2 * Kernel-based Virtual Machine driver for Linux
4 * This module enables machines with Intel VT-x extensions to run virtual
5 * machines without emulation or binary translation.
9 * Copyright (C) 2006 Qumranet, Inc.
12 * Yaniv Kamay <yaniv@qumranet.com>
13 * Avi Kivity <avi@qumranet.com>
15 * This work is licensed under the terms of the GNU GPL, version 2. See
16 * the COPYING file in the top-level directory.
23 #include <linux/kvm_host.h>
24 #include <linux/types.h>
25 #include <linux/string.h>
27 #include <linux/highmem.h>
28 #include <linux/module.h>
29 #include <linux/swap.h>
30 #include <linux/hugetlb.h>
31 #include <linux/compiler.h>
34 #include <asm/cmpxchg.h>
38 * When setting this variable to true it enables Two-Dimensional-Paging
39 * where the hardware walks 2 page tables:
40 * 1. the guest-virtual to guest-physical
41 * 2. while doing 1. it walks guest-physical to host-physical
42 * If the hardware supports that we don't need to do shadow paging.
44 bool tdp_enabled = false;
51 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
53 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
58 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
59 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
63 #define pgprintk(x...) do { } while (0)
64 #define rmap_printk(x...) do { } while (0)
68 #if defined(MMU_DEBUG) || defined(AUDIT)
73 #define ASSERT(x) do { } while (0)
77 printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
78 __FILE__, __LINE__, #x); \
82 #define PT_FIRST_AVAIL_BITS_SHIFT 9
83 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
85 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
87 #define PT64_LEVEL_BITS 9
89 #define PT64_LEVEL_SHIFT(level) \
90 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
92 #define PT64_LEVEL_MASK(level) \
93 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
95 #define PT64_INDEX(address, level)\
96 (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
99 #define PT32_LEVEL_BITS 10
101 #define PT32_LEVEL_SHIFT(level) \
102 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
104 #define PT32_LEVEL_MASK(level) \
105 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
107 #define PT32_INDEX(address, level)\
108 (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
111 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
112 #define PT64_DIR_BASE_ADDR_MASK \
113 (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
115 #define PT32_BASE_ADDR_MASK PAGE_MASK
116 #define PT32_DIR_BASE_ADDR_MASK \
117 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
119 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
122 #define PFERR_PRESENT_MASK (1U << 0)
123 #define PFERR_WRITE_MASK (1U << 1)
124 #define PFERR_USER_MASK (1U << 2)
125 #define PFERR_FETCH_MASK (1U << 4)
127 #define PT_DIRECTORY_LEVEL 2
128 #define PT_PAGE_TABLE_LEVEL 1
132 #define ACC_EXEC_MASK 1
133 #define ACC_WRITE_MASK PT_WRITABLE_MASK
134 #define ACC_USER_MASK PT_USER_MASK
135 #define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
137 struct kvm_pv_mmu_op_buffer {
141 char buf[512] __aligned(sizeof(long));
144 struct kvm_rmap_desc {
145 u64 *shadow_ptes[RMAP_EXT];
146 struct kvm_rmap_desc *more;
149 static struct kmem_cache *pte_chain_cache;
150 static struct kmem_cache *rmap_desc_cache;
151 static struct kmem_cache *mmu_page_header_cache;
153 static u64 __read_mostly shadow_trap_nonpresent_pte;
154 static u64 __read_mostly shadow_notrap_nonpresent_pte;
155 static u64 __read_mostly shadow_base_present_pte;
156 static u64 __read_mostly shadow_nx_mask;
157 static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
158 static u64 __read_mostly shadow_user_mask;
159 static u64 __read_mostly shadow_accessed_mask;
160 static u64 __read_mostly shadow_dirty_mask;
162 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
164 shadow_trap_nonpresent_pte = trap_pte;
165 shadow_notrap_nonpresent_pte = notrap_pte;
167 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
169 void kvm_mmu_set_base_ptes(u64 base_pte)
171 shadow_base_present_pte = base_pte;
173 EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
175 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
176 u64 dirty_mask, u64 nx_mask, u64 x_mask)
178 shadow_user_mask = user_mask;
179 shadow_accessed_mask = accessed_mask;
180 shadow_dirty_mask = dirty_mask;
181 shadow_nx_mask = nx_mask;
182 shadow_x_mask = x_mask;
184 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
186 static int is_write_protection(struct kvm_vcpu *vcpu)
188 return vcpu->arch.cr0 & X86_CR0_WP;
191 static int is_cpuid_PSE36(void)
196 static int is_nx(struct kvm_vcpu *vcpu)
198 return vcpu->arch.shadow_efer & EFER_NX;
201 static int is_present_pte(unsigned long pte)
203 return pte & PT_PRESENT_MASK;
206 static int is_shadow_present_pte(u64 pte)
208 return pte != shadow_trap_nonpresent_pte
209 && pte != shadow_notrap_nonpresent_pte;
212 static int is_large_pte(u64 pte)
214 return pte & PT_PAGE_SIZE_MASK;
217 static int is_writeble_pte(unsigned long pte)
219 return pte & PT_WRITABLE_MASK;
222 static int is_dirty_pte(unsigned long pte)
224 return pte & shadow_dirty_mask;
227 static int is_rmap_pte(u64 pte)
229 return is_shadow_present_pte(pte);
232 static pfn_t spte_to_pfn(u64 pte)
234 return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
237 static gfn_t pse36_gfn_delta(u32 gpte)
239 int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
241 return (gpte & PT32_DIR_PSE36_MASK) << shift;
244 static void set_shadow_pte(u64 *sptep, u64 spte)
247 set_64bit((unsigned long *)sptep, spte);
249 set_64bit((unsigned long long *)sptep, spte);
253 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
254 struct kmem_cache *base_cache, int min)
258 if (cache->nobjs >= min)
260 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
261 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
264 cache->objects[cache->nobjs++] = obj;
269 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
272 kfree(mc->objects[--mc->nobjs]);
275 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
280 if (cache->nobjs >= min)
282 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
283 page = alloc_page(GFP_KERNEL);
286 set_page_private(page, 0);
287 cache->objects[cache->nobjs++] = page_address(page);
292 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
295 free_page((unsigned long)mc->objects[--mc->nobjs]);
298 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
302 r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
306 r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
310 r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
313 r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
314 mmu_page_header_cache, 4);
319 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
321 mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache);
322 mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache);
323 mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
324 mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
327 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
333 p = mc->objects[--mc->nobjs];
338 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
340 return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
341 sizeof(struct kvm_pte_chain));
344 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
349 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
351 return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
352 sizeof(struct kvm_rmap_desc));
355 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
361 * Return the pointer to the largepage write count for a given
362 * gfn, handling slots that are not large page aligned.
364 static int *slot_largepage_idx(gfn_t gfn, struct kvm_memory_slot *slot)
368 idx = (gfn / KVM_PAGES_PER_HPAGE) -
369 (slot->base_gfn / KVM_PAGES_PER_HPAGE);
370 return &slot->lpage_info[idx].write_count;
373 static void account_shadowed(struct kvm *kvm, gfn_t gfn)
377 write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
381 static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
385 write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
387 WARN_ON(*write_count < 0);
390 static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
392 struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
396 largepage_idx = slot_largepage_idx(gfn, slot);
397 return *largepage_idx;
403 static int host_largepage_backed(struct kvm *kvm, gfn_t gfn)
405 struct vm_area_struct *vma;
408 addr = gfn_to_hva(kvm, gfn);
409 if (kvm_is_error_hva(addr))
412 vma = find_vma(current->mm, addr);
413 if (vma && is_vm_hugetlb_page(vma))
419 static int is_largepage_backed(struct kvm_vcpu *vcpu, gfn_t large_gfn)
421 struct kvm_memory_slot *slot;
423 if (has_wrprotected_page(vcpu->kvm, large_gfn))
426 if (!host_largepage_backed(vcpu->kvm, large_gfn))
429 slot = gfn_to_memslot(vcpu->kvm, large_gfn);
430 if (slot && slot->dirty_bitmap)
437 * Take gfn and return the reverse mapping to it.
438 * Note: gfn must be unaliased before this function get called
441 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int lpage)
443 struct kvm_memory_slot *slot;
446 slot = gfn_to_memslot(kvm, gfn);
448 return &slot->rmap[gfn - slot->base_gfn];
450 idx = (gfn / KVM_PAGES_PER_HPAGE) -
451 (slot->base_gfn / KVM_PAGES_PER_HPAGE);
453 return &slot->lpage_info[idx].rmap_pde;
457 * Reverse mapping data structures:
459 * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
460 * that points to page_address(page).
462 * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
463 * containing more mappings.
465 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn, int lpage)
467 struct kvm_mmu_page *sp;
468 struct kvm_rmap_desc *desc;
469 unsigned long *rmapp;
472 if (!is_rmap_pte(*spte))
474 gfn = unalias_gfn(vcpu->kvm, gfn);
475 sp = page_header(__pa(spte));
476 sp->gfns[spte - sp->spt] = gfn;
477 rmapp = gfn_to_rmap(vcpu->kvm, gfn, lpage);
479 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
480 *rmapp = (unsigned long)spte;
481 } else if (!(*rmapp & 1)) {
482 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
483 desc = mmu_alloc_rmap_desc(vcpu);
484 desc->shadow_ptes[0] = (u64 *)*rmapp;
485 desc->shadow_ptes[1] = spte;
486 *rmapp = (unsigned long)desc | 1;
488 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
489 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
490 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
492 if (desc->shadow_ptes[RMAP_EXT-1]) {
493 desc->more = mmu_alloc_rmap_desc(vcpu);
496 for (i = 0; desc->shadow_ptes[i]; ++i)
498 desc->shadow_ptes[i] = spte;
502 static void rmap_desc_remove_entry(unsigned long *rmapp,
503 struct kvm_rmap_desc *desc,
505 struct kvm_rmap_desc *prev_desc)
509 for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
511 desc->shadow_ptes[i] = desc->shadow_ptes[j];
512 desc->shadow_ptes[j] = NULL;
515 if (!prev_desc && !desc->more)
516 *rmapp = (unsigned long)desc->shadow_ptes[0];
519 prev_desc->more = desc->more;
521 *rmapp = (unsigned long)desc->more | 1;
522 mmu_free_rmap_desc(desc);
525 static void rmap_remove(struct kvm *kvm, u64 *spte)
527 struct kvm_rmap_desc *desc;
528 struct kvm_rmap_desc *prev_desc;
529 struct kvm_mmu_page *sp;
531 unsigned long *rmapp;
534 if (!is_rmap_pte(*spte))
536 sp = page_header(__pa(spte));
537 pfn = spte_to_pfn(*spte);
538 if (*spte & shadow_accessed_mask)
539 kvm_set_pfn_accessed(pfn);
540 if (is_writeble_pte(*spte))
541 kvm_release_pfn_dirty(pfn);
543 kvm_release_pfn_clean(pfn);
544 rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], is_large_pte(*spte));
546 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
548 } else if (!(*rmapp & 1)) {
549 rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte);
550 if ((u64 *)*rmapp != spte) {
551 printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n",
557 rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte);
558 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
561 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
562 if (desc->shadow_ptes[i] == spte) {
563 rmap_desc_remove_entry(rmapp,
575 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
577 struct kvm_rmap_desc *desc;
578 struct kvm_rmap_desc *prev_desc;
584 else if (!(*rmapp & 1)) {
586 return (u64 *)*rmapp;
589 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
593 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {
594 if (prev_spte == spte)
595 return desc->shadow_ptes[i];
596 prev_spte = desc->shadow_ptes[i];
603 static void rmap_write_protect(struct kvm *kvm, u64 gfn)
605 unsigned long *rmapp;
607 int write_protected = 0;
609 gfn = unalias_gfn(kvm, gfn);
610 rmapp = gfn_to_rmap(kvm, gfn, 0);
612 spte = rmap_next(kvm, rmapp, NULL);
615 BUG_ON(!(*spte & PT_PRESENT_MASK));
616 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
617 if (is_writeble_pte(*spte)) {
618 set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
621 spte = rmap_next(kvm, rmapp, spte);
623 if (write_protected) {
626 spte = rmap_next(kvm, rmapp, NULL);
627 pfn = spte_to_pfn(*spte);
628 kvm_set_pfn_dirty(pfn);
631 /* check for huge page mappings */
632 rmapp = gfn_to_rmap(kvm, gfn, 1);
633 spte = rmap_next(kvm, rmapp, NULL);
636 BUG_ON(!(*spte & PT_PRESENT_MASK));
637 BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
638 pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
639 if (is_writeble_pte(*spte)) {
640 rmap_remove(kvm, spte);
642 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
646 spte = rmap_next(kvm, rmapp, spte);
650 kvm_flush_remote_tlbs(kvm);
652 account_shadowed(kvm, gfn);
656 static int is_empty_shadow_page(u64 *spt)
661 for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
662 if (is_shadow_present_pte(*pos)) {
663 printk(KERN_ERR "%s: %p %llx\n", __func__,
671 static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
673 ASSERT(is_empty_shadow_page(sp->spt));
675 __free_page(virt_to_page(sp->spt));
676 __free_page(virt_to_page(sp->gfns));
678 ++kvm->arch.n_free_mmu_pages;
681 static unsigned kvm_page_table_hashfn(gfn_t gfn)
683 return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
686 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
689 struct kvm_mmu_page *sp;
691 sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
692 sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
693 sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
694 set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
695 list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
696 ASSERT(is_empty_shadow_page(sp->spt));
699 sp->parent_pte = parent_pte;
700 --vcpu->kvm->arch.n_free_mmu_pages;
704 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
705 struct kvm_mmu_page *sp, u64 *parent_pte)
707 struct kvm_pte_chain *pte_chain;
708 struct hlist_node *node;
713 if (!sp->multimapped) {
714 u64 *old = sp->parent_pte;
717 sp->parent_pte = parent_pte;
721 pte_chain = mmu_alloc_pte_chain(vcpu);
722 INIT_HLIST_HEAD(&sp->parent_ptes);
723 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
724 pte_chain->parent_ptes[0] = old;
726 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
727 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
729 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
730 if (!pte_chain->parent_ptes[i]) {
731 pte_chain->parent_ptes[i] = parent_pte;
735 pte_chain = mmu_alloc_pte_chain(vcpu);
737 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
738 pte_chain->parent_ptes[0] = parent_pte;
741 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
744 struct kvm_pte_chain *pte_chain;
745 struct hlist_node *node;
748 if (!sp->multimapped) {
749 BUG_ON(sp->parent_pte != parent_pte);
750 sp->parent_pte = NULL;
753 hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
754 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
755 if (!pte_chain->parent_ptes[i])
757 if (pte_chain->parent_ptes[i] != parent_pte)
759 while (i + 1 < NR_PTE_CHAIN_ENTRIES
760 && pte_chain->parent_ptes[i + 1]) {
761 pte_chain->parent_ptes[i]
762 = pte_chain->parent_ptes[i + 1];
765 pte_chain->parent_ptes[i] = NULL;
767 hlist_del(&pte_chain->link);
768 mmu_free_pte_chain(pte_chain);
769 if (hlist_empty(&sp->parent_ptes)) {
771 sp->parent_pte = NULL;
779 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
782 struct hlist_head *bucket;
783 struct kvm_mmu_page *sp;
784 struct hlist_node *node;
786 pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
787 index = kvm_page_table_hashfn(gfn);
788 bucket = &kvm->arch.mmu_page_hash[index];
789 hlist_for_each_entry(sp, node, bucket, hash_link)
790 if (sp->gfn == gfn && !sp->role.metaphysical
791 && !sp->role.invalid) {
792 pgprintk("%s: found role %x\n",
793 __func__, sp->role.word);
799 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
807 union kvm_mmu_page_role role;
810 struct hlist_head *bucket;
811 struct kvm_mmu_page *sp;
812 struct hlist_node *node;
815 role.glevels = vcpu->arch.mmu.root_level;
817 role.metaphysical = metaphysical;
818 role.access = access;
819 if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
820 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
821 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
822 role.quadrant = quadrant;
824 pgprintk("%s: looking gfn %lx role %x\n", __func__,
826 index = kvm_page_table_hashfn(gfn);
827 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
828 hlist_for_each_entry(sp, node, bucket, hash_link)
829 if (sp->gfn == gfn && sp->role.word == role.word) {
830 mmu_page_add_parent_pte(vcpu, sp, parent_pte);
831 pgprintk("%s: found\n", __func__);
834 ++vcpu->kvm->stat.mmu_cache_miss;
835 sp = kvm_mmu_alloc_page(vcpu, parent_pte);
838 pgprintk("%s: adding gfn %lx role %x\n", __func__, gfn, role.word);
841 hlist_add_head(&sp->hash_link, bucket);
843 rmap_write_protect(vcpu->kvm, gfn);
844 vcpu->arch.mmu.prefetch_page(vcpu, sp);
848 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
849 struct kvm_mmu_page *sp)
857 if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
858 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
859 if (is_shadow_present_pte(pt[i]))
860 rmap_remove(kvm, &pt[i]);
861 pt[i] = shadow_trap_nonpresent_pte;
863 kvm_flush_remote_tlbs(kvm);
867 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
870 if (is_shadow_present_pte(ent)) {
871 if (!is_large_pte(ent)) {
872 ent &= PT64_BASE_ADDR_MASK;
873 mmu_page_remove_parent_pte(page_header(ent),
877 rmap_remove(kvm, &pt[i]);
880 pt[i] = shadow_trap_nonpresent_pte;
882 kvm_flush_remote_tlbs(kvm);
885 static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
887 mmu_page_remove_parent_pte(sp, parent_pte);
890 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
894 for (i = 0; i < KVM_MAX_VCPUS; ++i)
896 kvm->vcpus[i]->arch.last_pte_updated = NULL;
899 static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
903 ++kvm->stat.mmu_shadow_zapped;
904 while (sp->multimapped || sp->parent_pte) {
905 if (!sp->multimapped)
906 parent_pte = sp->parent_pte;
908 struct kvm_pte_chain *chain;
910 chain = container_of(sp->parent_ptes.first,
911 struct kvm_pte_chain, link);
912 parent_pte = chain->parent_ptes[0];
915 kvm_mmu_put_page(sp, parent_pte);
916 set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte);
918 kvm_mmu_page_unlink_children(kvm, sp);
919 if (!sp->root_count) {
920 if (!sp->role.metaphysical)
921 unaccount_shadowed(kvm, sp->gfn);
922 hlist_del(&sp->hash_link);
923 kvm_mmu_free_page(kvm, sp);
925 list_move(&sp->link, &kvm->arch.active_mmu_pages);
926 sp->role.invalid = 1;
927 kvm_reload_remote_mmus(kvm);
929 kvm_mmu_reset_last_pte_updated(kvm);
933 * Changing the number of mmu pages allocated to the vm
934 * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
936 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
939 * If we set the number of mmu pages to be smaller be than the
940 * number of actived pages , we must to free some mmu pages before we
944 if ((kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages) >
946 int n_used_mmu_pages = kvm->arch.n_alloc_mmu_pages
947 - kvm->arch.n_free_mmu_pages;
949 while (n_used_mmu_pages > kvm_nr_mmu_pages) {
950 struct kvm_mmu_page *page;
952 page = container_of(kvm->arch.active_mmu_pages.prev,
953 struct kvm_mmu_page, link);
954 kvm_mmu_zap_page(kvm, page);
957 kvm->arch.n_free_mmu_pages = 0;
960 kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
961 - kvm->arch.n_alloc_mmu_pages;
963 kvm->arch.n_alloc_mmu_pages = kvm_nr_mmu_pages;
966 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
969 struct hlist_head *bucket;
970 struct kvm_mmu_page *sp;
971 struct hlist_node *node, *n;
974 pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
976 index = kvm_page_table_hashfn(gfn);
977 bucket = &kvm->arch.mmu_page_hash[index];
978 hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
979 if (sp->gfn == gfn && !sp->role.metaphysical) {
980 pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
982 kvm_mmu_zap_page(kvm, sp);
988 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
990 struct kvm_mmu_page *sp;
992 while ((sp = kvm_mmu_lookup_page(kvm, gfn)) != NULL) {
993 pgprintk("%s: zap %lx %x\n", __func__, gfn, sp->role.word);
994 kvm_mmu_zap_page(kvm, sp);
998 static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
1000 int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
1001 struct kvm_mmu_page *sp = page_header(__pa(pte));
1003 __set_bit(slot, &sp->slot_bitmap);
1006 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
1010 gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1012 if (gpa == UNMAPPED_GVA)
1015 down_read(¤t->mm->mmap_sem);
1016 page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1017 up_read(¤t->mm->mmap_sem);
1022 static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1023 unsigned pt_access, unsigned pte_access,
1024 int user_fault, int write_fault, int dirty,
1025 int *ptwrite, int largepage, gfn_t gfn,
1026 pfn_t pfn, bool speculative)
1029 int was_rmapped = 0;
1030 int was_writeble = is_writeble_pte(*shadow_pte);
1032 pgprintk("%s: spte %llx access %x write_fault %d"
1033 " user_fault %d gfn %lx\n",
1034 __func__, *shadow_pte, pt_access,
1035 write_fault, user_fault, gfn);
1037 if (is_rmap_pte(*shadow_pte)) {
1039 * If we overwrite a PTE page pointer with a 2MB PMD, unlink
1040 * the parent of the now unreachable PTE.
1042 if (largepage && !is_large_pte(*shadow_pte)) {
1043 struct kvm_mmu_page *child;
1044 u64 pte = *shadow_pte;
1046 child = page_header(pte & PT64_BASE_ADDR_MASK);
1047 mmu_page_remove_parent_pte(child, shadow_pte);
1048 } else if (pfn != spte_to_pfn(*shadow_pte)) {
1049 pgprintk("hfn old %lx new %lx\n",
1050 spte_to_pfn(*shadow_pte), pfn);
1051 rmap_remove(vcpu->kvm, shadow_pte);
1054 was_rmapped = is_large_pte(*shadow_pte);
1061 * We don't set the accessed bit, since we sometimes want to see
1062 * whether the guest actually used the pte (in order to detect
1065 spte = shadow_base_present_pte | shadow_dirty_mask;
1067 pte_access |= PT_ACCESSED_MASK;
1069 pte_access &= ~ACC_WRITE_MASK;
1070 if (pte_access & ACC_EXEC_MASK)
1071 spte |= shadow_x_mask;
1073 spte |= shadow_nx_mask;
1074 if (pte_access & ACC_USER_MASK)
1075 spte |= shadow_user_mask;
1077 spte |= PT_PAGE_SIZE_MASK;
1079 spte |= (u64)pfn << PAGE_SHIFT;
1081 if ((pte_access & ACC_WRITE_MASK)
1082 || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
1083 struct kvm_mmu_page *shadow;
1085 spte |= PT_WRITABLE_MASK;
1087 shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
1089 (largepage && has_wrprotected_page(vcpu->kvm, gfn))) {
1090 pgprintk("%s: found shadow page for %lx, marking ro\n",
1092 pte_access &= ~ACC_WRITE_MASK;
1093 if (is_writeble_pte(spte)) {
1094 spte &= ~PT_WRITABLE_MASK;
1095 kvm_x86_ops->tlb_flush(vcpu);
1102 if (pte_access & ACC_WRITE_MASK)
1103 mark_page_dirty(vcpu->kvm, gfn);
1105 pgprintk("%s: setting spte %llx\n", __func__, spte);
1106 pgprintk("instantiating %s PTE (%s) at %d (%llx) addr %llx\n",
1107 (spte&PT_PAGE_SIZE_MASK)? "2MB" : "4kB",
1108 (spte&PT_WRITABLE_MASK)?"RW":"R", gfn, spte, shadow_pte);
1109 set_shadow_pte(shadow_pte, spte);
1110 if (!was_rmapped && (spte & PT_PAGE_SIZE_MASK)
1111 && (spte & PT_PRESENT_MASK))
1112 ++vcpu->kvm->stat.lpages;
1114 page_header_update_slot(vcpu->kvm, shadow_pte, gfn);
1116 rmap_add(vcpu, shadow_pte, gfn, largepage);
1117 if (!is_rmap_pte(*shadow_pte))
1118 kvm_release_pfn_clean(pfn);
1121 kvm_release_pfn_dirty(pfn);
1123 kvm_release_pfn_clean(pfn);
1125 if (!ptwrite || !*ptwrite)
1126 vcpu->arch.last_pte_updated = shadow_pte;
1129 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
1133 static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
1134 int largepage, gfn_t gfn, pfn_t pfn,
1137 hpa_t table_addr = vcpu->arch.mmu.root_hpa;
1141 u32 index = PT64_INDEX(v, level);
1144 ASSERT(VALID_PAGE(table_addr));
1145 table = __va(table_addr);
1148 mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
1149 0, write, 1, &pt_write, 0, gfn, pfn, false);
1153 if (largepage && level == 2) {
1154 mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
1155 0, write, 1, &pt_write, 1, gfn, pfn, false);
1159 if (table[index] == shadow_trap_nonpresent_pte) {
1160 struct kvm_mmu_page *new_table;
1163 pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK)
1165 new_table = kvm_mmu_get_page(vcpu, pseudo_gfn,
1167 1, ACC_ALL, &table[index]);
1169 pgprintk("nonpaging_map: ENOMEM\n");
1170 kvm_release_pfn_clean(pfn);
1174 table[index] = __pa(new_table->spt)
1175 | PT_PRESENT_MASK | PT_WRITABLE_MASK
1176 | shadow_user_mask | shadow_x_mask;
1178 table_addr = table[index] & PT64_BASE_ADDR_MASK;
1182 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
1188 down_read(¤t->mm->mmap_sem);
1189 if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1190 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1194 pfn = gfn_to_pfn(vcpu->kvm, gfn);
1195 up_read(¤t->mm->mmap_sem);
1198 if (is_error_pfn(pfn)) {
1199 kvm_release_pfn_clean(pfn);
1203 spin_lock(&vcpu->kvm->mmu_lock);
1204 kvm_mmu_free_some_pages(vcpu);
1205 r = __direct_map(vcpu, v, write, largepage, gfn, pfn,
1207 spin_unlock(&vcpu->kvm->mmu_lock);
1214 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
1215 struct kvm_mmu_page *sp)
1219 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1220 sp->spt[i] = shadow_trap_nonpresent_pte;
1223 static void mmu_free_roots(struct kvm_vcpu *vcpu)
1226 struct kvm_mmu_page *sp;
1228 if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1230 spin_lock(&vcpu->kvm->mmu_lock);
1231 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1232 hpa_t root = vcpu->arch.mmu.root_hpa;
1234 sp = page_header(root);
1236 if (!sp->root_count && sp->role.invalid)
1237 kvm_mmu_zap_page(vcpu->kvm, sp);
1238 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1239 spin_unlock(&vcpu->kvm->mmu_lock);
1242 for (i = 0; i < 4; ++i) {
1243 hpa_t root = vcpu->arch.mmu.pae_root[i];
1246 root &= PT64_BASE_ADDR_MASK;
1247 sp = page_header(root);
1249 if (!sp->root_count && sp->role.invalid)
1250 kvm_mmu_zap_page(vcpu->kvm, sp);
1252 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1254 spin_unlock(&vcpu->kvm->mmu_lock);
1255 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1258 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
1262 struct kvm_mmu_page *sp;
1263 int metaphysical = 0;
1265 root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
1267 if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1268 hpa_t root = vcpu->arch.mmu.root_hpa;
1270 ASSERT(!VALID_PAGE(root));
1273 sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
1274 PT64_ROOT_LEVEL, metaphysical,
1276 root = __pa(sp->spt);
1278 vcpu->arch.mmu.root_hpa = root;
1281 metaphysical = !is_paging(vcpu);
1284 for (i = 0; i < 4; ++i) {
1285 hpa_t root = vcpu->arch.mmu.pae_root[i];
1287 ASSERT(!VALID_PAGE(root));
1288 if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
1289 if (!is_present_pte(vcpu->arch.pdptrs[i])) {
1290 vcpu->arch.mmu.pae_root[i] = 0;
1293 root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
1294 } else if (vcpu->arch.mmu.root_level == 0)
1296 sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
1297 PT32_ROOT_LEVEL, metaphysical,
1299 root = __pa(sp->spt);
1301 vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
1303 vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
1306 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
1311 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
1317 pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
1318 r = mmu_topup_memory_caches(vcpu);
1323 ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1325 gfn = gva >> PAGE_SHIFT;
1327 return nonpaging_map(vcpu, gva & PAGE_MASK,
1328 error_code & PFERR_WRITE_MASK, gfn);
1331 static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
1337 gfn_t gfn = gpa >> PAGE_SHIFT;
1340 ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1342 r = mmu_topup_memory_caches(vcpu);
1346 down_read(¤t->mm->mmap_sem);
1347 if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1348 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1351 pfn = gfn_to_pfn(vcpu->kvm, gfn);
1352 up_read(¤t->mm->mmap_sem);
1353 if (is_error_pfn(pfn)) {
1354 kvm_release_pfn_clean(pfn);
1357 spin_lock(&vcpu->kvm->mmu_lock);
1358 kvm_mmu_free_some_pages(vcpu);
1359 r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
1360 largepage, gfn, pfn, kvm_x86_ops->get_tdp_level());
1361 spin_unlock(&vcpu->kvm->mmu_lock);
1366 static void nonpaging_free(struct kvm_vcpu *vcpu)
1368 mmu_free_roots(vcpu);
1371 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
1373 struct kvm_mmu *context = &vcpu->arch.mmu;
1375 context->new_cr3 = nonpaging_new_cr3;
1376 context->page_fault = nonpaging_page_fault;
1377 context->gva_to_gpa = nonpaging_gva_to_gpa;
1378 context->free = nonpaging_free;
1379 context->prefetch_page = nonpaging_prefetch_page;
1380 context->root_level = 0;
1381 context->shadow_root_level = PT32E_ROOT_LEVEL;
1382 context->root_hpa = INVALID_PAGE;
1386 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
1388 ++vcpu->stat.tlb_flush;
1389 kvm_x86_ops->tlb_flush(vcpu);
1392 static void paging_new_cr3(struct kvm_vcpu *vcpu)
1394 pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
1395 mmu_free_roots(vcpu);
1398 static void inject_page_fault(struct kvm_vcpu *vcpu,
1402 kvm_inject_page_fault(vcpu, addr, err_code);
1405 static void paging_free(struct kvm_vcpu *vcpu)
1407 nonpaging_free(vcpu);
1411 #include "paging_tmpl.h"
1415 #include "paging_tmpl.h"
1418 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
1420 struct kvm_mmu *context = &vcpu->arch.mmu;
1422 ASSERT(is_pae(vcpu));
1423 context->new_cr3 = paging_new_cr3;
1424 context->page_fault = paging64_page_fault;
1425 context->gva_to_gpa = paging64_gva_to_gpa;
1426 context->prefetch_page = paging64_prefetch_page;
1427 context->free = paging_free;
1428 context->root_level = level;
1429 context->shadow_root_level = level;
1430 context->root_hpa = INVALID_PAGE;
1434 static int paging64_init_context(struct kvm_vcpu *vcpu)
1436 return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
1439 static int paging32_init_context(struct kvm_vcpu *vcpu)
1441 struct kvm_mmu *context = &vcpu->arch.mmu;
1443 context->new_cr3 = paging_new_cr3;
1444 context->page_fault = paging32_page_fault;
1445 context->gva_to_gpa = paging32_gva_to_gpa;
1446 context->free = paging_free;
1447 context->prefetch_page = paging32_prefetch_page;
1448 context->root_level = PT32_ROOT_LEVEL;
1449 context->shadow_root_level = PT32E_ROOT_LEVEL;
1450 context->root_hpa = INVALID_PAGE;
1454 static int paging32E_init_context(struct kvm_vcpu *vcpu)
1456 return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
1459 static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
1461 struct kvm_mmu *context = &vcpu->arch.mmu;
1463 context->new_cr3 = nonpaging_new_cr3;
1464 context->page_fault = tdp_page_fault;
1465 context->free = nonpaging_free;
1466 context->prefetch_page = nonpaging_prefetch_page;
1467 context->shadow_root_level = kvm_x86_ops->get_tdp_level();
1468 context->root_hpa = INVALID_PAGE;
1470 if (!is_paging(vcpu)) {
1471 context->gva_to_gpa = nonpaging_gva_to_gpa;
1472 context->root_level = 0;
1473 } else if (is_long_mode(vcpu)) {
1474 context->gva_to_gpa = paging64_gva_to_gpa;
1475 context->root_level = PT64_ROOT_LEVEL;
1476 } else if (is_pae(vcpu)) {
1477 context->gva_to_gpa = paging64_gva_to_gpa;
1478 context->root_level = PT32E_ROOT_LEVEL;
1480 context->gva_to_gpa = paging32_gva_to_gpa;
1481 context->root_level = PT32_ROOT_LEVEL;
1487 static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
1490 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1492 if (!is_paging(vcpu))
1493 return nonpaging_init_context(vcpu);
1494 else if (is_long_mode(vcpu))
1495 return paging64_init_context(vcpu);
1496 else if (is_pae(vcpu))
1497 return paging32E_init_context(vcpu);
1499 return paging32_init_context(vcpu);
1502 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
1504 vcpu->arch.update_pte.pfn = bad_pfn;
1507 return init_kvm_tdp_mmu(vcpu);
1509 return init_kvm_softmmu(vcpu);
1512 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
1515 if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
1516 vcpu->arch.mmu.free(vcpu);
1517 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1521 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
1523 destroy_kvm_mmu(vcpu);
1524 return init_kvm_mmu(vcpu);
1526 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
1528 int kvm_mmu_load(struct kvm_vcpu *vcpu)
1532 r = mmu_topup_memory_caches(vcpu);
1535 spin_lock(&vcpu->kvm->mmu_lock);
1536 kvm_mmu_free_some_pages(vcpu);
1537 mmu_alloc_roots(vcpu);
1538 spin_unlock(&vcpu->kvm->mmu_lock);
1539 kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
1540 kvm_mmu_flush_tlb(vcpu);
1544 EXPORT_SYMBOL_GPL(kvm_mmu_load);
1546 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
1548 mmu_free_roots(vcpu);
1551 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
1552 struct kvm_mmu_page *sp,
1556 struct kvm_mmu_page *child;
1559 if (is_shadow_present_pte(pte)) {
1560 if (sp->role.level == PT_PAGE_TABLE_LEVEL ||
1562 rmap_remove(vcpu->kvm, spte);
1564 child = page_header(pte & PT64_BASE_ADDR_MASK);
1565 mmu_page_remove_parent_pte(child, spte);
1568 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
1569 if (is_large_pte(pte))
1570 --vcpu->kvm->stat.lpages;
1573 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
1574 struct kvm_mmu_page *sp,
1578 if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
1579 if (!vcpu->arch.update_pte.largepage ||
1580 sp->role.glevels == PT32_ROOT_LEVEL) {
1581 ++vcpu->kvm->stat.mmu_pde_zapped;
1586 ++vcpu->kvm->stat.mmu_pte_updated;
1587 if (sp->role.glevels == PT32_ROOT_LEVEL)
1588 paging32_update_pte(vcpu, sp, spte, new);
1590 paging64_update_pte(vcpu, sp, spte, new);
1593 static bool need_remote_flush(u64 old, u64 new)
1595 if (!is_shadow_present_pte(old))
1597 if (!is_shadow_present_pte(new))
1599 if ((old ^ new) & PT64_BASE_ADDR_MASK)
1601 old ^= PT64_NX_MASK;
1602 new ^= PT64_NX_MASK;
1603 return (old & ~new & PT64_PERM_MASK) != 0;
1606 static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
1608 if (need_remote_flush(old, new))
1609 kvm_flush_remote_tlbs(vcpu->kvm);
1611 kvm_mmu_flush_tlb(vcpu);
1614 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
1616 u64 *spte = vcpu->arch.last_pte_updated;
1618 return !!(spte && (*spte & shadow_accessed_mask));
1621 static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1622 const u8 *new, int bytes)
1629 vcpu->arch.update_pte.largepage = 0;
1631 if (bytes != 4 && bytes != 8)
1635 * Assume that the pte write on a page table of the same type
1636 * as the current vcpu paging mode. This is nearly always true
1637 * (might be false while changing modes). Note it is verified later
1641 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
1642 if ((bytes == 4) && (gpa % 4 == 0)) {
1643 r = kvm_read_guest(vcpu->kvm, gpa & ~(u64)7, &gpte, 8);
1646 memcpy((void *)&gpte + (gpa % 8), new, 4);
1647 } else if ((bytes == 8) && (gpa % 8 == 0)) {
1648 memcpy((void *)&gpte, new, 8);
1651 if ((bytes == 4) && (gpa % 4 == 0))
1652 memcpy((void *)&gpte, new, 4);
1654 if (!is_present_pte(gpte))
1656 gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
1658 down_read(¤t->mm->mmap_sem);
1659 if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
1660 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1661 vcpu->arch.update_pte.largepage = 1;
1663 pfn = gfn_to_pfn(vcpu->kvm, gfn);
1664 up_read(¤t->mm->mmap_sem);
1666 if (is_error_pfn(pfn)) {
1667 kvm_release_pfn_clean(pfn);
1670 vcpu->arch.update_pte.gfn = gfn;
1671 vcpu->arch.update_pte.pfn = pfn;
1674 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1675 const u8 *new, int bytes)
1677 gfn_t gfn = gpa >> PAGE_SHIFT;
1678 struct kvm_mmu_page *sp;
1679 struct hlist_node *node, *n;
1680 struct hlist_head *bucket;
1684 unsigned offset = offset_in_page(gpa);
1686 unsigned page_offset;
1687 unsigned misaligned;
1694 pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
1695 mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes);
1696 spin_lock(&vcpu->kvm->mmu_lock);
1697 kvm_mmu_free_some_pages(vcpu);
1698 ++vcpu->kvm->stat.mmu_pte_write;
1699 kvm_mmu_audit(vcpu, "pre pte write");
1700 if (gfn == vcpu->arch.last_pt_write_gfn
1701 && !last_updated_pte_accessed(vcpu)) {
1702 ++vcpu->arch.last_pt_write_count;
1703 if (vcpu->arch.last_pt_write_count >= 3)
1706 vcpu->arch.last_pt_write_gfn = gfn;
1707 vcpu->arch.last_pt_write_count = 1;
1708 vcpu->arch.last_pte_updated = NULL;
1710 index = kvm_page_table_hashfn(gfn);
1711 bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1712 hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
1713 if (sp->gfn != gfn || sp->role.metaphysical)
1715 pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
1716 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
1717 misaligned |= bytes < 4;
1718 if (misaligned || flooded) {
1720 * Misaligned accesses are too much trouble to fix
1721 * up; also, they usually indicate a page is not used
1724 * If we're seeing too many writes to a page,
1725 * it may no longer be a page table, or we may be
1726 * forking, in which case it is better to unmap the
1729 pgprintk("misaligned: gpa %llx bytes %d role %x\n",
1730 gpa, bytes, sp->role.word);
1731 kvm_mmu_zap_page(vcpu->kvm, sp);
1732 ++vcpu->kvm->stat.mmu_flooded;
1735 page_offset = offset;
1736 level = sp->role.level;
1738 if (sp->role.glevels == PT32_ROOT_LEVEL) {
1739 page_offset <<= 1; /* 32->64 */
1741 * A 32-bit pde maps 4MB while the shadow pdes map
1742 * only 2MB. So we need to double the offset again
1743 * and zap two pdes instead of one.
1745 if (level == PT32_ROOT_LEVEL) {
1746 page_offset &= ~7; /* kill rounding error */
1750 quadrant = page_offset >> PAGE_SHIFT;
1751 page_offset &= ~PAGE_MASK;
1752 if (quadrant != sp->role.quadrant)
1755 spte = &sp->spt[page_offset / sizeof(*spte)];
1756 if ((gpa & (pte_size - 1)) || (bytes < pte_size)) {
1758 r = kvm_read_guest_atomic(vcpu->kvm,
1759 gpa & ~(u64)(pte_size - 1),
1761 new = (const void *)&gentry;
1767 mmu_pte_write_zap_pte(vcpu, sp, spte);
1769 mmu_pte_write_new_pte(vcpu, sp, spte, new);
1770 mmu_pte_write_flush_tlb(vcpu, entry, *spte);
1774 kvm_mmu_audit(vcpu, "post pte write");
1775 spin_unlock(&vcpu->kvm->mmu_lock);
1776 if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
1777 kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
1778 vcpu->arch.update_pte.pfn = bad_pfn;
1782 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
1787 gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1789 spin_lock(&vcpu->kvm->mmu_lock);
1790 r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1791 spin_unlock(&vcpu->kvm->mmu_lock);
1795 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
1797 while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) {
1798 struct kvm_mmu_page *sp;
1800 sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
1801 struct kvm_mmu_page, link);
1802 kvm_mmu_zap_page(vcpu->kvm, sp);
1803 ++vcpu->kvm->stat.mmu_recycled;
1807 int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
1810 enum emulation_result er;
1812 r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
1821 r = mmu_topup_memory_caches(vcpu);
1825 er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
1830 case EMULATE_DO_MMIO:
1831 ++vcpu->stat.mmio_exits;
1834 kvm_report_emulation_failure(vcpu, "pagetable");
1842 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
1844 void kvm_enable_tdp(void)
1848 EXPORT_SYMBOL_GPL(kvm_enable_tdp);
1850 static void free_mmu_pages(struct kvm_vcpu *vcpu)
1852 struct kvm_mmu_page *sp;
1854 while (!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
1855 sp = container_of(vcpu->kvm->arch.active_mmu_pages.next,
1856 struct kvm_mmu_page, link);
1857 kvm_mmu_zap_page(vcpu->kvm, sp);
1860 free_page((unsigned long)vcpu->arch.mmu.pae_root);
1863 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
1870 if (vcpu->kvm->arch.n_requested_mmu_pages)
1871 vcpu->kvm->arch.n_free_mmu_pages =
1872 vcpu->kvm->arch.n_requested_mmu_pages;
1874 vcpu->kvm->arch.n_free_mmu_pages =
1875 vcpu->kvm->arch.n_alloc_mmu_pages;
1877 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
1878 * Therefore we need to allocate shadow page tables in the first
1879 * 4GB of memory, which happens to fit the DMA32 zone.
1881 page = alloc_page(GFP_KERNEL | __GFP_DMA32);
1884 vcpu->arch.mmu.pae_root = page_address(page);
1885 for (i = 0; i < 4; ++i)
1886 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1891 free_mmu_pages(vcpu);
1895 int kvm_mmu_create(struct kvm_vcpu *vcpu)
1898 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1900 return alloc_mmu_pages(vcpu);
1903 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
1906 ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1908 return init_kvm_mmu(vcpu);
1911 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
1915 destroy_kvm_mmu(vcpu);
1916 free_mmu_pages(vcpu);
1917 mmu_free_memory_caches(vcpu);
1920 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
1922 struct kvm_mmu_page *sp;
1924 list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
1928 if (!test_bit(slot, &sp->slot_bitmap))
1932 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1934 if (pt[i] & PT_WRITABLE_MASK)
1935 pt[i] &= ~PT_WRITABLE_MASK;
1939 void kvm_mmu_zap_all(struct kvm *kvm)
1941 struct kvm_mmu_page *sp, *node;
1943 spin_lock(&kvm->mmu_lock);
1944 list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
1945 kvm_mmu_zap_page(kvm, sp);
1946 spin_unlock(&kvm->mmu_lock);
1948 kvm_flush_remote_tlbs(kvm);
1951 void kvm_mmu_remove_one_alloc_mmu_page(struct kvm *kvm)
1953 struct kvm_mmu_page *page;
1955 page = container_of(kvm->arch.active_mmu_pages.prev,
1956 struct kvm_mmu_page, link);
1957 kvm_mmu_zap_page(kvm, page);
1960 static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
1963 struct kvm *kvm_freed = NULL;
1964 int cache_count = 0;
1966 spin_lock(&kvm_lock);
1968 list_for_each_entry(kvm, &vm_list, vm_list) {
1971 spin_lock(&kvm->mmu_lock);
1972 npages = kvm->arch.n_alloc_mmu_pages -
1973 kvm->arch.n_free_mmu_pages;
1974 cache_count += npages;
1975 if (!kvm_freed && nr_to_scan > 0 && npages > 0) {
1976 kvm_mmu_remove_one_alloc_mmu_page(kvm);
1982 spin_unlock(&kvm->mmu_lock);
1985 list_move_tail(&kvm_freed->vm_list, &vm_list);
1987 spin_unlock(&kvm_lock);
1992 static struct shrinker mmu_shrinker = {
1993 .shrink = mmu_shrink,
1994 .seeks = DEFAULT_SEEKS * 10,
1997 static void mmu_destroy_caches(void)
1999 if (pte_chain_cache)
2000 kmem_cache_destroy(pte_chain_cache);
2001 if (rmap_desc_cache)
2002 kmem_cache_destroy(rmap_desc_cache);
2003 if (mmu_page_header_cache)
2004 kmem_cache_destroy(mmu_page_header_cache);
2007 void kvm_mmu_module_exit(void)
2009 mmu_destroy_caches();
2010 unregister_shrinker(&mmu_shrinker);
2013 int kvm_mmu_module_init(void)
2015 pte_chain_cache = kmem_cache_create("kvm_pte_chain",
2016 sizeof(struct kvm_pte_chain),
2018 if (!pte_chain_cache)
2020 rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
2021 sizeof(struct kvm_rmap_desc),
2023 if (!rmap_desc_cache)
2026 mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
2027 sizeof(struct kvm_mmu_page),
2029 if (!mmu_page_header_cache)
2032 register_shrinker(&mmu_shrinker);
2037 mmu_destroy_caches();
2042 * Caculate mmu pages needed for kvm.
2044 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
2047 unsigned int nr_mmu_pages;
2048 unsigned int nr_pages = 0;
2050 for (i = 0; i < kvm->nmemslots; i++)
2051 nr_pages += kvm->memslots[i].npages;
2053 nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
2054 nr_mmu_pages = max(nr_mmu_pages,
2055 (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
2057 return nr_mmu_pages;
2060 static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2063 if (len > buffer->len)
2068 static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2073 ret = pv_mmu_peek_buffer(buffer, len);
2078 buffer->processed += len;
2082 static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
2083 gpa_t addr, gpa_t value)
2088 if (!is_long_mode(vcpu) && !is_pae(vcpu))
2091 r = mmu_topup_memory_caches(vcpu);
2095 if (!emulator_write_phys(vcpu, addr, &value, bytes))
2101 static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2103 kvm_x86_ops->tlb_flush(vcpu);
2107 static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
2109 spin_lock(&vcpu->kvm->mmu_lock);
2110 mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
2111 spin_unlock(&vcpu->kvm->mmu_lock);
2115 static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
2116 struct kvm_pv_mmu_op_buffer *buffer)
2118 struct kvm_mmu_op_header *header;
2120 header = pv_mmu_peek_buffer(buffer, sizeof *header);
2123 switch (header->op) {
2124 case KVM_MMU_OP_WRITE_PTE: {
2125 struct kvm_mmu_op_write_pte *wpte;
2127 wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
2130 return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
2133 case KVM_MMU_OP_FLUSH_TLB: {
2134 struct kvm_mmu_op_flush_tlb *ftlb;
2136 ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
2139 return kvm_pv_mmu_flush_tlb(vcpu);
2141 case KVM_MMU_OP_RELEASE_PT: {
2142 struct kvm_mmu_op_release_pt *rpt;
2144 rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
2147 return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
2153 int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
2154 gpa_t addr, unsigned long *ret)
2157 struct kvm_pv_mmu_op_buffer buffer;
2159 buffer.ptr = buffer.buf;
2160 buffer.len = min_t(unsigned long, bytes, sizeof buffer.buf);
2161 buffer.processed = 0;
2163 r = kvm_read_guest(vcpu->kvm, addr, buffer.buf, buffer.len);
2167 while (buffer.len) {
2168 r = kvm_pv_mmu_op_one(vcpu, &buffer);
2177 *ret = buffer.processed;
2183 static const char *audit_msg;
2185 static gva_t canonicalize(gva_t gva)
2187 #ifdef CONFIG_X86_64
2188 gva = (long long)(gva << 16) >> 16;
2193 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
2194 gva_t va, int level)
2196 u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
2198 gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
2200 for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
2203 if (ent == shadow_trap_nonpresent_pte)
2206 va = canonicalize(va);
2208 if (ent == shadow_notrap_nonpresent_pte)
2209 printk(KERN_ERR "audit: (%s) nontrapping pte"
2210 " in nonleaf level: levels %d gva %lx"
2211 " level %d pte %llx\n", audit_msg,
2212 vcpu->arch.mmu.root_level, va, level, ent);
2214 audit_mappings_page(vcpu, ent, va, level - 1);
2216 gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, va);
2217 hpa_t hpa = (hpa_t)gpa_to_pfn(vcpu, gpa) << PAGE_SHIFT;
2219 if (is_shadow_present_pte(ent)
2220 && (ent & PT64_BASE_ADDR_MASK) != hpa)
2221 printk(KERN_ERR "xx audit error: (%s) levels %d"
2222 " gva %lx gpa %llx hpa %llx ent %llx %d\n",
2223 audit_msg, vcpu->arch.mmu.root_level,
2225 is_shadow_present_pte(ent));
2226 else if (ent == shadow_notrap_nonpresent_pte
2227 && !is_error_hpa(hpa))
2228 printk(KERN_ERR "audit: (%s) notrap shadow,"
2229 " valid guest gva %lx\n", audit_msg, va);
2230 kvm_release_pfn_clean(pfn);
2236 static void audit_mappings(struct kvm_vcpu *vcpu)
2240 if (vcpu->arch.mmu.root_level == 4)
2241 audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
2243 for (i = 0; i < 4; ++i)
2244 if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
2245 audit_mappings_page(vcpu,
2246 vcpu->arch.mmu.pae_root[i],
2251 static int count_rmaps(struct kvm_vcpu *vcpu)
2256 for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
2257 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
2258 struct kvm_rmap_desc *d;
2260 for (j = 0; j < m->npages; ++j) {
2261 unsigned long *rmapp = &m->rmap[j];
2265 if (!(*rmapp & 1)) {
2269 d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
2271 for (k = 0; k < RMAP_EXT; ++k)
2272 if (d->shadow_ptes[k])
2283 static int count_writable_mappings(struct kvm_vcpu *vcpu)
2286 struct kvm_mmu_page *sp;
2289 list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2292 if (sp->role.level != PT_PAGE_TABLE_LEVEL)
2295 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
2298 if (!(ent & PT_PRESENT_MASK))
2300 if (!(ent & PT_WRITABLE_MASK))
2308 static void audit_rmap(struct kvm_vcpu *vcpu)
2310 int n_rmap = count_rmaps(vcpu);
2311 int n_actual = count_writable_mappings(vcpu);
2313 if (n_rmap != n_actual)
2314 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
2315 __func__, audit_msg, n_rmap, n_actual);
2318 static void audit_write_protection(struct kvm_vcpu *vcpu)
2320 struct kvm_mmu_page *sp;
2321 struct kvm_memory_slot *slot;
2322 unsigned long *rmapp;
2325 list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2326 if (sp->role.metaphysical)
2329 slot = gfn_to_memslot(vcpu->kvm, sp->gfn);
2330 gfn = unalias_gfn(vcpu->kvm, sp->gfn);
2331 rmapp = &slot->rmap[gfn - slot->base_gfn];
2333 printk(KERN_ERR "%s: (%s) shadow page has writable"
2334 " mappings: gfn %lx role %x\n",
2335 __func__, audit_msg, sp->gfn,
2340 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
2347 audit_write_protection(vcpu);
2348 audit_mappings(vcpu);