| /* |
| * 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. |
| * |
| * 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. |
| * |
| */ |
| |
| #include "vmx.h" |
| #include "kvm.h" |
| #include "x86.h" |
| |
| #include <linux/types.h> |
| #include <linux/string.h> |
| #include <linux/mm.h> |
| #include <linux/highmem.h> |
| #include <linux/module.h> |
| |
| #include <asm/page.h> |
| #include <asm/cmpxchg.h> |
| |
| #undef MMU_DEBUG |
| |
| #undef AUDIT |
| |
| #ifdef AUDIT |
| static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg); |
| #else |
| static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {} |
| #endif |
| |
| #ifdef MMU_DEBUG |
| |
| #define pgprintk(x...) do { if (dbg) printk(x); } while (0) |
| #define rmap_printk(x...) do { if (dbg) printk(x); } while (0) |
| |
| #else |
| |
| #define pgprintk(x...) do { } while (0) |
| #define rmap_printk(x...) do { } while (0) |
| |
| #endif |
| |
| #if defined(MMU_DEBUG) || defined(AUDIT) |
| static int dbg = 1; |
| #endif |
| |
| #ifndef MMU_DEBUG |
| #define ASSERT(x) do { } while (0) |
| #else |
| #define ASSERT(x) \ |
| if (!(x)) { \ |
| printk(KERN_WARNING "assertion failed %s:%d: %s\n", \ |
| __FILE__, __LINE__, #x); \ |
| } |
| #endif |
| |
| #define PT64_PT_BITS 9 |
| #define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS) |
| #define PT32_PT_BITS 10 |
| #define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS) |
| |
| #define PT_WRITABLE_SHIFT 1 |
| |
| #define PT_PRESENT_MASK (1ULL << 0) |
| #define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT) |
| #define PT_USER_MASK (1ULL << 2) |
| #define PT_PWT_MASK (1ULL << 3) |
| #define PT_PCD_MASK (1ULL << 4) |
| #define PT_ACCESSED_MASK (1ULL << 5) |
| #define PT_DIRTY_MASK (1ULL << 6) |
| #define PT_PAGE_SIZE_MASK (1ULL << 7) |
| #define PT_PAT_MASK (1ULL << 7) |
| #define PT_GLOBAL_MASK (1ULL << 8) |
| #define PT64_NX_MASK (1ULL << 63) |
| |
| #define PT_PAT_SHIFT 7 |
| #define PT_DIR_PAT_SHIFT 12 |
| #define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT) |
| |
| #define PT32_DIR_PSE36_SIZE 4 |
| #define PT32_DIR_PSE36_SHIFT 13 |
| #define PT32_DIR_PSE36_MASK \ |
| (((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT) |
| |
| |
| #define PT_FIRST_AVAIL_BITS_SHIFT 9 |
| #define PT64_SECOND_AVAIL_BITS_SHIFT 52 |
| |
| #define PT_SHADOW_IO_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) |
| |
| #define VALID_PAGE(x) ((x) != INVALID_PAGE) |
| |
| #define PT64_LEVEL_BITS 9 |
| |
| #define PT64_LEVEL_SHIFT(level) \ |
| (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS) |
| |
| #define PT64_LEVEL_MASK(level) \ |
| (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level)) |
| |
| #define PT64_INDEX(address, level)\ |
| (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1)) |
| |
| |
| #define PT32_LEVEL_BITS 10 |
| |
| #define PT32_LEVEL_SHIFT(level) \ |
| (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS) |
| |
| #define PT32_LEVEL_MASK(level) \ |
| (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level)) |
| |
| #define PT32_INDEX(address, level)\ |
| (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1)) |
| |
| |
| #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1)) |
| #define PT64_DIR_BASE_ADDR_MASK \ |
| (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1)) |
| |
| #define PT32_BASE_ADDR_MASK PAGE_MASK |
| #define PT32_DIR_BASE_ADDR_MASK \ |
| (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1)) |
| |
| |
| #define PFERR_PRESENT_MASK (1U << 0) |
| #define PFERR_WRITE_MASK (1U << 1) |
| #define PFERR_USER_MASK (1U << 2) |
| #define PFERR_FETCH_MASK (1U << 4) |
| |
| #define PT64_ROOT_LEVEL 4 |
| #define PT32_ROOT_LEVEL 2 |
| #define PT32E_ROOT_LEVEL 3 |
| |
| #define PT_DIRECTORY_LEVEL 2 |
| #define PT_PAGE_TABLE_LEVEL 1 |
| |
| #define RMAP_EXT 4 |
| |
| struct kvm_rmap_desc { |
| u64 *shadow_ptes[RMAP_EXT]; |
| struct kvm_rmap_desc *more; |
| }; |
| |
| static struct kmem_cache *pte_chain_cache; |
| static struct kmem_cache *rmap_desc_cache; |
| static struct kmem_cache *mmu_page_header_cache; |
| |
| static u64 __read_mostly shadow_trap_nonpresent_pte; |
| static u64 __read_mostly shadow_notrap_nonpresent_pte; |
| |
| void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte) |
| { |
| shadow_trap_nonpresent_pte = trap_pte; |
| shadow_notrap_nonpresent_pte = notrap_pte; |
| } |
| EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes); |
| |
| static int is_write_protection(struct kvm_vcpu *vcpu) |
| { |
| return vcpu->cr0 & X86_CR0_WP; |
| } |
| |
| static int is_cpuid_PSE36(void) |
| { |
| return 1; |
| } |
| |
| static int is_nx(struct kvm_vcpu *vcpu) |
| { |
| return vcpu->shadow_efer & EFER_NX; |
| } |
| |
| static int is_present_pte(unsigned long pte) |
| { |
| return pte & PT_PRESENT_MASK; |
| } |
| |
| static int is_shadow_present_pte(u64 pte) |
| { |
| pte &= ~PT_SHADOW_IO_MARK; |
| return pte != shadow_trap_nonpresent_pte |
| && pte != shadow_notrap_nonpresent_pte; |
| } |
| |
| static int is_writeble_pte(unsigned long pte) |
| { |
| return pte & PT_WRITABLE_MASK; |
| } |
| |
| static int is_dirty_pte(unsigned long pte) |
| { |
| return pte & PT_DIRTY_MASK; |
| } |
| |
| static int is_io_pte(unsigned long pte) |
| { |
| return pte & PT_SHADOW_IO_MARK; |
| } |
| |
| static int is_rmap_pte(u64 pte) |
| { |
| return pte != shadow_trap_nonpresent_pte |
| && pte != shadow_notrap_nonpresent_pte; |
| } |
| |
| static void set_shadow_pte(u64 *sptep, u64 spte) |
| { |
| #ifdef CONFIG_X86_64 |
| set_64bit((unsigned long *)sptep, spte); |
| #else |
| set_64bit((unsigned long long *)sptep, spte); |
| #endif |
| } |
| |
| static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, |
| struct kmem_cache *base_cache, int min) |
| { |
| void *obj; |
| |
| if (cache->nobjs >= min) |
| return 0; |
| while (cache->nobjs < ARRAY_SIZE(cache->objects)) { |
| obj = kmem_cache_zalloc(base_cache, GFP_KERNEL); |
| if (!obj) |
| return -ENOMEM; |
| cache->objects[cache->nobjs++] = obj; |
| } |
| return 0; |
| } |
| |
| static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) |
| { |
| while (mc->nobjs) |
| kfree(mc->objects[--mc->nobjs]); |
| } |
| |
| static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache, |
| int min) |
| { |
| struct page *page; |
| |
| if (cache->nobjs >= min) |
| return 0; |
| while (cache->nobjs < ARRAY_SIZE(cache->objects)) { |
| page = alloc_page(GFP_KERNEL); |
| if (!page) |
| return -ENOMEM; |
| set_page_private(page, 0); |
| cache->objects[cache->nobjs++] = page_address(page); |
| } |
| return 0; |
| } |
| |
| static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc) |
| { |
| while (mc->nobjs) |
| free_page((unsigned long)mc->objects[--mc->nobjs]); |
| } |
| |
| static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu) |
| { |
| int r; |
| |
| kvm_mmu_free_some_pages(vcpu); |
| r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache, |
| pte_chain_cache, 4); |
| if (r) |
| goto out; |
| r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache, |
| rmap_desc_cache, 1); |
| if (r) |
| goto out; |
| r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 8); |
| if (r) |
| goto out; |
| r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache, |
| mmu_page_header_cache, 4); |
| out: |
| return r; |
| } |
| |
| static void mmu_free_memory_caches(struct kvm_vcpu *vcpu) |
| { |
| mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache); |
| mmu_free_memory_cache(&vcpu->mmu_rmap_desc_cache); |
| mmu_free_memory_cache_page(&vcpu->mmu_page_cache); |
| mmu_free_memory_cache(&vcpu->mmu_page_header_cache); |
| } |
| |
| static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc, |
| size_t size) |
| { |
| void *p; |
| |
| BUG_ON(!mc->nobjs); |
| p = mc->objects[--mc->nobjs]; |
| memset(p, 0, size); |
| return p; |
| } |
| |
| static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu) |
| { |
| return mmu_memory_cache_alloc(&vcpu->mmu_pte_chain_cache, |
| sizeof(struct kvm_pte_chain)); |
| } |
| |
| static void mmu_free_pte_chain(struct kvm_pte_chain *pc) |
| { |
| kfree(pc); |
| } |
| |
| static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu) |
| { |
| return mmu_memory_cache_alloc(&vcpu->mmu_rmap_desc_cache, |
| sizeof(struct kvm_rmap_desc)); |
| } |
| |
| static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd) |
| { |
| kfree(rd); |
| } |
| |
| /* |
| * Take gfn and return the reverse mapping to it. |
| * Note: gfn must be unaliased before this function get called |
| */ |
| |
| static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn) |
| { |
| struct kvm_memory_slot *slot; |
| |
| slot = gfn_to_memslot(kvm, gfn); |
| return &slot->rmap[gfn - slot->base_gfn]; |
| } |
| |
| /* |
| * Reverse mapping data structures: |
| * |
| * If rmapp bit zero is zero, then rmapp point to the shadw page table entry |
| * that points to page_address(page). |
| * |
| * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc |
| * containing more mappings. |
| */ |
| static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn) |
| { |
| struct kvm_mmu_page *page; |
| struct kvm_rmap_desc *desc; |
| unsigned long *rmapp; |
| int i; |
| |
| if (!is_rmap_pte(*spte)) |
| return; |
| gfn = unalias_gfn(vcpu->kvm, gfn); |
| page = page_header(__pa(spte)); |
| page->gfns[spte - page->spt] = gfn; |
| rmapp = gfn_to_rmap(vcpu->kvm, gfn); |
| if (!*rmapp) { |
| rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte); |
| *rmapp = (unsigned long)spte; |
| } else if (!(*rmapp & 1)) { |
| rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte); |
| desc = mmu_alloc_rmap_desc(vcpu); |
| desc->shadow_ptes[0] = (u64 *)*rmapp; |
| desc->shadow_ptes[1] = spte; |
| *rmapp = (unsigned long)desc | 1; |
| } else { |
| rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte); |
| desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul); |
| while (desc->shadow_ptes[RMAP_EXT-1] && desc->more) |
| desc = desc->more; |
| if (desc->shadow_ptes[RMAP_EXT-1]) { |
| desc->more = mmu_alloc_rmap_desc(vcpu); |
| desc = desc->more; |
| } |
| for (i = 0; desc->shadow_ptes[i]; ++i) |
| ; |
| desc->shadow_ptes[i] = spte; |
| } |
| } |
| |
| static void rmap_desc_remove_entry(unsigned long *rmapp, |
| struct kvm_rmap_desc *desc, |
| int i, |
| struct kvm_rmap_desc *prev_desc) |
| { |
| int j; |
| |
| for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j) |
| ; |
| desc->shadow_ptes[i] = desc->shadow_ptes[j]; |
| desc->shadow_ptes[j] = NULL; |
| if (j != 0) |
| return; |
| if (!prev_desc && !desc->more) |
| *rmapp = (unsigned long)desc->shadow_ptes[0]; |
| else |
| if (prev_desc) |
| prev_desc->more = desc->more; |
| else |
| *rmapp = (unsigned long)desc->more | 1; |
| mmu_free_rmap_desc(desc); |
| } |
| |
| static void rmap_remove(struct kvm *kvm, u64 *spte) |
| { |
| struct kvm_rmap_desc *desc; |
| struct kvm_rmap_desc *prev_desc; |
| struct kvm_mmu_page *page; |
| unsigned long *rmapp; |
| int i; |
| |
| if (!is_rmap_pte(*spte)) |
| return; |
| page = page_header(__pa(spte)); |
| kvm_release_page(pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> |
| PAGE_SHIFT)); |
| rmapp = gfn_to_rmap(kvm, page->gfns[spte - page->spt]); |
| if (!*rmapp) { |
| printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte); |
| BUG(); |
| } else if (!(*rmapp & 1)) { |
| rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte); |
| if ((u64 *)*rmapp != spte) { |
| printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n", |
| spte, *spte); |
| BUG(); |
| } |
| *rmapp = 0; |
| } else { |
| rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte); |
| desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul); |
| prev_desc = NULL; |
| while (desc) { |
| for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) |
| if (desc->shadow_ptes[i] == spte) { |
| rmap_desc_remove_entry(rmapp, |
| desc, i, |
| prev_desc); |
| return; |
| } |
| prev_desc = desc; |
| desc = desc->more; |
| } |
| BUG(); |
| } |
| } |
| |
| static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte) |
| { |
| struct kvm_rmap_desc *desc; |
| struct kvm_rmap_desc *prev_desc; |
| u64 *prev_spte; |
| int i; |
| |
| if (!*rmapp) |
| return NULL; |
| else if (!(*rmapp & 1)) { |
| if (!spte) |
| return (u64 *)*rmapp; |
| return NULL; |
| } |
| desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul); |
| prev_desc = NULL; |
| prev_spte = NULL; |
| while (desc) { |
| for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) { |
| if (prev_spte == spte) |
| return desc->shadow_ptes[i]; |
| prev_spte = desc->shadow_ptes[i]; |
| } |
| desc = desc->more; |
| } |
| return NULL; |
| } |
| |
| static void rmap_write_protect(struct kvm *kvm, u64 gfn) |
| { |
| unsigned long *rmapp; |
| u64 *spte; |
| |
| gfn = unalias_gfn(kvm, gfn); |
| rmapp = gfn_to_rmap(kvm, gfn); |
| |
| spte = rmap_next(kvm, rmapp, NULL); |
| while (spte) { |
| BUG_ON(!spte); |
| BUG_ON(!(*spte & PT_PRESENT_MASK)); |
| rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte); |
| if (is_writeble_pte(*spte)) |
| set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK); |
| kvm_flush_remote_tlbs(kvm); |
| spte = rmap_next(kvm, rmapp, spte); |
| } |
| } |
| |
| #ifdef MMU_DEBUG |
| static int is_empty_shadow_page(u64 *spt) |
| { |
| u64 *pos; |
| u64 *end; |
| |
| for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++) |
| if ((*pos & ~PT_SHADOW_IO_MARK) != shadow_trap_nonpresent_pte) { |
| printk(KERN_ERR "%s: %p %llx\n", __FUNCTION__, |
| pos, *pos); |
| return 0; |
| } |
| return 1; |
| } |
| #endif |
| |
| static void kvm_mmu_free_page(struct kvm *kvm, |
| struct kvm_mmu_page *page_head) |
| { |
| ASSERT(is_empty_shadow_page(page_head->spt)); |
| list_del(&page_head->link); |
| __free_page(virt_to_page(page_head->spt)); |
| __free_page(virt_to_page(page_head->gfns)); |
| kfree(page_head); |
| ++kvm->n_free_mmu_pages; |
| } |
| |
| static unsigned kvm_page_table_hashfn(gfn_t gfn) |
| { |
| return gfn; |
| } |
| |
| static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, |
| u64 *parent_pte) |
| { |
| struct kvm_mmu_page *page; |
| |
| if (!vcpu->kvm->n_free_mmu_pages) |
| return NULL; |
| |
| page = mmu_memory_cache_alloc(&vcpu->mmu_page_header_cache, |
| sizeof *page); |
| page->spt = mmu_memory_cache_alloc(&vcpu->mmu_page_cache, PAGE_SIZE); |
| page->gfns = mmu_memory_cache_alloc(&vcpu->mmu_page_cache, PAGE_SIZE); |
| set_page_private(virt_to_page(page->spt), (unsigned long)page); |
| list_add(&page->link, &vcpu->kvm->active_mmu_pages); |
| ASSERT(is_empty_shadow_page(page->spt)); |
| page->slot_bitmap = 0; |
| page->multimapped = 0; |
| page->parent_pte = parent_pte; |
| --vcpu->kvm->n_free_mmu_pages; |
| return page; |
| } |
| |
| static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu, |
| struct kvm_mmu_page *page, u64 *parent_pte) |
| { |
| struct kvm_pte_chain *pte_chain; |
| struct hlist_node *node; |
| int i; |
| |
| if (!parent_pte) |
| return; |
| if (!page->multimapped) { |
| u64 *old = page->parent_pte; |
| |
| if (!old) { |
| page->parent_pte = parent_pte; |
| return; |
| } |
| page->multimapped = 1; |
| pte_chain = mmu_alloc_pte_chain(vcpu); |
| INIT_HLIST_HEAD(&page->parent_ptes); |
| hlist_add_head(&pte_chain->link, &page->parent_ptes); |
| pte_chain->parent_ptes[0] = old; |
| } |
| hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link) { |
| if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1]) |
| continue; |
| for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) |
| if (!pte_chain->parent_ptes[i]) { |
| pte_chain->parent_ptes[i] = parent_pte; |
| return; |
| } |
| } |
| pte_chain = mmu_alloc_pte_chain(vcpu); |
| BUG_ON(!pte_chain); |
| hlist_add_head(&pte_chain->link, &page->parent_ptes); |
| pte_chain->parent_ptes[0] = parent_pte; |
| } |
| |
| static void mmu_page_remove_parent_pte(struct kvm_mmu_page *page, |
| u64 *parent_pte) |
| { |
| struct kvm_pte_chain *pte_chain; |
| struct hlist_node *node; |
| int i; |
| |
| if (!page->multimapped) { |
| BUG_ON(page->parent_pte != parent_pte); |
| page->parent_pte = NULL; |
| return; |
| } |
| hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link) |
| for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) { |
| if (!pte_chain->parent_ptes[i]) |
| break; |
| if (pte_chain->parent_ptes[i] != parent_pte) |
| continue; |
| while (i + 1 < NR_PTE_CHAIN_ENTRIES |
| && pte_chain->parent_ptes[i + 1]) { |
| pte_chain->parent_ptes[i] |
| = pte_chain->parent_ptes[i + 1]; |
| ++i; |
| } |
| pte_chain->parent_ptes[i] = NULL; |
| if (i == 0) { |
| hlist_del(&pte_chain->link); |
| mmu_free_pte_chain(pte_chain); |
| if (hlist_empty(&page->parent_ptes)) { |
| page->multimapped = 0; |
| page->parent_pte = NULL; |
| } |
| } |
| return; |
| } |
| BUG(); |
| } |
| |
| static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, |
| gfn_t gfn) |
| { |
| unsigned index; |
| struct hlist_head *bucket; |
| struct kvm_mmu_page *page; |
| struct hlist_node *node; |
| |
| pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn); |
| index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES; |
| bucket = &kvm->mmu_page_hash[index]; |
| hlist_for_each_entry(page, node, bucket, hash_link) |
| if (page->gfn == gfn && !page->role.metaphysical) { |
| pgprintk("%s: found role %x\n", |
| __FUNCTION__, page->role.word); |
| return page; |
| } |
| return NULL; |
| } |
| |
| static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, |
| gfn_t gfn, |
| gva_t gaddr, |
| unsigned level, |
| int metaphysical, |
| unsigned hugepage_access, |
| u64 *parent_pte) |
| { |
| union kvm_mmu_page_role role; |
| unsigned index; |
| unsigned quadrant; |
| struct hlist_head *bucket; |
| struct kvm_mmu_page *page; |
| struct hlist_node *node; |
| |
| role.word = 0; |
| role.glevels = vcpu->mmu.root_level; |
| role.level = level; |
| role.metaphysical = metaphysical; |
| role.hugepage_access = hugepage_access; |
| if (vcpu->mmu.root_level <= PT32_ROOT_LEVEL) { |
| quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level)); |
| quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1; |
| role.quadrant = quadrant; |
| } |
| pgprintk("%s: looking gfn %lx role %x\n", __FUNCTION__, |
| gfn, role.word); |
| index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES; |
| bucket = &vcpu->kvm->mmu_page_hash[index]; |
| hlist_for_each_entry(page, node, bucket, hash_link) |
| if (page->gfn == gfn && page->role.word == role.word) { |
| mmu_page_add_parent_pte(vcpu, page, parent_pte); |
| pgprintk("%s: found\n", __FUNCTION__); |
| return page; |
| } |
| page = kvm_mmu_alloc_page(vcpu, parent_pte); |
| if (!page) |
| return page; |
| pgprintk("%s: adding gfn %lx role %x\n", __FUNCTION__, gfn, role.word); |
| page->gfn = gfn; |
| page->role = role; |
| hlist_add_head(&page->hash_link, bucket); |
| vcpu->mmu.prefetch_page(vcpu, page); |
| if (!metaphysical) |
| rmap_write_protect(vcpu->kvm, gfn); |
| return page; |
| } |
| |
| static void kvm_mmu_page_unlink_children(struct kvm *kvm, |
| struct kvm_mmu_page *page) |
| { |
| unsigned i; |
| u64 *pt; |
| u64 ent; |
| |
| pt = page->spt; |
| |
| if (page->role.level == PT_PAGE_TABLE_LEVEL) { |
| for (i = 0; i < PT64_ENT_PER_PAGE; ++i) { |
| if (is_shadow_present_pte(pt[i])) |
| rmap_remove(kvm, &pt[i]); |
| pt[i] = shadow_trap_nonpresent_pte; |
| } |
| kvm_flush_remote_tlbs(kvm); |
| return; |
| } |
| |
| for (i = 0; i < PT64_ENT_PER_PAGE; ++i) { |
| ent = pt[i]; |
| |
| pt[i] = shadow_trap_nonpresent_pte; |
| if (!is_shadow_present_pte(ent)) |
| continue; |
| ent &= PT64_BASE_ADDR_MASK; |
| mmu_page_remove_parent_pte(page_header(ent), &pt[i]); |
| } |
| kvm_flush_remote_tlbs(kvm); |
| } |
| |
| static void kvm_mmu_put_page(struct kvm_mmu_page *page, |
| u64 *parent_pte) |
| { |
| mmu_page_remove_parent_pte(page, parent_pte); |
| } |
| |
| static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm) |
| { |
| int i; |
| |
| for (i = 0; i < KVM_MAX_VCPUS; ++i) |
| if (kvm->vcpus[i]) |
| kvm->vcpus[i]->last_pte_updated = NULL; |
| } |
| |
| static void kvm_mmu_zap_page(struct kvm *kvm, |
| struct kvm_mmu_page *page) |
| { |
| u64 *parent_pte; |
| |
| while (page->multimapped || page->parent_pte) { |
| if (!page->multimapped) |
| parent_pte = page->parent_pte; |
| else { |
| struct kvm_pte_chain *chain; |
| |
| chain = container_of(page->parent_ptes.first, |
| struct kvm_pte_chain, link); |
| parent_pte = chain->parent_ptes[0]; |
| } |
| BUG_ON(!parent_pte); |
| kvm_mmu_put_page(page, parent_pte); |
| set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte); |
| } |
| kvm_mmu_page_unlink_children(kvm, page); |
| if (!page->root_count) { |
| hlist_del(&page->hash_link); |
| kvm_mmu_free_page(kvm, page); |
| } else |
| list_move(&page->link, &kvm->active_mmu_pages); |
| kvm_mmu_reset_last_pte_updated(kvm); |
| } |
| |
| /* |
| * Changing the number of mmu pages allocated to the vm |
| * Note: if kvm_nr_mmu_pages is too small, you will get dead lock |
| */ |
| void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages) |
| { |
| /* |
| * If we set the number of mmu pages to be smaller be than the |
| * number of actived pages , we must to free some mmu pages before we |
| * change the value |
| */ |
| |
| if ((kvm->n_alloc_mmu_pages - kvm->n_free_mmu_pages) > |
| kvm_nr_mmu_pages) { |
| int n_used_mmu_pages = kvm->n_alloc_mmu_pages |
| - kvm->n_free_mmu_pages; |
| |
| while (n_used_mmu_pages > kvm_nr_mmu_pages) { |
| struct kvm_mmu_page *page; |
| |
| page = container_of(kvm->active_mmu_pages.prev, |
| struct kvm_mmu_page, link); |
| kvm_mmu_zap_page(kvm, page); |
| n_used_mmu_pages--; |
| } |
| kvm->n_free_mmu_pages = 0; |
| } |
| else |
| kvm->n_free_mmu_pages += kvm_nr_mmu_pages |
| - kvm->n_alloc_mmu_pages; |
| |
| kvm->n_alloc_mmu_pages = kvm_nr_mmu_pages; |
| } |
| |
| static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn) |
| { |
| unsigned index; |
| struct hlist_head *bucket; |
| struct kvm_mmu_page *page; |
| struct hlist_node *node, *n; |
| int r; |
| |
| pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn); |
| r = 0; |
| index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES; |
| bucket = &kvm->mmu_page_hash[index]; |
| hlist_for_each_entry_safe(page, node, n, bucket, hash_link) |
| if (page->gfn == gfn && !page->role.metaphysical) { |
| pgprintk("%s: gfn %lx role %x\n", __FUNCTION__, gfn, |
| page->role.word); |
| kvm_mmu_zap_page(kvm, page); |
| r = 1; |
| } |
| return r; |
| } |
| |
| static void mmu_unshadow(struct kvm *kvm, gfn_t gfn) |
| { |
| struct kvm_mmu_page *page; |
| |
| while ((page = kvm_mmu_lookup_page(kvm, gfn)) != NULL) { |
| pgprintk("%s: zap %lx %x\n", |
| __FUNCTION__, gfn, page->role.word); |
| kvm_mmu_zap_page(kvm, page); |
| } |
| } |
| |
| static void page_header_update_slot(struct kvm *kvm, void *pte, gpa_t gpa) |
| { |
| int slot = memslot_id(kvm, gfn_to_memslot(kvm, gpa >> PAGE_SHIFT)); |
| struct kvm_mmu_page *page_head = page_header(__pa(pte)); |
| |
| __set_bit(slot, &page_head->slot_bitmap); |
| } |
| |
| hpa_t gpa_to_hpa(struct kvm *kvm, gpa_t gpa) |
| { |
| struct page *page; |
| hpa_t hpa; |
| |
| ASSERT((gpa & HPA_ERR_MASK) == 0); |
| page = gfn_to_page(kvm, gpa >> PAGE_SHIFT); |
| hpa = ((hpa_t)page_to_pfn(page) << PAGE_SHIFT) | (gpa & (PAGE_SIZE-1)); |
| if (is_error_page(page)) |
| return hpa | HPA_ERR_MASK; |
| return hpa; |
| } |
| |
| hpa_t gva_to_hpa(struct kvm_vcpu *vcpu, gva_t gva) |
| { |
| gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva); |
| |
| if (gpa == UNMAPPED_GVA) |
| return UNMAPPED_GVA; |
| return gpa_to_hpa(vcpu->kvm, gpa); |
| } |
| |
| struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva) |
| { |
| gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva); |
| |
| if (gpa == UNMAPPED_GVA) |
| return NULL; |
| return pfn_to_page(gpa_to_hpa(vcpu->kvm, gpa) >> PAGE_SHIFT); |
| } |
| |
| static void nonpaging_new_cr3(struct kvm_vcpu *vcpu) |
| { |
| } |
| |
| static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p) |
| { |
| int level = PT32E_ROOT_LEVEL; |
| hpa_t table_addr = vcpu->mmu.root_hpa; |
| |
| for (; ; level--) { |
| u32 index = PT64_INDEX(v, level); |
| u64 *table; |
| u64 pte; |
| |
| ASSERT(VALID_PAGE(table_addr)); |
| table = __va(table_addr); |
| |
| if (level == 1) { |
| int was_rmapped; |
| |
| pte = table[index]; |
| was_rmapped = is_rmap_pte(pte); |
| if (is_shadow_present_pte(pte) && is_writeble_pte(pte)) |
| return 0; |
| mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT); |
| page_header_update_slot(vcpu->kvm, table, v); |
| table[index] = p | PT_PRESENT_MASK | PT_WRITABLE_MASK | |
| PT_USER_MASK; |
| if (!was_rmapped) |
| rmap_add(vcpu, &table[index], v >> PAGE_SHIFT); |
| else |
| kvm_release_page(pfn_to_page(p >> PAGE_SHIFT)); |
| return 0; |
| } |
| |
| if (table[index] == shadow_trap_nonpresent_pte) { |
| struct kvm_mmu_page *new_table; |
| gfn_t pseudo_gfn; |
| |
| pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK) |
| >> PAGE_SHIFT; |
| new_table = kvm_mmu_get_page(vcpu, pseudo_gfn, |
| v, level - 1, |
| 1, 3, &table[index]); |
| if (!new_table) { |
| pgprintk("nonpaging_map: ENOMEM\n"); |
| kvm_release_page(pfn_to_page(p >> PAGE_SHIFT)); |
| return -ENOMEM; |
| } |
| |
| table[index] = __pa(new_table->spt) | PT_PRESENT_MASK |
| | PT_WRITABLE_MASK | PT_USER_MASK; |
| } |
| table_addr = table[index] & PT64_BASE_ADDR_MASK; |
| } |
| } |
| |
| static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu, |
| struct kvm_mmu_page *sp) |
| { |
| int i; |
| |
| for (i = 0; i < PT64_ENT_PER_PAGE; ++i) |
| sp->spt[i] = shadow_trap_nonpresent_pte; |
| } |
| |
| static void mmu_free_roots(struct kvm_vcpu *vcpu) |
| { |
| int i; |
| struct kvm_mmu_page *page; |
| |
| if (!VALID_PAGE(vcpu->mmu.root_hpa)) |
| return; |
| #ifdef CONFIG_X86_64 |
| if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) { |
| hpa_t root = vcpu->mmu.root_hpa; |
| |
| page = page_header(root); |
| --page->root_count; |
| vcpu->mmu.root_hpa = INVALID_PAGE; |
| return; |
| } |
| #endif |
| for (i = 0; i < 4; ++i) { |
| hpa_t root = vcpu->mmu.pae_root[i]; |
| |
| if (root) { |
| root &= PT64_BASE_ADDR_MASK; |
| page = page_header(root); |
| --page->root_count; |
| } |
| vcpu->mmu.pae_root[i] = INVALID_PAGE; |
| } |
| vcpu->mmu.root_hpa = INVALID_PAGE; |
| } |
| |
| static void mmu_alloc_roots(struct kvm_vcpu *vcpu) |
| { |
| int i; |
| gfn_t root_gfn; |
| struct kvm_mmu_page *page; |
| |
| root_gfn = vcpu->cr3 >> PAGE_SHIFT; |
| |
| #ifdef CONFIG_X86_64 |
| if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) { |
| hpa_t root = vcpu->mmu.root_hpa; |
| |
| ASSERT(!VALID_PAGE(root)); |
| page = kvm_mmu_get_page(vcpu, root_gfn, 0, |
| PT64_ROOT_LEVEL, 0, 0, NULL); |
| root = __pa(page->spt); |
| ++page->root_count; |
| vcpu->mmu.root_hpa = root; |
| return; |
| } |
| #endif |
| for (i = 0; i < 4; ++i) { |
| hpa_t root = vcpu->mmu.pae_root[i]; |
| |
| ASSERT(!VALID_PAGE(root)); |
| if (vcpu->mmu.root_level == PT32E_ROOT_LEVEL) { |
| if (!is_present_pte(vcpu->pdptrs[i])) { |
| vcpu->mmu.pae_root[i] = 0; |
| continue; |
| } |
| root_gfn = vcpu->pdptrs[i] >> PAGE_SHIFT; |
| } else if (vcpu->mmu.root_level == 0) |
| root_gfn = 0; |
| page = kvm_mmu_get_page(vcpu, root_gfn, i << 30, |
| PT32_ROOT_LEVEL, !is_paging(vcpu), |
| 0, NULL); |
| root = __pa(page->spt); |
| ++page->root_count; |
| vcpu->mmu.pae_root[i] = root | PT_PRESENT_MASK; |
| } |
| vcpu->mmu.root_hpa = __pa(vcpu->mmu.pae_root); |
| } |
| |
| static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr) |
| { |
| return vaddr; |
| } |
| |
| static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva, |
| u32 error_code) |
| { |
| gpa_t addr = gva; |
| hpa_t paddr; |
| int r; |
| |
| r = mmu_topup_memory_caches(vcpu); |
| if (r) |
| return r; |
| |
| ASSERT(vcpu); |
| ASSERT(VALID_PAGE(vcpu->mmu.root_hpa)); |
| |
| |
| paddr = gpa_to_hpa(vcpu->kvm, addr & PT64_BASE_ADDR_MASK); |
| |
| if (is_error_hpa(paddr)) { |
| kvm_release_page(pfn_to_page((paddr & PT64_BASE_ADDR_MASK) |
| >> PAGE_SHIFT)); |
| return 1; |
| } |
| |
| return nonpaging_map(vcpu, addr & PAGE_MASK, paddr); |
| } |
| |
| static void nonpaging_free(struct kvm_vcpu *vcpu) |
| { |
| mmu_free_roots(vcpu); |
| } |
| |
| static int nonpaging_init_context(struct kvm_vcpu *vcpu) |
| { |
| struct kvm_mmu *context = &vcpu->mmu; |
| |
| context->new_cr3 = nonpaging_new_cr3; |
| context->page_fault = nonpaging_page_fault; |
| context->gva_to_gpa = nonpaging_gva_to_gpa; |
| context->free = nonpaging_free; |
| context->prefetch_page = nonpaging_prefetch_page; |
| context->root_level = 0; |
| context->shadow_root_level = PT32E_ROOT_LEVEL; |
| context->root_hpa = INVALID_PAGE; |
| return 0; |
| } |
| |
| static void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu) |
| { |
| ++vcpu->stat.tlb_flush; |
| kvm_x86_ops->tlb_flush(vcpu); |
| } |
| |
| static void paging_new_cr3(struct kvm_vcpu *vcpu) |
| { |
| pgprintk("%s: cr3 %lx\n", __FUNCTION__, vcpu->cr3); |
| mmu_free_roots(vcpu); |
| } |
| |
| static void inject_page_fault(struct kvm_vcpu *vcpu, |
| u64 addr, |
| u32 err_code) |
| { |
| kvm_x86_ops->inject_page_fault(vcpu, addr, err_code); |
| } |
| |
| static void paging_free(struct kvm_vcpu *vcpu) |
| { |
| nonpaging_free(vcpu); |
| } |
| |
| #define PTTYPE 64 |
| #include "paging_tmpl.h" |
| #undef PTTYPE |
| |
| #define PTTYPE 32 |
| #include "paging_tmpl.h" |
| #undef PTTYPE |
| |
| static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level) |
| { |
| struct kvm_mmu *context = &vcpu->mmu; |
| |
| ASSERT(is_pae(vcpu)); |
| context->new_cr3 = paging_new_cr3; |
| context->page_fault = paging64_page_fault; |
| context->gva_to_gpa = paging64_gva_to_gpa; |
| context->prefetch_page = paging64_prefetch_page; |
| context->free = paging_free; |
| context->root_level = level; |
| context->shadow_root_level = level; |
| context->root_hpa = INVALID_PAGE; |
| return 0; |
| } |
| |
| static int paging64_init_context(struct kvm_vcpu *vcpu) |
| { |
| return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL); |
| } |
| |
| static int paging32_init_context(struct kvm_vcpu *vcpu) |
| { |
| struct kvm_mmu *context = &vcpu->mmu; |
| |
| context->new_cr3 = paging_new_cr3; |
| context->page_fault = paging32_page_fault; |
| context->gva_to_gpa = paging32_gva_to_gpa; |
| context->free = paging_free; |
| context->prefetch_page = paging32_prefetch_page; |
| context->root_level = PT32_ROOT_LEVEL; |
| context->shadow_root_level = PT32E_ROOT_LEVEL; |
| context->root_hpa = INVALID_PAGE; |
| return 0; |
| } |
| |
| static int paging32E_init_context(struct kvm_vcpu *vcpu) |
| { |
| return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL); |
| } |
| |
| static int init_kvm_mmu(struct kvm_vcpu *vcpu) |
| { |
| ASSERT(vcpu); |
| ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa)); |
| |
| if (!is_paging(vcpu)) |
| return nonpaging_init_context(vcpu); |
| else if (is_long_mode(vcpu)) |
| return paging64_init_context(vcpu); |
| else if (is_pae(vcpu)) |
| return paging32E_init_context(vcpu); |
| else |
| return paging32_init_context(vcpu); |
| } |
| |
| static void destroy_kvm_mmu(struct kvm_vcpu *vcpu) |
| { |
| ASSERT(vcpu); |
| if (VALID_PAGE(vcpu->mmu.root_hpa)) { |
| vcpu->mmu.free(vcpu); |
| vcpu->mmu.root_hpa = INVALID_PAGE; |
| } |
| } |
| |
| int kvm_mmu_reset_context(struct kvm_vcpu *vcpu) |
| { |
| destroy_kvm_mmu(vcpu); |
| return init_kvm_mmu(vcpu); |
| } |
| EXPORT_SYMBOL_GPL(kvm_mmu_reset_context); |
| |
| int kvm_mmu_load(struct kvm_vcpu *vcpu) |
| { |
| int r; |
| |
| mutex_lock(&vcpu->kvm->lock); |
| r = mmu_topup_memory_caches(vcpu); |
| if (r) |
| goto out; |
| mmu_alloc_roots(vcpu); |
| kvm_x86_ops->set_cr3(vcpu, vcpu->mmu.root_hpa); |
| kvm_mmu_flush_tlb(vcpu); |
| out: |
| mutex_unlock(&vcpu->kvm->lock); |
| return r; |
| } |
| EXPORT_SYMBOL_GPL(kvm_mmu_load); |
| |
| void kvm_mmu_unload(struct kvm_vcpu *vcpu) |
| { |
| mmu_free_roots(vcpu); |
| } |
| |
| static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu, |
| struct kvm_mmu_page *page, |
| u64 *spte) |
| { |
| u64 pte; |
| struct kvm_mmu_page *child; |
| |
| pte = *spte; |
| if (is_shadow_present_pte(pte)) { |
| if (page->role.level == PT_PAGE_TABLE_LEVEL) |
| rmap_remove(vcpu->kvm, spte); |
| else { |
| child = page_header(pte & PT64_BASE_ADDR_MASK); |
| mmu_page_remove_parent_pte(child, spte); |
| } |
| } |
| set_shadow_pte(spte, shadow_trap_nonpresent_pte); |
| kvm_flush_remote_tlbs(vcpu->kvm); |
| } |
| |
| static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu, |
| struct kvm_mmu_page *page, |
| u64 *spte, |
| const void *new, int bytes, |
| int offset_in_pte) |
| { |
| if (page->role.level != PT_PAGE_TABLE_LEVEL) |
| return; |
| |
| if (page->role.glevels == PT32_ROOT_LEVEL) |
| paging32_update_pte(vcpu, page, spte, new, bytes, |
| offset_in_pte); |
| else |
| paging64_update_pte(vcpu, page, spte, new, bytes, |
| offset_in_pte); |
| } |
| |
| static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu) |
| { |
| u64 *spte = vcpu->last_pte_updated; |
| |
| return !!(spte && (*spte & PT_ACCESSED_MASK)); |
| } |
| |
| void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, |
| const u8 *new, int bytes) |
| { |
| gfn_t gfn = gpa >> PAGE_SHIFT; |
| struct kvm_mmu_page *page; |
| struct hlist_node *node, *n; |
| struct hlist_head *bucket; |
| unsigned index; |
| u64 *spte; |
| unsigned offset = offset_in_page(gpa); |
| unsigned pte_size; |
| unsigned page_offset; |
| unsigned misaligned; |
| unsigned quadrant; |
| int level; |
| int flooded = 0; |
| int npte; |
| |
| pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes); |
| kvm_mmu_audit(vcpu, "pre pte write"); |
| if (gfn == vcpu->last_pt_write_gfn |
| && !last_updated_pte_accessed(vcpu)) { |
| ++vcpu->last_pt_write_count; |
| if (vcpu->last_pt_write_count >= 3) |
| flooded = 1; |
| } else { |
| vcpu->last_pt_write_gfn = gfn; |
| vcpu->last_pt_write_count = 1; |
| vcpu->last_pte_updated = NULL; |
| } |
| index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES; |
| bucket = &vcpu->kvm->mmu_page_hash[index]; |
| hlist_for_each_entry_safe(page, node, n, bucket, hash_link) { |
| if (page->gfn != gfn || page->role.metaphysical) |
| continue; |
| pte_size = page->role.glevels == PT32_ROOT_LEVEL ? 4 : 8; |
| misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1); |
| misaligned |= bytes < 4; |
| if (misaligned || flooded) { |
| /* |
| * Misaligned accesses are too much trouble to fix |
| * up; also, they usually indicate a page is not used |
| * as a page table. |
| * |
| * 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. |
| */ |
| pgprintk("misaligned: gpa %llx bytes %d role %x\n", |
| gpa, bytes, page->role.word); |
| kvm_mmu_zap_page(vcpu->kvm, page); |
| continue; |
| } |
| page_offset = offset; |
| level = page->role.level; |
| npte = 1; |
| if (page->role.glevels == PT32_ROOT_LEVEL) { |
| 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; |
| npte = 2; |
| } |
| quadrant = page_offset >> PAGE_SHIFT; |
| page_offset &= ~PAGE_MASK; |
| if (quadrant != page->role.quadrant) |
| continue; |
| } |
| spte = &page->spt[page_offset / sizeof(*spte)]; |
| while (npte--) { |
| mmu_pte_write_zap_pte(vcpu, page, spte); |
| mmu_pte_write_new_pte(vcpu, page, spte, new, bytes, |
| page_offset & (pte_size - 1)); |
| ++spte; |
| } |
| } |
| kvm_mmu_audit(vcpu, "post pte write"); |
| } |
| |
| int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva) |
| { |
| gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva); |
| |
| return kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT); |
| } |
| |
| void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) |
| { |
| while (vcpu->kvm->n_free_mmu_pages < KVM_REFILL_PAGES) { |
| struct kvm_mmu_page *page; |
| |
| page = container_of(vcpu->kvm->active_mmu_pages.prev, |
| struct kvm_mmu_page, link); |
| kvm_mmu_zap_page(vcpu->kvm, page); |
| } |
| } |
| |
| int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code) |
| { |
| int r; |
| enum emulation_result er; |
| |
| mutex_lock(&vcpu->kvm->lock); |
| r = vcpu->mmu.page_fault(vcpu, cr2, error_code); |
| if (r < 0) |
| goto out; |
| |
| if (!r) { |
| r = 1; |
| goto out; |
| } |
| |
| er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0); |
| mutex_unlock(&vcpu->kvm->lock); |
| |
| switch (er) { |
| case EMULATE_DONE: |
| return 1; |
| case EMULATE_DO_MMIO: |
| ++vcpu->stat.mmio_exits; |
| return 0; |
| case EMULATE_FAIL: |
| kvm_report_emulation_failure(vcpu, "pagetable"); |
| return 1; |
| default: |
| BUG(); |
| } |
| out: |
| mutex_unlock(&vcpu->kvm->lock); |
| return r; |
| } |
| EXPORT_SYMBOL_GPL(kvm_mmu_page_fault); |
| |
| static void free_mmu_pages(struct kvm_vcpu *vcpu) |
| { |
| struct kvm_mmu_page *page; |
| |
| while (!list_empty(&vcpu->kvm->active_mmu_pages)) { |
| page = container_of(vcpu->kvm->active_mmu_pages.next, |
| struct kvm_mmu_page, link); |
| kvm_mmu_zap_page(vcpu->kvm, page); |
| } |
| free_page((unsigned long)vcpu->mmu.pae_root); |
| } |
| |
| static int alloc_mmu_pages(struct kvm_vcpu *vcpu) |
| { |
| struct page *page; |
| int i; |
| |
| ASSERT(vcpu); |
| |
| if (vcpu->kvm->n_requested_mmu_pages) |
| vcpu->kvm->n_free_mmu_pages = vcpu->kvm->n_requested_mmu_pages; |
| else |
| vcpu->kvm->n_free_mmu_pages = vcpu->kvm->n_alloc_mmu_pages; |
| /* |
| * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64. |
| * Therefore we need to allocate shadow page tables in the first |
| * 4GB of memory, which happens to fit the DMA32 zone. |
| */ |
| page = alloc_page(GFP_KERNEL | __GFP_DMA32); |
| if (!page) |
| goto error_1; |
| vcpu->mmu.pae_root = page_address(page); |
| for (i = 0; i < 4; ++i) |
| vcpu->mmu.pae_root[i] = INVALID_PAGE; |
| |
| return 0; |
| |
| error_1: |
| free_mmu_pages(vcpu); |
| return -ENOMEM; |
| } |
| |
| int kvm_mmu_create(struct kvm_vcpu *vcpu) |
| { |
| ASSERT(vcpu); |
| ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa)); |
| |
| return alloc_mmu_pages(vcpu); |
| } |
| |
| int kvm_mmu_setup(struct kvm_vcpu *vcpu) |
| { |
| ASSERT(vcpu); |
| ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa)); |
| |
| return init_kvm_mmu(vcpu); |
| } |
| |
| void kvm_mmu_destroy(struct kvm_vcpu *vcpu) |
| { |
| ASSERT(vcpu); |
| |
| destroy_kvm_mmu(vcpu); |
| free_mmu_pages(vcpu); |
| mmu_free_memory_caches(vcpu); |
| } |
| |
| void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot) |
| { |
| struct kvm_mmu_page *page; |
| |
| list_for_each_entry(page, &kvm->active_mmu_pages, link) { |
| int i; |
| u64 *pt; |
| |
| if (!test_bit(slot, &page->slot_bitmap)) |
| continue; |
| |
| pt = page->spt; |
| for (i = 0; i < PT64_ENT_PER_PAGE; ++i) |
| /* avoid RMW */ |
| if (pt[i] & PT_WRITABLE_MASK) |
| pt[i] &= ~PT_WRITABLE_MASK; |
| } |
| } |
| |
| void kvm_mmu_zap_all(struct kvm *kvm) |
| { |
| struct kvm_mmu_page *page, *node; |
| |
| list_for_each_entry_safe(page, node, &kvm->active_mmu_pages, link) |
| kvm_mmu_zap_page(kvm, page); |
| |
| kvm_flush_remote_tlbs(kvm); |
| } |
| |
| void kvm_mmu_module_exit(void) |
| { |
| if (pte_chain_cache) |
| kmem_cache_destroy(pte_chain_cache); |
| if (rmap_desc_cache) |
| kmem_cache_destroy(rmap_desc_cache); |
| if (mmu_page_header_cache) |
| kmem_cache_destroy(mmu_page_header_cache); |
| } |
| |
| int kvm_mmu_module_init(void) |
| { |
| pte_chain_cache = kmem_cache_create("kvm_pte_chain", |
| sizeof(struct kvm_pte_chain), |
| 0, 0, NULL); |
| if (!pte_chain_cache) |
| goto nomem; |
| rmap_desc_cache = kmem_cache_create("kvm_rmap_desc", |
| sizeof(struct kvm_rmap_desc), |
| 0, 0, NULL); |
| if (!rmap_desc_cache) |
| goto nomem; |
| |
| mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header", |
| sizeof(struct kvm_mmu_page), |
| 0, 0, NULL); |
| if (!mmu_page_header_cache) |
| goto nomem; |
| |
| return 0; |
| |
| nomem: |
| kvm_mmu_module_exit(); |
| return -ENOMEM; |
| } |
| |
| #ifdef AUDIT |
| |
| static const char *audit_msg; |
| |
| static gva_t canonicalize(gva_t gva) |
| { |
| #ifdef CONFIG_X86_64 |
| gva = (long long)(gva << 16) >> 16; |
| #endif |
| return gva; |
| } |
| |
| static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte, |
| gva_t va, int level) |
| { |
| u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK); |
| int i; |
| gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1)); |
| |
| for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) { |
| u64 ent = pt[i]; |
| |
| if (ent == shadow_trap_nonpresent_pte) |
| continue; |
| |
| va = canonicalize(va); |
| if (level > 1) { |
| if (ent == shadow_notrap_nonpresent_pte) |
| printk(KERN_ERR "audit: (%s) nontrapping pte" |
| " in nonleaf level: levels %d gva %lx" |
| " level %d pte %llx\n", audit_msg, |
| vcpu->mmu.root_level, va, level, ent); |
| |
| audit_mappings_page(vcpu, ent, va, level - 1); |
| } else { |
| gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, va); |
| hpa_t hpa = gpa_to_hpa(vcpu, gpa); |
| struct page *page; |
| |
| if (is_shadow_present_pte(ent) |
| && (ent & PT64_BASE_ADDR_MASK) != hpa) |
| printk(KERN_ERR "xx audit error: (%s) levels %d" |
| " gva %lx gpa %llx hpa %llx ent %llx %d\n", |
| audit_msg, vcpu->mmu.root_level, |
| va, gpa, hpa, ent, |
| is_shadow_present_pte(ent)); |
| else if (ent == shadow_notrap_nonpresent_pte |
| && !is_error_hpa(hpa)) |
| printk(KERN_ERR "audit: (%s) notrap shadow," |
| " valid guest gva %lx\n", audit_msg, va); |
| page = pfn_to_page((gpa & PT64_BASE_ADDR_MASK) |
| >> PAGE_SHIFT); |
| kvm_release_page(page); |
| |
| } |
| } |
| } |
| |
| static void audit_mappings(struct kvm_vcpu *vcpu) |
| { |
| unsigned i; |
| |
| if (vcpu->mmu.root_level == 4) |
| audit_mappings_page(vcpu, vcpu->mmu.root_hpa, 0, 4); |
| else |
| for (i = 0; i < 4; ++i) |
| if (vcpu->mmu.pae_root[i] & PT_PRESENT_MASK) |
| audit_mappings_page(vcpu, |
| vcpu->mmu.pae_root[i], |
| i << 30, |
| 2); |
| } |
| |
| static int count_rmaps(struct kvm_vcpu *vcpu) |
| { |
| int nmaps = 0; |
| int i, j, k; |
| |
| for (i = 0; i < KVM_MEMORY_SLOTS; ++i) { |
| struct kvm_memory_slot *m = &vcpu->kvm->memslots[i]; |
| struct kvm_rmap_desc *d; |
| |
| for (j = 0; j < m->npages; ++j) { |
| unsigned long *rmapp = &m->rmap[j]; |
| |
| if (!*rmapp) |
| continue; |
| if (!(*rmapp & 1)) { |
| ++nmaps; |
| continue; |
| } |
| d = (struct kvm_rmap_desc *)(*rmapp & ~1ul); |
| while (d) { |
| for (k = 0; k < RMAP_EXT; ++k) |
| if (d->shadow_ptes[k]) |
| ++nmaps; |
| else |
| break; |
| d = d->more; |
| } |
| } |
| } |
| return nmaps; |
| } |
| |
| static int count_writable_mappings(struct kvm_vcpu *vcpu) |
| { |
| int nmaps = 0; |
| struct kvm_mmu_page *page; |
| int i; |
| |
| list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) { |
| u64 *pt = page->spt; |
| |
| if (page->role.level != PT_PAGE_TABLE_LEVEL) |
| continue; |
| |
| for (i = 0; i < PT64_ENT_PER_PAGE; ++i) { |
| u64 ent = pt[i]; |
| |
| if (!(ent & PT_PRESENT_MASK)) |
| continue; |
| if (!(ent & PT_WRITABLE_MASK)) |
| continue; |
| ++nmaps; |
| } |
| } |
| return nmaps; |
| } |
| |
| static void audit_rmap(struct kvm_vcpu *vcpu) |
| { |
| int n_rmap = count_rmaps(vcpu); |
| int n_actual = count_writable_mappings(vcpu); |
| |
| if (n_rmap != n_actual) |
| printk(KERN_ERR "%s: (%s) rmap %d actual %d\n", |
| __FUNCTION__, audit_msg, n_rmap, n_actual); |
| } |
| |
| static void audit_write_protection(struct kvm_vcpu *vcpu) |
| { |
| struct kvm_mmu_page *page; |
| struct kvm_memory_slot *slot; |
| unsigned long *rmapp; |
| gfn_t gfn; |
| |
| list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) { |
| if (page->role.metaphysical) |
| continue; |
| |
| slot = gfn_to_memslot(vcpu->kvm, page->gfn); |
| gfn = unalias_gfn(vcpu->kvm, page->gfn); |
| rmapp = &slot->rmap[gfn - slot->base_gfn]; |
| if (*rmapp) |
| printk(KERN_ERR "%s: (%s) shadow page has writable" |
| " mappings: gfn %lx role %x\n", |
| __FUNCTION__, audit_msg, page->gfn, |
| page->role.word); |
| } |
| } |
| |
| static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) |
| { |
| int olddbg = dbg; |
| |
| dbg = 0; |
| audit_msg = msg; |
| audit_rmap(vcpu); |
| audit_write_protection(vcpu); |
| audit_mappings(vcpu); |
| dbg = olddbg; |
| } |
| |
| #endif |