diff options
Diffstat (limited to 'drivers/kvm/mmu.c')
| -rw-r--r-- | drivers/kvm/mmu.c | 1454 |
1 files changed, 1454 insertions, 0 deletions
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c new file mode 100644 index 0000000..be79377 --- /dev/null +++ b/drivers/kvm/mmu.c @@ -0,0 +1,1454 @@ +/* + * 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 <linux/types.h> +#include <linux/string.h> +#include <asm/page.h> +#include <linux/mm.h> +#include <linux/highmem.h> +#include <linux/module.h> + +#include "vmx.h" +#include "kvm.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 + +#define ASSERT(x) \ + if (!(x)) { \ + printk(KERN_WARNING "assertion failed %s:%d: %s\n", \ + __FILE__, __LINE__, #x); \ + } + +#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 PT32_PTE_COPY_MASK \ + (PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_DIRTY_MASK | PT_GLOBAL_MASK) + +#define PT64_PTE_COPY_MASK (PT64_NX_MASK | PT32_PTE_COPY_MASK) + +#define PT_FIRST_AVAIL_BITS_SHIFT 9 +#define PT64_SECOND_AVAIL_BITS_SHIFT 52 + +#define PT_SHADOW_PS_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) +#define PT_SHADOW_IO_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) + +#define PT_SHADOW_WRITABLE_SHIFT (PT_FIRST_AVAIL_BITS_SHIFT + 1) +#define PT_SHADOW_WRITABLE_MASK (1ULL << PT_SHADOW_WRITABLE_SHIFT) + +#define PT_SHADOW_USER_SHIFT (PT_SHADOW_WRITABLE_SHIFT + 1) +#define PT_SHADOW_USER_MASK (1ULL << (PT_SHADOW_USER_SHIFT)) + +#define PT_SHADOW_BITS_OFFSET (PT_SHADOW_WRITABLE_SHIFT - PT_WRITABLE_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) & PAGE_MASK) +#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 int is_write_protection(struct kvm_vcpu *vcpu) +{ + return vcpu->cr0 & CR0_WP_MASK; +} + +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_writeble_pte(unsigned long pte) +{ + return pte & PT_WRITABLE_MASK; +} + +static int is_io_pte(unsigned long pte) +{ + return pte & PT_SHADOW_IO_MARK; +} + +static int is_rmap_pte(u64 pte) +{ + return (pte & (PT_WRITABLE_MASK | PT_PRESENT_MASK)) + == (PT_WRITABLE_MASK | PT_PRESENT_MASK); +} + +static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, + size_t objsize, int min) +{ + void *obj; + + if (cache->nobjs >= min) + return 0; + while (cache->nobjs < ARRAY_SIZE(cache->objects)) { + obj = kzalloc(objsize, GFP_NOWAIT); + 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_caches(struct kvm_vcpu *vcpu) +{ + int r; + + r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache, + sizeof(struct kvm_pte_chain), 4); + if (r) + goto out; + r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache, + sizeof(struct kvm_rmap_desc), 1); +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); +} + +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 void mmu_memory_cache_free(struct kvm_mmu_memory_cache *mc, void *obj) +{ + if (mc->nobjs < KVM_NR_MEM_OBJS) + mc->objects[mc->nobjs++] = obj; + else + kfree(obj); +} + +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_vcpu *vcpu, + struct kvm_pte_chain *pc) +{ + mmu_memory_cache_free(&vcpu->mmu_pte_chain_cache, 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_vcpu *vcpu, + struct kvm_rmap_desc *rd) +{ + mmu_memory_cache_free(&vcpu->mmu_rmap_desc_cache, rd); +} + +/* + * Reverse mapping data structures: + * + * If page->private bit zero is zero, then page->private points to the + * shadow page table entry that points to page_address(page). + * + * If page->private bit zero is one, (then page->private & ~1) points + * to a struct kvm_rmap_desc containing more mappings. + */ +static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte) +{ + struct page *page; + struct kvm_rmap_desc *desc; + int i; + + if (!is_rmap_pte(*spte)) + return; + page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT); + if (!page->private) { + rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte); + page->private = (unsigned long)spte; + } else if (!(page->private & 1)) { + rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte); + desc = mmu_alloc_rmap_desc(vcpu); + desc->shadow_ptes[0] = (u64 *)page->private; + desc->shadow_ptes[1] = spte; + page->private = (unsigned long)desc | 1; + } else { + rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte); + desc = (struct kvm_rmap_desc *)(page->private & ~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(struct kvm_vcpu *vcpu, + struct page *page, + 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) + page->private = (unsigned long)desc->shadow_ptes[0]; + else + if (prev_desc) + prev_desc->more = desc->more; + else + page->private = (unsigned long)desc->more | 1; + mmu_free_rmap_desc(vcpu, desc); +} + +static void rmap_remove(struct kvm_vcpu *vcpu, u64 *spte) +{ + struct page *page; + struct kvm_rmap_desc *desc; + struct kvm_rmap_desc *prev_desc; + int i; + + if (!is_rmap_pte(*spte)) + return; + page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT); + if (!page->private) { + printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte); + BUG(); + } else if (!(page->private & 1)) { + rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte); + if ((u64 *)page->private != spte) { + printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n", + spte, *spte); + BUG(); + } + page->private = 0; + } else { + rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte); + desc = (struct kvm_rmap_desc *)(page->private & ~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(vcpu, page, + desc, i, + prev_desc); + return; + } + prev_desc = desc; + desc = desc->more; + } + BUG(); + } +} + +static void rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn) +{ + struct kvm *kvm = vcpu->kvm; + struct page *page; + struct kvm_memory_slot *slot; + struct kvm_rmap_desc *desc; + u64 *spte; + + slot = gfn_to_memslot(kvm, gfn); + BUG_ON(!slot); + page = gfn_to_page(slot, gfn); + + while (page->private) { + if (!(page->private & 1)) + spte = (u64 *)page->private; + else { + desc = (struct kvm_rmap_desc *)(page->private & ~1ul); + spte = desc->shadow_ptes[0]; + } + BUG_ON(!spte); + BUG_ON((*spte & PT64_BASE_ADDR_MASK) != + page_to_pfn(page) << PAGE_SHIFT); + BUG_ON(!(*spte & PT_PRESENT_MASK)); + BUG_ON(!(*spte & PT_WRITABLE_MASK)); + rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte); + rmap_remove(vcpu, spte); + kvm_arch_ops->tlb_flush(vcpu); + *spte &= ~(u64)PT_WRITABLE_MASK; + } +} + +static int is_empty_shadow_page(hpa_t page_hpa) +{ + u64 *pos; + u64 *end; + + for (pos = __va(page_hpa), end = pos + PAGE_SIZE / sizeof(u64); + pos != end; pos++) + if (*pos != 0) { + printk(KERN_ERR "%s: %p %llx\n", __FUNCTION__, + pos, *pos); + return 0; + } + return 1; +} + +static void kvm_mmu_free_page(struct kvm_vcpu *vcpu, hpa_t page_hpa) +{ + struct kvm_mmu_page *page_head = page_header(page_hpa); + + ASSERT(is_empty_shadow_page(page_hpa)); + list_del(&page_head->link); + page_head->page_hpa = page_hpa; + list_add(&page_head->link, &vcpu->free_pages); + ++vcpu->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 (list_empty(&vcpu->free_pages)) + return NULL; + + page = list_entry(vcpu->free_pages.next, struct kvm_mmu_page, link); + list_del(&page->link); + list_add(&page->link, &vcpu->kvm->active_mmu_pages); + ASSERT(is_empty_shadow_page(page->page_hpa)); + page->slot_bitmap = 0; + page->global = 1; + 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_vcpu *vcpu, + 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(vcpu, 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_vcpu *vcpu, + 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 = &vcpu->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, + 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; + 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); + if (!metaphysical) + rmap_write_protect(vcpu, gfn); + return page; +} + +static void kvm_mmu_page_unlink_children(struct kvm_vcpu *vcpu, + struct kvm_mmu_page *page) +{ + unsigned i; + u64 *pt; + u64 ent; + + pt = __va(page->page_hpa); + + if (page->role.level == PT_PAGE_TABLE_LEVEL) { + for (i = 0; i < PT64_ENT_PER_PAGE; ++i) { + if (pt[i] & PT_PRESENT_MASK) + rmap_remove(vcpu, &pt[i]); + pt[i] = 0; + } + kvm_arch_ops->tlb_flush(vcpu); + return; + } + + for (i = 0; i < PT64_ENT_PER_PAGE; ++i) { + ent = pt[i]; + + pt[i] = 0; + if (!(ent & PT_PRESENT_MASK)) + continue; + ent &= PT64_BASE_ADDR_MASK; + mmu_page_remove_parent_pte(vcpu, page_header(ent), &pt[i]); + } +} + +static void kvm_mmu_put_page(struct kvm_vcpu *vcpu, + struct kvm_mmu_page *page, + u64 *parent_pte) +{ + mmu_page_remove_parent_pte(vcpu, page, parent_pte); +} + +static void kvm_mmu_zap_page(struct kvm_vcpu *vcpu, + 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(vcpu, page, parent_pte); + *parent_pte = 0; + } + kvm_mmu_page_unlink_children(vcpu, page); + if (!page->root_count) { + hlist_del(&page->hash_link); + kvm_mmu_free_page(vcpu, page->page_hpa); + } else { + list_del(&page->link); + list_add(&page->link, &vcpu->kvm->active_mmu_pages); + } +} + +static int kvm_mmu_unprotect_page(struct kvm_vcpu *vcpu, 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 = &vcpu->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(vcpu, page); + r = 1; + } + return r; +} + +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 safe_gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa) +{ + hpa_t hpa = gpa_to_hpa(vcpu, gpa); + + return is_error_hpa(hpa) ? bad_page_address | (gpa & ~PAGE_MASK): hpa; +} + +hpa_t gpa_to_hpa(struct kvm_vcpu *vcpu, gpa_t gpa) +{ + struct kvm_memory_slot *slot; + struct page *page; + + ASSERT((gpa & HPA_ERR_MASK) == 0); + slot = gfn_to_memslot(vcpu->kvm, gpa >> PAGE_SHIFT); + if (!slot) + return gpa | HPA_ERR_MASK; + page = gfn_to_page(slot, gpa >> PAGE_SHIFT); + return ((hpa_t)page_to_pfn(page) << PAGE_SHIFT) + | (gpa & (PAGE_SIZE-1)); +} + +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, gpa); +} + +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) { + pte = table[index]; + if (is_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; + rmap_add(vcpu, &table[index]); + return 0; + } + + if (table[index] == 0) { + 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, &table[index]); + if (!new_table) { + pgprintk("nonpaging_map: ENOMEM\n"); + return -ENOMEM; + } + + table[index] = new_table->page_hpa | PT_PRESENT_MASK + | PT_WRITABLE_MASK | PT_USER_MASK; + } + table_addr = table[index] & PT64_BASE_ADDR_MASK; + } +} + +static void mmu_free_roots(struct kvm_vcpu *vcpu) +{ + int i; + struct kvm_mmu_page *page; + +#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 = 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]; + + ASSERT(VALID_PAGE(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, NULL); + root = page->page_hpa; + ++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) + 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), + NULL); + root = page->page_hpa; + ++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 , addr & PT64_BASE_ADDR_MASK); + + if (is_error_hpa(paddr)) + 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->root_level = 0; + context->shadow_root_level = PT32E_ROOT_LEVEL; + mmu_alloc_roots(vcpu); + ASSERT(VALID_PAGE(context->root_hpa)); + kvm_arch_ops->set_cr3(vcpu, context->root_hpa); + return 0; +} + +static void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu) +{ + ++kvm_stat.tlb_flush; + kvm_arch_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); + if (unlikely(vcpu->kvm->n_free_mmu_pages < KVM_MIN_FREE_MMU_PAGES)) + kvm_mmu_free_some_pages(vcpu); + mmu_alloc_roots(vcpu); + kvm_mmu_flush_tlb(vcpu); + kvm_arch_ops->set_cr3(vcpu, vcpu->mmu.root_hpa); +} + +static void mark_pagetable_nonglobal(void *shadow_pte) +{ + page_header(__pa(shadow_pte))->global = 0; +} + +static inline void set_pte_common(struct kvm_vcpu *vcpu, + u64 *shadow_pte, + gpa_t gaddr, + int dirty, + u64 access_bits, + gfn_t gfn) +{ + hpa_t paddr; + + *shadow_pte |= access_bits << PT_SHADOW_BITS_OFFSET; + if (!dirty) + access_bits &= ~PT_WRITABLE_MASK; + + paddr = gpa_to_hpa(vcpu, gaddr & PT64_BASE_ADDR_MASK); + + *shadow_pte |= access_bits; + + if (!(*shadow_pte & PT_GLOBAL_MASK)) + mark_pagetable_nonglobal(shadow_pte); + + if (is_error_hpa(paddr)) { + *shadow_pte |= gaddr; + *shadow_pte |= PT_SHADOW_IO_MARK; + *shadow_pte &= ~PT_PRESENT_MASK; + return; + } + + *shadow_pte |= paddr; + + if (access_bits & PT_WRITABLE_MASK) { + struct kvm_mmu_page *shadow; + + shadow = kvm_mmu_lookup_page(vcpu, gfn); + if (shadow) { + pgprintk("%s: found shadow page for %lx, marking ro\n", + __FUNCTION__, gfn); + access_bits &= ~PT_WRITABLE_MASK; + if (is_writeble_pte(*shadow_pte)) { + *shadow_pte &= ~PT_WRITABLE_MASK; + kvm_arch_ops->tlb_flush(vcpu); + } + } + } + + if (access_bits & PT_WRITABLE_MASK) + mark_page_dirty(vcpu->kvm, gaddr >> PAGE_SHIFT); + + page_header_update_slot(vcpu->kvm, shadow_pte, gaddr); + rmap_add(vcpu, shadow_pte); +} + +static void inject_page_fault(struct kvm_vcpu *vcpu, + u64 addr, + u32 err_code) +{ + kvm_arch_ops->inject_page_fault(vcpu, addr, err_code); +} + +static inline int fix_read_pf(u64 *shadow_ent) +{ + if ((*shadow_ent & PT_SHADOW_USER_MASK) && + !(*shadow_ent & PT_USER_MASK)) { + /* + * If supervisor write protect is disabled, we shadow kernel + * pages as user pages so we can trap the write access. + */ + *shadow_ent |= PT_USER_MASK; + *shadow_ent &= ~PT_WRITABLE_MASK; + + return 1; + + } + return 0; +} + +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->free = paging_free; + context->root_level = level; + context->shadow_root_level = level; + mmu_alloc_roots(vcpu); + ASSERT(VALID_PAGE(context->root_hpa)); + kvm_arch_ops->set_cr3(vcpu, context->root_hpa | + (vcpu->cr3 & (CR3_PCD_MASK | CR3_WPT_MASK))); + 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->root_level = PT32_ROOT_LEVEL; + context->shadow_root_level = PT32E_ROOT_LEVEL; + mmu_alloc_roots(vcpu); + ASSERT(VALID_PAGE(context->root_hpa)); + kvm_arch_ops->set_cr3(vcpu, context->root_hpa | + (vcpu->cr3 & (CR3_PCD_MASK | CR3_WPT_MASK))); + 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) +{ + int r; + + destroy_kvm_mmu(vcpu); + r = init_kvm_mmu(vcpu); + if (r < 0) + goto out; + r = mmu_topup_memory_caches(vcpu); +out: + return r; +} + +void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + struct kvm_mmu_page *page; + struct kvm_mmu_page *child; + struct hlist_node *node, *n; + struct hlist_head *bucket; + unsigned index; + u64 *spte; + u64 pte; + unsigned offset = offset_in_page(gpa); + unsigned pte_size; + unsigned page_offset; + unsigned misaligned; + int level; + int flooded = 0; + + pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes); + if (gfn == vcpu->last_pt_write_gfn) { + ++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; + } + 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); + 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, page); + continue; + } + page_offset = offset; + level = page->role.level; + if (page->role.glevels == PT32_ROOT_LEVEL) { + page_offset <<= 1; /* 32->64 */ + page_offset &= ~PAGE_MASK; + } + spte = __va(page->page_hpa); + spte += page_offset / sizeof(*spte); + pte = *spte; + if (is_present_pte(pte)) { + if (level == PT_PAGE_TABLE_LEVEL) + rmap_remove(vcpu, spte); + else { + child = page_header(pte & PT64_BASE_ADDR_MASK); + mmu_page_remove_parent_pte(vcpu, child, spte); + } + } + *spte = 0; + } +} + +void kvm_mmu_post_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes) +{ +} + +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, 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, page); + } +} +EXPORT_SYMBOL_GPL(kvm_mmu_free_some_pages); + +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, page); + } + while (!list_empty(&vcpu->free_pages)) { + page = list_entry(vcpu->free_pages.next, + struct kvm_mmu_page, link); + list_del(&page->link); + __free_page(pfn_to_page(page->page_hpa >> PAGE_SHIFT)); + page->page_hpa = INVALID_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); + + for (i = 0; i < KVM_NUM_MMU_PAGES; i++) { + struct kvm_mmu_page *page_header = &vcpu->page_header_buf[i]; + + INIT_LIST_HEAD(&page_header->link); + if ((page = alloc_page(GFP_KERNEL)) == NULL) + goto error_1; + page->private = (unsigned long)page_header; + page_header->page_hpa = (hpa_t)page_to_pfn(page) << PAGE_SHIFT; + memset(__va(page_header->page_hpa), 0, PAGE_SIZE); + list_add(&page_header->link, &vcpu->free_pages); + ++vcpu->kvm->n_free_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)); + ASSERT(list_empty(&vcpu->free_pages)); + + return alloc_mmu_pages(vcpu); +} + +int kvm_mmu_setup(struct kvm_vcpu *vcpu) +{ + ASSERT(vcpu); + ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa)); + ASSERT(!list_empty(&vcpu->free_pages)); + + 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_vcpu *vcpu, int slot) +{ + struct kvm *kvm = vcpu->kvm; + 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 = __va(page->page_hpa); + for (i = 0; i < PT64_ENT_PER_PAGE; ++i) + /* avoid RMW */ + if (pt[i] & PT_WRITABLE_MASK) { + rmap_remove(vcpu, &pt[i]); + pt[i] &= ~PT_WRITABLE_MASK; + } + } +} + +#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 & PT_PRESENT_MASK) + continue; + + va = canonicalize(va); + if (level > 1) + 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); + + if ((ent & PT_PRESENT_MASK) + && (ent & PT64_BASE_ADDR_MASK) != hpa) + printk(KERN_ERR "audit error: (%s) levels %d" + " gva %lx gpa %llx hpa %llx ent %llx\n", + audit_msg, vcpu->mmu.root_level, + va, gpa, hpa, ent); + } + } +} + +static void audit_mappings(struct kvm_vcpu *vcpu) +{ + int 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) { + struct page *page = m->phys_mem[j]; + + if (!page->private) + continue; + if (!(page->private & 1)) { + ++nmaps; + continue; + } + d = (struct kvm_rmap_desc *)(page->private & ~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 = __va(page->page_hpa); + + 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; + + list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) { + hfn_t hfn; + struct page *pg; + + if (page->role.metaphysical) + continue; + + hfn = gpa_to_hpa(vcpu, (gpa_t)page->gfn << PAGE_SHIFT) + >> PAGE_SHIFT; + pg = pfn_to_page(hfn); + if (pg->private) + 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 |