pages, regardless
+	 * of whether the huge page itself is mapped by a direct or indirect
+	 * shadow page, since the huge page region itself is being directly
+	 * mapped with smaller pages.
+	 */
+	role = kvm_mmu_child_role(huge_sptep, /*direct=*/true, access);
+
+	/* Direct SPs do not require a shadowed_info_cache. */
+	caches.page_header_cache = &kvm->arch.split_page_header_cache;
+	caches.shadow_page_cache = &kvm->arch.split_shadow_page_cache;
+
+	/* Safe to pass NULL for vCPU since requesting a direct SP. */
+	return __kvm_mmu_get_shadow_page(kvm, NULL, &caches, gfn, role);
+}
+
+static void shadow_mmu_split_huge_page(struct kvm *kvm,
+				       const struct kvm_memory_slot *slot,
+				       u64 *huge_sptep)
+
+{
+	struct kvm_mmu_memory_cache *cache = &kvm->arch.split_desc_cache;
+	u64 huge_spte = READ_ONCE(*huge_sptep);
+	struct kvm_mmu_page *sp;
+	bool flush = false;
+	u64 *sptep, spte;
+	gfn_t gfn;
+	int index;
+
+	sp = shadow_mmu_get_sp_for_split(kvm, huge_sptep);
+
+	for (index = 0; index < SPTE_ENT_PER_PAGE; index++) {
+		sptep = &sp->spt[index];
+		gfn = kvm_mmu_page_get_gfn(sp, index);
+
+		/*
+		 * The SP may already have populated SPTEs, e.g. if this huge
+		 * page is aliased by multiple sptes with the same access
+		 * permissions. These entries are guaranteed to map the same
+		 * gfn-to-pfn translation since the SP is direct, so no need to
+		 * modify them.
+		 *
+		 * However, if a given SPTE points to a lower level page table,
+		 * that lower level page table may only be partially populated.
+		 * Installing such SPTEs would effectively unmap a potion of the
+		 * huge page. Unmapping guest memory always requires a TLB flush
+		 * since a subsequent operation on the unmapped regions would
+		 * fail to detect the need to flush.
+		 */
+		if (is_shadow_present_pte(*sptep)) {
+			flush |= !is_last_spte(*sptep, sp->role.level);
+			continue;
+		}
+
+		spte = make_huge_page_split_spte(kvm, huge_spte, sp->role, index);
+		mmu_spte_set(sptep, spte);
+		__rmap_add(kvm, cache, slot, sptep, gfn, sp->role.access);
+	}
+
+	__link_shadow_page(kvm, cache, huge_sptep, sp, flush);
+}
+
+static int shadow_mmu_try_split_huge_page(struct kvm *kvm,
+					  const struct kvm_memory_slot *slot,
+					  u64 *huge_sptep)
+{
+	struct kvm_mmu_page *huge_sp = sptep_to_sp(huge_sptep);
+	int level, r = 0;
+	gfn_t gfn;
+	u64 spte;
+
+	/* Grab information for the tracepoint before dropping the MMU lock. */
+	gfn = kvm_mmu_page_get_gfn(huge_sp, spte_index(huge_sptep));
+	level = huge_sp->role.level;
+	spte = *huge_sptep;
+
+	if (kvm_mmu_available_pages(kvm) <= KVM_MIN_FREE_MMU_PAGES) {
+		r = -ENOSPC;
+		goto out;
+	}
+
+	if (need_topup_split_caches_or_resched(kvm)) {
+		write_unlock(&kvm->mmu_lock);
+		cond_resched();
+		/*
+		 * If the topup succeeds, return -EAGAIN to indicate that the
+		 * rmap iterator should be restarted because the MMU lock was
+		 * dropped.
+		 */
+		r = topup_split_caches(kvm) ?: -EAGAIN;
+		write_lock(&kvm->mmu_lock);
+		goto out;
+	}
+
+	shadow_mmu_split_huge_page(kvm, slot, huge_sptep);
+
+out:
+	trace_kvm_mmu_split_huge_page(gfn, spte, level, r);
+	return r;
+}
+
+static bool shadow_mmu_try_split_huge_pages(struct kvm *kvm,
+					    struct kvm_rmap_head *rmap_head,
+					    const struct kvm_memory_slot *slot)
+{
+	struct rmap_iterator iter;
+	struct kvm_mmu_page *sp;
+	u64 *huge_sptep;
+	int r;
+
+restart:
+	for_each_rmap_spte(rmap_head, &iter, huge_sptep) {
+		sp = sptep_to_sp(huge_sptep);
+
+		/* TDP MMU is enabled, so rmap only contains nested MMU SPs. */
+		if (WARN_ON_ONCE(!sp->role.guest_mode))
+			continue;
+
+		/* The rmaps should never contain non-leaf SPTEs. */
+		if (WARN_ON_ONCE(!is_large_pte(*huge_sptep)))
+			continue;
+
+		/* SPs with level >PG_LEVEL_4K should never by unsync. */
+		if (WARN_ON_ONCE(sp->unsync))
+			continue;
+
+		/* Don't bother splitting huge pages on invalid SPs. */
+		if (sp->role.invalid)
+			continue;
+
+		r = shadow_mmu_try_split_huge_page(kvm, slot, huge_sptep);
+
+		/*
+		 * The split succeeded or needs to be retried because the MMU
+		 * lock was dropped. Either way, restart the iterator to get it
+		 * back into a consistent state.
+		 */
+		if (!r || r == -EAGAIN)
+			goto restart;
+
+		/* The split failed and shouldn't be retried (e.g. -ENOMEM). */
+		break;
+	}
+
+	return false;
+}
+
+static void kvm_shadow_mmu_try_split_huge_pages(struct kvm *kvm,
+						const struct kvm_memory_slot *slot,
+						gfn_t start, gfn_t end,
+						int target_level)
+{
+	int level;
+
+	/*
+	 * Split huge pages starting with KVM_MAX_HUGEPAGE_LEVEL and working
+	 * down to the target level. This ensures pages are recursively split
+	 * all the way to the target level. There's no need to split pages
+	 * already at the target level.
+	 */
+	for (level = KVM_MAX_HUGEPAGE_LEVEL; level > target_level; level--)
+		__walk_slot_rmaps(kvm, slot, shadow_mmu_try_split_huge_pages,
+				  level, level, start, end - 1, true, false);
+}
+
+/* Must be called with the mmu_lock held in write-mode. */
+void kvm_mmu_try_split_huge_pages(struct kvm *kvm,
+				   const struct kvm_memory_slot *memslot,
+				   u64 start, u64 end,
+				   int target_level)
+{
+	if (!tdp_mmu_enabled)
+		return;
+
+	if (kvm_memslots_have_rmaps(kvm))
+		kvm_shadow_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level);
+
+	kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level, false);
+
+	/*
+	 * A TLB flush is unnecessary at this point for the same resons as in
+	 * kvm_mmu_slot_try_split_huge_pages().
+	 */
+}
+
+void kvm_mmu_slot_try_split_huge_pages(struct kvm *kvm,
+					const struct kvm_memory_slot *memslot,
+					int target_level)
+{
+	u64 start = memslot->base_gfn;
+	u64 end = start + memslot->npages;
+
+	if (!tdp_mmu_enabled)
+		return;
+
+	if (kvm_memslots_have_rmaps(kvm)) {
+		write_lock(&kvm->mmu_lock);
+		kvm_shadow_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level);
+		write_unlock(&kvm->mmu_lock);
+	}
+
+	read_lock(&kvm->mmu_lock);
+	kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level, true);
+	read_unlock(&kvm->mmu_lock);
+
+	/*
+	 * No TLB flush is necessary here. KVM will flush TLBs after
+	 * write-protecting and/or clearing dirty on the newly split SPTEs to
+	 * ensure that guest writes are reflected in the dirty log before the
+	 * ioctl to enable dirty logging on this memslot completes. Since the
+	 * split SPTEs retain the write and dirty bits of the huge SPTE, it is
+	 * safe for KVM to decide if a TLB flush is necessary based on the split
+	 * SPTEs.
+	 */
+}
+
+static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm,
+					 struct kvm_rmap_head *rmap_head,
+					 const struct kvm_memory_slot *slot)
+{
+	u64 *sptep;
+	struct rmap_iterator iter;
+	int need_tlb_flush = 0;
+	struct kvm_mmu_page *sp;
+
+restart:
+	for_each_rmap_spte(rmap_head, &iter, sptep) {
+		sp = sptep_to_sp(sptep);
+
+		/*
+		 * We cannot do huge page mapping for indirect shadow pages,
+		 * which are found on the last rmap (level = 1) when not using
+		 * tdp; such shadow pages are synced with the page table in
+		 * the guest, and the guest page table is using 4K page size
+		 * mapping if the indirect sp has level = 1.
+		 */
+		if (sp->role.direct &&
+		    sp->role.level < kvm_mmu_max_mapping_level(kvm, slot, sp->gfn,
+							       PG_LEVEL_NUM)) {
+			kvm_zap_one_rmap_spte(kvm, rmap_head, sptep);
+
+			if (kvm_available_flush_remote_tlbs_range())
+				kvm_flush_remote_tlbs_sptep(kvm, sptep);
+			else
+				need_tlb_flush = 1;
+
+			goto restart;
+		}
+	}
+
+	return need_tlb_flush;
+}
+
+static void kvm_rmap_zap_collapsible_sptes(struct kvm *kvm,
+					   const struct kvm_memory_slot *slot)
+{
+	/*
+	 * Note, use KVM_MAX_HUGEPAGE_LEVEL - 1 since there's no need to zap
+	 * pages that are already mapped at the maximum hugepage level.
+	 */
+	if (walk_slot_rmaps(kvm, slot, kvm_mmu_zap_collapsible_spte,
+			    PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL - 1, true))
+		kvm_flush_remote_tlbs_memslot(kvm, slot);
+}
+
+void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
+				   const struct kvm_memory_slot *slot)
+{
+	if (kvm_memslots_have_rmaps(kvm)) {
+		write_lock(&kvm->mmu_lock);
+		kvm_rmap_zap_collapsible_sptes(kvm, slot);
+		write_unlock(&kvm->mmu_lock);
+	}
+
+	if (tdp_mmu_enabled) {
+		read_lock(&kvm->mmu_lock);
+		kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot);
+		read_unlock(&kvm->mmu_lock);
+	}
+}
+
+void kvm_mmu_slot_leaf_clear_dirty(struct kvm *kvm,
+				   const struct kvm_memory_slot *memslot)
+{
+	if (kvm_memslots_have_rmaps(kvm)) {
+		write_lock(&kvm->mmu_lock);
+		/*
+		 * Clear dirty bits only on 4k SPTEs since the legacy MMU only
+		 * support dirty logging at a 4k granularity.
+		 */
+		walk_slot_rmaps_4k(kvm, memslot, __rmap_clear_dirty, false);
+		write_unlock(&kvm->mmu_lock);
+	}
+
+	if (tdp_mmu_enabled) {
+		read_lock(&kvm->mmu_lock);
+		kvm_tdp_mmu_clear_dirty_slot(kvm, memslot);
+		read_unlock(&kvm->mmu_lock);
+	}
+
+	/*
+	 * The caller will flush the TLBs after this function returns.
+	 *
+	 * It's also safe to flush TLBs out of mmu lock here as currently this
+	 * function is only used for dirty logging, in which case flushing TLB
+	 * out of mmu lock also guarantees no dirty pages will be lost in
+	 * dirty_bitmap.
+	 */
+}
+
+static void kvm_mmu_zap_all(struct kvm *kvm)
+{
+	struct kvm_mmu_page *sp, *node;
+	LIST_HEAD(invalid_list);
+	int ign;
+
+	write_lock(&kvm->mmu_lock);
+restart:
+	list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) {
+		if (WARN_ON_ONCE(sp->role.invalid))
+			continue;
+		if (__kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list, &ign))
+			goto restart;
+		if (cond_resched_rwlock_write(&kvm->mmu_lock))
+			goto restart;
+	}
+
+	kvm_mmu_commit_zap_page(kvm, &invalid_list);
+
+	if (tdp_mmu_enabled)
+		kvm_tdp_mmu_zap_all(kvm);
+
+	write_unlock(&kvm->mmu_lock);
+}
+
+void kvm_arch_flush_shadow_all(struct kvm *kvm)
+{
+	kvm_mmu_zap_all(kvm);
+}
+
+void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
+				   struct kvm_memory_slot *slot)
+{
+	kvm_mmu_zap_all_fast(kvm);
+}
+
+void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
+{
+	WARN_ON_ONCE(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
+
+	gen &= MMIO_SPTE_GEN_MASK;
+
+	/*
+	 * Generation numbers are incremented in multiples of the number of
+	 * address spaces in order to provide unique generations across all
+	 * address spaces.  Strip what is effectively the address space
+	 * modifier prior to checking for a wrap of the MMIO generation so
+	 * that a wrap in any address space is detected.
+	 */
+	gen &= ~((u64)KVM_ADDRESS_SPACE_NUM - 1);
+
+	/*
+	 * The very rare case: if the MMIO generation number has wrapped,
+	 * zap all shadow pages.
+	 */
+	if (unlikely(gen == 0)) {
+		kvm_debug_ratelimited("zapping shadow pages for mmio generation wraparound\n");
+		kvm_mmu_zap_all_fast(kvm);
+	}
+}
+
+static unsigned long mmu_shrink_scan(struct shrinker *shrink,
+				     struct shrink_control *sc)
+{
+	struct kvm *kvm;
+	int nr_to_scan = sc->nr_to_scan;
+	unsigned long freed = 0;
+
+	mutex_lock(&kvm_lock);
+
+	list_for_each_entry(kvm, &vm_list, vm_list) {
+		int idx;
+		LIST_HEAD(invalid_list);
+
+		/*
+		 * Never scan more than sc->nr_to_scan VM instances.
+		 * Will not hit this condition practically since we do not try
+		 * to shrink more than one VM and it is very unlikely to see
+		 * !n_used_mmu_pages so many times.
+		 */
+		if (!nr_to_scan--)
+			break;
+		/*
+		 * n_used_mmu_pages is accessed without holding kvm->mmu_lock
+		 * here. We may skip a VM instance errorneosly, but we do not
+		 * want to shrink a VM that only started to populate its MMU
+		 * anyway.
+		 */
+		if (!kvm->arch.n_used_mmu_pages &&
+		    !kvm_has_zapped_obsolete_pages(kvm))
+			continue;
+
+		idx = srcu_read_lock(&kvm->srcu);
+		write_lock(&kvm->mmu_lock);
+
+		if (kvm_has_zapped_obsolete_pages(kvm)) {
+			kvm_mmu_commit_zap_page(kvm,
+			      &kvm->arch.zapped_obsolete_pages);
+			goto unlock;
+		}
+
+		freed = kvm_mmu_zap_oldest_mmu_pages(kvm, sc->nr_to_scan);
+
+unlock:
+		write_unlock(&kvm->mmu_lock);
+		srcu_read_unlock(&kvm->srcu, idx);
+
+		/*
+		 * unfair on small ones
+		 * per-vm shrinkers cry out
+		 * sadness comes quickly
+		 */
+		list_move_tail(&kvm->vm_list, &vm_list);
+		break;
+	}
+
+	mutex_unlock(&kvm_lock);
+	return freed;
+}
+
+static unsigned long mmu_shrink_count(struct shrinker *shrink,
+				      struct shrink_control *sc)
+{
+	return percpu_counter_read_positive(&kvm_total_used_mmu_pages);
+}
+
+static struct shrinker mmu_shrinker = {
+	.count_objects = mmu_shrink_count,
+	.scan_objects = mmu_shrink_scan,
+	.seeks = DEFAULT_SEEKS * 10,
+};
+
+static void mmu_destroy_caches(void)
+{
+	kmem_cache_destroy(pte_list_desc_cache);
+	kmem_cache_destroy(mmu_page_header_cache);
+}
+
+static int get_nx_huge_pages(char *buffer, const struct kernel_param *kp)
+{
+	if (nx_hugepage_mitigation_hard_disabled)
+		return sysfs_emit(buffer, "never\n");
+
+	return param_get_bool(buffer, kp);
+}
+
+static bool get_nx_auto_mode(void)
+{
+	/* Return true when CPU has the bug, and mitigations are ON */
+	return boot_cpu_has_bug(X86_BUG_ITLB_MULTIHIT) && !cpu_mitigations_off();
+}
+
+static void __set_nx_huge_pages(bool val)
+{
+	nx_huge_pages = itlb_multihit_kvm_mitigation = val;
+}
+
+static int set_nx_huge_pages(const char *val, const struct kernel_param *kp)
+{
+	bool old_val = nx_huge_pages;
+	bool new_val;
+
+	if (nx_hugepage_mitigation_hard_disabled)
+		return -EPERM;
+
+	/* In "auto" mode deploy workaround only if CPU has the bug. */
+	if (sysfs_streq(val, "off")) {
+		new_val = 0;
+	} else if (sysfs_streq(val, "force")) {
+		new_val = 1;
+	} else if (sysfs_streq(val, "auto")) {
+		new_val = get_nx_auto_mode();
+	} else if (sysfs_streq(val, "never")) {
+		new_val = 0;
+
+		mutex_lock(&kvm_lock);
+		if (!list_empty(&vm_list)) {
+			mutex_unlock(&kvm_lock);
+			return -EBUSY;
+		}
+		nx_hugepage_mitigation_hard_disabled = true;
+		mutex_unlock(&kvm_lock);
+	} else if (kstrtobool(val, &new_val) < 0) {
+		return -EINVAL;
+	}
+
+	__set_nx_huge_pages(new_val);
+
+	if (new_val != old_val) {
+		struct kvm *kvm;
+
+		mutex_lock(&kvm_lock);
+
+		list_for_each_entry(kvm, &vm_list, vm_list) {
+			mutex_lock(&kvm->slots_lock);
+			kvm_mmu_zap_all_fast(kvm);
+			mutex_unlock(&kvm->slots_lock);
+
+			wake_up_process(kvm->arch.nx_huge_page_recovery_thread);
+		}
+		mutex_unlock(&kvm_lock);
+	}
+
+	return 0;
+}
+
+/*
+ * nx_huge_pages needs to be resolved to true/false when kvm.ko is loaded, as
+ * its default value of -1 is technically undefined behavior for a boolean.
+ * Forward the module init call to SPTE code so that it too can handle module
+ * params that need to be resolved/snapshot.
+ */
+void __init kvm_mmu_x86_module_init(void)
+{
+	if (nx_huge_pages == -1)
+		__set_nx_huge_pages(get_nx_auto_mode());
+
+	/*
+	 * Snapshot userspace's desire to enable the TDP MMU. Whether or not the
+	 * TDP MMU is actually enabled is determined in kvm_configure_mmu()
+	 * when the vendor module is loaded.
+	 */
+	tdp_mmu_allowed = tdp_mmu_enabled;
+
+	kvm_mmu_spte_module_init();
+}
+
+/*
+ * The bulk of the MMU initialization is deferred until the vendor module is
+ * loaded as many of the masks/values may be modified by VMX or SVM, i.e. need
+ * to be reset when a potentially different vendor module is loaded.
+ */
+int kvm_mmu_vendor_module_init(void)
+{
+	int ret = -ENOMEM;
+
+	/*
+	 * MMU roles use union aliasing which is, generally speaking, an
+	 * undefined behavior. However, we supposedly know how compilers behave
+	 * and the current status quo is unlikely to change. Guardians below are
+	 * supposed to let us know if the assumption becomes false.
+	 */
+	BUILD_BUG_ON(sizeof(union kvm_mmu_page_role) != sizeof(u32));
+	BUILD_BUG_ON(sizeof(union kvm_mmu_extended_role) != sizeof(u32));
+	BUILD_BUG_ON(sizeof(union kvm_cpu_role) != sizeof(u64));
+
+	kvm_mmu_reset_all_pte_masks();
+
+	pte_list_desc_cache = kmem_cache_create("pte_list_desc",
+					    sizeof(struct pte_list_desc),
+					    0, SLAB_ACCOUNT, NULL);
+	if (!pte_list_desc_cache)
+		goto out;
+
+	mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
+						  sizeof(struct kvm_mmu_page),
+						  0, SLAB_ACCOUNT, NULL);
+	if (!mmu_page_header_cache)
+		goto out;
+
+	if (percpu_counter_init(&kvm_total_used_mmu_pages, 0, GFP_KERNEL))
+		goto out;
+
+	ret = register_shrinker(&mmu_shrinker, "x86-mmu");
+	if (ret)
+		goto out_shrinker;
+
+	return 0;
+
+out_shrinker:
+	percpu_counter_destroy(&kvm_total_used_mmu_pages);
+out:
+	mmu_destroy_caches();
+	return ret;
+}
+
+void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
+{
+	kvm_mmu_unload(vcpu);
+	free_mmu_pages(&vcpu->arch.root_mmu);
+	free_mmu_pages(&vcpu->arch.guest_mmu);
+	mmu_free_memory_caches(vcpu);
+}
+
+void kvm_mmu_vendor_module_exit(void)
+{
+	mmu_destroy_caches();
+	percpu_counter_destroy(&kvm_total_used_mmu_pages);
+	unregister_shrinker(&mmu_shrinker);
+}
+
+/*
+ * Calculate the effective recovery period, accounting for '0' meaning "let KVM
+ * select a halving time of 1 hour".  Returns true if recovery is enabled.
+ */
+static bool calc_nx_huge_pages_recovery_period(uint *period)
+{
+	/*
+	 * Use READ_ONCE to get the params, this may be called outside of the
+	 * param setters, e.g. by the kthread to compute its next timeout.
+	 */
+	bool enabled = READ_ONCE(nx_huge_pages);
+	uint ratio = READ_ONCE(nx_huge_pages_recovery_ratio);
+
+	if (!enabled || !ratio)
+		return false;
+
+	*period = READ_ONCE(nx_huge_pages_recovery_period_ms);
+	if (!*period) {
+		/* Make sure the period is not less than one second.  */
+		ratio = min(ratio, 3600u);
+		*period = 60 * 60 * 1000 / ratio;
+	}
+	return true;
+}
+
+static int set_nx_huge_pages_recovery_param(const char *val, const struct kernel_param *kp)
+{
+	bool was_recovery_enabled, is_recovery_enabled;
+	uint old_period, new_period;
+	int err;
+
+	if (nx_hugepage_mitigation_hard_disabled)
+		return -EPERM;
+
+	was_recovery_enabled = calc_nx_huge_pages_recovery_period(&old_period);
+
+	err = param_set_uint(val, kp);
+	if (err)
+		return err;
+
+	is_recovery_enabled = calc_nx_huge_pages_recovery_period(&new_period);
+
+	if (is_recovery_enabled &&
+	    (!was_recovery_enabled || old_period > new_period)) {
+		struct kvm *kvm;
+
+		mutex_lock(&kvm_lock);
+
+		list_for_each_entry(kvm, &vm_list, vm_list)
+			wake_up_process(kvm->arch.nx_huge_page_recovery_thread);
+
+		mutex_unlock(&kvm_lock);
+	}
+
+	return err;
+}
+
+static void kvm_recover_nx_huge_pages(struct kvm *kvm)
+{
+	unsigned long nx_lpage_splits = kvm->stat.nx_lpage_splits;
+	struct kvm_memory_slot *slot;
+	int rcu_idx;
+	struct kvm_mmu_page *sp;
+	unsigned int ratio;
+	LIST_HEAD(invalid_list);
+	bool flush = false;
+	ulong to_zap;
+
+	rcu_idx = srcu_read_lock(&kvm->srcu);
+	write_lock(&kvm->mmu_lock);
+
+	/*
+	 * Zapping TDP MMU shadow pages, including the remote TLB flush, must
+	 * be done under RCU protection, because the pages are freed via RCU
+	 * callback.
+	 */
+	rcu_read_lock();
+
+	ratio = READ_ONCE(nx_huge_pages_recovery_ratio);
+	to_zap = ratio ? DIV_ROUND_UP(nx_lpage_splits, ratio) : 0;
+	for ( ; to_zap; --to_zap) {
+		if (list_empty(&kvm->arch.possible_nx_huge_pages))
+			break;
+
+		/*
+		 * We use a separate list instead of just using active_mmu_pages
+		 * because the number of shadow pages that be replaced with an
+		 * NX huge page is expected to be relatively small compared to
+		 * the total number of shadow pages.  And because the TDP MMU
+		 * doesn't use active_mmu_pages.
+		 */
+		sp = list_first_entry(&kvm->arch.possible_nx_huge_pages,
+				      struct kvm_mmu_page,
+				      possible_nx_huge_page_link);
+		WARN_ON_ONCE(!sp->nx_huge_page_disallowed);
+		WARN_ON_ONCE(!sp->role.direct);
+
+		/*
+		 * Unaccount and do not attempt to recover any NX Huge Pages
+		 * that are being dirty tracked, as they would just be faulted
+		 * back in as 4KiB pages. The NX Huge Pages in this slot will be
+		 * recovered, along with all the other huge pages in the slot,
+		 * when dirty logging is disabled.
+		 *
+		 * Since gfn_to_memslot() is relatively expensive, it helps to
+		 * skip it if it the test cannot possibly return true.  On the
+		 * other hand, if any memslot has logging enabled, chances are
+		 * good that all of them do, in which case unaccount_nx_huge_page()
+		 * is much cheaper than zapping the page.
+		 *
+		 * If a memslot update is in progress, reading an incorrect value
+		 * of kvm->nr_memslots_dirty_logging is not a problem: if it is
+		 * becoming zero, gfn_to_memslot() will be done unnecessarily; if
+		 * it is becoming nonzero, the page will be zapped unnecessarily.
+		 * Either way, this only affects efficiency in racy situations,
+		 * and not correctness.
+		 */
+		slot = NULL;
+		if (atomic_read(&kvm->nr_memslots_dirty_logging)) {
+			struct kvm_memslots *slots;
+
+			slots = kvm_memslots_for_spte_role(kvm, sp->role);
+			slot = __gfn_to_memslot(slots, sp->gfn);
+			WARN_ON_ONCE(!slot);
+		}
+
+		if (slot && kvm_slot_dirty_track_enabled(slot))
+			unaccount_nx_huge_page(kvm, sp);
+		else if (is_tdp_mmu_page(sp))
+			flush |= kvm_tdp_mmu_zap_sp(kvm, sp);
+		else
+			kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
+		WARN_ON_ONCE(sp->nx_huge_page_disallowed);
+
+		if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
+			kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
+			rcu_read_unlock();
+
+			cond_resched_rwlock_write(&kvm->mmu_lock);
+			flush = false;
+
+			rcu_read_lock();
+		}
+	}
+	kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
+
+	rcu_read_unlock();
+
+	write_unlock(&kvm->mmu_lock);
+	srcu_read_unlock(&kvm->srcu, rcu_idx);
+}
+
+static long get_nx_huge_page_recovery_timeout(u64 start_time)
+{
+	bool enabled;
+	uint period;
+
+	enabled = calc_nx_huge_pages_recovery_period(&period);
+
+	return enabled ? start_time + msecs_to_jiffies(period) - get_jiffies_64()
+		       : MAX_SCHEDULE_TIMEOUT;
+}
+
+static int kvm_nx_huge_page_recovery_worker(struct kvm *kvm, uintptr_t data)
+{
+	u64 start_time;
+	long remaining_time;
+
+	while (true) {
+		start_time = get_jiffies_64();
+		remaining_time = get_nx_huge_page_recovery_timeout(start_time);
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		while (!kthread_should_stop() && remaining_time > 0) {
+			schedule_timeout(remaining_time);
+			remaining_time = get_nx_huge_page_recovery_timeout(start_time);
+			set_current_state(TASK_INTERRUPTIBLE);
+		}
+
+		set_current_state(TASK_RUNNING);
+
+		if (kthread_should_stop())
+			return 0;
+
+		kvm_recover_nx_huge_pages(kvm);
+	}
+}
+
+int kvm_mmu_post_init_vm(struct kvm *kvm)
+{
+	int err;
+
+	if (nx_hugepage_mitigation_hard_disabled)
+		return 0;
+
+	err = kvm_vm_create_worker_thread(kvm, kvm_nx_huge_page_recovery_worker, 0,
+					  "kvm-nx-lpage-recovery",
+					  &kvm->arch.nx_huge_page_recovery_thread);
+	if (!err)
+		kthread_unpark(kvm->arch.nx_huge_page_recovery_thread);
+
+	return err;
+}
+
+void kvm_mmu_pre_destroy_vm(struct kvm *kvm)
+{
+	if (kvm->arch.nx_huge_page_recovery_thread)
+		kthread_stop(kvm->arch.nx_huge_page_recovery_thread);
+}
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
new file mode 100644
index 0000000000..decc1f1536
--- /dev/null
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -0,0 +1,350 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_X86_MMU_INTERNAL_H
+#define __KVM_X86_MMU_INTERNAL_H
+
+#include <linux/types.h>
+#include <linux/kvm_host.h>
+#include <asm/kvm_host.h>
+
+#ifdef CONFIG_KVM_PROVE_MMU
+#define KVM_MMU_WARN_ON(x) WARN_ON_ONCE(x)
+#else
+#define KVM_MMU_WARN_ON(x) BUILD_BUG_ON_INVALID(x)
+#endif
+
+/* Page table builder macros common to shadow (host) PTEs and guest PTEs. */
+#define __PT_LEVEL_SHIFT(level, bits_per_level)	\
+	(PAGE_SHIFT + ((level) - 1) * (bits_per_level))
+#define __PT_INDEX(address, level, bits_per_level) \
+	(((address) >> __PT_LEVEL_SHIFT(level, bits_per_level)) & ((1 << (bits_per_level)) - 1))
+
+#define __PT_LVL_ADDR_MASK(base_addr_mask, level, bits_per_level) \
+	((base_addr_mask) & ~((1ULL << (PAGE_SHIFT + (((level) - 1) * (bits_per_level)))) - 1))
+
+#define __PT_LVL_OFFSET_MASK(base_addr_mask, level, bits_per_level) \
+	((base_addr_mask) & ((1ULL << (PAGE_SHIFT + (((level) - 1) * (bits_per_level)))) - 1))
+
+#define __PT_ENT_PER_PAGE(bits_per_level)  (1 << (bits_per_level))
+
+/*
+ * Unlike regular MMU roots, PAE "roots", a.k.a. PDPTEs/PDPTRs, have a PRESENT
+ * bit, and thus are guaranteed to be non-zero when valid.  And, when a guest
+ * PDPTR is !PRESENT, its corresponding PAE root cannot be set to INVALID_PAGE,
+ * as the CPU would treat that as PRESENT PDPTR with reserved bits set.  Use
+ * '0' instead of INVALID_PAGE to indicate an invalid PAE root.
+ */
+#define INVALID_PAE_ROOT	0
+#define IS_VALID_PAE_ROOT(x)	(!!(x))
+
+static inline hpa_t kvm_mmu_get_dummy_root(void)
+{
+	return my_zero_pfn(0) << PAGE_SHIFT;
+}
+
+static inline bool kvm_mmu_is_dummy_root(hpa_t shadow_page)
+{
+	return is_zero_pfn(shadow_page >> PAGE_SHIFT);
+}
+
+typedef u64 __rcu *tdp_ptep_t;
+
+struct kvm_mmu_page {
+	/*
+	 * Note, "link" through "spt" fit in a single 64 byte cache line on
+	 * 64-bit kernels, keep it that way unless there's a reason not to.
+	 */
+	struct list_head link;
+	struct hlist_node hash_link;
+
+	bool tdp_mmu_page;
+	bool unsync;
+	union {
+		u8 mmu_valid_gen;
+
+		/* Only accessed under slots_lock.  */
+		bool tdp_mmu_scheduled_root_to_zap;
+	};
+
+	 /*
+	  * The shadow page can't be replaced by an equivalent huge page
+	  * because it is being used to map an executable page in the guest
+	  * and the NX huge page mitigation is enabled.
+	  */
+	bool nx_huge_page_disallowed;
+
+	/*
+	 * The following two entries are used to key the shadow page in the
+	 * hash table.
+	 */
+	union kvm_mmu_page_role role;
+	gfn_t gfn;
+
+	u64 *spt;
+
+	/*
+	 * Stores the result of the guest translation being shadowed by each
+	 * SPTE.  KVM shadows two types of guest translations: nGPA -> GPA
+	 * (shadow EPT/NPT) and GVA -> GPA (traditional shadow paging). In both
+	 * cases the result of the translation is a GPA and a set of access
+	 * constraints.
+	 *
+	 * The GFN is stored in the upper bits (PAGE_SHIFT) and the shadowed
+	 * access permissions are stored in the lower bits. Note, for
+	 * convenience and uniformity across guests, the access permissions are
+	 * stored in KVM format (e.g.  ACC_EXEC_MASK) not the raw guest format.
+	 */
+	u64 *shadowed_translation;
+
+	/* Currently serving as active root */
+	union {
+		int root_count;
+		refcount_t tdp_mmu_root_count;
+	};
+	unsigned int unsync_children;
+	union {
+		struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */
+		tdp_ptep_t ptep;
+	};
+	DECLARE_BITMAP(unsync_child_bitmap, 512);
+
+	/*
+	 * Tracks shadow pages that, if zapped, would allow KVM to create an NX
+	 * huge page.  A shadow page will have nx_huge_page_disallowed set but
+	 * not be on the list if a huge page is disallowed for other reasons,
+	 * e.g. because KVM is shadowing a PTE at the same gfn, the memslot
+	 * isn't properly aligned, etc...
+	 */
+	struct list_head possible_nx_huge_page_link;
+#ifdef CONFIG_X86_32
+	/*
+	 * Used out of the mmu-lock to avoid reading spte values while an
+	 * update is in progress; see the comments in __get_spte_lockless().
+	 */
+	int clear_spte_count;
+#endif
+
+	/* Number of writes since the last time traversal visited this page.  */
+	atomic_t write_flooding_count;
+
+#ifdef CONFIG_X86_64
+	/* Used for freeing the page asynchronously if it is a TDP MMU page. */
+	struct rcu_head rcu_head;
+#endif
+};
+
+extern struct kmem_cache *mmu_page_header_cache;
+
+static inline int kvm_mmu_role_as_id(union kvm_mmu_page_role role)
+{
+	return role.smm ? 1 : 0;
+}
+
+static inline int kvm_mmu_page_as_id(struct kvm_mmu_page *sp)
+{
+	return kvm_mmu_role_as_id(sp->role);
+}
+
+static inline bool kvm_mmu_page_ad_need_write_protect(struct kvm_mmu_page *sp)
+{
+	/*
+	 * When using the EPT page-modification log, the GPAs in the CPU dirty
+	 * log would come from L2 rather than L1.  Therefore, we need to rely
+	 * on write protection to record dirty pages, which bypasses PML, since
+	 * writes now result in a vmexit.  Note, the check on CPU dirty logging
+	 * being enabled is mandatory as the bits used to denote WP-only SPTEs
+	 * are reserved for PAE paging (32-bit KVM).
+	 */
+	return kvm_x86_ops.cpu_dirty_log_size && sp->role.guest_mode;
+}
+
+static inline gfn_t gfn_round_for_level(gfn_t gfn, int level)
+{
+	return gfn & -KVM_PAGES_PER_HPAGE(level);
+}
+
+int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot,
+			    gfn_t gfn, bool can_unsync, bool prefetch);
+
+void kvm_mmu_gfn_disallow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn);
+void kvm_mmu_gfn_allow_lpage(const struct kvm_memory_slot *slot, gfn_t gfn);
+bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
+				    struct kvm_memory_slot *slot, u64 gfn,
+				    int min_level);
+
+/* Flush the given page (huge or not) of guest memory. */
+static inline void kvm_flush_remote_tlbs_gfn(struct kvm *kvm, gfn_t gfn, int level)
+{
+	kvm_flush_remote_tlbs_range(kvm, gfn_round_for_level(gfn, level),
+				    KVM_PAGES_PER_HPAGE(level));
+}
+
+unsigned int pte_list_count(struct kvm_rmap_head *rmap_head);
+
+extern int nx_huge_pages;
+static inline bool is_nx_huge_page_enabled(struct kvm *kvm)
+{
+	return READ_ONCE(nx_huge_pages) && !kvm->arch.disable_nx_huge_pages;
+}
+
+struct kvm_page_fault {
+	/* arguments to kvm_mmu_do_page_fault.  */
+	const gpa_t addr;
+	const u32 error_code;
+	const bool prefetch;
+
+	/* Derived from error_code.  */
+	const bool exec;
+	const bool write;
+	const bool present;
+	const bool rsvd;
+	const bool user;
+
+	/* Derived from mmu and global state.  */
+	const bool is_tdp;
+	const bool nx_huge_page_workaround_enabled;
+
+	/*
+	 * Whether a >4KB mapping can be created or is forbidden due to NX
+	 * hugepages.
+	 */
+	bool huge_page_disallowed;
+
+	/*
+	 * Maximum page size that can be created for this fault; input to
+	 * FNAME(fetch), direct_map() and kvm_tdp_mmu_map().
+	 */
+	u8 max_level;
+
+	/*
+	 * Page size that can be created based on the max_level and the
+	 * page size used by the host mapping.
+	 */
+	u8 req_level;
+
+	/*
+	 * Page size that will be created based on the req_level and
+	 * huge_page_disallowed.
+	 */
+	u8 goal_level;
+
+	/* Shifted addr, or result of guest page table walk if addr is a gva.  */
+	gfn_t gfn;
+
+	/* The memslot containing gfn. May be NULL. */
+	struct kvm_memory_slot *slot;
+
+	/* Outputs of kvm_faultin_pfn.  */
+	unsigned long mmu_seq;
+	kvm_pfn_t pfn;
+	hva_t hva;
+	bool map_writable;
+
+	/*
+	 * Indicates the guest is trying to write a gfn that contains one or
+	 * more of the PTEs used to translate the write itself, i.e. the access
+	 * is changing its own translation in the guest page tables.
+	 */
+	bool write_fault_to_shadow_pgtable;
+};
+
+int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
+
+/*
+ * Return values of handle_mmio_page_fault(), mmu.page_fault(), fast_page_fault(),
+ * and of course kvm_mmu_do_page_fault().
+ *
+ * RET_PF_CONTINUE: So far, so good, keep handling the page fault.
+ * RET_PF_RETRY: let CPU fault again on the address.
+ * RET_PF_EMULATE: mmio page fault, emulate the instruction directly.
+ * RET_PF_INVALID: the spte is invalid, let the real page fault path update it.
+ * RET_PF_FIXED: The faulting entry has been fixed.
+ * RET_PF_SPURIOUS: The faulting entry was already fixed, e.g. by another vCPU.
+ *
+ * Any names added to this enum should be exported to userspace for use in
+ * tracepoints via TRACE_DEFINE_ENUM() in mmutrace.h
+ *
+ * Note, all values must be greater than or equal to zero so as not to encroach
+ * on -errno return values.  Somewhat arbitrarily use '0' for CONTINUE, which
+ * will allow for efficient machine code when checking for CONTINUE, e.g.
+ * "TEST %rax, %rax, JNZ", as all "stop!" values are non-zero.
+ */
+enum {
+	RET_PF_CONTINUE = 0,
+	RET_PF_RETRY,
+	RET_PF_EMULATE,
+	RET_PF_INVALID,
+	RET_PF_FIXED,
+	RET_PF_SPURIOUS,
+};
+
+static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
+					u32 err, bool prefetch, int *emulation_type)
+{
+	struct kvm_page_fault fault = {
+		.addr = cr2_or_gpa,
+		.error_code = err,
+		.exec = err & PFERR_FETCH_MASK,
+		.write = err & PFERR_WRITE_MASK,
+		.present = err & PFERR_PRESENT_MASK,
+		.rsvd = err & PFERR_RSVD_MASK,
+		.user = err & PFERR_USER_MASK,
+		.prefetch = prefetch,
+		.is_tdp = likely(vcpu->arch.mmu->page_fault == kvm_tdp_page_fault),
+		.nx_huge_page_workaround_enabled =
+			is_nx_huge_page_enabled(vcpu->kvm),
+
+		.max_level = KVM_MAX_HUGEPAGE_LEVEL,
+		.req_level = PG_LEVEL_4K,
+		.goal_level = PG_LEVEL_4K,
+	};
+	int r;
+
+	if (vcpu->arch.mmu->root_role.direct) {
+		fault.gfn = fault.addr >> PAGE_SHIFT;
+		fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn);
+	}
+
+	/*
+	 * Async #PF "faults", a.k.a. prefetch faults, are not faults from the
+	 * guest perspective and have already been counted at the time of the
+	 * original fault.
+	 */
+	if (!prefetch)
+		vcpu->stat.pf_taken++;
+
+	if (IS_ENABLED(CONFIG_RETPOLINE) && fault.is_tdp)
+		r = kvm_tdp_page_fault(vcpu, &fault);
+	else
+		r = vcpu->arch.mmu->page_fault(vcpu, &fault);
+
+	if (fault.write_fault_to_shadow_pgtable && emulation_type)
+		*emulation_type |= EMULTYPE_WRITE_PF_TO_SP;
+
+	/*
+	 * Similar to above, prefetch faults aren't truly spurious, and the
+	 * async #PF path doesn't do emulation.  Do count faults that are fixed
+	 * by the async #PF handler though, otherwise they'll never be counted.
+	 */
+	if (r == RET_PF_FIXED)
+		vcpu->stat.pf_fixed++;
+	else if (prefetch)
+		;
+	else if (r == RET_PF_EMULATE)
+		vcpu->stat.pf_emulate++;
+	else if (r == RET_PF_SPURIOUS)
+		vcpu->stat.pf_spurious++;
+	return r;
+}
+
+int kvm_mmu_max_mapping_level(struct kvm *kvm,
+			      const struct kvm_memory_slot *slot, gfn_t gfn,
+			      int max_level);
+void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
+void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level);
+
+void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc);
+
+void track_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp);
+void untrack_possible_nx_huge_page(struct kvm *kvm, struct kvm_mmu_page *sp);
+
+#endif /* __KVM_X86_MMU_INTERNAL_H */
diff --git a/arch/x86/kvm/mmu/mmutrace.h b/arch/x86/kvm/mmu/mmutrace.h
new file mode 100644
index 0000000000..ae86820cef
--- /dev/null
+++ b/arch/x86/kvm/mmu/mmutrace.h
@@ -0,0 +1,451 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#if !defined(_TRACE_KVMMMU_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_KVMMMU_H
+
+#include <linux/tracepoint.h>
+#include <linux/trace_events.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM kvmmmu
+
+#define KVM_MMU_PAGE_FIELDS		\
+	__field(__u8, mmu_valid_gen)	\
+	__field(__u64, gfn)		\
+	__field(__u32, role)		\
+	__field(__u32, root_count)	\
+	__field(bool, unsync)
+
+#define KVM_MMU_PAGE_ASSIGN(sp)				\
+	__entry->mmu_valid_gen = sp->mmu_valid_gen;	\
+	__entry->gfn = sp->gfn;				\
+	__entry->role = sp->role.word;			\
+	__entry->root_count = sp->root_count;		\
+	__entry->unsync = sp->unsync;
+
+#define KVM_MMU_PAGE_PRINTK() ({				        \
+	const char *saved_ptr = trace_seq_buffer_ptr(p);		\
+	static const char *access_str[] = {			        \
+		"---", "--x", "w--", "w-x", "-u-", "-ux", "wu-", "wux"  \
+	};							        \
+	union kvm_mmu_page_role role;				        \
+								        \
+	role.word = __entry->role;					\
+									\
+	trace_seq_printf(p, "sp gen %u gfn %llx l%u %u-byte q%u%s %s%s"	\
+			 " %snxe %sad root %u %s%c",			\
+			 __entry->mmu_valid_gen,			\
+			 __entry->gfn, role.level,			\
+			 role.has_4_byte_gpte ? 4 : 8,			\
+			 role.quadrant,					\
+			 role.direct ? " direct" : "",			\
+			 access_str[role.access],			\
+			 role.invalid ? " invalid" : "",		\
+			 role.efer_nx ? "" : "!",			\
+			 role.ad_disabled ? "!" : "",			\
+			 __entry->root_count,				\
+			 __entry->unsync ? "unsync" : "sync", 0);	\
+	saved_ptr;							\
+		})
+
+#define kvm_mmu_trace_pferr_flags       \
+	{ PFERR_PRESENT_MASK, "P" },	\
+	{ PFERR_WRITE_MASK, "W" },	\
+	{ PFERR_USER_MASK, "U" },	\
+	{ PFERR_RSVD_MASK, "RSVD" },	\
+	{ PFERR_FETCH_MASK, "F" }
+
+TRACE_DEFINE_ENUM(RET_PF_CONTINUE);
+TRACE_DEFINE_ENUM(RET_PF_RETRY);
+TRACE_DEFINE_ENUM(RET_PF_EMULATE);
+TRACE_DEFINE_ENUM(RET_PF_INVALID);
+TRACE_DEFINE_ENUM(RET_PF_FIXED);
+TRACE_DEFINE_ENUM(RET_PF_SPURIOUS);
+
+/*
+ * A pagetable walk has started
+ */
+TRACE_EVENT(
+	kvm_mmu_pagetable_walk,
+	TP_PROTO(u64 addr, u32 pferr),
+	TP_ARGS(addr, pferr),
+
+	TP_STRUCT__entry(
+		__field(__u64, addr)
+		__field(__u32, pferr)
+	),
+
+	TP_fast_assign(
+		__entry->addr = addr;
+		__entry->pferr = pferr;
+	),
+
+	TP_printk("addr %llx pferr %x %s", __entry->addr, __entry->pferr,
+		  __print_flags(__entry->pferr, "|", kvm_mmu_trace_pferr_flags))
+);
+
+
+/* We just walked a paging element */
+TRACE_EVENT(
+	kvm_mmu_paging_element,
+	TP_PROTO(u64 pte, int level),
+	TP_ARGS(pte, level),
+
+	TP_STRUCT__entry(
+		__field(__u64, pte)
+		__field(__u32, level)
+		),
+
+	TP_fast_assign(
+		__entry->pte = pte;
+		__entry->level = level;
+		),
+
+	TP_printk("pte %llx level %u", __entry->pte, __entry->level)
+);
+
+DECLARE_EVENT_CLASS(kvm_mmu_set_bit_class,
+
+	TP_PROTO(unsigned long table_gfn, unsigned index, unsigned size),
+
+	TP_ARGS(table_gfn, index, size),
+
+	TP_STRUCT__entry(
+		__field(__u64, gpa)
+	),
+
+	TP_fast_assign(
+		__entry->gpa = ((u64)table_gfn << PAGE_SHIFT)
+				+ index * size;
+		),
+
+	TP_printk("gpa %llx", __entry->gpa)
+);
+
+/* We set a pte accessed bit */
+DEFINE_EVENT(kvm_mmu_set_bit_class, kvm_mmu_set_accessed_bit,
+
+	TP_PROTO(unsigned long table_gfn, unsigned index, unsigned size),
+
+	TP_ARGS(table_gfn, index, size)
+);
+
+/* We set a pte dirty bit */
+DEFINE_EVENT(kvm_mmu_set_bit_class, kvm_mmu_set_dirty_bit,
+
+	TP_PROTO(unsigned long table_gfn, unsigned index, unsigned size),
+
+	TP_ARGS(table_gfn, index, size)
+);
+
+TRACE_EVENT(
+	kvm_mmu_walker_error,
+	TP_PROTO(u32 pferr),
+	TP_ARGS(pferr),
+
+	TP_STRUCT__entry(
+		__field(__u32, pferr)
+		),
+
+	TP_fast_assign(
+		__entry->pferr = pferr;
+		),
+
+	TP_printk("pferr %x %s", __entry->pferr,
+		  __print_flags(__entry->pferr, "|", kvm_mmu_trace_pferr_flags))
+);
+
+TRACE_EVENT(
+	kvm_mmu_get_page,
+	TP_PROTO(struct kvm_mmu_page *sp, bool created),
+	TP_ARGS(sp, created),
+
+	TP_STRUCT__entry(
+		KVM_MMU_PAGE_FIELDS
+		__field(bool, created)
+		),
+
+	TP_fast_assign(
+		KVM_MMU_PAGE_ASSIGN(sp)
+		__entry->created = created;
+		),
+
+	TP_printk("%s %s", KVM_MMU_PAGE_PRINTK(),
+		  __entry->created ? "new" : "existing")
+);
+
+DECLARE_EVENT_CLASS(kvm_mmu_page_class,
+
+	TP_PROTO(struct kvm_mmu_page *sp),
+	TP_ARGS(sp),
+
+	TP_STRUCT__entry(
+		KVM_MMU_PAGE_FIELDS
+	),
+
+	TP_fast_assign(
+		KVM_MMU_PAGE_ASSIGN(sp)
+	),
+
+	TP_printk("%s", KVM_MMU_PAGE_PRINTK())
+);
+
+DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_sync_page,
+	TP_PROTO(struct kvm_mmu_page *sp),
+
+	TP_ARGS(sp)
+);
+
+DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_unsync_page,
+	TP_PROTO(struct kvm_mmu_page *sp),
+
+	TP_ARGS(sp)
+);
+
+DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_prepare_zap_page,
+	TP_PROTO(struct kvm_mmu_page *sp),
+
+	TP_ARGS(sp)
+);
+
+TRACE_EVENT(
+	mark_mmio_spte,
+	TP_PROTO(u64 *sptep, gfn_t gfn, u64 spte),
+	TP_ARGS(sptep, gfn, spte),
+
+	TP_STRUCT__entry(
+		__field(void *, sptep)
+		__field(gfn_t, gfn)
+		__field(unsigned, access)
+		__field(unsigned int, gen)
+	),
+
+	TP_fast_assign(
+		__entry->sptep = sptep;
+		__entry->gfn = gfn;
+		__entry->access = spte & ACC_ALL;
+		__entry->gen = get_mmio_spte_generation(spte);
+	),
+
+	TP_printk("sptep:%p gfn %llx access %x gen %x", __entry->sptep,
+		  __entry->gfn, __entry->access, __entry->gen)
+);
+
+TRACE_EVENT(
+	handle_mmio_page_fault,
+	TP_PROTO(u64 addr, gfn_t gfn, unsigned access),
+	TP_ARGS(addr, gfn, access),
+
+	TP_STRUCT__entry(
+		__field(u64, addr)
+		__field(gfn_t, gfn)
+		__field(unsigned, access)
+	),
+
+	TP_fast_assign(
+		__entry->addr = addr;
+		__entry->gfn = gfn;
+		__entry->access = access;
+	),
+
+	TP_printk("addr:%llx gfn %llx access %x", __entry->addr, __entry->gfn,
+		  __entry->access)
+);
+
+TRACE_EVENT(
+	fast_page_fault,
+	TP_PROTO(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
+		 u64 *sptep, u64 old_spte, int ret),
+	TP_ARGS(vcpu, fault, sptep, old_spte, ret),
+
+	TP_STRUCT__entry(
+		__field(int, vcpu_id)
+		__field(gpa_t, cr2_or_gpa)
+		__field(u32, error_code)
+		__field(u64 *, sptep)
+		__field(u64, old_spte)
+		__field(u64, new_spte)
+		__field(int, ret)
+	),
+
+	TP_fast_assign(
+		__entry->vcpu_id = vcpu->vcpu_id;
+		__entry->cr2_or_gpa = fault->addr;
+		__entry->error_code = fault->error_code;
+		__entry->sptep = sptep;
+		__entry->old_spte = old_spte;
+		__entry->new_spte = *sptep;
+		__entry->ret = ret;
+	),
+
+	TP_printk("vcpu %d gva %llx error_code %s sptep %p old %#llx"
+		  " new %llx spurious %d fixed %d", __entry->vcpu_id,
+		  __entry->cr2_or_gpa, __print_flags(__entry->error_code, "|",
+		  kvm_mmu_trace_pferr_flags), __entry->sptep,
+		  __entry->old_spte, __entry->new_spte,
+		  __entry->ret == RET_PF_SPURIOUS, __entry->ret == RET_PF_FIXED
+	)
+);
+
+TRACE_EVENT(
+	kvm_mmu_zap_all_fast,
+	TP_PROTO(struct kvm *kvm),
+	TP_ARGS(kvm),
+
+	TP_STRUCT__entry(
+		__field(__u8, mmu_valid_gen)
+		__field(unsigned int, mmu_used_pages)
+	),
+
+	TP_fast_assign(
+		__entry->mmu_valid_gen = kvm->arch.mmu_valid_gen;
+		__entry->mmu_used_pages = kvm->arch.n_used_mmu_pages;
+	),
+
+	TP_printk("kvm-mmu-valid-gen %u used_pages %x",
+		  __entry->mmu_valid_gen, __entry->mmu_used_pages
+	)
+);
+
+
+TRACE_EVENT(
+	check_mmio_spte,
+	TP_PROTO(u64 spte, unsigned int kvm_gen, unsigned int spte_gen),
+	TP_ARGS(spte, kvm_gen, spte_gen),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, kvm_gen)
+		__field(unsigned int, spte_gen)
+		__field(u64, spte)
+	),
+
+	TP_fast_assign(
+		__entry->kvm_gen = kvm_gen;
+		__entry->spte_gen = spte_gen;
+		__entry->spte = spte;
+	),
+
+	TP_printk("spte %llx kvm_gen %x spte-gen %x valid %d", __entry->spte,
+		  __entry->kvm_gen, __entry->spte_gen,
+		  __entry->kvm_gen == __entry->spte_gen
+	)
+);
+
+TRACE_EVENT(
+	kvm_mmu_set_spte,
+	TP_PROTO(int level, gfn_t gfn, u64 *sptep),
+	TP_ARGS(level, gfn, sptep),
+
+	TP_STRUCT__entry(
+		__field(u64, gfn)
+		__field(u64, spte)
+		__field(u64, sptep)
+		__field(u8, level)
+		/* These depend on page entry type, so compute them now.  */
+		__field(bool, r)
+		__field(bool, x)
+		__field(signed char, u)
+	),
+
+	TP_fast_assign(
+		__entry->gfn = gfn;
+		__entry->spte = *sptep;
+		__entry->sptep = virt_to_phys(sptep);
+		__entry->level = level;
+		__entry->r = shadow_present_mask || (__entry->spte & PT_PRESENT_MASK);
+		__entry->x = is_executable_pte(__entry->spte);
+		__entry->u = shadow_user_mask ? !!(__entry->spte & shadow_user_mask) : -1;
+	),
+
+	TP_printk("gfn %llx spte %llx (%s%s%s%s) level %d at %llx",
+		  __entry->gfn, __entry->spte,
+		  __entry->r ? "r" : "-",
+		  __entry->spte & PT_WRITABLE_MASK ? "w" : "-",
+		  __entry->x ? "x" : "-",
+		  __entry->u == -1 ? "" : (__entry->u ? "u" : "-"),
+		  __entry->level, __entry->sptep
+	)
+);
+
+TRACE_EVENT(
+	kvm_mmu_spte_requested,
+	TP_PROTO(struct kvm_page_fault *fault),
+	TP_ARGS(fault),
+
+	TP_STRUCT__entry(
+		__field(u64, gfn)
+		__field(u64, pfn)
+		__field(u8, level)
+	),
+
+	TP_fast_assign(
+		__entry->gfn = fault->gfn;
+		__entry->pfn = fault->pfn | (fault->gfn & (KVM_PAGES_PER_HPAGE(fault->goal_level) - 1));
+		__entry->level = fault->goal_level;
+	),
+
+	TP_printk("gfn %llx pfn %llx level %d",
+		  __entry->gfn, __entry->pfn, __entry->level
+	)
+);
+
+TRACE_EVENT(
+	kvm_tdp_mmu_spte_changed,
+	TP_PROTO(int as_id, gfn_t gfn, int level, u64 old_spte, u64 new_spte),
+	TP_ARGS(as_id, gfn, level, old_spte, new_spte),
+
+	TP_STRUCT__entry(
+		__field(u64, gfn)
+		__field(u64, old_spte)
+		__field(u64, new_spte)
+		/* Level cannot be larger than 5 on x86, so it fits in a u8. */
+		__field(u8, level)
+		/* as_id can only be 0 or 1 x86, so it fits in a u8. */
+		__field(u8, as_id)
+	),
+
+	TP_fast_assign(
+		__entry->gfn = gfn;
+		__entry->old_spte = old_spte;
+		__entry->new_spte = new_spte;
+		__entry->level = level;
+		__entry->as_id = as_id;
+	),
+
+	TP_printk("as id %d gfn %llx level %d old_spte %llx new_spte %llx",
+		  __entry->as_id, __entry->gfn, __entry->level,
+		  __entry->old_spte, __entry->new_spte
+	)
+);
+
+TRACE_EVENT(
+	kvm_mmu_split_huge_page,
+	TP_PROTO(u64 gfn, u64 spte, int level, int errno),
+	TP_ARGS(gfn, spte, level, errno),
+
+	TP_STRUCT__entry(
+		__field(u64, gfn)
+		__field(u64, spte)
+		__field(int, level)
+		__field(int, errno)
+	),
+
+	TP_fast_assign(
+		__entry->gfn = gfn;
+		__entry->spte = spte;
+		__entry->level = level;
+		__entry->errno = errno;
+	),
+
+	TP_printk("gfn %llx spte %llx level %d errno %d",
+		  __entry->gfn, __entry->spte, __entry->level, __entry->errno)
+);
+
+#endif /* _TRACE_KVMMMU_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH mmu
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE mmutrace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
new file mode 100644
index 0000000000..c87da11f3a
--- /dev/null
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -0,0 +1,307 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Support KVM gust page tracking
+ *
+ * This feature allows us to track page access in guest. Currently, only
+ * write access is tracked.
+ *
+ * Copyright(C) 2015 Intel Corporation.
+ *
+ * Author:
+ *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/lockdep.h>
+#include <linux/kvm_host.h>
+#include <linux/rculist.h>
+
+#include "mmu.h"
+#include "mmu_internal.h"
+#include "page_track.h"
+
+bool kvm_page_track_write_tracking_enabled(struct kvm *kvm)
+{
+	return IS_ENABLED(CONFIG_KVM_EXTERNAL_WRITE_TRACKING) ||
+	       !tdp_enabled || kvm_shadow_root_allocated(kvm);
+}
+
+void kvm_page_track_free_memslot(struct kvm_memory_slot *slot)
+{
+	kvfree(slot->arch.gfn_write_track);
+	slot->arch.gfn_write_track = NULL;
+}
+
+static int __kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot,
+						 unsigned long npages)
+{
+	const size_t size = sizeof(*slot->arch.gfn_write_track);
+
+	if (!slot->arch.gfn_write_track)
+		slot->arch.gfn_write_track = __vcalloc(npages, size,
+						       GFP_KERNEL_ACCOUNT);
+
+	return slot->arch.gfn_write_track ? 0 : -ENOMEM;
+}
+
+int kvm_page_track_create_memslot(struct kvm *kvm,
+				  struct kvm_memory_slot *slot,
+				  unsigned long npages)
+{
+	if (!kvm_page_track_write_tracking_enabled(kvm))
+		return 0;
+
+	return __kvm_page_track_write_tracking_alloc(slot, npages);
+}
+
+int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot)
+{
+	return __kvm_page_track_write_tracking_alloc(slot, slot->npages);
+}
+
+static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn,
+				   short count)
+{
+	int index, val;
+
+	index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
+
+	val = slot->arch.gfn_write_track[index];
+
+	if (WARN_ON_ONCE(val + count < 0 || val + count > USHRT_MAX))
+		return;
+
+	slot->arch.gfn_write_track[index] += count;
+}
+
+void __kvm_write_track_add_gfn(struct kvm *kvm, struct kvm_memory_slot *slot,
+			       gfn_t gfn)
+{
+	lockdep_assert_held_write(&kvm->mmu_lock);
+
+	lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
+			    srcu_read_lock_held(&kvm->srcu));
+
+	if (KVM_BUG_ON(!kvm_page_track_write_tracking_enabled(kvm), kvm))
+		return;
+
+	update_gfn_write_track(slot, gfn, 1);
+
+	/*
+	 * new track stops large page mapping for the
+	 * tracked page.
+	 */
+	kvm_mmu_gfn_disallow_lpage(slot, gfn);
+
+	if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K))
+		kvm_flush_remote_tlbs(kvm);
+}
+
+void __kvm_write_track_remove_gfn(struct kvm *kvm,
+				  struct kvm_memory_slot *slot, gfn_t gfn)
+{
+	lockdep_assert_held_write(&kvm->mmu_lock);
+
+	lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
+			    srcu_read_lock_held(&kvm->srcu));
+
+	if (KVM_BUG_ON(!kvm_page_track_write_tracking_enabled(kvm), kvm))
+		return;
+
+	update_gfn_write_track(slot, gfn, -1);
+
+	/*
+	 * allow large page mapping for the tracked page
+	 * after the tracker is gone.
+	 */
+	kvm_mmu_gfn_allow_lpage(slot, gfn);
+}
+
+/*
+ * check if the corresponding access on the specified guest page is tracked.
+ */
+bool kvm_gfn_is_write_tracked(struct kvm *kvm,
+			      const struct kvm_memory_slot *slot, gfn_t gfn)
+{
+	int index;
+
+	if (!slot)
+		return false;
+
+	if (!kvm_page_track_write_tracking_enabled(kvm))
+		return false;
+
+	index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
+	return !!READ_ONCE(slot->arch.gfn_write_track[index]);
+}
+
+#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
+void kvm_page_track_cleanup(struct kvm *kvm)
+{
+	struct kvm_page_track_notifier_head *head;
+
+	head = &kvm->arch.track_notifier_head;
+	cleanup_srcu_struct(&head->track_srcu);
+}
+
+int kvm_page_track_init(struct kvm *kvm)
+{
+	struct kvm_page_track_notifier_head *head;
+
+	head = &kvm->arch.track_notifier_head;
+	INIT_HLIST_HEAD(&head->track_notifier_list);
+	return init_srcu_struct(&head->track_srcu);
+}
+
+/*
+ * register the notifier so that event interception for the tracked guest
+ * pages can be received.
+ */
+int kvm_page_track_register_notifier(struct kvm *kvm,
+				     struct kvm_page_track_notifier_node *n)
+{
+	struct kvm_page_track_notifier_head *head;
+
+	if (!kvm || kvm->mm != current->mm)
+		return -ESRCH;
+
+	kvm_get_kvm(kvm);
+
+	head = &kvm->arch.track_notifier_head;
+
+	write_lock(&kvm->mmu_lock);
+	hlist_add_head_rcu(&n->node, &head->track_notifier_list);
+	write_unlock(&kvm->mmu_lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_page_track_register_notifier);
+
+/*
+ * stop receiving the event interception. It is the opposed operation of
+ * kvm_page_track_register_notifier().
+ */
+void kvm_page_track_unregister_notifier(struct kvm *kvm,
+					struct kvm_page_track_notifier_node *n)
+{
+	struct kvm_page_track_notifier_head *head;
+
+	head = &kvm->arch.track_notifier_head;
+
+	write_lock(&kvm->mmu_lock);
+	hlist_del_rcu(&n->node);
+	write_unlock(&kvm->mmu_lock);
+	synchronize_srcu(&head->track_srcu);
+
+	kvm_put_kvm(kvm);
+}
+EXPORT_SYMBOL_GPL(kvm_page_track_unregister_notifier);
+
+/*
+ * Notify the node that write access is intercepted and write emulation is
+ * finished at this time.
+ *
+ * The node should figure out if the written page is the one that node is
+ * interested in by itself.
+ */
+void __kvm_page_track_write(struct kvm *kvm, gpa_t gpa, const u8 *new, int bytes)
+{
+	struct kvm_page_track_notifier_head *head;
+	struct kvm_page_track_notifier_node *n;
+	int idx;
+
+	head = &kvm->arch.track_notifier_head;
+
+	if (hlist_empty(&head->track_notifier_list))
+		return;
+
+	idx = srcu_read_lock(&head->track_srcu);
+	hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
+				  srcu_read_lock_held(&head->track_srcu))
+		if (n->track_write)
+			n->track_write(gpa, new, bytes, n);
+	srcu_read_unlock(&head->track_srcu, idx);
+}
+
+/*
+ * Notify external page track nodes that a memory region is being removed from
+ * the VM, e.g. so that users can free any associated metadata.
+ */
+void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
+{
+	struct kvm_page_track_notifier_head *head;
+	struct kvm_page_track_notifier_node *n;
+	int idx;
+
+	head = &kvm->arch.track_notifier_head;
+
+	if (hlist_empty(&head->track_notifier_list))
+		return;
+
+	idx = srcu_read_lock(&head->track_srcu);
+	hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
+				  srcu_read_lock_held(&head->track_srcu))
+		if (n->track_remove_region)
+			n->track_remove_region(slot->base_gfn, slot->npages, n);
+	srcu_read_unlock(&head->track_srcu, idx);
+}
+
+/*
+ * add guest page to the tracking pool so that corresponding access on that
+ * page will be intercepted.
+ *
+ * @kvm: the guest instance we are interested in.
+ * @gfn: the guest page.
+ */
+int kvm_write_track_add_gfn(struct kvm *kvm, gfn_t gfn)
+{
+	struct kvm_memory_slot *slot;
+	int idx;
+
+	idx = srcu_read_lock(&kvm->srcu);
+
+	slot = gfn_to_memslot(kvm, gfn);
+	if (!slot) {
+		srcu_read_unlock(&kvm->srcu, idx);
+		return -EINVAL;
+	}
+
+	write_lock(&kvm->mmu_lock);
+	__kvm_write_track_add_gfn(kvm, slot, gfn);
+	write_unlock(&kvm->mmu_lock);
+
+	srcu_read_unlock(&kvm->srcu, idx);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_write_track_add_gfn);
+
+/*
+ * remove the guest page from the tracking pool which stops the interception
+ * of corresponding access on that page.
+ *
+ * @kvm: the guest instance we are interested in.
+ * @gfn: the guest page.
+ */
+int kvm_write_track_remove_gfn(struct kvm *kvm, gfn_t gfn)
+{
+	struct kvm_memory_slot *slot;
+	int idx;
+
+	idx = srcu_read_lock(&kvm->srcu);
+
+	slot = gfn_to_memslot(kvm, gfn);
+	if (!slot) {
+		srcu_read_unlock(&kvm->srcu, idx);
+		return -EINVAL;
+	}
+
+	write_lock(&kvm->mmu_lock);
+	__kvm_write_track_remove_gfn(kvm, slot, gfn);
+	write_unlock(&kvm->mmu_lock);
+
+	srcu_read_unlock(&kvm->srcu, idx);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_write_track_remove_gfn);
+#endif
diff --git a/arch/x86/kvm/mmu/page_track.h b/arch/x86/kvm/mmu/page_track.h
new file mode 100644
index 0000000000..d4d72ed999
--- /dev/null
+++ b/arch/x86/kvm/mmu/page_track.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_X86_PAGE_TRACK_H
+#define __KVM_X86_PAGE_TRACK_H
+
+#include <linux/kvm_host.h>
+
+#include <asm/kvm_page_track.h>
+
+
+bool kvm_page_track_write_tracking_enabled(struct kvm *kvm);
+int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot);
+
+void kvm_page_track_free_memslot(struct kvm_memory_slot *slot);
+int kvm_page_track_create_memslot(struct kvm *kvm,
+				  struct kvm_memory_slot *slot,
+				  unsigned long npages);
+
+void __kvm_write_track_add_gfn(struct kvm *kvm, struct kvm_memory_slot *slot,
+			       gfn_t gfn);
+void __kvm_write_track_remove_gfn(struct kvm *kvm,
+				  struct kvm_memory_slot *slot, gfn_t gfn);
+
+bool kvm_gfn_is_write_tracked(struct kvm *kvm,
+			      const struct kvm_memory_slot *slot, gfn_t gfn);
+
+#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
+int kvm_page_track_init(struct kvm *kvm);
+void kvm_page_track_cleanup(struct kvm *kvm);
+
+void __kvm_page_track_write(struct kvm *kvm, gpa_t gpa, const u8 *new, int bytes);
+void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot);
+
+static inline bool kvm_page_track_has_external_user(struct kvm *kvm)
+{
+	return !hlist_empty(&kvm->arch.track_notifier_head.track_notifier_list);
+}
+#else
+static inline int kvm_page_track_init(struct kvm *kvm) { return 0; }
+static inline void kvm_page_track_cleanup(struct kvm *kvm) { }
+
+static inline void __kvm_page_track_write(struct kvm *kvm, gpa_t gpa,
+					  const u8 *new, int bytes) { }
+static inline void kvm_page_track_delete_slot(struct kvm *kvm,
+					      struct kvm_memory_slot *slot) { }
+
+static inline bool kvm_page_track_has_external_user(struct kvm *kvm) { return false; }
+
+#endif /* CONFIG_KVM_EXTERNAL_WRITE_TRACKING */
+
+static inline void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa,
+					const u8 *new, int bytes)
+{
+	__kvm_page_track_write(vcpu->kvm, gpa, new, bytes);
+
+	kvm_mmu_track_write(vcpu, gpa, new, bytes);
+}
+
+#endif /* __KVM_X86_PAGE_TRACK_H */
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
new file mode 100644
index 0000000000..c85255073f
--- /dev/null
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -0,0 +1,985 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Kernel-based Virtual Machine driver for Linux
+ *
+ * This module enables machines with Intel VT-x extensions to run virtual
+ * machines without emulation or binary translation.
+ *
+ * MMU support
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ * Copyright 2010 Red Hat, Inc. and/or its affiliates.
+ *
+ * Authors:
+ *   Yaniv Kamay  <yaniv@qumranet.com>
+ *   Avi Kivity   <avi@qumranet.com>
+ */
+
+/*
+ * The MMU needs to be able to access/walk 32-bit and 64-bit guest page tables,
+ * as well as guest EPT tables, so the code in this file is compiled thrice,
+ * once per guest PTE type.  The per-type defines are #undef'd at the end.
+ */
+
+#if PTTYPE == 64
+	#define pt_element_t u64
+	#define guest_walker guest_walker64
+	#define FNAME(name) paging##64_##name
+	#define PT_LEVEL_BITS 9
+	#define PT_GUEST_DIRTY_SHIFT PT_DIRTY_SHIFT
+	#define PT_GUEST_ACCESSED_SHIFT PT_ACCESSED_SHIFT
+	#define PT_HAVE_ACCESSED_DIRTY(mmu) true
+	#ifdef CONFIG_X86_64
+	#define PT_MAX_FULL_LEVELS PT64_ROOT_MAX_LEVEL
+	#else
+	#define PT_MAX_FULL_LEVELS 2
+	#endif
+#elif PTTYPE == 32
+	#define pt_element_t u32
+	#define guest_walker guest_walker32
+	#define FNAME(name) paging##32_##name
+	#define PT_LEVEL_BITS 10
+	#define PT_MAX_FULL_LEVELS 2
+	#define PT_GUEST_DIRTY_SHIFT PT_DIRTY_SHIFT
+	#define PT_GUEST_ACCESSED_SHIFT PT_ACCESSED_SHIFT
+	#define PT_HAVE_ACCESSED_DIRTY(mmu) true
+
+	#define PT32_DIR_PSE36_SIZE 4
+	#define PT32_DIR_PSE36_SHIFT 13
+	#define PT32_DIR_PSE36_MASK \
+		(((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT)
+#elif PTTYPE == PTTYPE_EPT
+	#define pt_element_t u64
+	#define guest_walker guest_walkerEPT
+	#define FNAME(name) ept_##name
+	#define PT_LEVEL_BITS 9
+	#define PT_GUEST_DIRTY_SHIFT 9
+	#define PT_GUEST_ACCESSED_SHIFT 8
+	#define PT_HAVE_ACCESSED_DIRTY(mmu) (!(mmu)->cpu_role.base.ad_disabled)
+	#define PT_MAX_FULL_LEVELS PT64_ROOT_MAX_LEVEL
+#else
+	#error Invalid PTTYPE value
+#endif
+
+/* Common logic, but per-type values.  These also need to be undefined. */
+#define PT_BASE_ADDR_MASK	((pt_element_t)(((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1)))
+#define PT_LVL_ADDR_MASK(lvl)	__PT_LVL_ADDR_MASK(PT_BASE_ADDR_MASK, lvl, PT_LEVEL_BITS)
+#define PT_LVL_OFFSET_MASK(lvl)	__PT_LVL_OFFSET_MASK(PT_BASE_ADDR_MASK, lvl, PT_LEVEL_BITS)
+#define PT_INDEX(addr, lvl)	__PT_INDEX(addr, lvl, PT_LEVEL_BITS)
+
+#define PT_GUEST_DIRTY_MASK    (1 << PT_GUEST_DIRTY_SHIFT)
+#define PT_GUEST_ACCESSED_MASK (1 << PT_GUEST_ACCESSED_SHIFT)
+
+#define gpte_to_gfn_lvl FNAME(gpte_to_gfn_lvl)
+#define gpte_to_gfn(pte) gpte_to_gfn_lvl((pte), PG_LEVEL_4K)
+
+/*
+ * The guest_walker structure emulates the behavior of the hardware page
+ * table walker.
+ */
+struct guest_walker {
+	int level;
+	unsigned max_level;
+	gfn_t table_gfn[PT_MAX_FULL_LEVELS];
+	pt_element_t ptes[PT_MAX_FULL_LEVELS];
+	pt_element_t prefetch_ptes[PTE_PREFETCH_NUM];
+	gpa_t pte_gpa[PT_MAX_FULL_LEVELS];
+	pt_element_t __user *ptep_user[PT_MAX_FULL_LEVELS];
+	bool pte_writable[PT_MAX_FULL_LEVELS];
+	unsigned int pt_access[PT_MAX_FULL_LEVELS];
+	unsigned int pte_access;
+	gfn_t gfn;
+	struct x86_exception fault;
+};
+
+#if PTTYPE == 32
+static inline gfn_t pse36_gfn_delta(u32 gpte)
+{
+	int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
+
+	return (gpte & PT32_DIR_PSE36_MASK) << shift;
+}
+#endif
+
+static gfn_t gpte_to_gfn_lvl(pt_element_t gpte, int lvl)
+{
+	return (gpte & PT_LVL_ADDR_MASK(lvl)) >> PAGE_SHIFT;
+}
+
+static inline void FNAME(protect_clean_gpte)(struct kvm_mmu *mmu, unsigned *access,
+					     unsigned gpte)
+{
+	unsigned mask;
+
+	/* dirty bit is not supported, so no need to track it */
+	if (!PT_HAVE_ACCESSED_DIRTY(mmu))
+		return;
+
+	BUILD_BUG_ON(PT_WRITABLE_MASK != ACC_WRITE_MASK);
+
+	mask = (unsigned)~ACC_WRITE_MASK;
+	/* Allow write access to dirty gptes */
+	mask |= (gpte >> (PT_GUEST_DIRTY_SHIFT - PT_WRITABLE_SHIFT)) &
+		PT_WRITABLE_MASK;
+	*access &= mask;
+}
+
+static inline int FNAME(is_present_gpte)(unsigned long pte)
+{
+#if PTTYPE != PTTYPE_EPT
+	return pte & PT_PRESENT_MASK;
+#else
+	return pte & 7;
+#endif
+}
+
+static bool FNAME(is_bad_mt_xwr)(struct rsvd_bits_validate *rsvd_check, u64 gpte)
+{
+#if PTTYPE != PTTYPE_EPT
+	return false;
+#else
+	return __is_bad_mt_xwr(rsvd_check, gpte);
+#endif
+}
+
+static bool FNAME(is_rsvd_bits_set)(struct kvm_mmu *mmu, u64 gpte, int level)
+{
+	return __is_rsvd_bits_set(&mmu->guest_rsvd_check, gpte, level) ||
+	       FNAME(is_bad_mt_xwr)(&mmu->guest_rsvd_check, gpte);
+}
+
+static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu,
+				  struct kvm_mmu_page *sp, u64 *spte,
+				  u64 gpte)
+{
+	if (!FNAME(is_present_gpte)(gpte))
+		goto no_present;
+
+	/* Prefetch only accessed entries (unless A/D bits are disabled). */
+	if (PT_HAVE_ACCESSED_DIRTY(vcpu->arch.mmu) &&
+	    !(gpte & PT_GUEST_ACCESSED_MASK))
+		goto no_present;
+
+	if (FNAME(is_rsvd_bits_set)(vcpu->arch.mmu, gpte, PG_LEVEL_4K))
+		goto no_present;
+
+	return false;
+
+no_present:
+	drop_spte(vcpu->kvm, spte);
+	return true;
+}
+
+/*
+ * For PTTYPE_EPT, a page table can be executable but not readable
+ * on supported processors. Therefore, set_spte does not automatically
+ * set bit 0 if execute only is supported. Here, we repurpose ACC_USER_MASK
+ * to signify readability since it isn't used in the EPT case
+ */
+static inline unsigned FNAME(gpte_access)(u64 gpte)
+{
+	unsigned access;
+#if PTTYPE == PTTYPE_EPT
+	access = ((gpte & VMX_EPT_WRITABLE_MASK) ? ACC_WRITE_MASK : 0) |
+		((gpte & VMX_EPT_EXECUTABLE_MASK) ? ACC_EXEC_MASK : 0) |
+		((gpte & VMX_EPT_READABLE_MASK) ? ACC_USER_MASK : 0);
+#else
+	BUILD_BUG_ON(ACC_EXEC_MASK != PT_PRESENT_MASK);
+	BUILD_BUG_ON(ACC_EXEC_MASK != 1);
+	access = gpte & (PT_WRITABLE_MASK | PT_USER_MASK | PT_PRESENT_MASK);
+	/* Combine NX with P (which is set here) to get ACC_EXEC_MASK.  */
+	access ^= (gpte >> PT64_NX_SHIFT);
+#endif
+
+	return access;
+}
+
+static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
+					     struct kvm_mmu *mmu,
+					     struct guest_walker *walker,
+					     gpa_t addr, int write_fault)
+{
+	unsigned level, index;
+	pt_element_t pte, orig_pte;
+	pt_element_t __user *ptep_user;
+	gfn_t table_gfn;
+	int ret;
+
+	/* dirty/accessed bits are not supported, so no need to update them */
+	if (!PT_HAVE_ACCESSED_DIRTY(mmu))
+		return 0;
+
+	for (level = walker->max_level; level >= walker->level; --level) {
+		pte = orig_pte = walker->ptes[level - 1];
+		table_gfn = walker->table_gfn[level - 1];
+		ptep_user = walker->ptep_user[level - 1];
+		index = offset_in_page(ptep_user) / sizeof(pt_element_t);
+		if (!(pte & PT_GUEST_ACCESSED_MASK)) {
+			trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(pte));
+			pte |= PT_GUEST_ACCESSED_MASK;
+		}
+		if (level == walker->level && write_fault &&
+				!(pte & PT_GUEST_DIRTY_MASK)) {
+			trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
+#if PTTYPE == PTTYPE_EPT
+			if (kvm_x86_ops.nested_ops->write_log_dirty(vcpu, addr))
+				return -EINVAL;
+#endif
+			pte |= PT_GUEST_DIRTY_MASK;
+		}
+		if (pte == orig_pte)
+			continue;
+
+		/*
+		 * If the slot is read-only, simply do not process the accessed
+		 * and dirty bits.  This is the correct thing to do if the slot
+		 * is ROM, and page tables in read-as-ROM/write-as-MMIO slots
+		 * are only supported if the accessed and dirty bits are already
+		 * set in the ROM (so that MMIO writes are never needed).
+		 *
+		 * Note that NPT does not allow this at all and faults, since
+		 * it always wants nested page table entries for the guest
+		 * page tables to be writable.  And EPT works but will simply
+		 * overwrite the read-only memory to set the accessed and dirty
+		 * bits.
+		 */
+		if (unlikely(!walker->pte_writable[level - 1]))
+			continue;
+
+		ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault);
+		if (ret)
+			return ret;
+
+		kvm_vcpu_mark_page_dirty(vcpu, table_gfn);
+		walker->ptes[level - 1] = pte;
+	}
+	return 0;
+}
+
+static inline unsigned FNAME(gpte_pkeys)(struct kvm_vcpu *vcpu, u64 gpte)
+{
+	unsigned pkeys = 0;
+#if PTTYPE == 64
+	pte_t pte = {.pte = gpte};
+
+	pkeys = pte_flags_pkey(pte_flags(pte));
+#endif
+	return pkeys;
+}
+
+static inline bool FNAME(is_last_gpte)(struct kvm_mmu *mmu,
+				       unsigned int level, unsigned int gpte)
+{
+	/*
+	 * For EPT and PAE paging (both variants), bit 7 is either reserved at
+	 * all level or indicates a huge page (ignoring CR3/EPTP).  In either
+	 * case, bit 7 being set terminates the walk.
+	 */
+#if PTTYPE == 32
+	/*
+	 * 32-bit paging requires special handling because bit 7 is ignored if
+	 * CR4.PSE=0, not reserved.  Clear bit 7 in the gpte if the level is
+	 * greater than the last level for which bit 7 is the PAGE_SIZE bit.
+	 *
+	 * The RHS has bit 7 set iff level < (2 + PSE).  If it is clear, bit 7
+	 * is not reserved and does not indicate a large page at this level,
+	 * so clear PT_PAGE_SIZE_MASK in gpte if that is the case.
+	 */
+	gpte &= level - (PT32_ROOT_LEVEL + mmu->cpu_role.ext.cr4_pse);
+#endif
+	/*
+	 * PG_LEVEL_4K always terminates.  The RHS has bit 7 set
+	 * iff level <= PG_LEVEL_4K, which for our purpose means
+	 * level == PG_LEVEL_4K; set PT_PAGE_SIZE_MASK in gpte then.
+	 */
+	gpte |= level - PG_LEVEL_4K - 1;
+
+	return gpte & PT_PAGE_SIZE_MASK;
+}
+/*
+ * Fetch a guest pte for a guest virtual address, or for an L2's GPA.
+ */
+static int FNAME(walk_addr_generic)(struct guest_walker *walker,
+				    struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+				    gpa_t addr, u64 access)
+{
+	int ret;
+	pt_element_t pte;
+	pt_element_t __user *ptep_user;
+	gfn_t table_gfn;
+	u64 pt_access, pte_access;
+	unsigned index, accessed_dirty, pte_pkey;
+	u64 nested_access;
+	gpa_t pte_gpa;
+	bool have_ad;
+	int offset;
+	u64 walk_nx_mask = 0;
+	const int write_fault = access & PFERR_WRITE_MASK;
+	const int user_fault  = access & PFERR_USER_MASK;
+	const int fetch_fault = access & PFERR_FETCH_MASK;
+	u16 errcode = 0;
+	gpa_t real_gpa;
+	gfn_t gfn;
+
+	trace_kvm_mmu_pagetable_walk(addr, access);
+retry_walk:
+	walker->level = mmu->cpu_role.base.level;
+	pte           = kvm_mmu_get_guest_pgd(vcpu, mmu);
+	have_ad       = PT_HAVE_ACCESSED_DIRTY(mmu);
+
+#if PTTYPE == 64
+	walk_nx_mask = 1ULL << PT64_NX_SHIFT;
+	if (walker->level == PT32E_ROOT_LEVEL) {
+		pte = mmu->get_pdptr(vcpu, (addr >> 30) & 3);
+		trace_kvm_mmu_paging_element(pte, walker->level);
+		if (!FNAME(is_present_gpte)(pte))
+			goto error;
+		--walker->level;
+	}
+#endif
+	walker->max_level = walker->level;
+
+	/*
+	 * FIXME: on Intel processors, loads of the PDPTE registers for PAE paging
+	 * by the MOV to CR instruction are treated as reads and do not cause the
+	 * processor to set the dirty flag in any EPT paging-structure entry.
+	 */
+	nested_access = (have_ad ? PFERR_WRITE_MASK : 0) | PFERR_USER_MASK;
+
+	pte_access = ~0;
+
+	/*
+	 * Queue a page fault for injection if this assertion fails, as callers
+	 * assume that walker.fault contains sane info on a walk failure.  I.e.
+	 * avoid making the situation worse by inducing even worse badness
+	 * between when the assertion fails and when KVM kicks the vCPU out to
+	 * userspace (because the VM is bugged).
+	 */
+	if (KVM_BUG_ON(is_long_mode(vcpu) && !is_pae(vcpu), vcpu->kvm))
+		goto error;
+
+	++walker->level;
+
+	do {
+		struct kvm_memory_slot *slot;
+		unsigned long host_addr;
+
+		pt_access = pte_access;
+		--walker->level;
+
+		index = PT_INDEX(addr, walker->level);
+		table_gfn = gpte_to_gfn(pte);
+		offset    = index * sizeof(pt_element_t);
+		pte_gpa   = gfn_to_gpa(table_gfn) + offset;
+
+		BUG_ON(walker->level < 1);
+		walker->table_gfn[walker->level - 1] = table_gfn;
+		walker->pte_gpa[walker->level - 1] = pte_gpa;
+
+		real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(table_gfn),
+					     nested_access, &walker->fault);
+
+		/*
+		 * FIXME: This can happen if emulation (for of an INS/OUTS
+		 * instruction) triggers a nested page fault.  The exit
+		 * qualification / exit info field will incorrectly have
+		 * "guest page access" as the nested page fault's cause,
+		 * instead of "guest page structure access".  To fix this,
+		 * the x86_exception struct should be augmented with enough
+		 * information to fix the exit_qualification or exit_info_1
+		 * fields.
+		 */
+		if (unlikely(real_gpa == INVALID_GPA))
+			return 0;
+
+		slot = kvm_vcpu_gfn_to_memslot(vcpu, gpa_to_gfn(real_gpa));
+		if (!kvm_is_visible_memslot(slot))
+			goto error;
+
+		host_addr = gfn_to_hva_memslot_prot(slot, gpa_to_gfn(real_gpa),
+					    &walker->pte_writable[walker->level - 1]);
+		if (unlikely(kvm_is_error_hva(host_addr)))
+			goto error;
+
+		ptep_user = (pt_element_t __user *)((void *)host_addr + offset);
+		if (unlikely(__get_user(pte, ptep_user)))
+			goto error;
+		walker->ptep_user[walker->level - 1] = ptep_user;
+
+		trace_kvm_mmu_paging_element(pte, walker->level);
+
+		/*
+		 * Inverting the NX it lets us AND it like other
+		 * permission bits.
+		 */
+		pte_access = pt_access & (pte ^ walk_nx_mask);
+
+		if (unlikely(!FNAME(is_present_gpte)(pte)))
+			goto error;
+
+		if (unlikely(FNAME(is_rsvd_bits_set)(mmu, pte, walker->level))) {
+			errcode = PFERR_RSVD_MASK | PFERR_PRESENT_MASK;
+			goto error;
+		}
+
+		walker->ptes[walker->level - 1] = pte;
+
+		/* Convert to ACC_*_MASK flags for struct guest_walker.  */
+		walker->pt_access[walker->level - 1] = FNAME(gpte_access)(pt_access ^ walk_nx_mask);
+	} while (!FNAME(is_last_gpte)(mmu, walker->level, pte));
+
+	pte_pkey = FNAME(gpte_pkeys)(vcpu, pte);
+	accessed_dirty = have_ad ? pte_access & PT_GUEST_ACCESSED_MASK : 0;
+
+	/* Convert to ACC_*_MASK flags for struct guest_walker.  */
+	walker->pte_access = FNAME(gpte_access)(pte_access ^ walk_nx_mask);
+	errcode = permission_fault(vcpu, mmu, walker->pte_access, pte_pkey, access);
+	if (unlikely(errcode))
+		goto error;
+
+	gfn = gpte_to_gfn_lvl(pte, walker->level);
+	gfn += (addr & PT_LVL_OFFSET_MASK(walker->level)) >> PAGE_SHIFT;
+
+#if PTTYPE == 32
+	if (walker->level > PG_LEVEL_4K && is_cpuid_PSE36())
+		gfn += pse36_gfn_delta(pte);
+#endif
+
+	real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(gfn), access, &walker->fault);
+	if (real_gpa == INVALID_GPA)
+		return 0;
+
+	walker->gfn = real_gpa >> PAGE_SHIFT;
+
+	if (!write_fault)
+		FNAME(protect_clean_gpte)(mmu, &walker->pte_access, pte);
+	else
+		/*
+		 * On a write fault, fold the dirty bit into accessed_dirty.
+		 * For modes without A/D bits support accessed_dirty will be
+		 * always clear.
+		 */
+		accessed_dirty &= pte >>
+			(PT_GUEST_DIRTY_SHIFT - PT_GUEST_ACCESSED_SHIFT);
+
+	if (unlikely(!accessed_dirty)) {
+		ret = FNAME(update_accessed_dirty_bits)(vcpu, mmu, walker,
+							addr, write_fault);
+		if (unlikely(ret < 0))
+			goto error;
+		else if (ret)
+			goto retry_walk;
+	}
+
+	return 1;
+
+error:
+	errcode |= write_fault | user_fault;
+	if (fetch_fault && (is_efer_nx(mmu) || is_cr4_smep(mmu)))
+		errcode |= PFERR_FETCH_MASK;
+
+	walker->fault.vector = PF_VECTOR;
+	walker->fault.error_code_valid = true;
+	walker->fault.error_code = errcode;
+
+#if PTTYPE == PTTYPE_EPT
+	/*
+	 * Use PFERR_RSVD_MASK in error_code to tell if EPT
+	 * misconfiguration requires to be injected. The detection is
+	 * done by is_rsvd_bits_set() above.
+	 *
+	 * We set up the value of exit_qualification to inject:
+	 * [2:0] - Derive from the access bits. The exit_qualification might be
+	 *         out of date if it is serving an EPT misconfiguration.
+	 * [5:3] - Calculated by the page walk of the guest EPT page tables
+	 * [7:8] - Derived from [7:8] of real exit_qualification
+	 *
+	 * The other bits are set to 0.
+	 */
+	if (!(errcode & PFERR_RSVD_MASK)) {
+		vcpu->arch.exit_qualification &= (EPT_VIOLATION_GVA_IS_VALID |
+						  EPT_VIOLATION_GVA_TRANSLATED);
+		if (write_fault)
+			vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_WRITE;
+		if (user_fault)
+			vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_READ;
+		if (fetch_fault)
+			vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_INSTR;
+
+		/*
+		 * Note, pte_access holds the raw RWX bits from the EPTE, not
+		 * ACC_*_MASK flags!
+		 */
+		vcpu->arch.exit_qualification |= (pte_access & VMX_EPT_RWX_MASK) <<
+						 EPT_VIOLATION_RWX_SHIFT;
+	}
+#endif
+	walker->fault.address = addr;
+	walker->fault.nested_page_fault = mmu != vcpu->arch.walk_mmu;
+	walker->fault.async_page_fault = false;
+
+	trace_kvm_mmu_walker_error(walker->fault.error_code);
+	return 0;
+}
+
+static int FNAME(walk_addr)(struct guest_walker *walker,
+			    struct kvm_vcpu *vcpu, gpa_t addr, u64 access)
+{
+	return FNAME(walk_addr_generic)(walker, vcpu, vcpu->arch.mmu, addr,
+					access);
+}
+
+static bool
+FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+		     u64 *spte, pt_element_t gpte)
+{
+	struct kvm_memory_slot *slot;
+	unsigned pte_access;
+	gfn_t gfn;
+	kvm_pfn_t pfn;
+
+	if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
+		return false;
+
+	gfn = gpte_to_gfn(gpte);
+	pte_access = sp->role.access & FNAME(gpte_access)(gpte);
+	FNAME(protect_clean_gpte)(vcpu->arch.mmu, &pte_access, gpte);
+
+	slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, pte_access & ACC_WRITE_MASK);
+	if (!slot)
+		return false;
+
+	pfn = gfn_to_pfn_memslot_atomic(slot, gfn);
+	if (is_error_pfn(pfn))
+		return false;
+
+	mmu_set_spte(vcpu, slot, spte, pte_access, gfn, pfn, NULL);
+	kvm_release_pfn_clean(pfn);
+	return true;
+}
+
+static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu,
+				struct guest_walker *gw, int level)
+{
+	pt_element_t curr_pte;
+	gpa_t base_gpa, pte_gpa = gw->pte_gpa[level - 1];
+	u64 mask;
+	int r, index;
+
+	if (level == PG_LEVEL_4K) {
+		mask = PTE_PREFETCH_NUM * sizeof(pt_element_t) - 1;
+		base_gpa = pte_gpa & ~mask;
+		index = (pte_gpa - base_gpa) / sizeof(pt_element_t);
+
+		r = kvm_vcpu_read_guest_atomic(vcpu, base_gpa,
+				gw->prefetch_ptes, sizeof(gw->prefetch_ptes));
+		curr_pte = gw->prefetch_ptes[index];
+	} else
+		r = kvm_vcpu_read_guest_atomic(vcpu, pte_gpa,
+				  &curr_pte, sizeof(curr_pte));
+
+	return r || curr_pte != gw->ptes[level - 1];
+}
+
+static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
+				u64 *sptep)
+{
+	struct kvm_mmu_page *sp;
+	pt_element_t *gptep = gw->prefetch_ptes;
+	u64 *spte;
+	int i;
+
+	sp = sptep_to_sp(sptep);
+
+	if (sp->role.level > PG_LEVEL_4K)
+		return;
+
+	/*
+	 * If addresses are being invalidated, skip prefetching to avoid
+	 * accidentally prefetching those addresses.
+	 */
+	if (unlikely(vcpu->kvm->mmu_invalidate_in_progress))
+		return;
+
+	if (sp->role.direct)
+		return __direct_pte_prefetch(vcpu, sp, sptep);
+
+	i = spte_index(sptep) & ~(PTE_PREFETCH_NUM - 1);
+	spte = sp->spt + i;
+
+	for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
+		if (spte == sptep)
+			continue;
+
+		if (is_shadow_present_pte(*spte))
+			continue;
+
+		if (!FNAME(prefetch_gpte)(vcpu, sp, spte, gptep[i]))
+			break;
+	}
+}
+
+/*
+ * Fetch a shadow pte for a specific level in the paging hierarchy.
+ * If the guest tries to write a write-protected page, we need to
+ * emulate this operation, return 1 to indicate this case.
+ */
+static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
+			 struct guest_walker *gw)
+{
+	struct kvm_mmu_page *sp = NULL;
+	struct kvm_shadow_walk_iterator it;
+	unsigned int direct_access, access;
+	int top_level, ret;
+	gfn_t base_gfn = fault->gfn;
+
+	WARN_ON_ONCE(gw->gfn != base_gfn);
+	direct_access = gw->pte_access;
+
+	top_level = vcpu->arch.mmu->cpu_role.base.level;
+	if (top_level == PT32E_ROOT_LEVEL)
+		top_level = PT32_ROOT_LEVEL;
+	/*
+	 * Verify that the top-level gpte is still there.  Since the page
+	 * is a root page, it is either write protected (and cannot be
+	 * changed from now on) or it is invalid (in which case, we don't
+	 * really care if it changes underneath us after this point).
+	 */
+	if (FNAME(gpte_changed)(vcpu, gw, top_level))
+		goto out_gpte_changed;
+
+	if (WARN_ON_ONCE(!VALID_PAGE(vcpu->arch.mmu->root.hpa)))
+		goto out_gpte_changed;
+
+	/*
+	 * Load a new root and retry the faulting instruction in the extremely
+	 * unlikely scenario that the guest root gfn became visible between
+	 * loading a dummy root and handling the resulting page fault, e.g. if
+	 * userspace create a memslot in the interim.
+	 */
+	if (unlikely(kvm_mmu_is_dummy_root(vcpu->arch.mmu->root.hpa))) {
+		kvm_make_request(KVM_REQ_MMU_FREE_OBSOLETE_ROOTS, vcpu);
+		goto out_gpte_changed;
+	}
+
+	for_each_shadow_entry(vcpu, fault->addr, it) {
+		gfn_t table_gfn;
+
+		clear_sp_write_flooding_count(it.sptep);
+		if (it.level == gw->level)
+			break;
+
+		table_gfn = gw->table_gfn[it.level - 2];
+		access = gw->pt_access[it.level - 2];
+		sp = kvm_mmu_get_child_sp(vcpu, it.sptep, table_gfn,
+					  false, access);
+
+		if (sp != ERR_PTR(-EEXIST)) {
+			/*
+			 * We must synchronize the pagetable before linking it
+			 * because the guest doesn't need to flush tlb when
+			 * the gpte is changed from non-present to present.
+			 * Otherwise, the guest may use the wrong mapping.
+			 *
+			 * For PG_LEVEL_4K, kvm_mmu_get_page() has already
+			 * synchronized it transiently via kvm_sync_page().
+			 *
+			 * For higher level pagetable, we synchronize it via
+			 * the slower mmu_sync_children().  If it needs to
+			 * break, some progress has been made; return
+			 * RET_PF_RETRY and retry on the next #PF.
+			 * KVM_REQ_MMU_SYNC is not necessary but it
+			 * expedites the process.
+			 */
+			if (sp->unsync_children &&
+			    mmu_sync_children(vcpu, sp, false))
+				return RET_PF_RETRY;
+		}
+
+		/*
+		 * Verify that the gpte in the page we've just write
+		 * protected is still there.
+		 */
+		if (FNAME(gpte_changed)(vcpu, gw, it.level - 1))
+			goto out_gpte_changed;
+
+		if (sp != ERR_PTR(-EEXIST))
+			link_shadow_page(vcpu, it.sptep, sp);
+
+		if (fault->write && table_gfn == fault->gfn)
+			fault->write_fault_to_shadow_pgtable = true;
+	}
+
+	/*
+	 * Adjust the hugepage size _after_ resolving indirect shadow pages.
+	 * KVM doesn't support mapping hugepages into the guest for gfns that
+	 * are being shadowed by KVM, i.e. allocating a new shadow page may
+	 * affect the allowed hugepage size.
+	 */
+	kvm_mmu_hugepage_adjust(vcpu, fault);
+
+	trace_kvm_mmu_spte_requested(fault);
+
+	for (; shadow_walk_okay(&it); shadow_walk_next(&it)) {
+		/*
+		 * We cannot overwrite existing page tables with an NX
+		 * large page, as the leaf could be executable.
+		 */
+		if (fault->nx_huge_page_workaround_enabled)
+			disallowed_hugepage_adjust(fault, *it.sptep, it.level);
+
+		base_gfn = gfn_round_for_level(fault->gfn, it.level);
+		if (it.level == fault->goal_level)
+			break;
+
+		validate_direct_spte(vcpu, it.sptep, direct_access);
+
+		sp = kvm_mmu_get_child_sp(vcpu, it.sptep, base_gfn,
+					  true, direct_access);
+		if (sp == ERR_PTR(-EEXIST))
+			continue;
+
+		link_shadow_page(vcpu, it.sptep, sp);
+		if (fault->huge_page_disallowed)
+			account_nx_huge_page(vcpu->kvm, sp,
+					     fault->req_level >= it.level);
+	}
+
+	if (WARN_ON_ONCE(it.level != fault->goal_level))
+		return -EFAULT;
+
+	ret = mmu_set_spte(vcpu, fault->slot, it.sptep, gw->pte_access,
+			   base_gfn, fault->pfn, fault);
+	if (ret == RET_PF_SPURIOUS)
+		return ret;
+
+	FNAME(pte_prefetch)(vcpu, gw, it.sptep);
+	return ret;
+
+out_gpte_changed:
+	return RET_PF_RETRY;
+}
+
+/*
+ * Page fault handler.  There are several causes for a page fault:
+ *   - there is no shadow pte for the guest pte
+ *   - write access through a shadow pte marked read only so that we can set
+ *     the dirty bit
+ *   - write access to a shadow pte marked read only so we can update the page
+ *     dirty bitmap, when userspace requests it
+ *   - mmio access; in this case we will never install a present shadow pte
+ *   - normal guest page fault due to the guest pte marked not present, not
+ *     writable, or not executable
+ *
+ *  Returns: 1 if we need to emulate the instruction, 0 otherwise, or
+ *           a negative value on error.
+ */
+static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+	struct guest_walker walker;
+	int r;
+
+	WARN_ON_ONCE(fault->is_tdp);
+
+	/*
+	 * Look up the guest pte for the faulting address.
+	 * If PFEC.RSVD is set, this is a shadow page fault.
+	 * The bit needs to be cleared before walking guest page tables.
+	 */
+	r = FNAME(walk_addr)(&walker, vcpu, fault->addr,
+			     fault->error_code & ~PFERR_RSVD_MASK);
+
+	/*
+	 * The page is not mapped by the guest.  Let the guest handle it.
+	 */
+	if (!r) {
+		if (!fault->prefetch)
+			kvm_inject_emulated_page_fault(vcpu, &walker.fault);
+
+		return RET_PF_RETRY;
+	}
+
+	fault->gfn = walker.gfn;
+	fault->max_level = walker.level;
+	fault->slot = kvm_vcpu_gfn_to_memslot(vcpu, fault->gfn);
+
+	if (page_fault_handle_page_track(vcpu, fault)) {
+		shadow_page_table_clear_flood(vcpu, fault->addr);
+		return RET_PF_EMULATE;
+	}
+
+	r = mmu_topup_memory_caches(vcpu, true);
+	if (r)
+		return r;
+
+	r = kvm_faultin_pfn(vcpu, fault, walker.pte_access);
+	if (r != RET_PF_CONTINUE)
+		return r;
+
+	/*
+	 * Do not change pte_access if the pfn is a mmio page, otherwise
+	 * we will cache the incorrect access into mmio spte.
+	 */
+	if (fault->write && !(walker.pte_access & ACC_WRITE_MASK) &&
+	    !is_cr0_wp(vcpu->arch.mmu) && !fault->user && fault->slot) {
+		walker.pte_access |= ACC_WRITE_MASK;
+		walker.pte_access &= ~ACC_USER_MASK;
+
+		/*
+		 * If we converted a user page to a kernel page,
+		 * so that the kernel can write to it when cr0.wp=0,
+		 * then we should prevent the kernel from executing it
+		 * if SMEP is enabled.
+		 */
+		if (is_cr4_smep(vcpu->arch.mmu))
+			walker.pte_access &= ~ACC_EXEC_MASK;
+	}
+
+	r = RET_PF_RETRY;
+	write_lock(&vcpu->kvm->mmu_lock);
+
+	if (is_page_fault_stale(vcpu, fault))
+		goto out_unlock;
+
+	r = make_mmu_pages_available(vcpu);
+	if (r)
+		goto out_unlock;
+	r = FNAME(fetch)(vcpu, fault, &walker);
+
+out_unlock:
+	write_unlock(&vcpu->kvm->mmu_lock);
+	kvm_release_pfn_clean(fault->pfn);
+	return r;
+}
+
+static gpa_t FNAME(get_level1_sp_gpa)(struct kvm_mmu_page *sp)
+{
+	int offset = 0;
+
+	WARN_ON_ONCE(sp->role.level != PG_LEVEL_4K);
+
+	if (PTTYPE == 32)
+		offset = sp->role.quadrant << SPTE_LEVEL_BITS;
+
+	return gfn_to_gpa(sp->gfn) + offset * sizeof(pt_element_t);
+}
+
+/* Note, @addr is a GPA when gva_to_gpa() translates an L2 GPA to an L1 GPA. */
+static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+			       gpa_t addr, u64 access,
+			       struct x86_exception *exception)
+{
+	struct guest_walker walker;
+	gpa_t gpa = INVALID_GPA;
+	int r;
+
+#ifndef CONFIG_X86_64
+	/* A 64-bit GVA should be impossible on 32-bit KVM. */
+	WARN_ON_ONCE((addr >> 32) && mmu == vcpu->arch.walk_mmu);
+#endif
+
+	r = FNAME(walk_addr_generic)(&walker, vcpu, mmu, addr, access);
+
+	if (r) {
+		gpa = gfn_to_gpa(walker.gfn);
+		gpa |= addr & ~PAGE_MASK;
+	} else if (exception)
+		*exception = walker.fault;
+
+	return gpa;
+}
+
+/*
+ * Using the information in sp->shadowed_translation (kvm_mmu_page_get_gfn()) is
+ * safe because:
+ * - The spte has a reference to the struct page, so the pfn for a given gfn
+ *   can't change unless all sptes pointing to it are nuked first.
+ *
+ * Returns
+ * < 0: failed to sync spte
+ *   0: the spte is synced and no tlb flushing is required
+ * > 0: the spte is synced and tlb flushing is required
+ */
+static int FNAME(sync_spte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int i)
+{
+	bool host_writable;
+	gpa_t first_pte_gpa;
+	u64 *sptep, spte;
+	struct kvm_memory_slot *slot;
+	unsigned pte_access;
+	pt_element_t gpte;
+	gpa_t pte_gpa;
+	gfn_t gfn;
+
+	if (WARN_ON_ONCE(!sp->spt[i]))
+		return 0;
+
+	first_pte_gpa = FNAME(get_level1_sp_gpa)(sp);
+	pte_gpa = first_pte_gpa + i * sizeof(pt_element_t);
+
+	if (kvm_vcpu_read_guest_atomic(vcpu, pte_gpa, &gpte,
+				       sizeof(pt_element_t)))
+		return -1;
+
+	if (FNAME(prefetch_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte))
+		return 1;
+
+	gfn = gpte_to_gfn(gpte);
+	pte_access = sp->role.access;
+	pte_access &= FNAME(gpte_access)(gpte);
+	FNAME(protect_clean_gpte)(vcpu->arch.mmu, &pte_access, gpte);
+
+	if (sync_mmio_spte(vcpu, &sp->spt[i], gfn, pte_access))
+		return 0;
+
+	/*
+	 * Drop the SPTE if the new protections would result in a RWX=0
+	 * SPTE or if the gfn is changing.  The RWX=0 case only affects
+	 * EPT with execute-only support, i.e. EPT without an effective
+	 * "present" bit, as all other paging modes will create a
+	 * read-only SPTE if pte_access is zero.
+	 */
+	if ((!pte_access && !shadow_present_mask) ||
+	    gfn != kvm_mmu_page_get_gfn(sp, i)) {
+		drop_spte(vcpu->kvm, &sp->spt[i]);
+		return 1;
+	}
+	/*
+	 * Do nothing if the permissions are unchanged.  The existing SPTE is
+	 * still, and prefetch_invalid_gpte() has verified that the A/D bits
+	 * are set in the "new" gPTE, i.e. there is no danger of missing an A/D
+	 * update due to A/D bits being set in the SPTE but not the gPTE.
+	 */
+	if (kvm_mmu_page_get_access(sp, i) == pte_access)
+		return 0;
+
+	/* Update the shadowed access bits in case they changed. */
+	kvm_mmu_page_set_access(sp, i, pte_access);
+
+	sptep = &sp->spt[i];
+	spte = *sptep;
+	host_writable = spte & shadow_host_writable_mask;
+	slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+	make_spte(vcpu, sp, slot, pte_access, gfn,
+		  spte_to_pfn(spte), spte, true, false,
+		  host_writable, &spte);
+
+	return mmu_spte_update(sptep, spte);
+}
+
+#undef pt_element_t
+#undef guest_walker
+#undef FNAME
+#undef PT_BASE_ADDR_MASK
+#undef PT_INDEX
+#undef PT_LVL_ADDR_MASK
+#undef PT_LVL_OFFSET_MASK
+#undef PT_LEVEL_BITS
+#undef PT_MAX_FULL_LEVELS
+#undef gpte_to_gfn
+#undef gpte_to_gfn_lvl
+#undef PT_GUEST_ACCESSED_MASK
+#undef PT_GUEST_DIRTY_MASK
+#undef PT_GUEST_DIRTY_SHIFT
+#undef PT_GUEST_ACCESSED_SHIFT
+#undef PT_HAVE_ACCESSED_DIRTY
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c
new file mode 100644
index 0000000000..4a599130e9
--- /dev/null
+++ b/arch/x86/kvm/mmu/spte.c
@@ -0,0 +1,517 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Kernel-based Virtual Machine driver for Linux
+ *
+ * Macros and functions to access KVM PTEs (also known as SPTEs)
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ * Copyright 2020 Red Hat, Inc. and/or its affiliates.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kvm_host.h>
+#include "mmu.h"
+#include "mmu_internal.h"
+#include "x86.h"
+#include "spte.h"
+
+#include <asm/e820/api.h>
+#include <asm/memtype.h>
+#include <asm/vmx.h>
+
+bool __read_mostly enable_mmio_caching = true;
+static bool __ro_after_init allow_mmio_caching;
+module_param_named(mmio_caching, enable_mmio_caching, bool, 0444);
+EXPORT_SYMBOL_GPL(enable_mmio_caching);
+
+u64 __read_mostly shadow_host_writable_mask;
+u64 __read_mostly shadow_mmu_writable_mask;
+u64 __read_mostly shadow_nx_mask;
+u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
+u64 __read_mostly shadow_user_mask;
+u64 __read_mostly shadow_accessed_mask;
+u64 __read_mostly shadow_dirty_mask;
+u64 __read_mostly shadow_mmio_value;
+u64 __read_mostly shadow_mmio_mask;
+u64 __read_mostly shadow_mmio_access_mask;
+u64 __read_mostly shadow_present_mask;
+u64 __read_mostly shadow_memtype_mask;
+u64 __read_mostly shadow_me_value;
+u64 __read_mostly shadow_me_mask;
+u64 __read_mostly shadow_acc_track_mask;
+
+u64 __read_mostly shadow_nonpresent_or_rsvd_mask;
+u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask;
+
+u8 __read_mostly shadow_phys_bits;
+
+void __init kvm_mmu_spte_module_init(void)
+{
+	/*
+	 * Snapshot userspace's desire to allow MMIO caching.  Whether or not
+	 * KVM can actually enable MMIO caching depends on vendor-specific
+	 * hardware capabilities and other module params that can't be resolved
+	 * until the vendor module is loaded, i.e. enable_mmio_caching can and
+	 * will change when the vendor module is (re)loaded.
+	 */
+	allow_mmio_caching = enable_mmio_caching;
+}
+
+static u64 generation_mmio_spte_mask(u64 gen)
+{
+	u64 mask;
+
+	WARN_ON_ONCE(gen & ~MMIO_SPTE_GEN_MASK);
+
+	mask = (gen << MMIO_SPTE_GEN_LOW_SHIFT) & MMIO_SPTE_GEN_LOW_MASK;
+	mask |= (gen << MMIO_SPTE_GEN_HIGH_SHIFT) & MMIO_SPTE_GEN_HIGH_MASK;
+	return mask;
+}
+
+u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access)
+{
+	u64 gen = kvm_vcpu_memslots(vcpu)->generation & MMIO_SPTE_GEN_MASK;
+	u64 spte = generation_mmio_spte_mask(gen);
+	u64 gpa = gfn << PAGE_SHIFT;
+
+	WARN_ON_ONCE(!shadow_mmio_value);
+
+	access &= shadow_mmio_access_mask;
+	spte |= shadow_mmio_value | access;
+	spte |= gpa | shadow_nonpresent_or_rsvd_mask;
+	spte |= (gpa & shadow_nonpresent_or_rsvd_mask)
+		<< SHADOW_NONPRESENT_OR_RSVD_MASK_LEN;
+
+	return spte;
+}
+
+static bool kvm_is_mmio_pfn(kvm_pfn_t pfn)
+{
+	if (pfn_valid(pfn))
+		return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)) &&
+			/*
+			 * Some reserved pages, such as those from NVDIMM
+			 * DAX devices, are not for MMIO, and can be mapped
+			 * with cached memory type for better performance.
+			 * However, the above check misconceives those pages
+			 * as MMIO, and results in KVM mapping them with UC
+			 * memory type, which would hurt the performance.
+			 * Therefore, we check the host memory type in addition
+			 * and only treat UC/UC-/WC pages as MMIO.
+			 */
+			(!pat_enabled() || pat_pfn_immune_to_uc_mtrr(pfn));
+
+	return !e820__mapped_raw_any(pfn_to_hpa(pfn),
+				     pfn_to_hpa(pfn + 1) - 1,
+				     E820_TYPE_RAM);
+}
+
+/*
+ * Returns true if the SPTE has bits that may be set without holding mmu_lock.
+ * The caller is responsible for checking if the SPTE is shadow-present, and
+ * for determining whether or not the caller cares about non-leaf SPTEs.
+ */
+bool spte_has_volatile_bits(u64 spte)
+{
+	/*
+	 * Always atomically update spte if it can be updated
+	 * out of mmu-lock, it can ensure dirty bit is not lost,
+	 * also, it can help us to get a stable is_writable_pte()
+	 * to ensure tlb flush is not missed.
+	 */
+	if (!is_writable_pte(spte) && is_mmu_writable_spte(spte))
+		return true;
+
+	if (is_access_track_spte(spte))
+		return true;
+
+	if (spte_ad_enabled(spte)) {
+		if (!(spte & shadow_accessed_mask) ||
+		    (is_writable_pte(spte) && !(spte & shadow_dirty_mask)))
+			return true;
+	}
+
+	return false;
+}
+
+bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+	       const struct kvm_memory_slot *slot,
+	       unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn,
+	       u64 old_spte, bool prefetch, bool can_unsync,
+	       bool host_writable, u64 *new_spte)
+{
+	int level = sp->role.level;
+	u64 spte = SPTE_MMU_PRESENT_MASK;
+	bool wrprot = false;
+
+	WARN_ON_ONCE(!pte_access && !shadow_present_mask);
+
+	if (sp->role.ad_disabled)
+		spte |= SPTE_TDP_AD_DISABLED;
+	else if (kvm_mmu_page_ad_need_write_protect(sp))
+		spte |= SPTE_TDP_AD_WRPROT_ONLY;
+
+	/*
+	 * For the EPT case, shadow_present_mask is 0 if hardware
+	 * supports exec-only page table entries.  In that case,
+	 * ACC_USER_MASK and shadow_user_mask are used to represent
+	 * read access.  See FNAME(gpte_access) in paging_tmpl.h.
+	 */
+	spte |= shadow_present_mask;
+	if (!prefetch)
+		spte |= spte_shadow_accessed_mask(spte);
+
+	/*
+	 * For simplicity, enforce the NX huge page mitigation even if not
+	 * strictly necessary.  KVM could ignore the mitigation if paging is
+	 * disabled in the guest, as the guest doesn't have any page tables to
+	 * abuse.  But to safely ignore the mitigation, KVM would have to
+	 * ensure a new MMU is loaded (or all shadow pages zapped) when CR0.PG
+	 * is toggled on, and that's a net negative for performance when TDP is
+	 * enabled.  When TDP is disabled, KVM will always switch to a new MMU
+	 * when CR0.PG is toggled, but leveraging that to ignore the mitigation
+	 * would tie make_spte() further to vCPU/MMU state, and add complexity
+	 * just to optimize a mode that is anything but performance critical.
+	 */
+	if (level > PG_LEVEL_4K && (pte_access & ACC_EXEC_MASK) &&
+	    is_nx_huge_page_enabled(vcpu->kvm)) {
+		pte_access &= ~ACC_EXEC_MASK;
+	}
+
+	if (pte_access & ACC_EXEC_MASK)
+		spte |= shadow_x_mask;
+	else
+		spte |= shadow_nx_mask;
+
+	if (pte_access & ACC_USER_MASK)
+		spte |= shadow_user_mask;
+
+	if (level > PG_LEVEL_4K)
+		spte |= PT_PAGE_SIZE_MASK;
+
+	if (shadow_memtype_mask)
+		spte |= static_call(kvm_x86_get_mt_mask)(vcpu, gfn,
+							 kvm_is_mmio_pfn(pfn));
+	if (host_writable)
+		spte |= shadow_host_writable_mask;
+	else
+		pte_access &= ~ACC_WRITE_MASK;
+
+	if (shadow_me_value && !kvm_is_mmio_pfn(pfn))
+		spte |= shadow_me_value;
+
+	spte |= (u64)pfn << PAGE_SHIFT;
+
+	if (pte_access & ACC_WRITE_MASK) {
+		spte |= PT_WRITABLE_MASK | shadow_mmu_writable_mask;
+
+		/*
+		 * Optimization: for pte sync, if spte was writable the hash
+		 * lookup is unnecessary (and expensive). Write protection
+		 * is responsibility of kvm_mmu_get_page / kvm_mmu_sync_roots.
+		 * Same reasoning can be applied to dirty page accounting.
+		 */
+		if (is_writable_pte(old_spte))
+			goto out;
+
+		/*
+		 * Unsync shadow pages that are reachable by the new, writable
+		 * SPTE.  Write-protect the SPTE if the page can't be unsync'd,
+		 * e.g. it's write-tracked (upper-level SPs) or has one or more
+		 * shadow pages and unsync'ing pages is not allowed.
+		 */
+		if (mmu_try_to_unsync_pages(vcpu->kvm, slot, gfn, can_unsync, prefetch)) {
+			wrprot = true;
+			pte_access &= ~ACC_WRITE_MASK;
+			spte &= ~(PT_WRITABLE_MASK | shadow_mmu_writable_mask);
+		}
+	}
+
+	if (pte_access & ACC_WRITE_MASK)
+		spte |= spte_shadow_dirty_mask(spte);
+
+out:
+	if (prefetch)
+		spte = mark_spte_for_access_track(spte);
+
+	WARN_ONCE(is_rsvd_spte(&vcpu->arch.mmu->shadow_zero_check, spte, level),
+		  "spte = 0x%llx, level = %d, rsvd bits = 0x%llx", spte, level,
+		  get_rsvd_bits(&vcpu->arch.mmu->shadow_zero_check, spte, level));
+
+	if ((spte & PT_WRITABLE_MASK) && kvm_slot_dirty_track_enabled(slot)) {
+		/* Enforced by kvm_mmu_hugepage_adjust. */
+		WARN_ON_ONCE(level > PG_LEVEL_4K);
+		mark_page_dirty_in_slot(vcpu->kvm, slot, gfn);
+	}
+
+	*new_spte = spte;
+	return wrprot;
+}
+
+static u64 make_spte_executable(u64 spte)
+{
+	bool is_access_track = is_access_track_spte(spte);
+
+	if (is_access_track)
+		spte = restore_acc_track_spte(spte);
+
+	spte &= ~shadow_nx_mask;
+	spte |= shadow_x_mask;
+
+	if (is_access_track)
+		spte = mark_spte_for_access_track(spte);
+
+	return spte;
+}
+
+/*
+ * Construct an SPTE that maps a sub-page of the given huge page SPTE where
+ * `index` identifies which sub-page.
+ *
+ * This is used during huge page splitting to build the SPTEs that make up the
+ * new page table.
+ */
+u64 make_huge_page_split_spte(struct kvm *kvm, u64 huge_spte, union kvm_mmu_page_role role,
+			      int index)
+{
+	u64 child_spte;
+
+	if (WARN_ON_ONCE(!is_shadow_present_pte(huge_spte)))
+		return 0;
+
+	if (WARN_ON_ONCE(!is_large_pte(huge_spte)))
+		return 0;
+
+	child_spte = huge_spte;
+
+	/*
+	 * The child_spte already has the base address of the huge page being
+	 * split. So we just have to OR in the offset to the page at the next
+	 * lower level for the given index.
+	 */
+	child_spte |= (index * KVM_PAGES_PER_HPAGE(role.level)) << PAGE_SHIFT;
+
+	if (role.level == PG_LEVEL_4K) {
+		child_spte &= ~PT_PAGE_SIZE_MASK;
+
+		/*
+		 * When splitting to a 4K page where execution is allowed, mark
+		 * the page executable as the NX hugepage mitigation no longer
+		 * applies.
+		 */
+		if ((role.access & ACC_EXEC_MASK) && is_nx_huge_page_enabled(kvm))
+			child_spte = make_spte_executable(child_spte);
+	}
+
+	return child_spte;
+}
+
+
+u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled)
+{
+	u64 spte = SPTE_MMU_PRESENT_MASK;
+
+	spte |= __pa(child_pt) | shadow_present_mask | PT_WRITABLE_MASK |
+		shadow_user_mask | shadow_x_mask | shadow_me_value;
+
+	if (ad_disabled)
+		spte |= SPTE_TDP_AD_DISABLED;
+	else
+		spte |= shadow_accessed_mask;
+
+	return spte;
+}
+
+u64 kvm_mmu_changed_pte_notifier_make_spte(u64 old_spte, kvm_pfn_t new_pfn)
+{
+	u64 new_spte;
+
+	new_spte = old_spte & ~SPTE_BASE_ADDR_MASK;
+	new_spte |= (u64)new_pfn << PAGE_SHIFT;
+
+	new_spte &= ~PT_WRITABLE_MASK;
+	new_spte &= ~shadow_host_writable_mask;
+	new_spte &= ~shadow_mmu_writable_mask;
+
+	new_spte = mark_spte_for_access_track(new_spte);
+
+	return new_spte;
+}
+
+u64 mark_spte_for_access_track(u64 spte)
+{
+	if (spte_ad_enabled(spte))
+		return spte & ~shadow_accessed_mask;
+
+	if (is_access_track_spte(spte))
+		return spte;
+
+	check_spte_writable_invariants(spte);
+
+	WARN_ONCE(spte & (SHADOW_ACC_TRACK_SAVED_BITS_MASK <<
+			  SHADOW_ACC_TRACK_SAVED_BITS_SHIFT),
+		  "Access Tracking saved bit locations are not zero\n");
+
+	spte |= (spte & SHADOW_ACC_TRACK_SAVED_BITS_MASK) <<
+		SHADOW_ACC_TRACK_SAVED_BITS_SHIFT;
+	spte &= ~shadow_acc_track_mask;
+
+	return spte;
+}
+
+void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask)
+{
+	BUG_ON((u64)(unsigned)access_mask != access_mask);
+	WARN_ON(mmio_value & shadow_nonpresent_or_rsvd_lower_gfn_mask);
+
+	/*
+	 * Reset to the original module param value to honor userspace's desire
+	 * to (dis)allow MMIO caching.  Update the param itself so that
+	 * userspace can see whether or not KVM is actually using MMIO caching.
+	 */
+	enable_mmio_caching = allow_mmio_caching;
+	if (!enable_mmio_caching)
+		mmio_value = 0;
+
+	/*
+	 * The mask must contain only bits that are carved out specifically for
+	 * the MMIO SPTE mask, e.g. to ensure there's no overlap with the MMIO
+	 * generation.
+	 */
+	if (WARN_ON(mmio_mask & ~SPTE_MMIO_ALLOWED_MASK))
+		mmio_value = 0;
+
+	/*
+	 * Disable MMIO caching if the MMIO value collides with the bits that
+	 * are used to hold the relocated GFN when the L1TF mitigation is
+	 * enabled.  This should never fire as there is no known hardware that
+	 * can trigger this condition, e.g. SME/SEV CPUs that require a custom
+	 * MMIO value are not susceptible to L1TF.
+	 */
+	if (WARN_ON(mmio_value & (shadow_nonpresent_or_rsvd_mask <<
+				  SHADOW_NONPRESENT_OR_RSVD_MASK_LEN)))
+		mmio_value = 0;
+
+	/*
+	 * The masked MMIO value must obviously match itself and a removed SPTE
+	 * must not get a false positive.  Removed SPTEs and MMIO SPTEs should
+	 * never collide as MMIO must set some RWX bits, and removed SPTEs must
+	 * not set any RWX bits.
+	 */
+	if (WARN_ON((mmio_value & mmio_mask) != mmio_value) ||
+	    WARN_ON(mmio_value && (REMOVED_SPTE & mmio_mask) == mmio_value))
+		mmio_value = 0;
+
+	if (!mmio_value)
+		enable_mmio_caching = false;
+
+	shadow_mmio_value = mmio_value;
+	shadow_mmio_mask  = mmio_mask;
+	shadow_mmio_access_mask = access_mask;
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_set_mmio_spte_mask);
+
+void kvm_mmu_set_me_spte_mask(u64 me_value, u64 me_mask)
+{
+	/* shadow_me_value must be a subset of shadow_me_mask */
+	if (WARN_ON(me_value & ~me_mask))
+		me_value = me_mask = 0;
+
+	shadow_me_value = me_value;
+	shadow_me_mask = me_mask;
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_set_me_spte_mask);
+
+void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only)
+{
+	shadow_user_mask	= VMX_EPT_READABLE_MASK;
+	shadow_accessed_mask	= has_ad_bits ? VMX_EPT_ACCESS_BIT : 0ull;
+	shadow_dirty_mask	= has_ad_bits ? VMX_EPT_DIRTY_BIT : 0ull;
+	shadow_nx_mask		= 0ull;
+	shadow_x_mask		= VMX_EPT_EXECUTABLE_MASK;
+	shadow_present_mask	= has_exec_only ? 0ull : VMX_EPT_READABLE_MASK;
+	/*
+	 * EPT overrides the host MTRRs, and so KVM must program the desired
+	 * memtype directly into the SPTEs.  Note, this mask is just the mask
+	 * of all bits that factor into the memtype, the actual memtype must be
+	 * dynamically calculated, e.g. to ensure host MMIO is mapped UC.
+	 */
+	shadow_memtype_mask	= VMX_EPT_MT_MASK | VMX_EPT_IPAT_BIT;
+	shadow_acc_track_mask	= VMX_EPT_RWX_MASK;
+	shadow_host_writable_mask = EPT_SPTE_HOST_WRITABLE;
+	shadow_mmu_writable_mask  = EPT_SPTE_MMU_WRITABLE;
+
+	/*
+	 * EPT Misconfigurations are generated if the value of bits 2:0
+	 * of an EPT paging-structure entry is 110b (write/execute).
+	 */
+	kvm_mmu_set_mmio_spte_mask(VMX_EPT_MISCONFIG_WX_VALUE,
+				   VMX_EPT_RWX_MASK, 0);
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_set_ept_masks);
+
+void kvm_mmu_reset_all_pte_masks(void)
+{
+	u8 low_phys_bits;
+	u64 mask;
+
+	shadow_phys_bits = kvm_get_shadow_phys_bits();
+
+	/*
+	 * If the CPU has 46 or less physical address bits, then set an
+	 * appropriate mask to guard against L1TF attacks. Otherwise, it is
+	 * assumed that the CPU is not vulnerable to L1TF.
+	 *
+	 * Some Intel CPUs address the L1 cache using more PA bits than are
+	 * reported by CPUID. Use the PA width of the L1 cache when possible
+	 * to achieve more effective mitigation, e.g. if system RAM overlaps
+	 * the most significant bits of legal physical address space.
+	 */
+	shadow_nonpresent_or_rsvd_mask = 0;
+	low_phys_bits = boot_cpu_data.x86_phys_bits;
+	if (boot_cpu_has_bug(X86_BUG_L1TF) &&
+	    !WARN_ON_ONCE(boot_cpu_data.x86_cache_bits >=
+			  52 - SHADOW_NONPRESENT_OR_RSVD_MASK_LEN)) {
+		low_phys_bits = boot_cpu_data.x86_cache_bits
+			- SHADOW_NONPRESENT_OR_RSVD_MASK_LEN;
+		shadow_nonpresent_or_rsvd_mask =
+			rsvd_bits(low_phys_bits, boot_cpu_data.x86_cache_bits - 1);
+	}
+
+	shadow_nonpresent_or_rsvd_lower_gfn_mask =
+		GENMASK_ULL(low_phys_bits - 1, PAGE_SHIFT);
+
+	shadow_user_mask	= PT_USER_MASK;
+	shadow_accessed_mask	= PT_ACCESSED_MASK;
+	shadow_dirty_mask	= PT_DIRTY_MASK;
+	shadow_nx_mask		= PT64_NX_MASK;
+	shadow_x_mask		= 0;
+	shadow_present_mask	= PT_PRESENT_MASK;
+
+	/*
+	 * For shadow paging and NPT, KVM uses PAT entry '0' to encode WB
+	 * memtype in the SPTEs, i.e. relies on host MTRRs to provide the
+	 * correct memtype (WB is the "weakest" memtype).
+	 */
+	shadow_memtype_mask	= 0;
+	shadow_acc_track_mask	= 0;
+	shadow_me_mask		= 0;
+	shadow_me_value		= 0;
+
+	shadow_host_writable_mask = DEFAULT_SPTE_HOST_WRITABLE;
+	shadow_mmu_writable_mask  = DEFAULT_SPTE_MMU_WRITABLE;
+
+	/*
+	 * Set a reserved PA bit in MMIO SPTEs to generate page faults with
+	 * PFEC.RSVD=1 on MMIO accesses.  64-bit PTEs (PAE, x86-64, and EPT
+	 * paging) support a maximum of 52 bits of PA, i.e. if the CPU supports
+	 * 52-bit physical addresses then there are no reserved PA bits in the
+	 * PTEs and so the reserved PA approach must be disabled.
+	 */
+	if (shadow_phys_bits < 52)
+		mask = BIT_ULL(51) | PT_PRESENT_MASK;
+	else
+		mask = 0;
+
+	kvm_mmu_set_mmio_spte_mask(mask, mask, ACC_WRITE_MASK | ACC_USER_MASK);
+}
diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
new file mode 100644
index 0000000000..a129951c9a
--- /dev/null
+++ b/arch/x86/kvm/mmu/spte.h
@@ -0,0 +1,504 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#ifndef KVM_X86_MMU_SPTE_H
+#define KVM_X86_MMU_SPTE_H
+
+#include "mmu.h"
+#include "mmu_internal.h"
+
+/*
+ * A MMU present SPTE is backed by actual memory and may or may not be present
+ * in hardware.  E.g. MMIO SPTEs are not considered present.  Use bit 11, as it
+ * is ignored by all flavors of SPTEs and checking a low bit often generates
+ * better code than for a high bit, e.g. 56+.  MMU present checks are pervasive
+ * enough that the improved code generation is noticeable in KVM's footprint.
+ */
+#define SPTE_MMU_PRESENT_MASK		BIT_ULL(11)
+
+/*
+ * TDP SPTES (more specifically, EPT SPTEs) may not have A/D bits, and may also
+ * be restricted to using write-protection (for L2 when CPU dirty logging, i.e.
+ * PML, is enabled).  Use bits 52 and 53 to hold the type of A/D tracking that
+ * is must be employed for a given TDP SPTE.
+ *
+ * Note, the "enabled" mask must be '0', as bits 62:52 are _reserved_ for PAE
+ * paging, including NPT PAE.  This scheme works because legacy shadow paging
+ * is guaranteed to have A/D bits and write-protection is forced only for
+ * TDP with CPU dirty logging (PML).  If NPT ever gains PML-like support, it
+ * must be restricted to 64-bit KVM.
+ */
+#define SPTE_TDP_AD_SHIFT		52
+#define SPTE_TDP_AD_MASK		(3ULL << SPTE_TDP_AD_SHIFT)
+#define SPTE_TDP_AD_ENABLED		(0ULL << SPTE_TDP_AD_SHIFT)
+#define SPTE_TDP_AD_DISABLED		(1ULL << SPTE_TDP_AD_SHIFT)
+#define SPTE_TDP_AD_WRPROT_ONLY		(2ULL << SPTE_TDP_AD_SHIFT)
+static_assert(SPTE_TDP_AD_ENABLED == 0);
+
+#ifdef CONFIG_DYNAMIC_PHYSICAL_MASK
+#define SPTE_BASE_ADDR_MASK (physical_mask & ~(u64)(PAGE_SIZE-1))
+#else
+#define SPTE_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
+#endif
+
+#define SPTE_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | shadow_user_mask \
+			| shadow_x_mask | shadow_nx_mask | shadow_me_mask)
+
+#define ACC_EXEC_MASK    1
+#define ACC_WRITE_MASK   PT_WRITABLE_MASK
+#define ACC_USER_MASK    PT_USER_MASK
+#define ACC_ALL          (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
+
+/* The mask for the R/X bits in EPT PTEs */
+#define SPTE_EPT_READABLE_MASK			0x1ull
+#define SPTE_EPT_EXECUTABLE_MASK		0x4ull
+
+#define SPTE_LEVEL_BITS			9
+#define SPTE_LEVEL_SHIFT(level)		__PT_LEVEL_SHIFT(level, SPTE_LEVEL_BITS)
+#define SPTE_INDEX(address, level)	__PT_INDEX(address, level, SPTE_LEVEL_BITS)
+#define SPTE_ENT_PER_PAGE		__PT_ENT_PER_PAGE(SPTE_LEVEL_BITS)
+
+/*
+ * The mask/shift to use for saving the original R/X bits when marking the PTE
+ * as not-present for access tracking purposes. We do not save the W bit as the
+ * PTEs being access tracked also need to be dirty tracked, so the W bit will be
+ * restored only when a write is attempted to the page.  This mask obviously
+ * must not overlap the A/D type mask.
+ */
+#define SHADOW_ACC_TRACK_SAVED_BITS_MASK (SPTE_EPT_READABLE_MASK | \
+					  SPTE_EPT_EXECUTABLE_MASK)
+#define SHADOW_ACC_TRACK_SAVED_BITS_SHIFT 54
+#define SHADOW_ACC_TRACK_SAVED_MASK	(SHADOW_ACC_TRACK_SAVED_BITS_MASK << \
+					 SHADOW_ACC_TRACK_SAVED_BITS_SHIFT)
+static_assert(!(SPTE_TDP_AD_MASK & SHADOW_ACC_TRACK_SAVED_MASK));
+
+/*
+ * {DEFAULT,EPT}_SPTE_{HOST,MMU}_WRITABLE are used to keep track of why a given
+ * SPTE is write-protected. See is_writable_pte() for details.
+ */
+
+/* Bits 9 and 10 are ignored by all non-EPT PTEs. */
+#define DEFAULT_SPTE_HOST_WRITABLE	BIT_ULL(9)
+#define DEFAULT_SPTE_MMU_WRITABLE	BIT_ULL(10)
+
+/*
+ * Low ignored bits are at a premium for EPT, use high ignored bits, taking care
+ * to not overlap the A/D type mask or the saved access bits of access-tracked
+ * SPTEs when A/D bits are disabled.
+ */
+#define EPT_SPTE_HOST_WRITABLE		BIT_ULL(57)
+#define EPT_SPTE_MMU_WRITABLE		BIT_ULL(58)
+
+static_assert(!(EPT_SPTE_HOST_WRITABLE & SPTE_TDP_AD_MASK));
+static_assert(!(EPT_SPTE_MMU_WRITABLE & SPTE_TDP_AD_MASK));
+static_assert(!(EPT_SPTE_HOST_WRITABLE & SHADOW_ACC_TRACK_SAVED_MASK));
+static_assert(!(EPT_SPTE_MMU_WRITABLE & SHADOW_ACC_TRACK_SAVED_MASK));
+
+/* Defined only to keep the above static asserts readable. */
+#undef SHADOW_ACC_TRACK_SAVED_MASK
+
+/*
+ * Due to limited space in PTEs, the MMIO generation is a 19 bit subset of
+ * the memslots generation and is derived as follows:
+ *
+ * Bits 0-7 of the MMIO generation are propagated to spte bits 3-10
+ * Bits 8-18 of the MMIO generation are propagated to spte bits 52-62
+ *
+ * The KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS flag is intentionally not included in
+ * the MMIO generation number, as doing so would require stealing a bit from
+ * the "real" generation number and thus effectively halve the maximum number
+ * of MMIO generations that can be handled before encountering a wrap (which
+ * requires a full MMU zap).  The flag is instead explicitly queried when
+ * checking for MMIO spte cache hits.
+ */
+
+#define MMIO_SPTE_GEN_LOW_START		3
+#define MMIO_SPTE_GEN_LOW_END		10
+
+#define MMIO_SPTE_GEN_HIGH_START	52
+#define MMIO_SPTE_GEN_HIGH_END		62
+
+#define MMIO_SPTE_GEN_LOW_MASK		GENMASK_ULL(MMIO_SPTE_GEN_LOW_END, \
+						    MMIO_SPTE_GEN_LOW_START)
+#define MMIO_SPTE_GEN_HIGH_MASK		GENMASK_ULL(MMIO_SPTE_GEN_HIGH_END, \
+						    MMIO_SPTE_GEN_HIGH_START)
+static_assert(!(SPTE_MMU_PRESENT_MASK &
+		(MMIO_SPTE_GEN_LOW_MASK | MMIO_SPTE_GEN_HIGH_MASK)));
+
+/*
+ * The SPTE MMIO mask must NOT overlap the MMIO generation bits or the
+ * MMU-present bit.  The generation obviously co-exists with the magic MMIO
+ * mask/value, and MMIO SPTEs are considered !MMU-present.
+ *
+ * The SPTE MMIO mask is allowed to use hardware "present" bits (i.e. all EPT
+ * RWX bits), all physical address bits (legal PA bits are used for "fast" MMIO
+ * and so they're off-limits for generation; additional checks ensure the mask
+ * doesn't overlap legal PA bits), and bit 63 (carved out for future usage).
+ */
+#define SPTE_MMIO_ALLOWED_MASK (BIT_ULL(63) | GENMASK_ULL(51, 12) | GENMASK_ULL(2, 0))
+static_assert(!(SPTE_MMIO_ALLOWED_MASK &
+		(SPTE_MMU_PRESENT_MASK | MMIO_SPTE_GEN_LOW_MASK | MMIO_SPTE_GEN_HIGH_MASK)));
+
+#define MMIO_SPTE_GEN_LOW_BITS		(MMIO_SPTE_GEN_LOW_END - MMIO_SPTE_GEN_LOW_START + 1)
+#define MMIO_SPTE_GEN_HIGH_BITS		(MMIO_SPTE_GEN_HIGH_END - MMIO_SPTE_GEN_HIGH_START + 1)
+
+/* remember to adjust the comment above as well if you change these */
+static_assert(MMIO_SPTE_GEN_LOW_BITS == 8 && MMIO_SPTE_GEN_HIGH_BITS == 11);
+
+#define MMIO_SPTE_GEN_LOW_SHIFT		(MMIO_SPTE_GEN_LOW_START - 0)
+#define MMIO_SPTE_GEN_HIGH_SHIFT	(MMIO_SPTE_GEN_HIGH_START - MMIO_SPTE_GEN_LOW_BITS)
+
+#define MMIO_SPTE_GEN_MASK		GENMASK_ULL(MMIO_SPTE_GEN_LOW_BITS + MMIO_SPTE_GEN_HIGH_BITS - 1, 0)
+
+extern u64 __read_mostly shadow_host_writable_mask;
+extern u64 __read_mostly shadow_mmu_writable_mask;
+extern u64 __read_mostly shadow_nx_mask;
+extern u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
+extern u64 __read_mostly shadow_user_mask;
+extern u64 __read_mostly shadow_accessed_mask;
+extern u64 __read_mostly shadow_dirty_mask;
+extern u64 __read_mostly shadow_mmio_value;
+extern u64 __read_mostly shadow_mmio_mask;
+extern u64 __read_mostly shadow_mmio_access_mask;
+extern u64 __read_mostly shadow_present_mask;
+extern u64 __read_mostly shadow_memtype_mask;
+extern u64 __read_mostly shadow_me_value;
+extern u64 __read_mostly shadow_me_mask;
+
+/*
+ * SPTEs in MMUs without A/D bits are marked with SPTE_TDP_AD_DISABLED;
+ * shadow_acc_track_mask is the set of bits to be cleared in non-accessed
+ * pages.
+ */
+extern u64 __read_mostly shadow_acc_track_mask;
+
+/*
+ * This mask must be set on all non-zero Non-Present or Reserved SPTEs in order
+ * to guard against L1TF attacks.
+ */
+extern u64 __read_mostly shadow_nonpresent_or_rsvd_mask;
+
+/*
+ * The number of high-order 1 bits to use in the mask above.
+ */
+#define SHADOW_NONPRESENT_OR_RSVD_MASK_LEN 5
+
+/*
+ * If a thread running without exclusive control of the MMU lock must perform a
+ * multi-part operation on an SPTE, it can set the SPTE to REMOVED_SPTE as a
+ * non-present intermediate value. Other threads which encounter this value
+ * should not modify the SPTE.
+ *
+ * Use a semi-arbitrary value that doesn't set RWX bits, i.e. is not-present on
+ * both AMD and Intel CPUs, and doesn't set PFN bits, i.e. doesn't create a L1TF
+ * vulnerability.  Use only low bits to avoid 64-bit immediates.
+ *
+ * Only used by the TDP MMU.
+ */
+#define REMOVED_SPTE	0x5a0ULL
+
+/* Removed SPTEs must not be misconstrued as shadow present PTEs. */
+static_assert(!(REMOVED_SPTE & SPTE_MMU_PRESENT_MASK));
+
+static inline bool is_removed_spte(u64 spte)
+{
+	return spte == REMOVED_SPTE;
+}
+
+/* Get an SPTE's index into its parent's page table (and the spt array). */
+static inline int spte_index(u64 *sptep)
+{
+	return ((unsigned long)sptep / sizeof(*sptep)) & (SPTE_ENT_PER_PAGE - 1);
+}
+
+/*
+ * In some cases, we need to preserve the GFN of a non-present or reserved
+ * SPTE when we usurp the upper five bits of the physical address space to
+ * defend against L1TF, e.g. for MMIO SPTEs.  To preserve the GFN, we'll
+ * shift bits of the GFN that overlap with shadow_nonpresent_or_rsvd_mask
+ * left into the reserved bits, i.e. the GFN in the SPTE will be split into
+ * high and low parts.  This mask covers the lower bits of the GFN.
+ */
+extern u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask;
+
+static inline struct kvm_mmu_page *to_shadow_page(hpa_t shadow_page)
+{
+	struct page *page = pfn_to_page((shadow_page) >> PAGE_SHIFT);
+
+	return (struct kvm_mmu_page *)page_private(page);
+}
+
+static inline struct kvm_mmu_page *spte_to_child_sp(u64 spte)
+{
+	return to_shadow_page(spte & SPTE_BASE_ADDR_MASK);
+}
+
+static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep)
+{
+	return to_shadow_page(__pa(sptep));
+}
+
+static inline struct kvm_mmu_page *root_to_sp(hpa_t root)
+{
+	if (kvm_mmu_is_dummy_root(root))
+		return NULL;
+
+	/*
+	 * The "root" may be a special root, e.g. a PAE entry, treat it as a
+	 * SPTE to ensure any non-PA bits are dropped.
+	 */
+	return spte_to_child_sp(root);
+}
+
+static inline bool is_mmio_spte(u64 spte)
+{
+	return (spte & shadow_mmio_mask) == shadow_mmio_value &&
+	       likely(enable_mmio_caching);
+}
+
+static inline bool is_shadow_present_pte(u64 pte)
+{
+	return !!(pte & SPTE_MMU_PRESENT_MASK);
+}
+
+/*
+ * Returns true if A/D bits are supported in hardware and are enabled by KVM.
+ * When enabled, KVM uses A/D bits for all non-nested MMUs.  Because L1 can
+ * disable A/D bits in EPTP12, SP and SPTE variants are needed to handle the
+ * scenario where KVM is using A/D bits for L1, but not L2.
+ */
+static inline bool kvm_ad_enabled(void)
+{
+	return !!shadow_accessed_mask;
+}
+
+static inline bool sp_ad_disabled(struct kvm_mmu_page *sp)
+{
+	return sp->role.ad_disabled;
+}
+
+static inline bool spte_ad_enabled(u64 spte)
+{
+	KVM_MMU_WARN_ON(!is_shadow_present_pte(spte));
+	return (spte & SPTE_TDP_AD_MASK) != SPTE_TDP_AD_DISABLED;
+}
+
+static inline bool spte_ad_need_write_protect(u64 spte)
+{
+	KVM_MMU_WARN_ON(!is_shadow_present_pte(spte));
+	/*
+	 * This is benign for non-TDP SPTEs as SPTE_TDP_AD_ENABLED is '0',
+	 * and non-TDP SPTEs will never set these bits.  Optimize for 64-bit
+	 * TDP and do the A/D type check unconditionally.
+	 */
+	return (spte & SPTE_TDP_AD_MASK) != SPTE_TDP_AD_ENABLED;
+}
+
+static inline u64 spte_shadow_accessed_mask(u64 spte)
+{
+	KVM_MMU_WARN_ON(!is_shadow_present_pte(spte));
+	return spte_ad_enabled(spte) ? shadow_accessed_mask : 0;
+}
+
+static inline u64 spte_shadow_dirty_mask(u64 spte)
+{
+	KVM_MMU_WARN_ON(!is_shadow_present_pte(spte));
+	return spte_ad_enabled(spte) ? shadow_dirty_mask : 0;
+}
+
+static inline bool is_access_track_spte(u64 spte)
+{
+	return !spte_ad_enabled(spte) && (spte & shadow_acc_track_mask) == 0;
+}
+
+static inline bool is_large_pte(u64 pte)
+{
+	return pte & PT_PAGE_SIZE_MASK;
+}
+
+static inline bool is_last_spte(u64 pte, int level)
+{
+	return (level == PG_LEVEL_4K) || is_large_pte(pte);
+}
+
+static inline bool is_executable_pte(u64 spte)
+{
+	return (spte & (shadow_x_mask | shadow_nx_mask)) == shadow_x_mask;
+}
+
+static inline kvm_pfn_t spte_to_pfn(u64 pte)
+{
+	return (pte & SPTE_BASE_ADDR_MASK) >> PAGE_SHIFT;
+}
+
+static inline bool is_accessed_spte(u64 spte)
+{
+	u64 accessed_mask = spte_shadow_accessed_mask(spte);
+
+	return accessed_mask ? spte & accessed_mask
+			     : !is_access_track_spte(spte);
+}
+
+static inline bool is_dirty_spte(u64 spte)
+{
+	u64 dirty_mask = spte_shadow_dirty_mask(spte);
+
+	return dirty_mask ? spte & dirty_mask : spte & PT_WRITABLE_MASK;
+}
+
+static inline u64 get_rsvd_bits(struct rsvd_bits_validate *rsvd_check, u64 pte,
+				int level)
+{
+	int bit7 = (pte >> 7) & 1;
+
+	return rsvd_check->rsvd_bits_mask[bit7][level-1];
+}
+
+static inline bool __is_rsvd_bits_set(struct rsvd_bits_validate *rsvd_check,
+				      u64 pte, int level)
+{
+	return pte & get_rsvd_bits(rsvd_check, pte, level);
+}
+
+static inline bool __is_bad_mt_xwr(struct rsvd_bits_validate *rsvd_check,
+				   u64 pte)
+{
+	return rsvd_check->bad_mt_xwr & BIT_ULL(pte & 0x3f);
+}
+
+static __always_inline bool is_rsvd_spte(struct rsvd_bits_validate *rsvd_check,
+					 u64 spte, int level)
+{
+	return __is_bad_mt_xwr(rsvd_check, spte) ||
+	       __is_rsvd_bits_set(rsvd_check, spte, level);
+}
+
+/*
+ * A shadow-present leaf SPTE may be non-writable for 4 possible reasons:
+ *
+ *  1. To intercept writes for dirty logging. KVM write-protects huge pages
+ *     so that they can be split down into the dirty logging
+ *     granularity (4KiB) whenever the guest writes to them. KVM also
+ *     write-protects 4KiB pages so that writes can be recorded in the dirty log
+ *     (e.g. if not using PML). SPTEs are write-protected for dirty logging
+ *     during the VM-iotcls that enable dirty logging.
+ *
+ *  2. To intercept writes to guest page tables that KVM is shadowing. When a
+ *     guest writes to its page table the corresponding shadow page table will
+ *     be marked "unsync". That way KVM knows which shadow page tables need to
+ *     be updated on the next TLB flush, INVLPG, etc. and which do not.
+ *
+ *  3. To prevent guest writes to read-only memory, such as for memory in a
+ *     read-only memslot or guest memory backed by a read-only VMA. Writes to
+ *     such pages are disallowed entirely.
+ *
+ *  4. To emulate the Accessed bit for SPTEs without A/D bits.  Note, in this
+ *     case, the SPTE is access-protected, not just write-protected!
+ *
+ * For cases #1 and #4, KVM can safely make such SPTEs writable without taking
+ * mmu_lock as capturing the Accessed/Dirty state doesn't require taking it.
+ * To differentiate #1 and #4 from #2 and #3, KVM uses two software-only bits
+ * in the SPTE:
+ *
+ *  shadow_mmu_writable_mask, aka MMU-writable -
+ *    Cleared on SPTEs that KVM is currently write-protecting for shadow paging
+ *    purposes (case 2 above).
+ *
+ *  shadow_host_writable_mask, aka Host-writable -
+ *    Cleared on SPTEs that are not host-writable (case 3 above)
+ *
+ * Note, not all possible combinations of PT_WRITABLE_MASK,
+ * shadow_mmu_writable_mask, and shadow_host_writable_mask are valid. A given
+ * SPTE can be in only one of the following states, which map to the
+ * aforementioned 3 cases:
+ *
+ *   shadow_host_writable_mask | shadow_mmu_writable_mask | PT_WRITABLE_MASK
+ *   ------------------------- | ------------------------ | ----------------
+ *   1                         | 1                        | 1       (writable)
+ *   1                         | 1                        | 0       (case 1)
+ *   1                         | 0                        | 0       (case 2)
+ *   0                         | 0                        | 0       (case 3)
+ *
+ * The valid combinations of these bits are checked by
+ * check_spte_writable_invariants() whenever an SPTE is modified.
+ *
+ * Clearing the MMU-writable bit is always done under the MMU lock and always
+ * accompanied by a TLB flush before dropping the lock to avoid corrupting the
+ * shadow page tables between vCPUs. Write-protecting an SPTE for dirty logging
+ * (which does not clear the MMU-writable bit), does not flush TLBs before
+ * dropping the lock, as it only needs to synchronize guest writes with the
+ * dirty bitmap. Similarly, making the SPTE inaccessible (and non-writable) for
+ * access-tracking via the clear_young() MMU notifier also does not flush TLBs.
+ *
+ * So, there is the problem: clearing the MMU-writable bit can encounter a
+ * write-protected SPTE while CPUs still have writable mappings for that SPTE
+ * cached in their TLB. To address this, KVM always flushes TLBs when
+ * write-protecting SPTEs if the MMU-writable bit is set on the old SPTE.
+ *
+ * The Host-writable bit is not modified on present SPTEs, it is only set or
+ * cleared when an SPTE is first faulted in from non-present and then remains
+ * immutable.
+ */
+static inline bool is_writable_pte(unsigned long pte)
+{
+	return pte & PT_WRITABLE_MASK;
+}
+
+/* Note: spte must be a shadow-present leaf SPTE. */
+static inline void check_spte_writable_invariants(u64 spte)
+{
+	if (spte & shadow_mmu_writable_mask)
+		WARN_ONCE(!(spte & shadow_host_writable_mask),
+			  KBUILD_MODNAME ": MMU-writable SPTE is not Host-writable: %llx",
+			  spte);
+	else
+		WARN_ONCE(is_writable_pte(spte),
+			  KBUILD_MODNAME ": Writable SPTE is not MMU-writable: %llx", spte);
+}
+
+static inline bool is_mmu_writable_spte(u64 spte)
+{
+	return spte & shadow_mmu_writable_mask;
+}
+
+static inline u64 get_mmio_spte_generation(u64 spte)
+{
+	u64 gen;
+
+	gen = (spte & MMIO_SPTE_GEN_LOW_MASK) >> MMIO_SPTE_GEN_LOW_SHIFT;
+	gen |= (spte & MMIO_SPTE_GEN_HIGH_MASK) >> MMIO_SPTE_GEN_HIGH_SHIFT;
+	return gen;
+}
+
+bool spte_has_volatile_bits(u64 spte);
+
+bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+	       const struct kvm_memory_slot *slot,
+	       unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn,
+	       u64 old_spte, bool prefetch, bool can_unsync,
+	       bool host_writable, u64 *new_spte);
+u64 make_huge_page_split_spte(struct kvm *kvm, u64 huge_spte,
+		      	      union kvm_mmu_page_role role, int index);
+u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled);
+u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access);
+u64 mark_spte_for_access_track(u64 spte);
+
+/* Restore an acc-track PTE back to a regular PTE */
+static inline u64 restore_acc_track_spte(u64 spte)
+{
+	u64 saved_bits = (spte >> SHADOW_ACC_TRACK_SAVED_BITS_SHIFT)
+			 & SHADOW_ACC_TRACK_SAVED_BITS_MASK;
+
+	spte &= ~shadow_acc_track_mask;
+	spte &= ~(SHADOW_ACC_TRACK_SAVED_BITS_MASK <<
+		  SHADOW_ACC_TRACK_SAVED_BITS_SHIFT);
+	spte |= saved_bits;
+
+	return spte;
+}
+
+u64 kvm_mmu_changed_pte_notifier_make_spte(u64 old_spte, kvm_pfn_t new_pfn);
+
+void __init kvm_mmu_spte_module_init(void);
+void kvm_mmu_reset_all_pte_masks(void);
+
+#endif
diff --git a/arch/x86/kvm/mmu/tdp_iter.c b/arch/x86/kvm/mmu/tdp_iter.c
new file mode 100644
index 0000000000..bd30ebfb2f
--- /dev/null
+++ b/arch/x86/kvm/mmu/tdp_iter.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include "mmu_internal.h"
+#include "tdp_iter.h"
+#include "spte.h"
+
+/*
+ * Recalculates the pointer to the SPTE for the current GFN and level and
+ * reread the SPTE.
+ */
+static void tdp_iter_refresh_sptep(struct tdp_iter *iter)
+{
+	iter->sptep = iter->pt_path[iter->level - 1] +
+		SPTE_INDEX(iter->gfn << PAGE_SHIFT, iter->level);
+	iter->old_spte = kvm_tdp_mmu_read_spte(iter->sptep);
+}
+
+/*
+ * Return the TDP iterator to the root PT and allow it to continue its
+ * traversal over the paging structure from there.
+ */
+void tdp_iter_restart(struct tdp_iter *iter)
+{
+	iter->yielded = false;
+	iter->yielded_gfn = iter->next_last_level_gfn;
+	iter->level = iter->root_level;
+
+	iter->gfn = gfn_round_for_level(iter->next_last_level_gfn, iter->level);
+	tdp_iter_refresh_sptep(iter);
+
+	iter->valid = true;
+}
+
+/*
+ * Sets a TDP iterator to walk a pre-order traversal of the paging structure
+ * rooted at root_pt, starting with the walk to translate next_last_level_gfn.
+ */
+void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root,
+		    int min_level, gfn_t next_last_level_gfn)
+{
+	if (WARN_ON_ONCE(!root || (root->role.level < 1) ||
+			 (root->role.level > PT64_ROOT_MAX_LEVEL))) {
+		iter->valid = false;
+		return;
+	}
+
+	iter->next_last_level_gfn = next_last_level_gfn;
+	iter->root_level = root->role.level;
+	iter->min_level = min_level;
+	iter->pt_path[iter->root_level - 1] = (tdp_ptep_t)root->spt;
+	iter->as_id = kvm_mmu_page_as_id(root);
+
+	tdp_iter_restart(iter);
+}
+
+/*
+ * Given an SPTE and its level, returns a pointer containing the host virtual
+ * address of the child page table referenced by the SPTE. Returns null if
+ * there is no such entry.
+ */
+tdp_ptep_t spte_to_child_pt(u64 spte, int level)
+{
+	/*
+	 * There's no child entry if this entry isn't present or is a
+	 * last-level entry.
+	 */
+	if (!is_shadow_present_pte(spte) || is_last_spte(spte, level))
+		return NULL;
+
+	return (tdp_ptep_t)__va(spte_to_pfn(spte) << PAGE_SHIFT);
+}
+
+/*
+ * Steps down one level in the paging structure towards the goal GFN. Returns
+ * true if the iterator was able to step down a level, false otherwise.
+ */
+static bool try_step_down(struct tdp_iter *iter)
+{
+	tdp_ptep_t child_pt;
+
+	if (iter->level == iter->min_level)
+		return false;
+
+	/*
+	 * Reread the SPTE before stepping down to avoid traversing into page
+	 * tables that are no longer linked from this entry.
+	 */
+	iter->old_spte = kvm_tdp_mmu_read_spte(iter->sptep);
+
+	child_pt = spte_to_child_pt(iter->old_spte, iter->level);
+	if (!child_pt)
+		return false;
+
+	iter->level--;
+	iter->pt_path[iter->level - 1] = child_pt;
+	iter->gfn = gfn_round_for_level(iter->next_last_level_gfn, iter->level);
+	tdp_iter_refresh_sptep(iter);
+
+	return true;
+}
+
+/*
+ * Steps to the next entry in the current page table, at the current page table
+ * level. The next entry could point to a page backing guest memory or another
+ * page table, or it could be non-present. Returns true if the iterator was
+ * able to step to the next entry in the page table, false if the iterator was
+ * already at the end of the current page table.
+ */
+static bool try_step_side(struct tdp_iter *iter)
+{
+	/*
+	 * Check if the iterator is already at the end of the current page
+	 * table.
+	 */
+	if (SPTE_INDEX(iter->gfn << PAGE_SHIFT, iter->level) ==
+	    (SPTE_ENT_PER_PAGE - 1))
+		return false;
+
+	iter->gfn += KVM_PAGES_PER_HPAGE(iter->level);
+	iter->next_last_level_gfn = iter->gfn;
+	iter->sptep++;
+	iter->old_spte = kvm_tdp_mmu_read_spte(iter->sptep);
+
+	return true;
+}
+
+/*
+ * Tries to traverse back up a level in the paging structure so that the walk
+ * can continue from the next entry in the parent page table. Returns true on a
+ * successful step up, false if already in the root page.
+ */
+static bool try_step_up(struct tdp_iter *iter)
+{
+	if (iter->level == iter->root_level)
+		return false;
+
+	iter->level++;
+	iter->gfn = gfn_round_for_level(iter->gfn, iter->level);
+	tdp_iter_refresh_sptep(iter);
+
+	return true;
+}
+
+/*
+ * Step to the next SPTE in a pre-order traversal of the paging structure.
+ * To get to the next SPTE, the iterator either steps down towards the goal
+ * GFN, if at a present, non-last-level SPTE, or over to a SPTE mapping a
+ * highter GFN.
+ *
+ * The basic algorithm is as follows:
+ * 1. If the current SPTE is a non-last-level SPTE, step down into the page
+ *    table it points to.
+ * 2. If the iterator cannot step down, it will try to step to the next SPTE
+ *    in the current page of the paging structure.
+ * 3. If the iterator cannot step to the next entry in the current page, it will
+ *    try to step up to the parent paging structure page. In this case, that
+ *    SPTE will have already been visited, and so the iterator must also step
+ *    to the side again.
+ */
+void tdp_iter_next(struct tdp_iter *iter)
+{
+	if (iter->yielded) {
+		tdp_iter_restart(iter);
+		return;
+	}
+
+	if (try_step_down(iter))
+		return;
+
+	do {
+		if (try_step_side(iter))
+			return;
+	} while (try_step_up(iter));
+	iter->valid = false;
+}
+
diff --git a/arch/x86/kvm/mmu/tdp_iter.h b/arch/x86/kvm/mmu/tdp_iter.h
new file mode 100644
index 0000000000..fae559559a
--- /dev/null
+++ b/arch/x86/kvm/mmu/tdp_iter.h
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifndef __KVM_X86_MMU_TDP_ITER_H
+#define __KVM_X86_MMU_TDP_ITER_H
+
+#include <linux/kvm_host.h>
+
+#include "mmu.h"
+#include "spte.h"
+
+/*
+ * TDP MMU SPTEs are RCU protected to allow paging structures (non-leaf SPTEs)
+ * to be zapped while holding mmu_lock for read, and to allow TLB flushes to be
+ * batched without having to collect the list of zapped SPs.  Flows that can
+ * remove SPs must service pending TLB flushes prior to dropping RCU protection.
+ */
+static inline u64 kvm_tdp_mmu_read_spte(tdp_ptep_t sptep)
+{
+	return READ_ONCE(*rcu_dereference(sptep));
+}
+
+static inline u64 kvm_tdp_mmu_write_spte_atomic(tdp_ptep_t sptep, u64 new_spte)
+{
+	return xchg(rcu_dereference(sptep), new_spte);
+}
+
+static inline void __kvm_tdp_mmu_write_spte(tdp_ptep_t sptep, u64 new_spte)
+{
+	WRITE_ONCE(*rcu_dereference(sptep), new_spte);
+}
+
+/*
+ * SPTEs must be modified atomically if they are shadow-present, leaf
+ * SPTEs, and have volatile bits, i.e. has bits that can be set outside
+ * of mmu_lock.  The Writable bit can be set by KVM's fast page fault
+ * handler, and Accessed and Dirty bits can be set by the CPU.
+ *
+ * Note, non-leaf SPTEs do have Accessed bits and those bits are
+ * technically volatile, but KVM doesn't consume the Accessed bit of
+ * non-leaf SPTEs, i.e. KVM doesn't care if it clobbers the bit.  This
+ * logic needs to be reassessed if KVM were to use non-leaf Accessed
+ * bits, e.g. to skip stepping down into child SPTEs when aging SPTEs.
+ */
+static inline bool kvm_tdp_mmu_spte_need_atomic_write(u64 old_spte, int level)
+{
+	return is_shadow_present_pte(old_spte) &&
+	       is_last_spte(old_spte, level) &&
+	       spte_has_volatile_bits(old_spte);
+}
+
+static inline u64 kvm_tdp_mmu_write_spte(tdp_ptep_t sptep, u64 old_spte,
+					 u64 new_spte, int level)
+{
+	if (kvm_tdp_mmu_spte_need_atomic_write(old_spte, level))
+		return kvm_tdp_mmu_write_spte_atomic(sptep, new_spte);
+
+	__kvm_tdp_mmu_write_spte(sptep, new_spte);
+	return old_spte;
+}
+
+static inline u64 tdp_mmu_clear_spte_bits(tdp_ptep_t sptep, u64 old_spte,
+					  u64 mask, int level)
+{
+	atomic64_t *sptep_atomic;
+
+	if (kvm_tdp_mmu_spte_need_atomic_write(old_spte, level)) {
+		sptep_atomic = (atomic64_t *)rcu_dereference(sptep);
+		return (u64)atomic64_fetch_and(~mask, sptep_atomic);
+	}
+
+	__kvm_tdp_mmu_write_spte(sptep, old_spte & ~mask);
+	return old_spte;
+}
+
+/*
+ * A TDP iterator performs a pre-order walk over a TDP paging structure.
+ */
+struct tdp_iter {
+	/*
+	 * The iterator will traverse the paging structure towards the mapping
+	 * for this GFN.
+	 */
+	gfn_t next_last_level_gfn;
+	/*
+	 * The next_last_level_gfn at the time when the thread last
+	 * yielded. Only yielding when the next_last_level_gfn !=
+	 * yielded_gfn helps ensure forward progress.
+	 */
+	gfn_t yielded_gfn;
+	/* Pointers to the page tables traversed to reach the current SPTE */
+	tdp_ptep_t pt_path[PT64_ROOT_MAX_LEVEL];
+	/* A pointer to the current SPTE */
+	tdp_ptep_t sptep;
+	/* The lowest GFN mapped by the current SPTE */
+	gfn_t gfn;
+	/* The level of the root page given to the iterator */
+	int root_level;
+	/* The lowest level the iterator should traverse to */
+	int min_level;
+	/* The iterator's current level within the paging structure */
+	int level;
+	/* The address space ID, i.e. SMM vs. regular. */
+	int as_id;
+	/* A snapshot of the value at sptep */
+	u64 old_spte;
+	/*
+	 * Whether the iterator has a valid state. This will be false if the
+	 * iterator walks off the end of the paging structure.
+	 */
+	bool valid;
+	/*
+	 * True if KVM dropped mmu_lock and yielded in the middle of a walk, in
+	 * which case tdp_iter_next() needs to restart the walk at the root
+	 * level instead of advancing to the next entry.
+	 */
+	bool yielded;
+};
+
+/*
+ * Iterates over every SPTE mapping the GFN range [start, end) in a
+ * preorder traversal.
+ */
+#define for_each_tdp_pte_min_level(iter, root, min_level, start, end) \
+	for (tdp_iter_start(&iter, root, min_level, start); \
+	     iter.valid && iter.gfn < end;		     \
+	     tdp_iter_next(&iter))
+
+#define for_each_tdp_pte(iter, root, start, end) \
+	for_each_tdp_pte_min_level(iter, root, PG_LEVEL_4K, start, end)
+
+tdp_ptep_t spte_to_child_pt(u64 pte, int level);
+
+void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root,
+		    int min_level, gfn_t next_last_level_gfn);
+void tdp_iter_next(struct tdp_iter *iter);
+void tdp_iter_restart(struct tdp_iter *iter);
+
+#endif /* __KVM_X86_MMU_TDP_ITER_H */
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
new file mode 100644
index 0000000000..6cd4dd631a
--- /dev/null
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -0,0 +1,1817 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include "mmu.h"
+#include "mmu_internal.h"
+#include "mmutrace.h"
+#include "tdp_iter.h"
+#include "tdp_mmu.h"
+#include "spte.h"
+
+#include <asm/cmpxchg.h>
+#include <trace/events/kvm.h>
+
+/* Initializes the TDP MMU for the VM, if enabled. */
+void kvm_mmu_init_tdp_mmu(struct kvm *kvm)
+{
+	INIT_LIST_HEAD(&kvm->arch.tdp_mmu_roots);
+	spin_lock_init(&kvm->arch.tdp_mmu_pages_lock);
+}
+
+/* Arbitrarily returns true so that this may be used in if statements. */
+static __always_inline bool kvm_lockdep_assert_mmu_lock_held(struct kvm *kvm,
+							     bool shared)
+{
+	if (shared)
+		lockdep_assert_held_read(&kvm->mmu_lock);
+	else
+		lockdep_assert_held_write(&kvm->mmu_lock);
+
+	return true;
+}
+
+void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm)
+{
+	/*
+	 * Invalidate all roots, which besides the obvious, schedules all roots
+	 * for zapping and thus puts the TDP MMU's reference to each root, i.e.
+	 * ultimately frees all roots.
+	 */
+	kvm_tdp_mmu_invalidate_all_roots(kvm);
+	kvm_tdp_mmu_zap_invalidated_roots(kvm);
+
+	WARN_ON(atomic64_read(&kvm->arch.tdp_mmu_pages));
+	WARN_ON(!list_empty(&kvm->arch.tdp_mmu_roots));
+
+	/*
+	 * Ensure that all the outstanding RCU callbacks to free shadow pages
+	 * can run before the VM is torn down.  Putting the last reference to
+	 * zapped roots will create new callbacks.
+	 */
+	rcu_barrier();
+}
+
+static void tdp_mmu_free_sp(struct kvm_mmu_page *sp)
+{
+	free_page((unsigned long)sp->spt);
+	kmem_cache_free(mmu_page_header_cache, sp);
+}
+
+/*
+ * This is called through call_rcu in order to free TDP page table memory
+ * safely with respect to other kernel threads that may be operating on
+ * the memory.
+ * By only accessing TDP MMU page table memory in an RCU read critical
+ * section, and freeing it after a grace period, lockless access to that
+ * memory won't use it after it is freed.
+ */
+static void tdp_mmu_free_sp_rcu_callback(struct rcu_head *head)
+{
+	struct kvm_mmu_page *sp = container_of(head, struct kvm_mmu_page,
+					       rcu_head);
+
+	tdp_mmu_free_sp(sp);
+}
+
+void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root,
+			  bool shared)
+{
+	kvm_lockdep_assert_mmu_lock_held(kvm, shared);
+
+	if (!refcount_dec_and_test(&root->tdp_mmu_root_count))
+		return;
+
+	/*
+	 * The TDP MMU itself holds a reference to each root until the root is
+	 * explicitly invalidated, i.e. the final reference should be never be
+	 * put for a valid root.
+	 */
+	KVM_BUG_ON(!is_tdp_mmu_page(root) || !root->role.invalid, kvm);
+
+	spin_lock(&kvm->arch.tdp_mmu_pages_lock);
+	list_del_rcu(&root->link);
+	spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
+	call_rcu(&root->rcu_head, tdp_mmu_free_sp_rcu_callback);
+}
+
+/*
+ * Returns the next root after @prev_root (or the first root if @prev_root is
+ * NULL).  A reference to the returned root is acquired, and the reference to
+ * @prev_root is released (the caller obviously must hold a reference to
+ * @prev_root if it's non-NULL).
+ *
+ * If @only_valid is true, invalid roots are skipped.
+ *
+ * Returns NULL if the end of tdp_mmu_roots was reached.
+ */
+static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm,
+					      struct kvm_mmu_page *prev_root,
+					      bool shared, bool only_valid)
+{
+	struct kvm_mmu_page *next_root;
+
+	rcu_read_lock();
+
+	if (prev_root)
+		next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots,
+						  &prev_root->link,
+						  typeof(*prev_root), link);
+	else
+		next_root = list_first_or_null_rcu(&kvm->arch.tdp_mmu_roots,
+						   typeof(*next_root), link);
+
+	while (next_root) {
+		if ((!only_valid || !next_root->role.invalid) &&
+		    kvm_tdp_mmu_get_root(next_root))
+			break;
+
+		next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots,
+				&next_root->link, typeof(*next_root), link);
+	}
+
+	rcu_read_unlock();
+
+	if (prev_root)
+		kvm_tdp_mmu_put_root(kvm, prev_root, shared);
+
+	return next_root;
+}
+
+/*
+ * Note: this iterator gets and puts references to the roots it iterates over.
+ * This makes it safe to release the MMU lock and yield within the loop, but
+ * if exiting the loop early, the caller must drop the reference to the most
+ * recent root. (Unless keeping a live reference is desirable.)
+ *
+ * If shared is set, this function is operating under the MMU lock in read
+ * mode. In the unlikely event that this thread must free a root, the lock
+ * will be temporarily dropped and reacquired in write mode.
+ */
+#define __for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared, _only_valid)\
+	for (_root = tdp_mmu_next_root(_kvm, NULL, _shared, _only_valid);	\
+	     _root;								\
+	     _root = tdp_mmu_next_root(_kvm, _root, _shared, _only_valid))	\
+		if (kvm_lockdep_assert_mmu_lock_held(_kvm, _shared) &&		\
+		    kvm_mmu_page_as_id(_root) != _as_id) {			\
+		} else
+
+#define for_each_valid_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared)	\
+	__for_each_tdp_mmu_root_yield_safe(_kvm, _root, _as_id, _shared, true)
+
+#define for_each_tdp_mmu_root_yield_safe(_kvm, _root, _shared)			\
+	for (_root = tdp_mmu_next_root(_kvm, NULL, _shared, false);		\
+	     _root;								\
+	     _root = tdp_mmu_next_root(_kvm, _root, _shared, false))		\
+		if (!kvm_lockdep_assert_mmu_lock_held(_kvm, _shared)) {		\
+		} else
+
+/*
+ * Iterate over all TDP MMU roots.  Requires that mmu_lock be held for write,
+ * the implication being that any flow that holds mmu_lock for read is
+ * inherently yield-friendly and should use the yield-safe variant above.
+ * Holding mmu_lock for write obviates the need for RCU protection as the list
+ * is guaranteed to be stable.
+ */
+#define for_each_tdp_mmu_root(_kvm, _root, _as_id)			\
+	list_for_each_entry(_root, &_kvm->arch.tdp_mmu_roots, link)	\
+		if (kvm_lockdep_assert_mmu_lock_held(_kvm, false) &&	\
+		    kvm_mmu_page_as_id(_root) != _as_id) {		\
+		} else
+
+static struct kvm_mmu_page *tdp_mmu_alloc_sp(struct kvm_vcpu *vcpu)
+{
+	struct kvm_mmu_page *sp;
+
+	sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
+	sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache);
+
+	return sp;
+}
+
+static void tdp_mmu_init_sp(struct kvm_mmu_page *sp, tdp_ptep_t sptep,
+			    gfn_t gfn, union kvm_mmu_page_role role)
+{
+	INIT_LIST_HEAD(&sp->possible_nx_huge_page_link);
+
+	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
+
+	sp->role = role;
+	sp->gfn = gfn;
+	sp->ptep = sptep;
+	sp->tdp_mmu_page = true;
+
+	trace_kvm_mmu_get_page(sp, true);
+}
+
+static void tdp_mmu_init_child_sp(struct kvm_mmu_page *child_sp,
+				  struct tdp_iter *iter)
+{
+	struct kvm_mmu_page *parent_sp;
+	union kvm_mmu_page_role role;
+
+	parent_sp = sptep_to_sp(rcu_dereference(iter->sptep));
+
+	role = parent_sp->role;
+	role.level--;
+
+	tdp_mmu_init_sp(child_sp, iter->sptep, iter->gfn, role);
+}
+
+hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu)
+{
+	union kvm_mmu_page_role role = vcpu->arch.mmu->root_role;
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_mmu_page *root;
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+
+	/*
+	 * Check for an existing root before allocating a new one.  Note, the
+	 * role check prevents consuming an invalid root.
+	 */
+	for_each_tdp_mmu_root(kvm, root, kvm_mmu_role_as_id(role)) {
+		if (root->role.word == role.word &&
+		    kvm_tdp_mmu_get_root(root))
+			goto out;
+	}
+
+	root = tdp_mmu_alloc_sp(vcpu);
+	tdp_mmu_init_sp(root, NULL, 0, role);
+
+	/*
+	 * TDP MMU roots are kept until they are explicitly invalidated, either
+	 * by a memslot update or by the destruction of the VM.  Initialize the
+	 * refcount to two; one reference for the vCPU, and one reference for
+	 * the TDP MMU itself, which is held until the root is invalidated and
+	 * is ultimately put by kvm_tdp_mmu_zap_invalidated_roots().
+	 */
+	refcount_set(&root->tdp_mmu_root_count, 2);
+
+	spin_lock(&kvm->arch.tdp_mmu_pages_lock);
+	list_add_rcu(&root->link, &kvm->arch.tdp_mmu_roots);
+	spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
+
+out:
+	return __pa(root->spt);
+}
+
+static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
+				u64 old_spte, u64 new_spte, int level,
+				bool shared);
+
+static void tdp_account_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	kvm_account_pgtable_pages((void *)sp->spt, +1);
+	atomic64_inc(&kvm->arch.tdp_mmu_pages);
+}
+
+static void tdp_unaccount_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	kvm_account_pgtable_pages((void *)sp->spt, -1);
+	atomic64_dec(&kvm->arch.tdp_mmu_pages);
+}
+
+/**
+ * tdp_mmu_unlink_sp() - Remove a shadow page from the list of used pages
+ *
+ * @kvm: kvm instance
+ * @sp: the page to be removed
+ * @shared: This operation may not be running under the exclusive use of
+ *	    the MMU lock and the operation must synchronize with other
+ *	    threads that might be adding or removing pages.
+ */
+static void tdp_mmu_unlink_sp(struct kvm *kvm, struct kvm_mmu_page *sp,
+			      bool shared)
+{
+	tdp_unaccount_mmu_page(kvm, sp);
+
+	if (!sp->nx_huge_page_disallowed)
+		return;
+
+	if (shared)
+		spin_lock(&kvm->arch.tdp_mmu_pages_lock);
+	else
+		lockdep_assert_held_write(&kvm->mmu_lock);
+
+	sp->nx_huge_page_disallowed = false;
+	untrack_possible_nx_huge_page(kvm, sp);
+
+	if (shared)
+		spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
+}
+
+/**
+ * handle_removed_pt() - handle a page table removed from the TDP structure
+ *
+ * @kvm: kvm instance
+ * @pt: the page removed from the paging structure
+ * @shared: This operation may not be running under the exclusive use
+ *	    of the MMU lock and the operation must synchronize with other
+ *	    threads that might be modifying SPTEs.
+ *
+ * Given a page table that has been removed from the TDP paging structure,
+ * iterates through the page table to clear SPTEs and free child page tables.
+ *
+ * Note that pt is passed in as a tdp_ptep_t, but it does not need RCU
+ * protection. Since this thread removed it from the paging structure,
+ * this thread will be responsible for ensuring the page is freed. Hence the
+ * early rcu_dereferences in the function.
+ */
+static void handle_removed_pt(struct kvm *kvm, tdp_ptep_t pt, bool shared)
+{
+	struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(pt));
+	int level = sp->role.level;
+	gfn_t base_gfn = sp->gfn;
+	int i;
+
+	trace_kvm_mmu_prepare_zap_page(sp);
+
+	tdp_mmu_unlink_sp(kvm, sp, shared);
+
+	for (i = 0; i < SPTE_ENT_PER_PAGE; i++) {
+		tdp_ptep_t sptep = pt + i;
+		gfn_t gfn = base_gfn + i * KVM_PAGES_PER_HPAGE(level);
+		u64 old_spte;
+
+		if (shared) {
+			/*
+			 * Set the SPTE to a nonpresent value that other
+			 * threads will not overwrite. If the SPTE was
+			 * already marked as removed then another thread
+			 * handling a page fault could overwrite it, so
+			 * set the SPTE until it is set from some other
+			 * value to the removed SPTE value.
+			 */
+			for (;;) {
+				old_spte = kvm_tdp_mmu_write_spte_atomic(sptep, REMOVED_SPTE);
+				if (!is_removed_spte(old_spte))
+					break;
+				cpu_relax();
+			}
+		} else {
+			/*
+			 * If the SPTE is not MMU-present, there is no backing
+			 * page associated with the SPTE and so no side effects
+			 * that need to be recorded, and exclusive ownership of
+			 * mmu_lock ensures the SPTE can't be made present.
+			 * Note, zapping MMIO SPTEs is also unnecessary as they
+			 * are guarded by the memslots generation, not by being
+			 * unreachable.
+			 */
+			old_spte = kvm_tdp_mmu_read_spte(sptep);
+			if (!is_shadow_present_pte(old_spte))
+				continue;
+
+			/*
+			 * Use the common helper instead of a raw WRITE_ONCE as
+			 * the SPTE needs to be updated atomically if it can be
+			 * modified by a different vCPU outside of mmu_lock.
+			 * Even though the parent SPTE is !PRESENT, the TLB
+			 * hasn't yet been flushed, and both Intel and AMD
+			 * document that A/D assists can use upper-level PxE
+			 * entries that are cached in the TLB, i.e. the CPU can
+			 * still access the page and mark it dirty.
+			 *
+			 * No retry is needed in the atomic update path as the
+			 * sole concern is dropping a Dirty bit, i.e. no other
+			 * task can zap/remove the SPTE as mmu_lock is held for
+			 * write.  Marking the SPTE as a removed SPTE is not
+			 * strictly necessary for the same reason, but using
+			 * the remove SPTE value keeps the shared/exclusive
+			 * paths consistent and allows the handle_changed_spte()
+			 * call below to hardcode the new value to REMOVED_SPTE.
+			 *
+			 * Note, even though dropping a Dirty bit is the only
+			 * scenario where a non-atomic update could result in a
+			 * functional bug, simply checking the Dirty bit isn't
+			 * sufficient as a fast page fault could read the upper
+			 * level SPTE before it is zapped, and then make this
+			 * target SPTE writable, resume the guest, and set the
+			 * Dirty bit between reading the SPTE above and writing
+			 * it here.
+			 */
+			old_spte = kvm_tdp_mmu_write_spte(sptep, old_spte,
+							  REMOVED_SPTE, level);
+		}
+		handle_changed_spte(kvm, kvm_mmu_page_as_id(sp), gfn,
+				    old_spte, REMOVED_SPTE, level, shared);
+	}
+
+	call_rcu(&sp->rcu_head, tdp_mmu_free_sp_rcu_callback);
+}
+
+/**
+ * handle_changed_spte - handle bookkeeping associated with an SPTE change
+ * @kvm: kvm instance
+ * @as_id: the address space of the paging structure the SPTE was a part of
+ * @gfn: the base GFN that was mapped by the SPTE
+ * @old_spte: The value of the SPTE before the change
+ * @new_spte: The value of the SPTE after the change
+ * @level: the level of the PT the SPTE is part of in the paging structure
+ * @shared: This operation may not be running under the exclusive use of
+ *	    the MMU lock and the operation must synchronize with other
+ *	    threads that might be modifying SPTEs.
+ *
+ * Handle bookkeeping that might result from the modification of a SPTE.  Note,
+ * dirty logging updates are handled in common code, not here (see make_spte()
+ * and fast_pf_fix_direct_spte()).
+ */
+static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
+				u64 old_spte, u64 new_spte, int level,
+				bool shared)
+{
+	bool was_present = is_shadow_present_pte(old_spte);
+	bool is_present = is_shadow_present_pte(new_spte);
+	bool was_leaf = was_present && is_last_spte(old_spte, level);
+	bool is_leaf = is_present && is_last_spte(new_spte, level);
+	bool pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte);
+
+	WARN_ON_ONCE(level > PT64_ROOT_MAX_LEVEL);
+	WARN_ON_ONCE(level < PG_LEVEL_4K);
+	WARN_ON_ONCE(gfn & (KVM_PAGES_PER_HPAGE(level) - 1));
+
+	/*
+	 * If this warning were to trigger it would indicate that there was a
+	 * missing MMU notifier or a race with some notifier handler.
+	 * A present, leaf SPTE should never be directly replaced with another
+	 * present leaf SPTE pointing to a different PFN. A notifier handler
+	 * should be zapping the SPTE before the main MM's page table is
+	 * changed, or the SPTE should be zeroed, and the TLBs flushed by the
+	 * thread before replacement.
+	 */
+	if (was_leaf && is_leaf && pfn_changed) {
+		pr_err("Invalid SPTE change: cannot replace a present leaf\n"
+		       "SPTE with another present leaf SPTE mapping a\n"
+		       "different PFN!\n"
+		       "as_id: %d gfn: %llx old_spte: %llx new_spte: %llx level: %d",
+		       as_id, gfn, old_spte, new_spte, level);
+
+		/*
+		 * Crash the host to prevent error propagation and guest data
+		 * corruption.
+		 */
+		BUG();
+	}
+
+	if (old_spte == new_spte)
+		return;
+
+	trace_kvm_tdp_mmu_spte_changed(as_id, gfn, level, old_spte, new_spte);
+
+	if (is_leaf)
+		check_spte_writable_invariants(new_spte);
+
+	/*
+	 * The only times a SPTE should be changed from a non-present to
+	 * non-present state is when an MMIO entry is installed/modified/
+	 * removed. In that case, there is nothing to do here.
+	 */
+	if (!was_present && !is_present) {
+		/*
+		 * If this change does not involve a MMIO SPTE or removed SPTE,
+		 * it is unexpected. Log the change, though it should not
+		 * impact the guest since both the former and current SPTEs
+		 * are nonpresent.
+		 */
+		if (WARN_ON_ONCE(!is_mmio_spte(old_spte) &&
+				 !is_mmio_spte(new_spte) &&
+				 !is_removed_spte(new_spte)))
+			pr_err("Unexpected SPTE change! Nonpresent SPTEs\n"
+			       "should not be replaced with another,\n"
+			       "different nonpresent SPTE, unless one or both\n"
+			       "are MMIO SPTEs, or the new SPTE is\n"
+			       "a temporary removed SPTE.\n"
+			       "as_id: %d gfn: %llx old_spte: %llx new_spte: %llx level: %d",
+			       as_id, gfn, old_spte, new_spte, level);
+		return;
+	}
+
+	if (is_leaf != was_leaf)
+		kvm_update_page_stats(kvm, level, is_leaf ? 1 : -1);
+
+	if (was_leaf && is_dirty_spte(old_spte) &&
+	    (!is_present || !is_dirty_spte(new_spte) || pfn_changed))
+		kvm_set_pfn_dirty(spte_to_pfn(old_spte));
+
+	/*
+	 * Recursively handle child PTs if the change removed a subtree from
+	 * the paging structure.  Note the WARN on the PFN changing without the
+	 * SPTE being converted to a hugepage (leaf) or being zapped.  Shadow
+	 * pages are kernel allocations and should never be migrated.
+	 */
+	if (was_present && !was_leaf &&
+	    (is_leaf || !is_present || WARN_ON_ONCE(pfn_changed)))
+		handle_removed_pt(kvm, spte_to_child_pt(old_spte, level), shared);
+
+	if (was_leaf && is_accessed_spte(old_spte) &&
+	    (!is_present || !is_accessed_spte(new_spte) || pfn_changed))
+		kvm_set_pfn_accessed(spte_to_pfn(old_spte));
+}
+
+/*
+ * tdp_mmu_set_spte_atomic - Set a TDP MMU SPTE atomically
+ * and handle the associated bookkeeping.  Do not mark the page dirty
+ * in KVM's dirty bitmaps.
+ *
+ * If setting the SPTE fails because it has changed, iter->old_spte will be
+ * refreshed to the current value of the spte.
+ *
+ * @kvm: kvm instance
+ * @iter: a tdp_iter instance currently on the SPTE that should be set
+ * @new_spte: The value the SPTE should be set to
+ * Return:
+ * * 0      - If the SPTE was set.
+ * * -EBUSY - If the SPTE cannot be set. In this case this function will have
+ *            no side-effects other than setting iter->old_spte to the last
+ *            known value of the spte.
+ */
+static inline int tdp_mmu_set_spte_atomic(struct kvm *kvm,
+					  struct tdp_iter *iter,
+					  u64 new_spte)
+{
+	u64 *sptep = rcu_dereference(iter->sptep);
+
+	/*
+	 * The caller is responsible for ensuring the old SPTE is not a REMOVED
+	 * SPTE.  KVM should never attempt to zap or manipulate a REMOVED SPTE,
+	 * and pre-checking before inserting a new SPTE is advantageous as it
+	 * avoids unnecessary work.
+	 */
+	WARN_ON_ONCE(iter->yielded || is_removed_spte(iter->old_spte));
+
+	lockdep_assert_held_read(&kvm->mmu_lock);
+
+	/*
+	 * Note, fast_pf_fix_direct_spte() can also modify TDP MMU SPTEs and
+	 * does not hold the mmu_lock.  On failure, i.e. if a different logical
+	 * CPU modified the SPTE, try_cmpxchg64() updates iter->old_spte with
+	 * the current value, so the caller operates on fresh data, e.g. if it
+	 * retries tdp_mmu_set_spte_atomic()
+	 */
+	if (!try_cmpxchg64(sptep, &iter->old_spte, new_spte))
+		return -EBUSY;
+
+	handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte,
+			    new_spte, iter->level, true);
+
+	return 0;
+}
+
+static inline int tdp_mmu_zap_spte_atomic(struct kvm *kvm,
+					  struct tdp_iter *iter)
+{
+	int ret;
+
+	/*
+	 * Freeze the SPTE by setting it to a special,
+	 * non-present value. This will stop other threads from
+	 * immediately installing a present entry in its place
+	 * before the TLBs are flushed.
+	 */
+	ret = tdp_mmu_set_spte_atomic(kvm, iter, REMOVED_SPTE);
+	if (ret)
+		return ret;
+
+	kvm_flush_remote_tlbs_gfn(kvm, iter->gfn, iter->level);
+
+	/*
+	 * No other thread can overwrite the removed SPTE as they must either
+	 * wait on the MMU lock or use tdp_mmu_set_spte_atomic() which will not
+	 * overwrite the special removed SPTE value. No bookkeeping is needed
+	 * here since the SPTE is going from non-present to non-present.  Use
+	 * the raw write helper to avoid an unnecessary check on volatile bits.
+	 */
+	__kvm_tdp_mmu_write_spte(iter->sptep, 0);
+
+	return 0;
+}
+
+
+/*
+ * tdp_mmu_set_spte - Set a TDP MMU SPTE and handle the associated bookkeeping
+ * @kvm:	      KVM instance
+ * @as_id:	      Address space ID, i.e. regular vs. SMM
+ * @sptep:	      Pointer to the SPTE
+ * @old_spte:	      The current value of the SPTE
+ * @new_spte:	      The new value that will be set for the SPTE
+ * @gfn:	      The base GFN that was (or will be) mapped by the SPTE
+ * @level:	      The level _containing_ the SPTE (its parent PT's level)
+ *
+ * Returns the old SPTE value, which _may_ be different than @old_spte if the
+ * SPTE had voldatile bits.
+ */
+static u64 tdp_mmu_set_spte(struct kvm *kvm, int as_id, tdp_ptep_t sptep,
+			    u64 old_spte, u64 new_spte, gfn_t gfn, int level)
+{
+	lockdep_assert_held_write(&kvm->mmu_lock);
+
+	/*
+	 * No thread should be using this function to set SPTEs to or from the
+	 * temporary removed SPTE value.
+	 * If operating under the MMU lock in read mode, tdp_mmu_set_spte_atomic
+	 * should be used. If operating under the MMU lock in write mode, the
+	 * use of the removed SPTE should not be necessary.
+	 */
+	WARN_ON_ONCE(is_removed_spte(old_spte) || is_removed_spte(new_spte));
+
+	old_spte = kvm_tdp_mmu_write_spte(sptep, old_spte, new_spte, level);
+
+	handle_changed_spte(kvm, as_id, gfn, old_spte, new_spte, level, false);
+	return old_spte;
+}
+
+static inline void tdp_mmu_iter_set_spte(struct kvm *kvm, struct tdp_iter *iter,
+					 u64 new_spte)
+{
+	WARN_ON_ONCE(iter->yielded);
+	iter->old_spte = tdp_mmu_set_spte(kvm, iter->as_id, iter->sptep,
+					  iter->old_spte, new_spte,
+					  iter->gfn, iter->level);
+}
+
+#define tdp_root_for_each_pte(_iter, _root, _start, _end) \
+	for_each_tdp_pte(_iter, _root, _start, _end)
+
+#define tdp_root_for_each_leaf_pte(_iter, _root, _start, _end)	\
+	tdp_root_for_each_pte(_iter, _root, _start, _end)		\
+		if (!is_shadow_present_pte(_iter.old_spte) ||		\
+		    !is_last_spte(_iter.old_spte, _iter.level))		\
+			continue;					\
+		else
+
+#define tdp_mmu_for_each_pte(_iter, _mmu, _start, _end)		\
+	for_each_tdp_pte(_iter, root_to_sp(_mmu->root.hpa), _start, _end)
+
+/*
+ * Yield if the MMU lock is contended or this thread needs to return control
+ * to the scheduler.
+ *
+ * If this function should yield and flush is set, it will perform a remote
+ * TLB flush before yielding.
+ *
+ * If this function yields, iter->yielded is set and the caller must skip to
+ * the next iteration, where tdp_iter_next() will reset the tdp_iter's walk
+ * over the paging structures to allow the iterator to continue its traversal
+ * from the paging structure root.
+ *
+ * Returns true if this function yielded.
+ */
+static inline bool __must_check tdp_mmu_iter_cond_resched(struct kvm *kvm,
+							  struct tdp_iter *iter,
+							  bool flush, bool shared)
+{
+	WARN_ON_ONCE(iter->yielded);
+
+	/* Ensure forward progress has been made before yielding. */
+	if (iter->next_last_level_gfn == iter->yielded_gfn)
+		return false;
+
+	if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
+		if (flush)
+			kvm_flush_remote_tlbs(kvm);
+
+		rcu_read_unlock();
+
+		if (shared)
+			cond_resched_rwlock_read(&kvm->mmu_lock);
+		else
+			cond_resched_rwlock_write(&kvm->mmu_lock);
+
+		rcu_read_lock();
+
+		WARN_ON_ONCE(iter->gfn > iter->next_last_level_gfn);
+
+		iter->yielded = true;
+	}
+
+	return iter->yielded;
+}
+
+static inline gfn_t tdp_mmu_max_gfn_exclusive(void)
+{
+	/*
+	 * Bound TDP MMU walks at host.MAXPHYADDR.  KVM disallows memslots with
+	 * a gpa range that would exceed the max gfn, and KVM does not create
+	 * MMIO SPTEs for "impossible" gfns, instead sending such accesses down
+	 * the slow emulation path every time.
+	 */
+	return kvm_mmu_max_gfn() + 1;
+}
+
+static void __tdp_mmu_zap_root(struct kvm *kvm, struct kvm_mmu_page *root,
+			       bool shared, int zap_level)
+{
+	struct tdp_iter iter;
+
+	gfn_t end = tdp_mmu_max_gfn_exclusive();
+	gfn_t start = 0;
+
+	for_each_tdp_pte_min_level(iter, root, zap_level, start, end) {
+retry:
+		if (tdp_mmu_iter_cond_resched(kvm, &iter, false, shared))
+			continue;
+
+		if (!is_shadow_present_pte(iter.old_spte))
+			continue;
+
+		if (iter.level > zap_level)
+			continue;
+
+		if (!shared)
+			tdp_mmu_iter_set_spte(kvm, &iter, 0);
+		else if (tdp_mmu_set_spte_atomic(kvm, &iter, 0))
+			goto retry;
+	}
+}
+
+static void tdp_mmu_zap_root(struct kvm *kvm, struct kvm_mmu_page *root,
+			     bool shared)
+{
+
+	/*
+	 * The root must have an elevated refcount so that it's reachable via
+	 * mmu_notifier callbacks, which allows this path to yield and drop
+	 * mmu_lock.  When handling an unmap/release mmu_notifier command, KVM
+	 * must drop all references to relevant pages prior to completing the
+	 * callback.  Dropping mmu_lock with an unreachable root would result
+	 * in zapping SPTEs after a relevant mmu_notifier callback completes
+	 * and lead to use-after-free as zapping a SPTE triggers "writeback" of
+	 * dirty accessed bits to the SPTE's associated struct page.
+	 */
+	WARN_ON_ONCE(!refcount_read(&root->tdp_mmu_root_count));
+
+	kvm_lockdep_assert_mmu_lock_held(kvm, shared);
+
+	rcu_read_lock();
+
+	/*
+	 * To avoid RCU stalls due to recursively removing huge swaths of SPs,
+	 * split the zap into two passes.  On the first pass, zap at the 1gb
+	 * level, and then zap top-level SPs on the second pass.  "1gb" is not
+	 * arbitrary, as KVM must be able to zap a 1gb shadow page without
+	 * inducing a stall to allow in-place replacement with a 1gb hugepage.
+	 *
+	 * Because zapping a SP recurses on its children, stepping down to
+	 * PG_LEVEL_4K in the iterator itself is unnecessary.
+	 */
+	__tdp_mmu_zap_root(kvm, root, shared, PG_LEVEL_1G);
+	__tdp_mmu_zap_root(kvm, root, shared, root->role.level);
+
+	rcu_read_unlock();
+}
+
+bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+	u64 old_spte;
+
+	/*
+	 * This helper intentionally doesn't allow zapping a root shadow page,
+	 * which doesn't have a parent page table and thus no associated entry.
+	 */
+	if (WARN_ON_ONCE(!sp->ptep))
+		return false;
+
+	old_spte = kvm_tdp_mmu_read_spte(sp->ptep);
+	if (WARN_ON_ONCE(!is_shadow_present_pte(old_spte)))
+		return false;
+
+	tdp_mmu_set_spte(kvm, kvm_mmu_page_as_id(sp), sp->ptep, old_spte, 0,
+			 sp->gfn, sp->role.level + 1);
+
+	return true;
+}
+
+/*
+ * If can_yield is true, will release the MMU lock and reschedule if the
+ * scheduler needs the CPU or there is contention on the MMU lock. If this
+ * function cannot yield, it will not release the MMU lock or reschedule and
+ * the caller must ensure it does not supply too large a GFN range, or the
+ * operation can cause a soft lockup.
+ */
+static bool tdp_mmu_zap_leafs(struct kvm *kvm, struct kvm_mmu_page *root,
+			      gfn_t start, gfn_t end, bool can_yield, bool flush)
+{
+	struct tdp_iter iter;
+
+	end = min(end, tdp_mmu_max_gfn_exclusive());
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+
+	rcu_read_lock();
+
+	for_each_tdp_pte_min_level(iter, root, PG_LEVEL_4K, start, end) {
+		if (can_yield &&
+		    tdp_mmu_iter_cond_resched(kvm, &iter, flush, false)) {
+			flush = false;
+			continue;
+		}
+
+		if (!is_shadow_present_pte(iter.old_spte) ||
+		    !is_last_spte(iter.old_spte, iter.level))
+			continue;
+
+		tdp_mmu_iter_set_spte(kvm, &iter, 0);
+		flush = true;
+	}
+
+	rcu_read_unlock();
+
+	/*
+	 * Because this flow zaps _only_ leaf SPTEs, the caller doesn't need
+	 * to provide RCU protection as no 'struct kvm_mmu_page' will be freed.
+	 */
+	return flush;
+}
+
+/*
+ * Zap leaf SPTEs for the range of gfns, [start, end), for all roots. Returns
+ * true if a TLB flush is needed before releasing the MMU lock, i.e. if one or
+ * more SPTEs were zapped since the MMU lock was last acquired.
+ */
+bool kvm_tdp_mmu_zap_leafs(struct kvm *kvm, gfn_t start, gfn_t end, bool flush)
+{
+	struct kvm_mmu_page *root;
+
+	for_each_tdp_mmu_root_yield_safe(kvm, root, false)
+		flush = tdp_mmu_zap_leafs(kvm, root, start, end, true, flush);
+
+	return flush;
+}
+
+void kvm_tdp_mmu_zap_all(struct kvm *kvm)
+{
+	struct kvm_mmu_page *root;
+
+	/*
+	 * Zap all roots, including invalid roots, as all SPTEs must be dropped
+	 * before returning to the caller.  Zap directly even if the root is
+	 * also being zapped by a worker.  Walking zapped top-level SPTEs isn't
+	 * all that expensive and mmu_lock is already held, which means the
+	 * worker has yielded, i.e. flushing the work instead of zapping here
+	 * isn't guaranteed to be any faster.
+	 *
+	 * A TLB flush is unnecessary, KVM zaps everything if and only the VM
+	 * is being destroyed or the userspace VMM has exited.  In both cases,
+	 * KVM_RUN is unreachable, i.e. no vCPUs will ever service the request.
+	 */
+	for_each_tdp_mmu_root_yield_safe(kvm, root, false)
+		tdp_mmu_zap_root(kvm, root, false);
+}
+
+/*
+ * Zap all invalidated roots to ensure all SPTEs are dropped before the "fast
+ * zap" completes.
+ */
+void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm)
+{
+	struct kvm_mmu_page *root;
+
+	read_lock(&kvm->mmu_lock);
+
+	for_each_tdp_mmu_root_yield_safe(kvm, root, true) {
+		if (!root->tdp_mmu_scheduled_root_to_zap)
+			continue;
+
+		root->tdp_mmu_scheduled_root_to_zap = false;
+		KVM_BUG_ON(!root->role.invalid, kvm);
+
+		/*
+		 * A TLB flush is not necessary as KVM performs a local TLB
+		 * flush when allocating a new root (see kvm_mmu_load()), and
+		 * when migrating a vCPU to a different pCPU.  Note, the local
+		 * TLB flush on reuse also invalidates paging-structure-cache
+		 * entries, i.e. TLB entries for intermediate paging structures,
+		 * that may be zapped, as such entries are associated with the
+		 * ASID on both VMX and SVM.
+		 */
+		tdp_mmu_zap_root(kvm, root, true);
+
+		/*
+		 * The referenced needs to be put *after* zapping the root, as
+		 * the root must be reachable by mmu_notifiers while it's being
+		 * zapped
+		 */
+		kvm_tdp_mmu_put_root(kvm, root, true);
+	}
+
+	read_unlock(&kvm->mmu_lock);
+}
+
+/*
+ * Mark each TDP MMU root as invalid to prevent vCPUs from reusing a root that
+ * is about to be zapped, e.g. in response to a memslots update.  The actual
+ * zapping is done separately so that it happens with mmu_lock with read,
+ * whereas invalidating roots must be done with mmu_lock held for write (unless
+ * the VM is being destroyed).
+ *
+ * Note, kvm_tdp_mmu_zap_invalidated_roots() is gifted the TDP MMU's reference.
+ * See kvm_tdp_mmu_get_vcpu_root_hpa().
+ */
+void kvm_tdp_mmu_invalidate_all_roots(struct kvm *kvm)
+{
+	struct kvm_mmu_page *root;
+
+	/*
+	 * mmu_lock must be held for write to ensure that a root doesn't become
+	 * invalid while there are active readers (invalidating a root while
+	 * there are active readers may or may not be problematic in practice,
+	 * but it's uncharted territory and not supported).
+	 *
+	 * Waive the assertion if there are no users of @kvm, i.e. the VM is
+	 * being destroyed after all references have been put, or if no vCPUs
+	 * have been created (which means there are no roots), i.e. the VM is
+	 * being destroyed in an error path of KVM_CREATE_VM.
+	 */
+	if (IS_ENABLED(CONFIG_PROVE_LOCKING) &&
+	    refcount_read(&kvm->users_count) && kvm->created_vcpus)
+		lockdep_assert_held_write(&kvm->mmu_lock);
+
+	/*
+	 * As above, mmu_lock isn't held when destroying the VM!  There can't
+	 * be other references to @kvm, i.e. nothing else can invalidate roots
+	 * or get/put references to roots.
+	 */
+	list_for_each_entry(root, &kvm->arch.tdp_mmu_roots, link) {
+		/*
+		 * Note, invalid roots can outlive a memslot update!  Invalid
+		 * roots must be *zapped* before the memslot update completes,
+		 * but a different task can acquire a reference and keep the
+		 * root alive after its been zapped.
+		 */
+		if (!root->role.invalid) {
+			root->tdp_mmu_scheduled_root_to_zap = true;
+			root->role.invalid = true;
+		}
+	}
+}
+
+/*
+ * Installs a last-level SPTE to handle a TDP page fault.
+ * (NPT/EPT violation/misconfiguration)
+ */
+static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu,
+					  struct kvm_page_fault *fault,
+					  struct tdp_iter *iter)
+{
+	struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(iter->sptep));
+	u64 new_spte;
+	int ret = RET_PF_FIXED;
+	bool wrprot = false;
+
+	if (WARN_ON_ONCE(sp->role.level != fault->goal_level))
+		return RET_PF_RETRY;
+
+	if (unlikely(!fault->slot))
+		new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL);
+	else
+		wrprot = make_spte(vcpu, sp, fault->slot, ACC_ALL, iter->gfn,
+					 fault->pfn, iter->old_spte, fault->prefetch, true,
+					 fault->map_writable, &new_spte);
+
+	if (new_spte == iter->old_spte)
+		ret = RET_PF_SPURIOUS;
+	else if (tdp_mmu_set_spte_atomic(vcpu->kvm, iter, new_spte))
+		return RET_PF_RETRY;
+	else if (is_shadow_present_pte(iter->old_spte) &&
+		 !is_last_spte(iter->old_spte, iter->level))
+		kvm_flush_remote_tlbs_gfn(vcpu->kvm, iter->gfn, iter->level);
+
+	/*
+	 * If the page fault was caused by a write but the page is write
+	 * protected, emulation is needed. If the emulation was skipped,
+	 * the vCPU would have the same fault again.
+	 */
+	if (wrprot) {
+		if (fault->write)
+			ret = RET_PF_EMULATE;
+	}
+
+	/* If a MMIO SPTE is installed, the MMIO will need to be emulated. */
+	if (unlikely(is_mmio_spte(new_spte))) {
+		vcpu->stat.pf_mmio_spte_created++;
+		trace_mark_mmio_spte(rcu_dereference(iter->sptep), iter->gfn,
+				     new_spte);
+		ret = RET_PF_EMULATE;
+	} else {
+		trace_kvm_mmu_set_spte(iter->level, iter->gfn,
+				       rcu_dereference(iter->sptep));
+	}
+
+	return ret;
+}
+
+/*
+ * tdp_mmu_link_sp - Replace the given spte with an spte pointing to the
+ * provided page table.
+ *
+ * @kvm: kvm instance
+ * @iter: a tdp_iter instance currently on the SPTE that should be set
+ * @sp: The new TDP page table to install.
+ * @shared: This operation is running under the MMU lock in read mode.
+ *
+ * Returns: 0 if the new page table was installed. Non-0 if the page table
+ *          could not be installed (e.g. the atomic compare-exchange failed).
+ */
+static int tdp_mmu_link_sp(struct kvm *kvm, struct tdp_iter *iter,
+			   struct kvm_mmu_page *sp, bool shared)
+{
+	u64 spte = make_nonleaf_spte(sp->spt, !kvm_ad_enabled());
+	int ret = 0;
+
+	if (shared) {
+		ret = tdp_mmu_set_spte_atomic(kvm, iter, spte);
+		if (ret)
+			return ret;
+	} else {
+		tdp_mmu_iter_set_spte(kvm, iter, spte);
+	}
+
+	tdp_account_mmu_page(kvm, sp);
+
+	return 0;
+}
+
+static int tdp_mmu_split_huge_page(struct kvm *kvm, struct tdp_iter *iter,
+				   struct kvm_mmu_page *sp, bool shared);
+
+/*
+ * Handle a TDP page fault (NPT/EPT violation/misconfiguration) by installing
+ * page tables and SPTEs to translate the faulting guest physical address.
+ */
+int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+	struct kvm_mmu *mmu = vcpu->arch.mmu;
+	struct kvm *kvm = vcpu->kvm;
+	struct tdp_iter iter;
+	struct kvm_mmu_page *sp;
+	int ret = RET_PF_RETRY;
+
+	kvm_mmu_hugepage_adjust(vcpu, fault);
+
+	trace_kvm_mmu_spte_requested(fault);
+
+	rcu_read_lock();
+
+	tdp_mmu_for_each_pte(iter, mmu, fault->gfn, fault->gfn + 1) {
+		int r;
+
+		if (fault->nx_huge_page_workaround_enabled)
+			disallowed_hugepage_adjust(fault, iter.old_spte, iter.level);
+
+		/*
+		 * If SPTE has been frozen by another thread, just give up and
+		 * retry, avoiding unnecessary page table allocation and free.
+		 */
+		if (is_removed_spte(iter.old_spte))
+			goto retry;
+
+		if (iter.level == fault->goal_level)
+			goto map_target_level;
+
+		/* Step down into the lower level page table if it exists. */
+		if (is_shadow_present_pte(iter.old_spte) &&
+		    !is_large_pte(iter.old_spte))
+			continue;
+
+		/*
+		 * The SPTE is either non-present or points to a huge page that
+		 * needs to be split.
+		 */
+		sp = tdp_mmu_alloc_sp(vcpu);
+		tdp_mmu_init_child_sp(sp, &iter);
+
+		sp->nx_huge_page_disallowed = fault->huge_page_disallowed;
+
+		if (is_shadow_present_pte(iter.old_spte))
+			r = tdp_mmu_split_huge_page(kvm, &iter, sp, true);
+		else
+			r = tdp_mmu_link_sp(kvm, &iter, sp, true);
+
+		/*
+		 * Force the guest to retry if installing an upper level SPTE
+		 * failed, e.g. because a different task modified the SPTE.
+		 */
+		if (r) {
+			tdp_mmu_free_sp(sp);
+			goto retry;
+		}
+
+		if (fault->huge_page_disallowed &&
+		    fault->req_level >= iter.level) {
+			spin_lock(&kvm->arch.tdp_mmu_pages_lock);
+			if (sp->nx_huge_page_disallowed)
+				track_possible_nx_huge_page(kvm, sp);
+			spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
+		}
+	}
+
+	/*
+	 * The walk aborted before reaching the target level, e.g. because the
+	 * iterator detected an upper level SPTE was frozen during traversal.
+	 */
+	WARN_ON_ONCE(iter.level == fault->goal_level);
+	goto retry;
+
+map_target_level:
+	ret = tdp_mmu_map_handle_target_level(vcpu, fault, &iter);
+
+retry:
+	rcu_read_unlock();
+	return ret;
+}
+
+bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range,
+				 bool flush)
+{
+	struct kvm_mmu_page *root;
+
+	__for_each_tdp_mmu_root_yield_safe(kvm, root, range->slot->as_id, false, false)
+		flush = tdp_mmu_zap_leafs(kvm, root, range->start, range->end,
+					  range->may_block, flush);
+
+	return flush;
+}
+
+typedef bool (*tdp_handler_t)(struct kvm *kvm, struct tdp_iter *iter,
+			      struct kvm_gfn_range *range);
+
+static __always_inline bool kvm_tdp_mmu_handle_gfn(struct kvm *kvm,
+						   struct kvm_gfn_range *range,
+						   tdp_handler_t handler)
+{
+	struct kvm_mmu_page *root;
+	struct tdp_iter iter;
+	bool ret = false;
+
+	/*
+	 * Don't support rescheduling, none of the MMU notifiers that funnel
+	 * into this helper allow blocking; it'd be dead, wasteful code.
+	 */
+	for_each_tdp_mmu_root(kvm, root, range->slot->as_id) {
+		rcu_read_lock();
+
+		tdp_root_for_each_leaf_pte(iter, root, range->start, range->end)
+			ret |= handler(kvm, &iter, range);
+
+		rcu_read_unlock();
+	}
+
+	return ret;
+}
+
+/*
+ * Mark the SPTEs range of GFNs [start, end) unaccessed and return non-zero
+ * if any of the GFNs in the range have been accessed.
+ *
+ * No need to mark the corresponding PFN as accessed as this call is coming
+ * from the clear_young() or clear_flush_young() notifier, which uses the
+ * return value to determine if the page has been accessed.
+ */
+static bool age_gfn_range(struct kvm *kvm, struct tdp_iter *iter,
+			  struct kvm_gfn_range *range)
+{
+	u64 new_spte;
+
+	/* If we have a non-accessed entry we don't need to change the pte. */
+	if (!is_accessed_spte(iter->old_spte))
+		return false;
+
+	if (spte_ad_enabled(iter->old_spte)) {
+		iter->old_spte = tdp_mmu_clear_spte_bits(iter->sptep,
+							 iter->old_spte,
+							 shadow_accessed_mask,
+							 iter->level);
+		new_spte = iter->old_spte & ~shadow_accessed_mask;
+	} else {
+		/*
+		 * Capture the dirty status of the page, so that it doesn't get
+		 * lost when the SPTE is marked for access tracking.
+		 */
+		if (is_writable_pte(iter->old_spte))
+			kvm_set_pfn_dirty(spte_to_pfn(iter->old_spte));
+
+		new_spte = mark_spte_for_access_track(iter->old_spte);
+		iter->old_spte = kvm_tdp_mmu_write_spte(iter->sptep,
+							iter->old_spte, new_spte,
+							iter->level);
+	}
+
+	trace_kvm_tdp_mmu_spte_changed(iter->as_id, iter->gfn, iter->level,
+				       iter->old_spte, new_spte);
+	return true;
+}
+
+bool kvm_tdp_mmu_age_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	return kvm_tdp_mmu_handle_gfn(kvm, range, age_gfn_range);
+}
+
+static bool test_age_gfn(struct kvm *kvm, struct tdp_iter *iter,
+			 struct kvm_gfn_range *range)
+{
+	return is_accessed_spte(iter->old_spte);
+}
+
+bool kvm_tdp_mmu_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	return kvm_tdp_mmu_handle_gfn(kvm, range, test_age_gfn);
+}
+
+static bool set_spte_gfn(struct kvm *kvm, struct tdp_iter *iter,
+			 struct kvm_gfn_range *range)
+{
+	u64 new_spte;
+
+	/* Huge pages aren't expected to be modified without first being zapped. */
+	WARN_ON_ONCE(pte_huge(range->arg.pte) || range->start + 1 != range->end);
+
+	if (iter->level != PG_LEVEL_4K ||
+	    !is_shadow_present_pte(iter->old_spte))
+		return false;
+
+	/*
+	 * Note, when changing a read-only SPTE, it's not strictly necessary to
+	 * zero the SPTE before setting the new PFN, but doing so preserves the
+	 * invariant that the PFN of a present * leaf SPTE can never change.
+	 * See handle_changed_spte().
+	 */
+	tdp_mmu_iter_set_spte(kvm, iter, 0);
+
+	if (!pte_write(range->arg.pte)) {
+		new_spte = kvm_mmu_changed_pte_notifier_make_spte(iter->old_spte,
+								  pte_pfn(range->arg.pte));
+
+		tdp_mmu_iter_set_spte(kvm, iter, new_spte);
+	}
+
+	return true;
+}
+
+/*
+ * Handle the changed_pte MMU notifier for the TDP MMU.
+ * data is a pointer to the new pte_t mapping the HVA specified by the MMU
+ * notifier.
+ * Returns non-zero if a flush is needed before releasing the MMU lock.
+ */
+bool kvm_tdp_mmu_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	/*
+	 * No need to handle the remote TLB flush under RCU protection, the
+	 * target SPTE _must_ be a leaf SPTE, i.e. cannot result in freeing a
+	 * shadow page. See the WARN on pfn_changed in handle_changed_spte().
+	 */
+	return kvm_tdp_mmu_handle_gfn(kvm, range, set_spte_gfn);
+}
+
+/*
+ * Remove write access from all SPTEs at or above min_level that map GFNs
+ * [start, end). Returns true if an SPTE has been changed and the TLBs need to
+ * be flushed.
+ */
+static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
+			     gfn_t start, gfn_t end, int min_level)
+{
+	struct tdp_iter iter;
+	u64 new_spte;
+	bool spte_set = false;
+
+	rcu_read_lock();
+
+	BUG_ON(min_level > KVM_MAX_HUGEPAGE_LEVEL);
+
+	for_each_tdp_pte_min_level(iter, root, min_level, start, end) {
+retry:
+		if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true))
+			continue;
+
+		if (!is_shadow_present_pte(iter.old_spte) ||
+		    !is_last_spte(iter.old_spte, iter.level) ||
+		    !(iter.old_spte & PT_WRITABLE_MASK))
+			continue;
+
+		new_spte = iter.old_spte & ~PT_WRITABLE_MASK;
+
+		if (tdp_mmu_set_spte_atomic(kvm, &iter, new_spte))
+			goto retry;
+
+		spte_set = true;
+	}
+
+	rcu_read_unlock();
+	return spte_set;
+}
+
+/*
+ * Remove write access from all the SPTEs mapping GFNs in the memslot. Will
+ * only affect leaf SPTEs down to min_level.
+ * Returns true if an SPTE has been changed and the TLBs need to be flushed.
+ */
+bool kvm_tdp_mmu_wrprot_slot(struct kvm *kvm,
+			     const struct kvm_memory_slot *slot, int min_level)
+{
+	struct kvm_mmu_page *root;
+	bool spte_set = false;
+
+	lockdep_assert_held_read(&kvm->mmu_lock);
+
+	for_each_valid_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true)
+		spte_set |= wrprot_gfn_range(kvm, root, slot->base_gfn,
+			     slot->base_gfn + slot->npages, min_level);
+
+	return spte_set;
+}
+
+static struct kvm_mmu_page *__tdp_mmu_alloc_sp_for_split(gfp_t gfp)
+{
+	struct kvm_mmu_page *sp;
+
+	gfp |= __GFP_ZERO;
+
+	sp = kmem_cache_alloc(mmu_page_header_cache, gfp);
+	if (!sp)
+		return NULL;
+
+	sp->spt = (void *)__get_free_page(gfp);
+	if (!sp->spt) {
+		kmem_cache_free(mmu_page_header_cache, sp);
+		return NULL;
+	}
+
+	return sp;
+}
+
+static struct kvm_mmu_page *tdp_mmu_alloc_sp_for_split(struct kvm *kvm,
+						       struct tdp_iter *iter,
+						       bool shared)
+{
+	struct kvm_mmu_page *sp;
+
+	/*
+	 * Since we are allocating while under the MMU lock we have to be
+	 * careful about GFP flags. Use GFP_NOWAIT to avoid blocking on direct
+	 * reclaim and to avoid making any filesystem callbacks (which can end
+	 * up invoking KVM MMU notifiers, resulting in a deadlock).
+	 *
+	 * If this allocation fails we drop the lock and retry with reclaim
+	 * allowed.
+	 */
+	sp = __tdp_mmu_alloc_sp_for_split(GFP_NOWAIT | __GFP_ACCOUNT);
+	if (sp)
+		return sp;
+
+	rcu_read_unlock();
+
+	if (shared)
+		read_unlock(&kvm->mmu_lock);
+	else
+		write_unlock(&kvm->mmu_lock);
+
+	iter->yielded = true;
+	sp = __tdp_mmu_alloc_sp_for_split(GFP_KERNEL_ACCOUNT);
+
+	if (shared)
+		read_lock(&kvm->mmu_lock);
+	else
+		write_lock(&kvm->mmu_lock);
+
+	rcu_read_lock();
+
+	return sp;
+}
+
+/* Note, the caller is responsible for initializing @sp. */
+static int tdp_mmu_split_huge_page(struct kvm *kvm, struct tdp_iter *iter,
+				   struct kvm_mmu_page *sp, bool shared)
+{
+	const u64 huge_spte = iter->old_spte;
+	const int level = iter->level;
+	int ret, i;
+
+	/*
+	 * No need for atomics when writing to sp->spt since the page table has
+	 * not been linked in yet and thus is not reachable from any other CPU.
+	 */
+	for (i = 0; i < SPTE_ENT_PER_PAGE; i++)
+		sp->spt[i] = make_huge_page_split_spte(kvm, huge_spte, sp->role, i);
+
+	/*
+	 * Replace the huge spte with a pointer to the populated lower level
+	 * page table. Since we are making this change without a TLB flush vCPUs
+	 * will see a mix of the split mappings and the original huge mapping,
+	 * depending on what's currently in their TLB. This is fine from a
+	 * correctness standpoint since the translation will be the same either
+	 * way.
+	 */
+	ret = tdp_mmu_link_sp(kvm, iter, sp, shared);
+	if (ret)
+		goto out;
+
+	/*
+	 * tdp_mmu_link_sp_atomic() will handle subtracting the huge page we
+	 * are overwriting from the page stats. But we have to manually update
+	 * the page stats with the new present child pages.
+	 */
+	kvm_update_page_stats(kvm, level - 1, SPTE_ENT_PER_PAGE);
+
+out:
+	trace_kvm_mmu_split_huge_page(iter->gfn, huge_spte, level, ret);
+	return ret;
+}
+
+static int tdp_mmu_split_huge_pages_root(struct kvm *kvm,
+					 struct kvm_mmu_page *root,
+					 gfn_t start, gfn_t end,
+					 int target_level, bool shared)
+{
+	struct kvm_mmu_page *sp = NULL;
+	struct tdp_iter iter;
+	int ret = 0;
+
+	rcu_read_lock();
+
+	/*
+	 * Traverse the page table splitting all huge pages above the target
+	 * level into one lower level. For example, if we encounter a 1GB page
+	 * we split it into 512 2MB pages.
+	 *
+	 * Since the TDP iterator uses a pre-order traversal, we are guaranteed
+	 * to visit an SPTE before ever visiting its children, which means we
+	 * will correctly recursively split huge pages that are more than one
+	 * level above the target level (e.g. splitting a 1GB to 512 2MB pages,
+	 * and then splitting each of those to 512 4KB pages).
+	 */
+	for_each_tdp_pte_min_level(iter, root, target_level + 1, start, end) {
+retry:
+		if (tdp_mmu_iter_cond_resched(kvm, &iter, false, shared))
+			continue;
+
+		if (!is_shadow_present_pte(iter.old_spte) || !is_large_pte(iter.old_spte))
+			continue;
+
+		if (!sp) {
+			sp = tdp_mmu_alloc_sp_for_split(kvm, &iter, shared);
+			if (!sp) {
+				ret = -ENOMEM;
+				trace_kvm_mmu_split_huge_page(iter.gfn,
+							      iter.old_spte,
+							      iter.level, ret);
+				break;
+			}
+
+			if (iter.yielded)
+				continue;
+		}
+
+		tdp_mmu_init_child_sp(sp, &iter);
+
+		if (tdp_mmu_split_huge_page(kvm, &iter, sp, shared))
+			goto retry;
+
+		sp = NULL;
+	}
+
+	rcu_read_unlock();
+
+	/*
+	 * It's possible to exit the loop having never used the last sp if, for
+	 * example, a vCPU doing HugePage NX splitting wins the race and
+	 * installs its own sp in place of the last sp we tried to split.
+	 */
+	if (sp)
+		tdp_mmu_free_sp(sp);
+
+	return ret;
+}
+
+
+/*
+ * Try to split all huge pages mapped by the TDP MMU down to the target level.
+ */
+void kvm_tdp_mmu_try_split_huge_pages(struct kvm *kvm,
+				      const struct kvm_memory_slot *slot,
+				      gfn_t start, gfn_t end,
+				      int target_level, bool shared)
+{
+	struct kvm_mmu_page *root;
+	int r = 0;
+
+	kvm_lockdep_assert_mmu_lock_held(kvm, shared);
+
+	for_each_valid_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, shared) {
+		r = tdp_mmu_split_huge_pages_root(kvm, root, start, end, target_level, shared);
+		if (r) {
+			kvm_tdp_mmu_put_root(kvm, root, shared);
+			break;
+		}
+	}
+}
+
+/*
+ * Clear the dirty status of all the SPTEs mapping GFNs in the memslot. If
+ * AD bits are enabled, this will involve clearing the dirty bit on each SPTE.
+ * If AD bits are not enabled, this will require clearing the writable bit on
+ * each SPTE. Returns true if an SPTE has been changed and the TLBs need to
+ * be flushed.
+ */
+static bool clear_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
+			   gfn_t start, gfn_t end)
+{
+	u64 dbit = kvm_ad_enabled() ? shadow_dirty_mask : PT_WRITABLE_MASK;
+	struct tdp_iter iter;
+	bool spte_set = false;
+
+	rcu_read_lock();
+
+	tdp_root_for_each_leaf_pte(iter, root, start, end) {
+retry:
+		if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true))
+			continue;
+
+		if (!is_shadow_present_pte(iter.old_spte))
+			continue;
+
+		KVM_MMU_WARN_ON(kvm_ad_enabled() &&
+				spte_ad_need_write_protect(iter.old_spte));
+
+		if (!(iter.old_spte & dbit))
+			continue;
+
+		if (tdp_mmu_set_spte_atomic(kvm, &iter, iter.old_spte & ~dbit))
+			goto retry;
+
+		spte_set = true;
+	}
+
+	rcu_read_unlock();
+	return spte_set;
+}
+
+/*
+ * Clear the dirty status of all the SPTEs mapping GFNs in the memslot. If
+ * AD bits are enabled, this will involve clearing the dirty bit on each SPTE.
+ * If AD bits are not enabled, this will require clearing the writable bit on
+ * each SPTE. Returns true if an SPTE has been changed and the TLBs need to
+ * be flushed.
+ */
+bool kvm_tdp_mmu_clear_dirty_slot(struct kvm *kvm,
+				  const struct kvm_memory_slot *slot)
+{
+	struct kvm_mmu_page *root;
+	bool spte_set = false;
+
+	lockdep_assert_held_read(&kvm->mmu_lock);
+
+	for_each_valid_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true)
+		spte_set |= clear_dirty_gfn_range(kvm, root, slot->base_gfn,
+				slot->base_gfn + slot->npages);
+
+	return spte_set;
+}
+
+/*
+ * Clears the dirty status of all the 4k SPTEs mapping GFNs for which a bit is
+ * set in mask, starting at gfn. The given memslot is expected to contain all
+ * the GFNs represented by set bits in the mask. If AD bits are enabled,
+ * clearing the dirty status will involve clearing the dirty bit on each SPTE
+ * or, if AD bits are not enabled, clearing the writable bit on each SPTE.
+ */
+static void clear_dirty_pt_masked(struct kvm *kvm, struct kvm_mmu_page *root,
+				  gfn_t gfn, unsigned long mask, bool wrprot)
+{
+	u64 dbit = (wrprot || !kvm_ad_enabled()) ? PT_WRITABLE_MASK :
+						   shadow_dirty_mask;
+	struct tdp_iter iter;
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+
+	rcu_read_lock();
+
+	tdp_root_for_each_leaf_pte(iter, root, gfn + __ffs(mask),
+				    gfn + BITS_PER_LONG) {
+		if (!mask)
+			break;
+
+		KVM_MMU_WARN_ON(kvm_ad_enabled() &&
+				spte_ad_need_write_protect(iter.old_spte));
+
+		if (iter.level > PG_LEVEL_4K ||
+		    !(mask & (1UL << (iter.gfn - gfn))))
+			continue;
+
+		mask &= ~(1UL << (iter.gfn - gfn));
+
+		if (!(iter.old_spte & dbit))
+			continue;
+
+		iter.old_spte = tdp_mmu_clear_spte_bits(iter.sptep,
+							iter.old_spte, dbit,
+							iter.level);
+
+		trace_kvm_tdp_mmu_spte_changed(iter.as_id, iter.gfn, iter.level,
+					       iter.old_spte,
+					       iter.old_spte & ~dbit);
+		kvm_set_pfn_dirty(spte_to_pfn(iter.old_spte));
+	}
+
+	rcu_read_unlock();
+}
+
+/*
+ * Clears the dirty status of all the 4k SPTEs mapping GFNs for which a bit is
+ * set in mask, starting at gfn. The given memslot is expected to contain all
+ * the GFNs represented by set bits in the mask. If AD bits are enabled,
+ * clearing the dirty status will involve clearing the dirty bit on each SPTE
+ * or, if AD bits are not enabled, clearing the writable bit on each SPTE.
+ */
+void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm,
+				       struct kvm_memory_slot *slot,
+				       gfn_t gfn, unsigned long mask,
+				       bool wrprot)
+{
+	struct kvm_mmu_page *root;
+
+	for_each_tdp_mmu_root(kvm, root, slot->as_id)
+		clear_dirty_pt_masked(kvm, root, gfn, mask, wrprot);
+}
+
+static void zap_collapsible_spte_range(struct kvm *kvm,
+				       struct kvm_mmu_page *root,
+				       const struct kvm_memory_slot *slot)
+{
+	gfn_t start = slot->base_gfn;
+	gfn_t end = start + slot->npages;
+	struct tdp_iter iter;
+	int max_mapping_level;
+
+	rcu_read_lock();
+
+	for_each_tdp_pte_min_level(iter, root, PG_LEVEL_2M, start, end) {
+retry:
+		if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true))
+			continue;
+
+		if (iter.level > KVM_MAX_HUGEPAGE_LEVEL ||
+		    !is_shadow_present_pte(iter.old_spte))
+			continue;
+
+		/*
+		 * Don't zap leaf SPTEs, if a leaf SPTE could be replaced with
+		 * a large page size, then its parent would have been zapped
+		 * instead of stepping down.
+		 */
+		if (is_last_spte(iter.old_spte, iter.level))
+			continue;
+
+		/*
+		 * If iter.gfn resides outside of the slot, i.e. the page for
+		 * the current level overlaps but is not contained by the slot,
+		 * then the SPTE can't be made huge.  More importantly, trying
+		 * to query that info from slot->arch.lpage_info will cause an
+		 * out-of-bounds access.
+		 */
+		if (iter.gfn < start || iter.gfn >= end)
+			continue;
+
+		max_mapping_level = kvm_mmu_max_mapping_level(kvm, slot,
+							      iter.gfn, PG_LEVEL_NUM);
+		if (max_mapping_level < iter.level)
+			continue;
+
+		/* Note, a successful atomic zap also does a remote TLB flush. */
+		if (tdp_mmu_zap_spte_atomic(kvm, &iter))
+			goto retry;
+	}
+
+	rcu_read_unlock();
+}
+
+/*
+ * Zap non-leaf SPTEs (and free their associated page tables) which could
+ * be replaced by huge pages, for GFNs within the slot.
+ */
+void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm,
+				       const struct kvm_memory_slot *slot)
+{
+	struct kvm_mmu_page *root;
+
+	lockdep_assert_held_read(&kvm->mmu_lock);
+
+	for_each_valid_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true)
+		zap_collapsible_spte_range(kvm, root, slot);
+}
+
+/*
+ * Removes write access on the last level SPTE mapping this GFN and unsets the
+ * MMU-writable bit to ensure future writes continue to be intercepted.
+ * Returns true if an SPTE was set and a TLB flush is needed.
+ */
+static bool write_protect_gfn(struct kvm *kvm, struct kvm_mmu_page *root,
+			      gfn_t gfn, int min_level)
+{
+	struct tdp_iter iter;
+	u64 new_spte;
+	bool spte_set = false;
+
+	BUG_ON(min_level > KVM_MAX_HUGEPAGE_LEVEL);
+
+	rcu_read_lock();
+
+	for_each_tdp_pte_min_level(iter, root, min_level, gfn, gfn + 1) {
+		if (!is_shadow_present_pte(iter.old_spte) ||
+		    !is_last_spte(iter.old_spte, iter.level))
+			continue;
+
+		new_spte = iter.old_spte &
+			~(PT_WRITABLE_MASK | shadow_mmu_writable_mask);
+
+		if (new_spte == iter.old_spte)
+			break;
+
+		tdp_mmu_iter_set_spte(kvm, &iter, new_spte);
+		spte_set = true;
+	}
+
+	rcu_read_unlock();
+
+	return spte_set;
+}
+
+/*
+ * Removes write access on the last level SPTE mapping this GFN and unsets the
+ * MMU-writable bit to ensure future writes continue to be intercepted.
+ * Returns true if an SPTE was set and a TLB flush is needed.
+ */
+bool kvm_tdp_mmu_write_protect_gfn(struct kvm *kvm,
+				   struct kvm_memory_slot *slot, gfn_t gfn,
+				   int min_level)
+{
+	struct kvm_mmu_page *root;
+	bool spte_set = false;
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+	for_each_tdp_mmu_root(kvm, root, slot->as_id)
+		spte_set |= write_protect_gfn(kvm, root, gfn, min_level);
+
+	return spte_set;
+}
+
+/*
+ * Return the level of the lowest level SPTE added to sptes.
+ * That SPTE may be non-present.
+ *
+ * Must be called between kvm_tdp_mmu_walk_lockless_{begin,end}.
+ */
+int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes,
+			 int *root_level)
+{
+	struct tdp_iter iter;
+	struct kvm_mmu *mmu = vcpu->arch.mmu;
+	gfn_t gfn = addr >> PAGE_SHIFT;
+	int leaf = -1;
+
+	*root_level = vcpu->arch.mmu->root_role.level;
+
+	tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) {
+		leaf = iter.level;
+		sptes[leaf] = iter.old_spte;
+	}
+
+	return leaf;
+}
+
+/*
+ * Returns the last level spte pointer of the shadow page walk for the given
+ * gpa, and sets *spte to the spte value. This spte may be non-preset. If no
+ * walk could be performed, returns NULL and *spte does not contain valid data.
+ *
+ * Contract:
+ *  - Must be called between kvm_tdp_mmu_walk_lockless_{begin,end}.
+ *  - The returned sptep must not be used after kvm_tdp_mmu_walk_lockless_end.
+ *
+ * WARNING: This function is only intended to be called during fast_page_fault.
+ */
+u64 *kvm_tdp_mmu_fast_pf_get_last_sptep(struct kvm_vcpu *vcpu, u64 addr,
+					u64 *spte)
+{
+	struct tdp_iter iter;
+	struct kvm_mmu *mmu = vcpu->arch.mmu;
+	gfn_t gfn = addr >> PAGE_SHIFT;
+	tdp_ptep_t sptep = NULL;
+
+	tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) {
+		*spte = iter.old_spte;
+		sptep = iter.sptep;
+	}
+
+	/*
+	 * Perform the rcu_dereference to get the raw spte pointer value since
+	 * we are passing it up to fast_page_fault, which is shared with the
+	 * legacy MMU and thus does not retain the TDP MMU-specific __rcu
+	 * annotation.
+	 *
+	 * This is safe since fast_page_fault obeys the contracts of this
+	 * function as well as all TDP MMU contracts around modifying SPTEs
+	 * outside of mmu_lock.
+	 */
+	return rcu_dereference(sptep);
+}
diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
new file mode 100644
index 0000000000..733a3aef3a
--- /dev/null
+++ b/arch/x86/kvm/mmu/tdp_mmu.h
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifndef __KVM_X86_MMU_TDP_MMU_H
+#define __KVM_X86_MMU_TDP_MMU_H
+
+#include <linux/kvm_host.h>
+
+#include "spte.h"
+
+void kvm_mmu_init_tdp_mmu(struct kvm *kvm);
+void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm);
+
+hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu);
+
+__must_check static inline bool kvm_tdp_mmu_get_root(struct kvm_mmu_page *root)
+{
+	return refcount_inc_not_zero(&root->tdp_mmu_root_count);
+}
+
+void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root,
+			  bool shared);
+
+bool kvm_tdp_mmu_zap_leafs(struct kvm *kvm, gfn_t start, gfn_t end, bool flush);
+bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp);
+void kvm_tdp_mmu_zap_all(struct kvm *kvm);
+void kvm_tdp_mmu_invalidate_all_roots(struct kvm *kvm);
+void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm);
+
+int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
+
+bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range,
+				 bool flush);
+bool kvm_tdp_mmu_age_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range);
+bool kvm_tdp_mmu_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range);
+bool kvm_tdp_mmu_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range);
+
+bool kvm_tdp_mmu_wrprot_slot(struct kvm *kvm,
+			     const struct kvm_memory_slot *slot, int min_level);
+bool kvm_tdp_mmu_clear_dirty_slot(struct kvm *kvm,
+				  const struct kvm_memory_slot *slot);
+void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm,
+				       struct kvm_memory_slot *slot,
+				       gfn_t gfn, unsigned long mask,
+				       bool wrprot);
+void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm,
+				       const struct kvm_memory_slot *slot);
+
+bool kvm_tdp_mmu_write_protect_gfn(struct kvm *kvm,
+				   struct kvm_memory_slot *slot, gfn_t gfn,
+				   int min_level);
+
+void kvm_tdp_mmu_try_split_huge_pages(struct kvm *kvm,
+				      const struct kvm_memory_slot *slot,
+				      gfn_t start, gfn_t end,
+				      int target_level, bool shared);
+
+static inline void kvm_tdp_mmu_walk_lockless_begin(void)
+{
+	rcu_read_lock();
+}
+
+static inline void kvm_tdp_mmu_walk_lockless_end(void)
+{
+	rcu_read_unlock();
+}
+
+int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes,
+			 int *root_level);
+u64 *kvm_tdp_mmu_fast_pf_get_last_sptep(struct kvm_vcpu *vcpu, u64 addr,
+					u64 *spte);
+
+#ifdef CONFIG_X86_64
+static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return sp->tdp_mmu_page; }
+#else
+static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return false; }
+#endif
+
+#endif /* __KVM_X86_MMU_TDP_MMU_H */