diff options
Diffstat (limited to 'arch/x86/kvm/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 1885 |
1 files changed, 1885 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c new file mode 100644 index 000000000000..8efdcdbebb03 --- /dev/null +++ b/arch/x86/kvm/mmu.c @@ -0,0 +1,1885 @@ +/* + * 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 "mmu.h" + +#include <linux/kvm_host.h> +#include <linux/types.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/highmem.h> +#include <linux/module.h> +#include <linux/swap.h> + +#include <asm/page.h> +#include <asm/cmpxchg.h> +#include <asm/io.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_SHIFT 63 +#define PT64_NX_MASK (1ULL << PT64_NX_SHIFT) + +#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 PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \ + | PT64_NX_MASK) + +#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 + +#define ACC_EXEC_MASK 1 +#define ACC_WRITE_MASK PT_WRITABLE_MASK +#define ACC_USER_MASK PT_USER_MASK +#define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK) + +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->arch.cr0 & X86_CR0_WP; +} + +static int is_cpuid_PSE36(void) +{ + return 1; +} + +static int is_nx(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.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 gfn_t pse36_gfn_delta(u32 gpte) +{ + int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT; + + return (gpte & PT32_DIR_PSE36_MASK) << shift; +} + +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; + + r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache, + pte_chain_cache, 4); + if (r) + goto out; + r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache, + rmap_desc_cache, 1); + if (r) + goto out; + r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8); + if (r) + goto out; + r = mmu_topup_memory_cache(&vcpu->arch.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->arch.mmu_pte_chain_cache); + mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache); + mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache); + mmu_free_memory_cache(&vcpu->arch.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->arch.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->arch.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 *sp; + struct kvm_rmap_desc *desc; + unsigned long *rmapp; + int i; + + if (!is_rmap_pte(*spte)) + return; + gfn = unalias_gfn(vcpu->kvm, gfn); + sp = page_header(__pa(spte)); + sp->gfns[spte - sp->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 *sp; + struct page *page; + unsigned long *rmapp; + int i; + + if (!is_rmap_pte(*spte)) + return; + sp = page_header(__pa(spte)); + page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT); + mark_page_accessed(page); + if (is_writeble_pte(*spte)) + kvm_release_page_dirty(page); + else + kvm_release_page_clean(page); + rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->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; + int write_protected = 0; + + 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); + write_protected = 1; + } + spte = rmap_next(kvm, rmapp, spte); + } + if (write_protected) + kvm_flush_remote_tlbs(kvm); +} + +#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 *sp) +{ + ASSERT(is_empty_shadow_page(sp->spt)); + list_del(&sp->link); + __free_page(virt_to_page(sp->spt)); + __free_page(virt_to_page(sp->gfns)); + kfree(sp); + ++kvm->arch.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 *sp; + + sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp); + sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE); + sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE); + set_page_private(virt_to_page(sp->spt), (unsigned long)sp); + list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); + ASSERT(is_empty_shadow_page(sp->spt)); + sp->slot_bitmap = 0; + sp->multimapped = 0; + sp->parent_pte = parent_pte; + --vcpu->kvm->arch.n_free_mmu_pages; + return sp; +} + +static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu, + struct kvm_mmu_page *sp, u64 *parent_pte) +{ + struct kvm_pte_chain *pte_chain; + struct hlist_node *node; + int i; + + if (!parent_pte) + return; + if (!sp->multimapped) { + u64 *old = sp->parent_pte; + + if (!old) { + sp->parent_pte = parent_pte; + return; + } + sp->multimapped = 1; + pte_chain = mmu_alloc_pte_chain(vcpu); + INIT_HLIST_HEAD(&sp->parent_ptes); + hlist_add_head(&pte_chain->link, &sp->parent_ptes); + pte_chain->parent_ptes[0] = old; + } + hlist_for_each_entry(pte_chain, node, &sp->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, &sp->parent_ptes); + pte_chain->parent_ptes[0] = parent_pte; +} + +static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp, + u64 *parent_pte) +{ + struct kvm_pte_chain *pte_chain; + struct hlist_node *node; + int i; + + if (!sp->multimapped) { + BUG_ON(sp->parent_pte != parent_pte); + sp->parent_pte = NULL; + return; + } + hlist_for_each_entry(pte_chain, node, &sp->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(&sp->parent_ptes)) { + sp->multimapped = 0; + sp->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 *sp; + 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->arch.mmu_page_hash[index]; + hlist_for_each_entry(sp, node, bucket, hash_link) + if (sp->gfn == gfn && !sp->role.metaphysical) { + pgprintk("%s: found role %x\n", + __FUNCTION__, sp->role.word); + return sp; + } + 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 access, + u64 *parent_pte, + bool *new_page) +{ + union kvm_mmu_page_role role; + unsigned index; + unsigned quadrant; + struct hlist_head *bucket; + struct kvm_mmu_page *sp; + struct hlist_node *node; + + role.word = 0; + role.glevels = vcpu->arch.mmu.root_level; + role.level = level; + role.metaphysical = metaphysical; + role.access = access; + if (vcpu->arch.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->arch.mmu_page_hash[index]; + hlist_for_each_entry(sp, node, bucket, hash_link) + if (sp->gfn == gfn && sp->role.word == role.word) { + mmu_page_add_parent_pte(vcpu, sp, parent_pte); + pgprintk("%s: found\n", __FUNCTION__); + return sp; + } + ++vcpu->kvm->stat.mmu_cache_miss; + sp = kvm_mmu_alloc_page(vcpu, parent_pte); + if (!sp) + return sp; + pgprintk("%s: adding gfn %lx role %x\n", __FUNCTION__, gfn, role.word); + sp->gfn = gfn; + sp->role = role; + hlist_add_head(&sp->hash_link, bucket); + vcpu->arch.mmu.prefetch_page(vcpu, sp); + if (!metaphysical) + rmap_write_protect(vcpu->kvm, gfn); + if (new_page) + *new_page = 1; + return sp; +} + +static void kvm_mmu_page_unlink_children(struct kvm *kvm, + struct kvm_mmu_page *sp) +{ + unsigned i; + u64 *pt; + u64 ent; + + pt = sp->spt; + + if (sp->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 *sp, u64 *parent_pte) +{ + mmu_page_remove_parent_pte(sp, 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]->arch.last_pte_updated = NULL; +} + +static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp) +{ + u64 *parent_pte; + + ++kvm->stat.mmu_shadow_zapped; + while (sp->multimapped || sp->parent_pte) { + if (!sp->multimapped) + parent_pte = sp->parent_pte; + else { + struct kvm_pte_chain *chain; + + chain = container_of(sp->parent_ptes.first, + struct kvm_pte_chain, link); + parent_pte = chain->parent_ptes[0]; + } + BUG_ON(!parent_pte); + kvm_mmu_put_page(sp, parent_pte); + set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte); + } + kvm_mmu_page_unlink_children(kvm, sp); + if (!sp->root_count) { + hlist_del(&sp->hash_link); + kvm_mmu_free_page(kvm, sp); + } else + list_move(&sp->link, &kvm->arch.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->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages) > + kvm_nr_mmu_pages) { + int n_used_mmu_pages = kvm->arch.n_alloc_mmu_pages + - kvm->arch.n_free_mmu_pages; + + while (n_used_mmu_pages > kvm_nr_mmu_pages) { + struct kvm_mmu_page *page; + + page = container_of(kvm->arch.active_mmu_pages.prev, + struct kvm_mmu_page, link); + kvm_mmu_zap_page(kvm, page); + n_used_mmu_pages--; + } + kvm->arch.n_free_mmu_pages = 0; + } + else + kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages + - kvm->arch.n_alloc_mmu_pages; + + kvm->arch.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 *sp; + 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->arch.mmu_page_hash[index]; + hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) + if (sp->gfn == gfn && !sp->role.metaphysical) { + pgprintk("%s: gfn %lx role %x\n", __FUNCTION__, gfn, + sp->role.word); + kvm_mmu_zap_page(kvm, sp); + r = 1; + } + return r; +} + +static void mmu_unshadow(struct kvm *kvm, gfn_t gfn) +{ + struct kvm_mmu_page *sp; + + while ((sp = kvm_mmu_lookup_page(kvm, gfn)) != NULL) { + pgprintk("%s: zap %lx %x\n", __FUNCTION__, gfn, sp->role.word); + kvm_mmu_zap_page(kvm, sp); + } +} + +static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn) +{ + int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn)); + struct kvm_mmu_page *sp = page_header(__pa(pte)); + + __set_bit(slot, &sp->slot_bitmap); +} + +struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva) +{ + gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva); + + if (gpa == UNMAPPED_GVA) + return NULL; + return gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT); +} + +static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte, + unsigned pt_access, unsigned pte_access, + int user_fault, int write_fault, int dirty, + int *ptwrite, gfn_t gfn, struct page *page) +{ + u64 spte; + int was_rmapped = is_rmap_pte(*shadow_pte); + int was_writeble = is_writeble_pte(*shadow_pte); + + pgprintk("%s: spte %llx access %x write_fault %d" + " user_fault %d gfn %lx\n", + __FUNCTION__, *shadow_pte, pt_access, + write_fault, user_fault, gfn); + + /* + * We don't set the accessed bit, since we sometimes want to see + * whether the guest actually used the pte (in order to detect + * demand paging). + */ + spte = PT_PRESENT_MASK | PT_DIRTY_MASK; + if (!dirty) + pte_access &= ~ACC_WRITE_MASK; + if (!(pte_access & ACC_EXEC_MASK)) + spte |= PT64_NX_MASK; + + spte |= PT_PRESENT_MASK; + if (pte_access & ACC_USER_MASK) + spte |= PT_USER_MASK; + + if (is_error_page(page)) { + set_shadow_pte(shadow_pte, + shadow_trap_nonpresent_pte | PT_SHADOW_IO_MARK); + kvm_release_page_clean(page); + return; + } + + spte |= page_to_phys(page); + + if ((pte_access & ACC_WRITE_MASK) + || (write_fault && !is_write_protection(vcpu) && !user_fault)) { + struct kvm_mmu_page *shadow; + + spte |= PT_WRITABLE_MASK; + if (user_fault) { + mmu_unshadow(vcpu->kvm, gfn); + goto unshadowed; + } + + shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn); + if (shadow) { + pgprintk("%s: found shadow page for %lx, marking ro\n", + __FUNCTION__, gfn); + pte_access &= ~ACC_WRITE_MASK; + if (is_writeble_pte(spte)) { + spte &= ~PT_WRITABLE_MASK; + kvm_x86_ops->tlb_flush(vcpu); + } + if (write_fault) + *ptwrite = 1; + } + } + +unshadowed: + + if (pte_access & ACC_WRITE_MASK) + mark_page_dirty(vcpu->kvm, gfn); + + pgprintk("%s: setting spte %llx\n", __FUNCTION__, spte); + set_shadow_pte(shadow_pte, spte); + page_header_update_slot(vcpu->kvm, shadow_pte, gfn); + if (!was_rmapped) { + rmap_add(vcpu, shadow_pte, gfn); + if (!is_rmap_pte(*shadow_pte)) + kvm_release_page_clean(page); + } else { + if (was_writeble) + kvm_release_page_dirty(page); + else + kvm_release_page_clean(page); + } + if (!ptwrite || !*ptwrite) + vcpu->arch.last_pte_updated = shadow_pte; +} + +static void nonpaging_new_cr3(struct kvm_vcpu *vcpu) +{ +} + +static int __nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, + gfn_t gfn, struct page *page) +{ + int level = PT32E_ROOT_LEVEL; + hpa_t table_addr = vcpu->arch.mmu.root_hpa; + int pt_write = 0; + + for (; ; level--) { + u32 index = PT64_INDEX(v, level); + u64 *table; + + ASSERT(VALID_PAGE(table_addr)); + table = __va(table_addr); + + if (level == 1) { + mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL, + 0, write, 1, &pt_write, gfn, page); + return pt_write || is_io_pte(table[index]); + } + + 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, ACC_ALL, &table[index], + NULL); + if (!new_table) { + pgprintk("nonpaging_map: ENOMEM\n"); + kvm_release_page_clean(page); + 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 int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn) +{ + int r; + + struct page *page; + + down_read(¤t->mm->mmap_sem); + page = gfn_to_page(vcpu->kvm, gfn); + + spin_lock(&vcpu->kvm->mmu_lock); + kvm_mmu_free_some_pages(vcpu); + r = __nonpaging_map(vcpu, v, write, gfn, page); + spin_unlock(&vcpu->kvm->mmu_lock); + + up_read(¤t->mm->mmap_sem); + + return r; +} + + +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 *sp; + + if (!VALID_PAGE(vcpu->arch.mmu.root_hpa)) + return; + spin_lock(&vcpu->kvm->mmu_lock); +#ifdef CONFIG_X86_64 + if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) { + hpa_t root = vcpu->arch.mmu.root_hpa; + + sp = page_header(root); + --sp->root_count; + vcpu->arch.mmu.root_hpa = INVALID_PAGE; + spin_unlock(&vcpu->kvm->mmu_lock); + return; + } +#endif + for (i = 0; i < 4; ++i) { + hpa_t root = vcpu->arch.mmu.pae_root[i]; + + if (root) { + root &= PT64_BASE_ADDR_MASK; + sp = page_header(root); + --sp->root_count; + } + vcpu->arch.mmu.pae_root[i] = INVALID_PAGE; + } + spin_unlock(&vcpu->kvm->mmu_lock); + vcpu->arch.mmu.root_hpa = INVALID_PAGE; +} + +static void mmu_alloc_roots(struct kvm_vcpu *vcpu) +{ + int i; + gfn_t root_gfn; + struct kvm_mmu_page *sp; + + root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT; + +#ifdef CONFIG_X86_64 + if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) { + hpa_t root = vcpu->arch.mmu.root_hpa; + + ASSERT(!VALID_PAGE(root)); + sp = kvm_mmu_get_page(vcpu, root_gfn, 0, + PT64_ROOT_LEVEL, 0, ACC_ALL, NULL, NULL); + root = __pa(sp->spt); + ++sp->root_count; + vcpu->arch.mmu.root_hpa = root; + return; + } +#endif + for (i = 0; i < 4; ++i) { + hpa_t root = vcpu->arch.mmu.pae_root[i]; + + ASSERT(!VALID_PAGE(root)); + if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) { + if (!is_present_pte(vcpu->arch.pdptrs[i])) { + vcpu->arch.mmu.pae_root[i] = 0; + continue; + } + root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT; + } else if (vcpu->arch.mmu.root_level == 0) + root_gfn = 0; + sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30, + PT32_ROOT_LEVEL, !is_paging(vcpu), + ACC_ALL, NULL, NULL); + root = __pa(sp->spt); + ++sp->root_count; + vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK; + } + vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.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) +{ + gfn_t gfn; + int r; + + pgprintk("%s: gva %lx error %x\n", __FUNCTION__, gva, error_code); + r = mmu_topup_memory_caches(vcpu); + if (r) + return r; + + ASSERT(vcpu); + ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa)); + + gfn = gva >> PAGE_SHIFT; + + return nonpaging_map(vcpu, gva & PAGE_MASK, + error_code & PFERR_WRITE_MASK, gfn); +} + +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->arch.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; +} + +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_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->arch.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->arch.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->arch.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->arch.mmu.root_hpa)) { + vcpu->arch.mmu.free(vcpu); + vcpu->arch.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; + + r = mmu_topup_memory_caches(vcpu); + if (r) + goto out; + spin_lock(&vcpu->kvm->mmu_lock); + kvm_mmu_free_some_pages(vcpu); + mmu_alloc_roots(vcpu); + spin_unlock(&vcpu->kvm->mmu_lock); + kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa); + kvm_mmu_flush_tlb(vcpu); +out: + 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 *sp, + u64 *spte) +{ + u64 pte; + struct kvm_mmu_page *child; + + pte = *spte; + if (is_shadow_present_pte(pte)) { + if (sp->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); +} + +static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu, + struct kvm_mmu_page *sp, + u64 *spte, + const void *new, int bytes, + int offset_in_pte) +{ + if (sp->role.level != PT_PAGE_TABLE_LEVEL) { + ++vcpu->kvm->stat.mmu_pde_zapped; + return; + } + + ++vcpu->kvm->stat.mmu_pte_updated; + if (sp->role.glevels == PT32_ROOT_LEVEL) + paging32_update_pte(vcpu, sp, spte, new, bytes, offset_in_pte); + else + paging64_update_pte(vcpu, sp, spte, new, bytes, offset_in_pte); +} + +static bool need_remote_flush(u64 old, u64 new) +{ + if (!is_shadow_present_pte(old)) + return false; + if (!is_shadow_present_pte(new)) + return true; + if ((old ^ new) & PT64_BASE_ADDR_MASK) + return true; + old ^= PT64_NX_MASK; + new ^= PT64_NX_MASK; + return (old & ~new & PT64_PERM_MASK) != 0; +} + +static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new) +{ + if (need_remote_flush(old, new)) + kvm_flush_remote_tlbs(vcpu->kvm); + else + kvm_mmu_flush_tlb(vcpu); +} + +static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu) +{ + u64 *spte = vcpu->arch.last_pte_updated; + + return !!(spte && (*spte & PT_ACCESSED_MASK)); +} + +static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, + const u8 *new, int bytes) +{ + gfn_t gfn; + int r; + u64 gpte = 0; + + if (bytes != 4 && bytes != 8) + return; + + /* + * Assume that the pte write on a page table of the same type + * as the current vcpu paging mode. This is nearly always true + * (might be false while changing modes). Note it is verified later + * by update_pte(). + */ + if (is_pae(vcpu)) { + /* Handle a 32-bit guest writing two halves of a 64-bit gpte */ + if ((bytes == 4) && (gpa % 4 == 0)) { + r = kvm_read_guest(vcpu->kvm, gpa & ~(u64)7, &gpte, 8); + if (r) + return; + memcpy((void *)&gpte + (gpa % 8), new, 4); + } else if ((bytes == 8) && (gpa % 8 == 0)) { + memcpy((void *)&gpte, new, 8); + } + } else { + if ((bytes == 4) && (gpa % 4 == 0)) + memcpy((void *)&gpte, new, 4); + } + if (!is_present_pte(gpte)) + return; + gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT; + vcpu->arch.update_pte.gfn = gfn; + vcpu->arch.update_pte.page = gfn_to_page(vcpu->kvm, gfn); +} + +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 *sp; + struct hlist_node *node, *n; + struct hlist_head *bucket; + unsigned index; + u64 entry; + 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); + mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes); + spin_lock(&vcpu->kvm->mmu_lock); + kvm_mmu_free_some_pages(vcpu); + ++vcpu->kvm->stat.mmu_pte_write; + kvm_mmu_audit(vcpu, "pre pte write"); + if (gfn == vcpu->arch.last_pt_write_gfn + && !last_updated_pte_accessed(vcpu)) { + ++vcpu->arch.last_pt_write_count; + if (vcpu->arch.last_pt_write_count >= 3) + flooded = 1; + } else { + vcpu->arch.last_pt_write_gfn = gfn; + vcpu->arch.last_pt_write_count = 1; + vcpu->arch.last_pte_updated = NULL; + } + index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES; + bucket = &vcpu->kvm->arch.mmu_page_hash[index]; + hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) { + if (sp->gfn != gfn || sp->role.metaphysical) + continue; + pte_size = sp->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, sp->role.word); + kvm_mmu_zap_page(vcpu->kvm, sp); + ++vcpu->kvm->stat.mmu_flooded; + continue; + } + page_offset = offset; + level = sp->role.level; + npte = 1; + if (sp->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 != sp->role.quadrant) + continue; + } + spte = &sp->spt[page_offset / sizeof(*spte)]; + while (npte--) { + entry = *spte; + mmu_pte_write_zap_pte(vcpu, sp, spte); + mmu_pte_write_new_pte(vcpu, sp, spte, new, bytes, + page_offset & (pte_size - 1)); + mmu_pte_write_flush_tlb(vcpu, entry, *spte); + ++spte; + } + } + kvm_mmu_audit(vcpu, "post pte write"); + spin_unlock(&vcpu->kvm->mmu_lock); + if (vcpu->arch.update_pte.page) { + kvm_release_page_clean(vcpu->arch.update_pte.page); + vcpu->arch.update_pte.page = NULL; + } +} + +int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva) +{ + gpa_t gpa; + int r; + + down_read(¤t->mm->mmap_sem); + gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva); + up_read(¤t->mm->mmap_sem); + + spin_lock(&vcpu->kvm->mmu_lock); + r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT); + spin_unlock(&vcpu->kvm->mmu_lock); + return r; +} + +void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) +{ + while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) { + struct kvm_mmu_page *sp; + + sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev, + struct kvm_mmu_page, link); + kvm_mmu_zap_page(vcpu->kvm, sp); + ++vcpu->kvm->stat.mmu_recycled; + } +} + +int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code) +{ + int r; + enum emulation_result er; + + r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code); + if (r < 0) + goto out; + + if (!r) { + r = 1; + goto out; + } + + r = mmu_topup_memory_caches(vcpu); + if (r) + goto out; + + er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0); + + 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: + return r; +} +EXPORT_SYMBOL_GPL(kvm_mmu_page_fault); + +static void free_mmu_pages(struct kvm_vcpu *vcpu) +{ + struct kvm_mmu_page *sp; + + while (!list_empty(&vcpu->kvm->arch.active_mmu_pages)) { + sp = container_of(vcpu->kvm->arch.active_mmu_pages.next, + struct kvm_mmu_page, link); + kvm_mmu_zap_page(vcpu->kvm, sp); + } + free_page((unsigned long)vcpu->arch.mmu.pae_root); +} + +static int alloc_mmu_pages(struct kvm_vcpu *vcpu) +{ + struct page *page; + int i; + + ASSERT(vcpu); + + if (vcpu->kvm->arch.n_requested_mmu_pages) + vcpu->kvm->arch.n_free_mmu_pages = + vcpu->kvm->arch.n_requested_mmu_pages; + else + vcpu->kvm->arch.n_free_mmu_pages = + vcpu->kvm->arch.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->arch.mmu.pae_root = page_address(page); + for (i = 0; i < 4; ++i) + vcpu->arch.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->arch.mmu.root_hpa)); + + return alloc_mmu_pages(vcpu); +} + +int kvm_mmu_setup(struct kvm_vcpu *vcpu) +{ + ASSERT(vcpu); + ASSERT(!VALID_PAGE(vcpu->arch.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 *sp; + + list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) { + int i; + u64 *pt; + + if (!test_bit(slot, &sp->slot_bitmap)) + continue; + + pt = sp->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 *sp, *node; + + spin_lock(&kvm->mmu_lock); + list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) + kvm_mmu_zap_page(kvm, sp); + spin_unlock(&kvm->mmu_lock); + + 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; +} + +/* + * Caculate mmu pages needed for kvm. + */ +unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm) +{ + int i; + unsigned int nr_mmu_pages; + unsigned int nr_pages = 0; + + for (i = 0; i < kvm->nmemslots; i++) + nr_pages += kvm->memslots[i].npages; + + nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000; + nr_mmu_pages = max(nr_mmu_pages, + (unsigned int) KVM_MIN_ALLOC_MMU_PAGES); + + return nr_mmu_pages; +} + +#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->arch.mmu.root_level, va, level, ent); + + audit_mappings_page(vcpu, ent, va, level - 1); + } else { + gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, va); + struct page *page = gpa_to_page(vcpu, gpa); + hpa_t hpa = page_to_phys(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->arch.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); + kvm_release_page_clean(page); + + } + } +} + +static void audit_mappings(struct kvm_vcpu *vcpu) +{ + unsigned i; + + if (vcpu->arch.mmu.root_level == 4) + audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4); + else + for (i = 0; i < 4; ++i) + if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK) + audit_mappings_page(vcpu, + vcpu->arch.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 *sp; + int i; + + list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) { + u64 *pt = sp->spt; + + if (sp->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 *sp; + struct kvm_memory_slot *slot; + unsigned long *rmapp; + gfn_t gfn; + + list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) { + if (sp->role.metaphysical) + continue; + + slot = gfn_to_memslot(vcpu->kvm, sp->gfn); + gfn = unalias_gfn(vcpu->kvm, sp->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, sp->gfn, + sp->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 |
