Adding upstream version 4.19.249.upstream/4.19.249

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

1 files changed, 1083 insertions, 0 deletions

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
new file mode 100644
index 000000000..9e15818de
--- /dev/null
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -0,0 +1,1083 @@
+/*
+ * 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>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+/*
+ * We need the mmu code to access both 32-bit and 64-bit guest ptes,
+ * so the code in this file is compiled twice, once per pte size.
+ */
+
+#if PTTYPE == 64
+	#define pt_element_t u64
+	#define guest_walker guest_walker64
+	#define FNAME(name) paging##64_##name
+	#define PT_BASE_ADDR_MASK PT64_BASE_ADDR_MASK
+	#define PT_LVL_ADDR_MASK(lvl) PT64_LVL_ADDR_MASK(lvl)
+	#define PT_LVL_OFFSET_MASK(lvl) PT64_LVL_OFFSET_MASK(lvl)
+	#define PT_INDEX(addr, level) PT64_INDEX(addr, level)
+	#define PT_LEVEL_BITS PT64_LEVEL_BITS
+	#define PT_GUEST_DIRTY_SHIFT PT_DIRTY_SHIFT
+	#define PT_GUEST_ACCESSED_SHIFT PT_ACCESSED_SHIFT
+	#define PT_HAVE_ACCESSED_DIRTY(mmu) true
+	#ifdef CONFIG_X86_64
+	#define PT_MAX_FULL_LEVELS PT64_ROOT_MAX_LEVEL
+	#define CMPXCHG cmpxchg
+	#else
+	#define CMPXCHG cmpxchg64
+	#define PT_MAX_FULL_LEVELS 2
+	#endif
+#elif PTTYPE == 32
+	#define pt_element_t u32
+	#define guest_walker guest_walker32
+	#define FNAME(name) paging##32_##name
+	#define PT_BASE_ADDR_MASK PT32_BASE_ADDR_MASK
+	#define PT_LVL_ADDR_MASK(lvl) PT32_LVL_ADDR_MASK(lvl)
+	#define PT_LVL_OFFSET_MASK(lvl) PT32_LVL_OFFSET_MASK(lvl)
+	#define PT_INDEX(addr, level) PT32_INDEX(addr, level)
+	#define PT_LEVEL_BITS PT32_LEVEL_BITS
+	#define PT_MAX_FULL_LEVELS 2
+	#define PT_GUEST_DIRTY_SHIFT PT_DIRTY_SHIFT
+	#define PT_GUEST_ACCESSED_SHIFT PT_ACCESSED_SHIFT
+	#define PT_HAVE_ACCESSED_DIRTY(mmu) true
+	#define CMPXCHG cmpxchg
+#elif PTTYPE == PTTYPE_EPT
+	#define pt_element_t u64
+	#define guest_walker guest_walkerEPT
+	#define FNAME(name) ept_##name
+	#define PT_BASE_ADDR_MASK PT64_BASE_ADDR_MASK
+	#define PT_LVL_ADDR_MASK(lvl) PT64_LVL_ADDR_MASK(lvl)
+	#define PT_LVL_OFFSET_MASK(lvl) PT64_LVL_OFFSET_MASK(lvl)
+	#define PT_INDEX(addr, level) PT64_INDEX(addr, level)
+	#define PT_LEVEL_BITS PT64_LEVEL_BITS
+	#define PT_GUEST_DIRTY_SHIFT 9
+	#define PT_GUEST_ACCESSED_SHIFT 8
+	#define PT_HAVE_ACCESSED_DIRTY(mmu) ((mmu)->ept_ad)
+	#define CMPXCHG cmpxchg64
+	#define PT_MAX_FULL_LEVELS 4
+#else
+	#error Invalid PTTYPE value
+#endif
+
+#define PT_GUEST_DIRTY_MASK    (1 << PT_GUEST_DIRTY_SHIFT)
+#define PT_GUEST_ACCESSED_MASK (1 << PT_GUEST_ACCESSED_SHIFT)
+
+#define gpte_to_gfn_lvl FNAME(gpte_to_gfn_lvl)
+#define gpte_to_gfn(pte) gpte_to_gfn_lvl((pte), PT_PAGE_TABLE_LEVEL)
+
+/*
+ * The guest_walker structure emulates the behavior of the hardware page
+ * table walker.
+ */
+struct guest_walker {
+	int level;
+	unsigned max_level;
+	gfn_t table_gfn[PT_MAX_FULL_LEVELS];
+	pt_element_t ptes[PT_MAX_FULL_LEVELS];
+	pt_element_t prefetch_ptes[PTE_PREFETCH_NUM];
+	gpa_t pte_gpa[PT_MAX_FULL_LEVELS];
+	pt_element_t __user *ptep_user[PT_MAX_FULL_LEVELS];
+	bool pte_writable[PT_MAX_FULL_LEVELS];
+	unsigned int pt_access[PT_MAX_FULL_LEVELS];
+	unsigned int pte_access;
+	gfn_t gfn;
+	struct x86_exception fault;
+};
+
+static gfn_t gpte_to_gfn_lvl(pt_element_t gpte, int lvl)
+{
+	return (gpte & PT_LVL_ADDR_MASK(lvl)) >> PAGE_SHIFT;
+}
+
+static inline void FNAME(protect_clean_gpte)(struct kvm_mmu *mmu, unsigned *access,
+					     unsigned gpte)
+{
+	unsigned mask;
+
+	/* dirty bit is not supported, so no need to track it */
+	if (!PT_HAVE_ACCESSED_DIRTY(mmu))
+		return;
+
+	BUILD_BUG_ON(PT_WRITABLE_MASK != ACC_WRITE_MASK);
+
+	mask = (unsigned)~ACC_WRITE_MASK;
+	/* Allow write access to dirty gptes */
+	mask |= (gpte >> (PT_GUEST_DIRTY_SHIFT - PT_WRITABLE_SHIFT)) &
+		PT_WRITABLE_MASK;
+	*access &= mask;
+}
+
+static inline int FNAME(is_present_gpte)(unsigned long pte)
+{
+#if PTTYPE != PTTYPE_EPT
+	return pte & PT_PRESENT_MASK;
+#else
+	return pte & 7;
+#endif
+}
+
+static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+			       pt_element_t __user *ptep_user, unsigned index,
+			       pt_element_t orig_pte, pt_element_t new_pte)
+{
+	int npages;
+	pt_element_t ret;
+	pt_element_t *table;
+	struct page *page;
+
+	npages = get_user_pages_fast((unsigned long)ptep_user, 1, 1, &page);
+	/* Check if the user is doing something meaningless. */
+	if (unlikely(npages != 1))
+		return -EFAULT;
+
+	table = kmap_atomic(page);
+	ret = CMPXCHG(&table[index], orig_pte, new_pte);
+	kunmap_atomic(table);
+
+	kvm_release_page_dirty(page);
+
+	return (ret != orig_pte);
+}
+
+static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu,
+				  struct kvm_mmu_page *sp, u64 *spte,
+				  u64 gpte)
+{
+	if (is_rsvd_bits_set(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL))
+		goto no_present;
+
+	if (!FNAME(is_present_gpte)(gpte))
+		goto no_present;
+
+	/* if accessed bit is not supported prefetch non accessed gpte */
+	if (PT_HAVE_ACCESSED_DIRTY(&vcpu->arch.mmu) && !(gpte & PT_GUEST_ACCESSED_MASK))
+		goto no_present;
+
+	return false;
+
+no_present:
+	drop_spte(vcpu->kvm, spte);
+	return true;
+}
+
+/*
+ * For PTTYPE_EPT, a page table can be executable but not readable
+ * on supported processors. Therefore, set_spte does not automatically
+ * set bit 0 if execute only is supported. Here, we repurpose ACC_USER_MASK
+ * to signify readability since it isn't used in the EPT case
+ */
+static inline unsigned FNAME(gpte_access)(u64 gpte)
+{
+	unsigned access;
+#if PTTYPE == PTTYPE_EPT
+	access = ((gpte & VMX_EPT_WRITABLE_MASK) ? ACC_WRITE_MASK : 0) |
+		((gpte & VMX_EPT_EXECUTABLE_MASK) ? ACC_EXEC_MASK : 0) |
+		((gpte & VMX_EPT_READABLE_MASK) ? ACC_USER_MASK : 0);
+#else
+	BUILD_BUG_ON(ACC_EXEC_MASK != PT_PRESENT_MASK);
+	BUILD_BUG_ON(ACC_EXEC_MASK != 1);
+	access = gpte & (PT_WRITABLE_MASK | PT_USER_MASK | PT_PRESENT_MASK);
+	/* Combine NX with P (which is set here) to get ACC_EXEC_MASK.  */
+	access ^= (gpte >> PT64_NX_SHIFT);
+#endif
+
+	return access;
+}
+
+static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu,
+					     struct kvm_mmu *mmu,
+					     struct guest_walker *walker,
+					     gpa_t addr, int write_fault)
+{
+	unsigned level, index;
+	pt_element_t pte, orig_pte;
+	pt_element_t __user *ptep_user;
+	gfn_t table_gfn;
+	int ret;
+
+	/* dirty/accessed bits are not supported, so no need to update them */
+	if (!PT_HAVE_ACCESSED_DIRTY(mmu))
+		return 0;
+
+	for (level = walker->max_level; level >= walker->level; --level) {
+		pte = orig_pte = walker->ptes[level - 1];
+		table_gfn = walker->table_gfn[level - 1];
+		ptep_user = walker->ptep_user[level - 1];
+		index = offset_in_page(ptep_user) / sizeof(pt_element_t);
+		if (!(pte & PT_GUEST_ACCESSED_MASK)) {
+			trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(pte));
+			pte |= PT_GUEST_ACCESSED_MASK;
+		}
+		if (level == walker->level && write_fault &&
+				!(pte & PT_GUEST_DIRTY_MASK)) {
+			trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
+#if PTTYPE == PTTYPE_EPT
+			if (kvm_arch_write_log_dirty(vcpu, addr))
+				return -EINVAL;
+#endif
+			pte |= PT_GUEST_DIRTY_MASK;
+		}
+		if (pte == orig_pte)
+			continue;
+
+		/*
+		 * If the slot is read-only, simply do not process the accessed
+		 * and dirty bits.  This is the correct thing to do if the slot
+		 * is ROM, and page tables in read-as-ROM/write-as-MMIO slots
+		 * are only supported if the accessed and dirty bits are already
+		 * set in the ROM (so that MMIO writes are never needed).
+		 *
+		 * Note that NPT does not allow this at all and faults, since
+		 * it always wants nested page table entries for the guest
+		 * page tables to be writable.  And EPT works but will simply
+		 * overwrite the read-only memory to set the accessed and dirty
+		 * bits.
+		 */
+		if (unlikely(!walker->pte_writable[level - 1]))
+			continue;
+
+		ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index, orig_pte, pte);
+		if (ret)
+			return ret;
+
+		kvm_vcpu_mark_page_dirty(vcpu, table_gfn);
+		walker->ptes[level - 1] = pte;
+	}
+	return 0;
+}
+
+static inline unsigned FNAME(gpte_pkeys)(struct kvm_vcpu *vcpu, u64 gpte)
+{
+	unsigned pkeys = 0;
+#if PTTYPE == 64
+	pte_t pte = {.pte = gpte};
+
+	pkeys = pte_flags_pkey(pte_flags(pte));
+#endif
+	return pkeys;
+}
+
+/*
+ * Fetch a guest pte for a guest virtual address, or for an L2's GPA.
+ */
+static int FNAME(walk_addr_generic)(struct guest_walker *walker,
+				    struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+				    gpa_t addr, u32 access)
+{
+	int ret;
+	pt_element_t pte;
+	pt_element_t __user *uninitialized_var(ptep_user);
+	gfn_t table_gfn;
+	u64 pt_access, pte_access;
+	unsigned index, accessed_dirty, pte_pkey;
+	unsigned nested_access;
+	gpa_t pte_gpa;
+	bool have_ad;
+	int offset;
+	u64 walk_nx_mask = 0;
+	const int write_fault = access & PFERR_WRITE_MASK;
+	const int user_fault  = access & PFERR_USER_MASK;
+	const int fetch_fault = access & PFERR_FETCH_MASK;
+	u16 errcode = 0;
+	gpa_t real_gpa;
+	gfn_t gfn;
+
+	trace_kvm_mmu_pagetable_walk(addr, access);
+retry_walk:
+	walker->level = mmu->root_level;
+	pte           = mmu->get_cr3(vcpu);
+	have_ad       = PT_HAVE_ACCESSED_DIRTY(mmu);
+
+#if PTTYPE == 64
+	walk_nx_mask = 1ULL << PT64_NX_SHIFT;
+	if (walker->level == PT32E_ROOT_LEVEL) {
+		pte = mmu->get_pdptr(vcpu, (addr >> 30) & 3);
+		trace_kvm_mmu_paging_element(pte, walker->level);
+		if (!FNAME(is_present_gpte)(pte))
+			goto error;
+		--walker->level;
+	}
+#endif
+	walker->max_level = walker->level;
+	ASSERT(!(is_long_mode(vcpu) && !is_pae(vcpu)));
+
+	/*
+	 * FIXME: on Intel processors, loads of the PDPTE registers for PAE paging
+	 * by the MOV to CR instruction are treated as reads and do not cause the
+	 * processor to set the dirty flag in any EPT paging-structure entry.
+	 */
+	nested_access = (have_ad ? PFERR_WRITE_MASK : 0) | PFERR_USER_MASK;
+
+	pte_access = ~0;
+	++walker->level;
+
+	do {
+		gfn_t real_gfn;
+		unsigned long host_addr;
+
+		pt_access = pte_access;
+		--walker->level;
+
+		index = PT_INDEX(addr, walker->level);
+		table_gfn = gpte_to_gfn(pte);
+		offset    = index * sizeof(pt_element_t);
+		pte_gpa   = gfn_to_gpa(table_gfn) + offset;
+
+		BUG_ON(walker->level < 1);
+		walker->table_gfn[walker->level - 1] = table_gfn;
+		walker->pte_gpa[walker->level - 1] = pte_gpa;
+
+		real_gfn = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn),
+					      nested_access,
+					      &walker->fault);
+
+		/*
+		 * FIXME: This can happen if emulation (for of an INS/OUTS
+		 * instruction) triggers a nested page fault.  The exit
+		 * qualification / exit info field will incorrectly have
+		 * "guest page access" as the nested page fault's cause,
+		 * instead of "guest page structure access".  To fix this,
+		 * the x86_exception struct should be augmented with enough
+		 * information to fix the exit_qualification or exit_info_1
+		 * fields.
+		 */
+		if (unlikely(real_gfn == UNMAPPED_GVA))
+			return 0;
+
+		real_gfn = gpa_to_gfn(real_gfn);
+
+		host_addr = kvm_vcpu_gfn_to_hva_prot(vcpu, real_gfn,
+					    &walker->pte_writable[walker->level - 1]);
+		if (unlikely(kvm_is_error_hva(host_addr)))
+			goto error;
+
+		ptep_user = (pt_element_t __user *)((void *)host_addr + offset);
+		if (unlikely(__copy_from_user(&pte, ptep_user, sizeof(pte))))
+			goto error;
+		walker->ptep_user[walker->level - 1] = ptep_user;
+
+		trace_kvm_mmu_paging_element(pte, walker->level);
+
+		/*
+		 * Inverting the NX it lets us AND it like other
+		 * permission bits.
+		 */
+		pte_access = pt_access & (pte ^ walk_nx_mask);
+
+		if (unlikely(!FNAME(is_present_gpte)(pte)))
+			goto error;
+
+		if (unlikely(is_rsvd_bits_set(mmu, pte, walker->level))) {
+			errcode = PFERR_RSVD_MASK | PFERR_PRESENT_MASK;
+			goto error;
+		}
+
+		walker->ptes[walker->level - 1] = pte;
+
+		/* Convert to ACC_*_MASK flags for struct guest_walker.  */
+		walker->pt_access[walker->level - 1] = FNAME(gpte_access)(pt_access ^ walk_nx_mask);
+	} while (!is_last_gpte(mmu, walker->level, pte));
+
+	pte_pkey = FNAME(gpte_pkeys)(vcpu, pte);
+	accessed_dirty = have_ad ? pte_access & PT_GUEST_ACCESSED_MASK : 0;
+
+	/* Convert to ACC_*_MASK flags for struct guest_walker.  */
+	walker->pte_access = FNAME(gpte_access)(pte_access ^ walk_nx_mask);
+	errcode = permission_fault(vcpu, mmu, walker->pte_access, pte_pkey, access);
+	if (unlikely(errcode))
+		goto error;
+
+	gfn = gpte_to_gfn_lvl(pte, walker->level);
+	gfn += (addr & PT_LVL_OFFSET_MASK(walker->level)) >> PAGE_SHIFT;
+
+	if (PTTYPE == 32 && walker->level == PT_DIRECTORY_LEVEL && is_cpuid_PSE36())
+		gfn += pse36_gfn_delta(pte);
+
+	real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn), access, &walker->fault);
+	if (real_gpa == UNMAPPED_GVA)
+		return 0;
+
+	walker->gfn = real_gpa >> PAGE_SHIFT;
+
+	if (!write_fault)
+		FNAME(protect_clean_gpte)(mmu, &walker->pte_access, pte);
+	else
+		/*
+		 * On a write fault, fold the dirty bit into accessed_dirty.
+		 * For modes without A/D bits support accessed_dirty will be
+		 * always clear.
+		 */
+		accessed_dirty &= pte >>
+			(PT_GUEST_DIRTY_SHIFT - PT_GUEST_ACCESSED_SHIFT);
+
+	if (unlikely(!accessed_dirty)) {
+		ret = FNAME(update_accessed_dirty_bits)(vcpu, mmu, walker,
+							addr, write_fault);
+		if (unlikely(ret < 0))
+			goto error;
+		else if (ret)
+			goto retry_walk;
+	}
+
+	pgprintk("%s: pte %llx pte_access %x pt_access %x\n",
+		 __func__, (u64)pte, walker->pte_access,
+		 walker->pt_access[walker->level - 1]);
+	return 1;
+
+error:
+	errcode |= write_fault | user_fault;
+	if (fetch_fault && (mmu->nx ||
+			    kvm_read_cr4_bits(vcpu, X86_CR4_SMEP)))
+		errcode |= PFERR_FETCH_MASK;
+
+	walker->fault.vector = PF_VECTOR;
+	walker->fault.error_code_valid = true;
+	walker->fault.error_code = errcode;
+
+#if PTTYPE == PTTYPE_EPT
+	/*
+	 * Use PFERR_RSVD_MASK in error_code to to tell if EPT
+	 * misconfiguration requires to be injected. The detection is
+	 * done by is_rsvd_bits_set() above.
+	 *
+	 * We set up the value of exit_qualification to inject:
+	 * [2:0] - Derive from the access bits. The exit_qualification might be
+	 *         out of date if it is serving an EPT misconfiguration.
+	 * [5:3] - Calculated by the page walk of the guest EPT page tables
+	 * [7:8] - Derived from [7:8] of real exit_qualification
+	 *
+	 * The other bits are set to 0.
+	 */
+	if (!(errcode & PFERR_RSVD_MASK)) {
+		vcpu->arch.exit_qualification &= 0x180;
+		if (write_fault)
+			vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_WRITE;
+		if (user_fault)
+			vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_READ;
+		if (fetch_fault)
+			vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_INSTR;
+		vcpu->arch.exit_qualification |= (pte_access & 0x7) << 3;
+	}
+#endif
+	walker->fault.address = addr;
+	walker->fault.nested_page_fault = mmu != vcpu->arch.walk_mmu;
+
+	trace_kvm_mmu_walker_error(walker->fault.error_code);
+	return 0;
+}
+
+static int FNAME(walk_addr)(struct guest_walker *walker,
+			    struct kvm_vcpu *vcpu, gpa_t addr, u32 access)
+{
+	return FNAME(walk_addr_generic)(walker, vcpu, &vcpu->arch.mmu, addr,
+					access);
+}
+
+#if PTTYPE != PTTYPE_EPT
+static int FNAME(walk_addr_nested)(struct guest_walker *walker,
+				   struct kvm_vcpu *vcpu, gva_t addr,
+				   u32 access)
+{
+	return FNAME(walk_addr_generic)(walker, vcpu, &vcpu->arch.nested_mmu,
+					addr, access);
+}
+#endif
+
+static bool
+FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+		     u64 *spte, pt_element_t gpte, bool no_dirty_log)
+{
+	unsigned pte_access;
+	gfn_t gfn;
+	kvm_pfn_t pfn;
+
+	if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
+		return false;
+
+	pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
+
+	gfn = gpte_to_gfn(gpte);
+	pte_access = sp->role.access & FNAME(gpte_access)(gpte);
+	FNAME(protect_clean_gpte)(&vcpu->arch.mmu, &pte_access, gpte);
+	pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
+			no_dirty_log && (pte_access & ACC_WRITE_MASK));
+	if (is_error_pfn(pfn))
+		return false;
+
+	/*
+	 * we call mmu_set_spte() with host_writable = true because
+	 * pte_prefetch_gfn_to_pfn always gets a writable pfn.
+	 */
+	mmu_set_spte(vcpu, spte, pte_access, 0, PT_PAGE_TABLE_LEVEL, gfn, pfn,
+		     true, true);
+
+	kvm_release_pfn_clean(pfn);
+	return true;
+}
+
+static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+			      u64 *spte, const void *pte)
+{
+	pt_element_t gpte = *(const pt_element_t *)pte;
+
+	FNAME(prefetch_gpte)(vcpu, sp, spte, gpte, false);
+}
+
+static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu,
+				struct guest_walker *gw, int level)
+{
+	pt_element_t curr_pte;
+	gpa_t base_gpa, pte_gpa = gw->pte_gpa[level - 1];
+	u64 mask;
+	int r, index;
+
+	if (level == PT_PAGE_TABLE_LEVEL) {
+		mask = PTE_PREFETCH_NUM * sizeof(pt_element_t) - 1;
+		base_gpa = pte_gpa & ~mask;
+		index = (pte_gpa - base_gpa) / sizeof(pt_element_t);
+
+		r = kvm_vcpu_read_guest_atomic(vcpu, base_gpa,
+				gw->prefetch_ptes, sizeof(gw->prefetch_ptes));
+		curr_pte = gw->prefetch_ptes[index];
+	} else
+		r = kvm_vcpu_read_guest_atomic(vcpu, pte_gpa,
+				  &curr_pte, sizeof(curr_pte));
+
+	return r || curr_pte != gw->ptes[level - 1];
+}
+
+static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
+				u64 *sptep)
+{
+	struct kvm_mmu_page *sp;
+	pt_element_t *gptep = gw->prefetch_ptes;
+	u64 *spte;
+	int i;
+
+	sp = page_header(__pa(sptep));
+
+	if (sp->role.level > PT_PAGE_TABLE_LEVEL)
+		return;
+
+	if (sp->role.direct)
+		return __direct_pte_prefetch(vcpu, sp, sptep);
+
+	i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
+	spte = sp->spt + i;
+
+	for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
+		if (spte == sptep)
+			continue;
+
+		if (is_shadow_present_pte(*spte))
+			continue;
+
+		if (!FNAME(prefetch_gpte)(vcpu, sp, spte, gptep[i], true))
+			break;
+	}
+}
+
+/*
+ * Fetch a shadow pte for a specific level in the paging hierarchy.
+ * If the guest tries to write a write-protected page, we need to
+ * emulate this operation, return 1 to indicate this case.
+ */
+static int FNAME(fetch)(struct kvm_vcpu *vcpu, gpa_t addr,
+			 struct guest_walker *gw,
+			 int write_fault, int hlevel,
+			 kvm_pfn_t pfn, bool map_writable, bool prefault,
+			 bool lpage_disallowed)
+{
+	struct kvm_mmu_page *sp = NULL;
+	struct kvm_shadow_walk_iterator it;
+	unsigned int direct_access, access;
+	int top_level, ret;
+	gfn_t gfn, base_gfn;
+
+	direct_access = gw->pte_access;
+
+	top_level = vcpu->arch.mmu.root_level;
+	if (top_level == PT32E_ROOT_LEVEL)
+		top_level = PT32_ROOT_LEVEL;
+	/*
+	 * Verify that the top-level gpte is still there.  Since the page
+	 * is a root page, it is either write protected (and cannot be
+	 * changed from now on) or it is invalid (in which case, we don't
+	 * really care if it changes underneath us after this point).
+	 */
+	if (FNAME(gpte_changed)(vcpu, gw, top_level))
+		goto out_gpte_changed;
+
+	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
+		goto out_gpte_changed;
+
+	for (shadow_walk_init(&it, vcpu, addr);
+	     shadow_walk_okay(&it) && it.level > gw->level;
+	     shadow_walk_next(&it)) {
+		gfn_t table_gfn;
+
+		clear_sp_write_flooding_count(it.sptep);
+		drop_large_spte(vcpu, it.sptep);
+
+		sp = NULL;
+		if (!is_shadow_present_pte(*it.sptep)) {
+			table_gfn = gw->table_gfn[it.level - 2];
+			access = gw->pt_access[it.level - 2];
+			sp = kvm_mmu_get_page(vcpu, table_gfn, addr, it.level-1,
+					      false, access);
+		}
+
+		/*
+		 * Verify that the gpte in the page we've just write
+		 * protected is still there.
+		 */
+		if (FNAME(gpte_changed)(vcpu, gw, it.level - 1))
+			goto out_gpte_changed;
+
+		if (sp)
+			link_shadow_page(vcpu, it.sptep, sp);
+	}
+
+	/*
+	 * FNAME(page_fault) might have clobbered the bottom bits of
+	 * gw->gfn, restore them from the virtual address.
+	 */
+	gfn = gw->gfn | ((addr & PT_LVL_OFFSET_MASK(gw->level)) >> PAGE_SHIFT);
+	base_gfn = gfn;
+
+	trace_kvm_mmu_spte_requested(addr, gw->level, pfn);
+
+	for (; shadow_walk_okay(&it); shadow_walk_next(&it)) {
+		clear_sp_write_flooding_count(it.sptep);
+
+		/*
+		 * We cannot overwrite existing page tables with an NX
+		 * large page, as the leaf could be executable.
+		 */
+		disallowed_hugepage_adjust(it, gfn, &pfn, &hlevel);
+
+		base_gfn = gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
+		if (it.level == hlevel)
+			break;
+
+		validate_direct_spte(vcpu, it.sptep, direct_access);
+
+		drop_large_spte(vcpu, it.sptep);
+
+		if (!is_shadow_present_pte(*it.sptep)) {
+			sp = kvm_mmu_get_page(vcpu, base_gfn, addr,
+					      it.level - 1, true, direct_access);
+			link_shadow_page(vcpu, it.sptep, sp);
+			if (lpage_disallowed)
+				account_huge_nx_page(vcpu->kvm, sp);
+		}
+	}
+
+	ret = mmu_set_spte(vcpu, it.sptep, gw->pte_access, write_fault,
+			   it.level, base_gfn, pfn, prefault, map_writable);
+	FNAME(pte_prefetch)(vcpu, gw, it.sptep);
+	++vcpu->stat.pf_fixed;
+	return ret;
+
+out_gpte_changed:
+	return RET_PF_RETRY;
+}
+
+ /*
+ * To see whether the mapped gfn can write its page table in the current
+ * mapping.
+ *
+ * It is the helper function of FNAME(page_fault). When guest uses large page
+ * size to map the writable gfn which is used as current page table, we should
+ * force kvm to use small page size to map it because new shadow page will be
+ * created when kvm establishes shadow page table that stop kvm using large
+ * page size. Do it early can avoid unnecessary #PF and emulation.
+ *
+ * @write_fault_to_shadow_pgtable will return true if the fault gfn is
+ * currently used as its page table.
+ *
+ * Note: the PDPT page table is not checked for PAE-32 bit guest. It is ok
+ * since the PDPT is always shadowed, that means, we can not use large page
+ * size to map the gfn which is used as PDPT.
+ */
+static bool
+FNAME(is_self_change_mapping)(struct kvm_vcpu *vcpu,
+			      struct guest_walker *walker, int user_fault,
+			      bool *write_fault_to_shadow_pgtable)
+{
+	int level;
+	gfn_t mask = ~(KVM_PAGES_PER_HPAGE(walker->level) - 1);
+	bool self_changed = false;
+
+	if (!(walker->pte_access & ACC_WRITE_MASK ||
+	      (!is_write_protection(vcpu) && !user_fault)))
+		return false;
+
+	for (level = walker->level; level <= walker->max_level; level++) {
+		gfn_t gfn = walker->gfn ^ walker->table_gfn[level - 1];
+
+		self_changed |= !(gfn & mask);
+		*write_fault_to_shadow_pgtable |= !gfn;
+	}
+
+	return self_changed;
+}
+
+/*
+ * Page fault handler.  There are several causes for a page fault:
+ *   - there is no shadow pte for the guest pte
+ *   - write access through a shadow pte marked read only so that we can set
+ *     the dirty bit
+ *   - write access to a shadow pte marked read only so we can update the page
+ *     dirty bitmap, when userspace requests it
+ *   - mmio access; in this case we will never install a present shadow pte
+ *   - normal guest page fault due to the guest pte marked not present, not
+ *     writable, or not executable
+ *
+ *  Returns: 1 if we need to emulate the instruction, 0 otherwise, or
+ *           a negative value on error.
+ */
+static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
+			     bool prefault)
+{
+	int write_fault = error_code & PFERR_WRITE_MASK;
+	int user_fault = error_code & PFERR_USER_MASK;
+	struct guest_walker walker;
+	int r;
+	kvm_pfn_t pfn;
+	int level = PT_PAGE_TABLE_LEVEL;
+	unsigned long mmu_seq;
+	bool map_writable, is_self_change_mapping;
+	bool lpage_disallowed = (error_code & PFERR_FETCH_MASK) &&
+				is_nx_huge_page_enabled();
+	bool force_pt_level = lpage_disallowed;
+
+	pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
+
+	r = mmu_topup_memory_caches(vcpu);
+	if (r)
+		return r;
+
+	/*
+	 * If PFEC.RSVD is set, this is a shadow page fault.
+	 * The bit needs to be cleared before walking guest page tables.
+	 */
+	error_code &= ~PFERR_RSVD_MASK;
+
+	/*
+	 * Look up the guest pte for the faulting address.
+	 */
+	r = FNAME(walk_addr)(&walker, vcpu, addr, error_code);
+
+	/*
+	 * The page is not mapped by the guest.  Let the guest handle it.
+	 */
+	if (!r) {
+		pgprintk("%s: guest page fault\n", __func__);
+		if (!prefault)
+			inject_page_fault(vcpu, &walker.fault);
+
+		return RET_PF_RETRY;
+	}
+
+	if (page_fault_handle_page_track(vcpu, error_code, walker.gfn)) {
+		shadow_page_table_clear_flood(vcpu, addr);
+		return RET_PF_EMULATE;
+	}
+
+	vcpu->arch.write_fault_to_shadow_pgtable = false;
+
+	is_self_change_mapping = FNAME(is_self_change_mapping)(vcpu,
+	      &walker, user_fault, &vcpu->arch.write_fault_to_shadow_pgtable);
+
+	if (walker.level >= PT_DIRECTORY_LEVEL && !is_self_change_mapping) {
+		level = mapping_level(vcpu, walker.gfn, &force_pt_level);
+		if (likely(!force_pt_level)) {
+			level = min(walker.level, level);
+			walker.gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE(level) - 1);
+		}
+	} else
+		force_pt_level = true;
+
+	mmu_seq = vcpu->kvm->mmu_notifier_seq;
+	smp_rmb();
+
+	if (try_async_pf(vcpu, prefault, walker.gfn, addr, &pfn, write_fault,
+			 &map_writable))
+		return RET_PF_RETRY;
+
+	if (handle_abnormal_pfn(vcpu, addr, walker.gfn, pfn, walker.pte_access, &r))
+		return r;
+
+	/*
+	 * Do not change pte_access if the pfn is a mmio page, otherwise
+	 * we will cache the incorrect access into mmio spte.
+	 */
+	if (write_fault && !(walker.pte_access & ACC_WRITE_MASK) &&
+	     !is_write_protection(vcpu) && !user_fault &&
+	      !is_noslot_pfn(pfn)) {
+		walker.pte_access |= ACC_WRITE_MASK;
+		walker.pte_access &= ~ACC_USER_MASK;
+
+		/*
+		 * If we converted a user page to a kernel page,
+		 * so that the kernel can write to it when cr0.wp=0,
+		 * then we should prevent the kernel from executing it
+		 * if SMEP is enabled.
+		 */
+		if (kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))
+			walker.pte_access &= ~ACC_EXEC_MASK;
+	}
+
+	r = RET_PF_RETRY;
+	spin_lock(&vcpu->kvm->mmu_lock);
+	if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
+		goto out_unlock;
+
+	kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
+	if (make_mmu_pages_available(vcpu) < 0)
+		goto out_unlock;
+	if (!force_pt_level)
+		transparent_hugepage_adjust(vcpu, walker.gfn, &pfn, &level);
+	r = FNAME(fetch)(vcpu, addr, &walker, write_fault,
+			 level, pfn, map_writable, prefault, lpage_disallowed);
+	kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);
+
+out_unlock:
+	spin_unlock(&vcpu->kvm->mmu_lock);
+	kvm_release_pfn_clean(pfn);
+	return r;
+}
+
+static gpa_t FNAME(get_level1_sp_gpa)(struct kvm_mmu_page *sp)
+{
+	int offset = 0;
+
+	WARN_ON(sp->role.level != PT_PAGE_TABLE_LEVEL);
+
+	if (PTTYPE == 32)
+		offset = sp->role.quadrant << PT64_LEVEL_BITS;
+
+	return gfn_to_gpa(sp->gfn) + offset * sizeof(pt_element_t);
+}
+
+static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa)
+{
+	struct kvm_shadow_walk_iterator iterator;
+	struct kvm_mmu_page *sp;
+	int level;
+	u64 *sptep;
+
+	vcpu_clear_mmio_info(vcpu, gva);
+
+	/*
+	 * No need to check return value here, rmap_can_add() can
+	 * help us to skip pte prefetch later.
+	 */
+	mmu_topup_memory_caches(vcpu);
+
+	if (!VALID_PAGE(root_hpa)) {
+		WARN_ON(1);
+		return;
+	}
+
+	spin_lock(&vcpu->kvm->mmu_lock);
+	for_each_shadow_entry_using_root(vcpu, root_hpa, gva, iterator) {
+		level = iterator.level;
+		sptep = iterator.sptep;
+
+		sp = page_header(__pa(sptep));
+		if (is_last_spte(*sptep, level)) {
+			pt_element_t gpte;
+			gpa_t pte_gpa;
+
+			if (!sp->unsync)
+				break;
+
+			pte_gpa = FNAME(get_level1_sp_gpa)(sp);
+			pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t);
+
+			if (mmu_page_zap_pte(vcpu->kvm, sp, sptep))
+				kvm_flush_remote_tlbs(vcpu->kvm);
+
+			if (!rmap_can_add(vcpu))
+				break;
+
+			if (kvm_vcpu_read_guest_atomic(vcpu, pte_gpa, &gpte,
+						       sizeof(pt_element_t)))
+				break;
+
+			FNAME(update_pte)(vcpu, sp, sptep, &gpte);
+		}
+
+		if (!is_shadow_present_pte(*sptep) || !sp->unsync_children)
+			break;
+	}
+	spin_unlock(&vcpu->kvm->mmu_lock);
+}
+
+/* Note, @addr is a GPA when gva_to_gpa() translates an L2 GPA to an L1 GPA. */
+static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gpa_t addr, u32 access,
+			       struct x86_exception *exception)
+{
+	struct guest_walker walker;
+	gpa_t gpa = UNMAPPED_GVA;
+	int r;
+
+	r = FNAME(walk_addr)(&walker, vcpu, addr, access);
+
+	if (r) {
+		gpa = gfn_to_gpa(walker.gfn);
+		gpa |= addr & ~PAGE_MASK;
+	} else if (exception)
+		*exception = walker.fault;
+
+	return gpa;
+}
+
+#if PTTYPE != PTTYPE_EPT
+/* Note, gva_to_gpa_nested() is only used to translate L2 GVAs. */
+static gpa_t FNAME(gva_to_gpa_nested)(struct kvm_vcpu *vcpu, gpa_t vaddr,
+				      u32 access,
+				      struct x86_exception *exception)
+{
+	struct guest_walker walker;
+	gpa_t gpa = UNMAPPED_GVA;
+	int r;
+
+#ifndef CONFIG_X86_64
+	/* A 64-bit GVA should be impossible on 32-bit KVM. */
+	WARN_ON_ONCE(vaddr >> 32);
+#endif
+
+	r = FNAME(walk_addr_nested)(&walker, vcpu, vaddr, access);
+
+	if (r) {
+		gpa = gfn_to_gpa(walker.gfn);
+		gpa |= vaddr & ~PAGE_MASK;
+	} else if (exception)
+		*exception = walker.fault;
+
+	return gpa;
+}
+#endif
+
+/*
+ * Using the cached information from sp->gfns is safe because:
+ * - The spte has a reference to the struct page, so the pfn for a given gfn
+ *   can't change unless all sptes pointing to it are nuked first.
+ *
+ * Note:
+ *   We should flush all tlbs if spte is dropped even though guest is
+ *   responsible for it. Since if we don't, kvm_mmu_notifier_invalidate_page
+ *   and kvm_mmu_notifier_invalidate_range_start detect the mapping page isn't
+ *   used by guest then tlbs are not flushed, so guest is allowed to access the
+ *   freed pages.
+ *   And we increase kvm->tlbs_dirty to delay tlbs flush in this case.
+ */
+static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+	int i, nr_present = 0;
+	bool host_writable;
+	gpa_t first_pte_gpa;
+	int set_spte_ret = 0;
+
+	/* direct kvm_mmu_page can not be unsync. */
+	BUG_ON(sp->role.direct);
+
+	first_pte_gpa = FNAME(get_level1_sp_gpa)(sp);
+
+	for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
+		unsigned pte_access;
+		pt_element_t gpte;
+		gpa_t pte_gpa;
+		gfn_t gfn;
+
+		if (!sp->spt[i])
+			continue;
+
+		pte_gpa = first_pte_gpa + i * sizeof(pt_element_t);
+
+		if (kvm_vcpu_read_guest_atomic(vcpu, pte_gpa, &gpte,
+					       sizeof(pt_element_t)))
+			return 0;
+
+		if (FNAME(prefetch_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte)) {
+			/*
+			 * Update spte before increasing tlbs_dirty to make
+			 * sure no tlb flush is lost after spte is zapped; see
+			 * the comments in kvm_flush_remote_tlbs().
+			 */
+			smp_wmb();
+			vcpu->kvm->tlbs_dirty++;
+			continue;
+		}
+
+		gfn = gpte_to_gfn(gpte);
+		pte_access = sp->role.access;
+		pte_access &= FNAME(gpte_access)(gpte);
+		FNAME(protect_clean_gpte)(&vcpu->arch.mmu, &pte_access, gpte);
+
+		if (sync_mmio_spte(vcpu, &sp->spt[i], gfn, pte_access,
+		      &nr_present))
+			continue;
+
+		if (gfn != sp->gfns[i]) {
+			drop_spte(vcpu->kvm, &sp->spt[i]);
+			/*
+			 * The same as above where we are doing
+			 * prefetch_invalid_gpte().
+			 */
+			smp_wmb();
+			vcpu->kvm->tlbs_dirty++;
+			continue;
+		}
+
+		nr_present++;
+
+		host_writable = sp->spt[i] & SPTE_HOST_WRITEABLE;
+
+		set_spte_ret |= set_spte(vcpu, &sp->spt[i],
+					 pte_access, PT_PAGE_TABLE_LEVEL,
+					 gfn, spte_to_pfn(sp->spt[i]),
+					 true, false, host_writable);
+	}
+
+	if (set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH)
+		kvm_flush_remote_tlbs(vcpu->kvm);
+
+	return nr_present;
+}
+
+#undef pt_element_t
+#undef guest_walker
+#undef FNAME
+#undef PT_BASE_ADDR_MASK
+#undef PT_INDEX
+#undef PT_LVL_ADDR_MASK
+#undef PT_LVL_OFFSET_MASK
+#undef PT_LEVEL_BITS
+#undef PT_MAX_FULL_LEVELS
+#undef gpte_to_gfn
+#undef gpte_to_gfn_lvl
+#undef CMPXCHG
+#undef PT_GUEST_ACCESSED_MASK
+#undef PT_GUEST_DIRTY_MASK
+#undef PT_GUEST_DIRTY_SHIFT
+#undef PT_GUEST_ACCESSED_SHIFT
+#undef PT_HAVE_ACCESSED_DIRTY