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-rw-r--r--arch/x86/kvm/mmu/mmu.c7161
1 files changed, 7161 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);
+}