/* * Kernel-based Virtual Machine driver for Linux * * This module enables machines with Intel VT-x extensions to run virtual * machines without emulation or binary translation. * * MMU support * * Copyright (C) 2006 Qumranet, Inc. * Copyright 2010 Red Hat, Inc. and/or its affiliates. * * Authors: * Yaniv Kamay * Avi Kivity * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * */ #include "irq.h" #include "mmu.h" #include "x86.h" #include "kvm_cache_regs.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * When setting this variable to true it enables Two-Dimensional-Paging * where the hardware walks 2 page tables: * 1. the guest-virtual to guest-physical * 2. while doing 1. it walks guest-physical to host-physical * If the hardware supports that we don't need to do shadow paging. */ bool tdp_enabled = false; enum { AUDIT_PRE_PAGE_FAULT, AUDIT_POST_PAGE_FAULT, AUDIT_PRE_PTE_WRITE, AUDIT_POST_PTE_WRITE, AUDIT_PRE_SYNC, AUDIT_POST_SYNC }; #undef MMU_DEBUG #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 #ifdef MMU_DEBUG static bool dbg = 0; module_param(dbg, bool, 0644); #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 PTE_PREFETCH_NUM 8 #define PT_FIRST_AVAIL_BITS_SHIFT 9 #define PT64_SECOND_AVAIL_BITS_SHIFT 52 #define PT64_LEVEL_BITS 9 #define PT64_LEVEL_SHIFT(level) \ (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS) #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_LVL_OFFSET_MASK(level) \ (PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \ * PT32_LEVEL_BITS))) - 1)) #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 PT64_LVL_ADDR_MASK(level) \ (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \ * PT64_LEVEL_BITS))) - 1)) #define PT64_LVL_OFFSET_MASK(level) \ (PT64_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \ * 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 PT32_LVL_ADDR_MASK(level) \ (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \ * PT32_LEVEL_BITS))) - 1)) #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \ | PT64_NX_MASK) #define PTE_LIST_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) #include #define CREATE_TRACE_POINTS #include "mmutrace.h" #define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level) struct pte_list_desc { u64 *sptes[PTE_LIST_EXT]; struct pte_list_desc *more; }; struct kvm_shadow_walk_iterator { u64 addr; hpa_t shadow_addr; u64 *sptep; int level; unsigned index; }; #define for_each_shadow_entry(_vcpu, _addr, _walker) \ for (shadow_walk_init(&(_walker), _vcpu, _addr); \ shadow_walk_okay(&(_walker)); \ shadow_walk_next(&(_walker))) #define for_each_shadow_entry_lockless(_vcpu, _addr, _walker, spte) \ for (shadow_walk_init(&(_walker), _vcpu, _addr); \ shadow_walk_okay(&(_walker)) && \ ({ spte = mmu_spte_get_lockless(_walker.sptep); 1; }); \ __shadow_walk_next(&(_walker), spte)) static struct kmem_cache *pte_list_desc_cache; static struct kmem_cache *mmu_page_header_cache; static struct percpu_counter kvm_total_used_mmu_pages; static u64 __read_mostly shadow_nx_mask; static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */ static u64 __read_mostly shadow_user_mask; static u64 __read_mostly shadow_accessed_mask; static u64 __read_mostly shadow_dirty_mask; static u64 __read_mostly shadow_mmio_mask; static void mmu_spte_set(u64 *sptep, u64 spte); void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask) { shadow_mmio_mask = mmio_mask; } EXPORT_SYMBOL_GPL(kvm_mmu_set_mmio_spte_mask); static void mark_mmio_spte(u64 *sptep, u64 gfn, unsigned access) { access &= ACC_WRITE_MASK | ACC_USER_MASK; trace_mark_mmio_spte(sptep, gfn, access); mmu_spte_set(sptep, shadow_mmio_mask | access | gfn << PAGE_SHIFT); } static bool is_mmio_spte(u64 spte) { return (spte & shadow_mmio_mask) == shadow_mmio_mask; } static gfn_t get_mmio_spte_gfn(u64 spte) { return (spte & ~shadow_mmio_mask) >> PAGE_SHIFT; } static unsigned get_mmio_spte_access(u64 spte) { return (spte & ~shadow_mmio_mask) & ~PAGE_MASK; } static bool set_mmio_spte(u64 *sptep, gfn_t gfn, pfn_t pfn, unsigned access) { if (unlikely(is_noslot_pfn(pfn))) { mark_mmio_spte(sptep, gfn, access); return true; } return false; } static inline u64 rsvd_bits(int s, int e) { return ((1ULL << (e - s + 1)) - 1) << s; } void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask, u64 dirty_mask, u64 nx_mask, u64 x_mask) { shadow_user_mask = user_mask; shadow_accessed_mask = accessed_mask; shadow_dirty_mask = dirty_mask; shadow_nx_mask = nx_mask; shadow_x_mask = x_mask; } EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes); static int is_cpuid_PSE36(void) { return 1; } static int is_nx(struct kvm_vcpu *vcpu) { return vcpu->arch.efer & EFER_NX; } static int is_shadow_present_pte(u64 pte) { return pte & PT_PRESENT_MASK && !is_mmio_spte(pte); } static int is_large_pte(u64 pte) { return pte & PT_PAGE_SIZE_MASK; } static int is_dirty_gpte(unsigned long pte) { return pte & PT_DIRTY_MASK; } static int is_rmap_spte(u64 pte) { return is_shadow_present_pte(pte); } static int is_last_spte(u64 pte, int level) { if (level == PT_PAGE_TABLE_LEVEL) return 1; if (is_large_pte(pte)) return 1; return 0; } static pfn_t spte_to_pfn(u64 pte) { return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT; } static gfn_t pse36_gfn_delta(u32 gpte) { int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT; return (gpte & PT32_DIR_PSE36_MASK) << shift; } #ifdef CONFIG_X86_64 static void __set_spte(u64 *sptep, u64 spte) { *sptep = spte; } static void __update_clear_spte_fast(u64 *sptep, u64 spte) { *sptep = spte; } static u64 __update_clear_spte_slow(u64 *sptep, u64 spte) { return xchg(sptep, spte); } static u64 __get_spte_lockless(u64 *sptep) { return ACCESS_ONCE(*sptep); } static bool __check_direct_spte_mmio_pf(u64 spte) { /* It is valid if the spte is zapped. */ return spte == 0ull; } #else union split_spte { struct { u32 spte_low; u32 spte_high; }; u64 spte; }; static void count_spte_clear(u64 *sptep, u64 spte) { struct kvm_mmu_page *sp = page_header(__pa(sptep)); if (is_shadow_present_pte(spte)) return; /* Ensure the spte is completely set before we increase the count */ smp_wmb(); sp->clear_spte_count++; } static void __set_spte(u64 *sptep, u64 spte) { union split_spte *ssptep, sspte; ssptep = (union split_spte *)sptep; sspte = (union split_spte)spte; ssptep->spte_high = sspte.spte_high; /* * If we map the spte from nonpresent to present, We should store * the high bits firstly, then set present bit, so cpu can not * fetch this spte while we are setting the spte. */ smp_wmb(); ssptep->spte_low = sspte.spte_low; } static void __update_clear_spte_fast(u64 *sptep, u64 spte) { union split_spte *ssptep, sspte; ssptep = (union split_spte *)sptep; sspte = (union split_spte)spte; ssptep->spte_low = sspte.spte_low; /* * If we map the spte from present to nonpresent, we should clear * present bit firstly to avoid vcpu fetch the old high bits. */ smp_wmb(); ssptep->spte_high = sspte.spte_high; count_spte_clear(sptep, spte); } static u64 __update_clear_spte_slow(u64 *sptep, u64 spte) { union split_spte *ssptep, sspte, orig; ssptep = (union split_spte *)sptep; sspte = (union split_spte)spte; /* xchg acts as a barrier before the setting of the high bits */ orig.spte_low = xchg(&ssptep->spte_low, sspte.spte_low); orig.spte_high = ssptep->spte_high; ssptep->spte_high = sspte.spte_high; count_spte_clear(sptep, spte); return orig.spte; } /* * The idea using the light way get the spte on x86_32 guest is from * gup_get_pte(arch/x86/mm/gup.c). * The difference is we can not catch the spte tlb flush if we leave * guest mode, so we emulate it by increase clear_spte_count when spte * is cleared. */ static u64 __get_spte_lockless(u64 *sptep) { struct kvm_mmu_page *sp = page_header(__pa(sptep)); union split_spte spte, *orig = (union split_spte *)sptep; int count; retry: count = sp->clear_spte_count; smp_rmb(); spte.spte_low = orig->spte_low; smp_rmb(); spte.spte_high = orig->spte_high; smp_rmb(); if (unlikely(spte.spte_low != orig->spte_low || count != sp->clear_spte_count)) goto retry; return spte.spte; } static bool __check_direct_spte_mmio_pf(u64 spte) { union split_spte sspte = (union split_spte)spte; u32 high_mmio_mask = shadow_mmio_mask >> 32; /* It is valid if the spte is zapped. */ if (spte == 0ull) return true; /* It is valid if the spte is being zapped. */ if (sspte.spte_low == 0ull && (sspte.spte_high & high_mmio_mask) == high_mmio_mask) return true; return false; } #endif static bool spte_has_volatile_bits(u64 spte) { if (!shadow_accessed_mask) return false; if (!is_shadow_present_pte(spte)) return false; if ((spte & shadow_accessed_mask) && (!is_writable_pte(spte) || (spte & shadow_dirty_mask))) return false; return true; } static bool spte_is_bit_cleared(u64 old_spte, u64 new_spte, u64 bit_mask) { return (old_spte & bit_mask) && !(new_spte & bit_mask); } /* Rules for using mmu_spte_set: * Set the sptep from nonpresent to present. * Note: the sptep being assigned *must* be either not present * or in a state where the hardware will not attempt to update * the spte. */ static void mmu_spte_set(u64 *sptep, u64 new_spte) { WARN_ON(is_shadow_present_pte(*sptep)); __set_spte(sptep, new_spte); } /* Rules for using mmu_spte_update: * Update the state bits, it means the mapped pfn is not changged. */ static void mmu_spte_update(u64 *sptep, u64 new_spte) { u64 mask, old_spte = *sptep; WARN_ON(!is_rmap_spte(new_spte)); if (!is_shadow_present_pte(old_spte)) return mmu_spte_set(sptep, new_spte); new_spte |= old_spte & shadow_dirty_mask; mask = shadow_accessed_mask; if (is_writable_pte(old_spte)) mask |= shadow_dirty_mask; if (!spte_has_volatile_bits(old_spte) || (new_spte & mask) == mask) __update_clear_spte_fast(sptep, new_spte); else old_spte = __update_clear_spte_slow(sptep, new_spte); if (!shadow_accessed_mask) return; if (spte_is_bit_cleared(old_spte, new_spte, shadow_accessed_mask)) kvm_set_pfn_accessed(spte_to_pfn(old_spte)); if (spte_is_bit_cleared(old_spte, new_spte, shadow_dirty_mask)) kvm_set_pfn_dirty(spte_to_pfn(old_spte)); } /* * Rules for using mmu_spte_clear_track_bits: * It sets the sptep from present to nonpresent, and track the * state bits, it is used to clear the last level sptep. */ static int mmu_spte_clear_track_bits(u64 *sptep) { pfn_t pfn; u64 old_spte = *sptep; if (!spte_has_volatile_bits(old_spte)) __update_clear_spte_fast(sptep, 0ull); else old_spte = __update_clear_spte_slow(sptep, 0ull); if (!is_rmap_spte(old_spte)) return 0; pfn = spte_to_pfn(old_spte); if (!shadow_accessed_mask || old_spte & shadow_accessed_mask) kvm_set_pfn_accessed(pfn); if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask)) kvm_set_pfn_dirty(pfn); return 1; } /* * Rules for using mmu_spte_clear_no_track: * Directly clear spte without caring the state bits of sptep, * it is used to set the upper level spte. */ static void mmu_spte_clear_no_track(u64 *sptep) { __update_clear_spte_fast(sptep, 0ull); } static u64 mmu_spte_get_lockless(u64 *sptep) { return __get_spte_lockless(sptep); } static void walk_shadow_page_lockless_begin(struct kvm_vcpu *vcpu) { rcu_read_lock(); atomic_inc(&vcpu->kvm->arch.reader_counter); /* Increase the counter before walking shadow page table */ smp_mb__after_atomic_inc(); } static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu) { /* Decrease the counter after walking shadow page table finished */ smp_mb__before_atomic_dec(); atomic_dec(&vcpu->kvm->arch.reader_counter); rcu_read_unlock(); } 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 int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache) { return cache->nobjs; } static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc, struct kmem_cache *cache) { while (mc->nobjs) kmem_cache_free(cache, mc->objects[--mc->nobjs]); } static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache, int min) { void *page; if (cache->nobjs >= min) return 0; while (cache->nobjs < ARRAY_SIZE(cache->objects)) { page = (void *)__get_free_page(GFP_KERNEL); if (!page) return -ENOMEM; cache->objects[cache->nobjs++] = 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_list_desc_cache, pte_list_desc_cache, 8 + PTE_PREFETCH_NUM); 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_list_desc_cache, pte_list_desc_cache); mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache); mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache, 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]; return p; } static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu) { return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache, sizeof(struct pte_list_desc)); } static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc) { kmem_cache_free(pte_list_desc_cache, pte_list_desc); } static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index) { if (!sp->role.direct) return sp->gfns[index]; return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS)); } static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn) { if (sp->role.direct) BUG_ON(gfn != kvm_mmu_page_get_gfn(sp, index)); else sp->gfns[index] = gfn; } /* * Return the pointer to the large page information for a given gfn, * handling slots that are not large page aligned. */ static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn, struct kvm_memory_slot *slot, int level) { unsigned long idx; idx = (gfn >> KVM_HPAGE_GFN_SHIFT(level)) - (slot->base_gfn >> KVM_HPAGE_GFN_SHIFT(level)); return &slot->lpage_info[level - 2][idx]; } static void account_shadowed(struct kvm *kvm, gfn_t gfn) { struct kvm_memory_slot *slot; struct kvm_lpage_info *linfo; int i; slot = gfn_to_memslot(kvm, gfn); for (i = PT_DIRECTORY_LEVEL; i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) { linfo = lpage_info_slot(gfn, slot, i); linfo->write_count += 1; } kvm->arch.indirect_shadow_pages++; } static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn) { struct kvm_memory_slot *slot; struct kvm_lpage_info *linfo; int i; slot = gfn_to_memslot(kvm, gfn); for (i = PT_DIRECTORY_LEVEL; i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) { linfo = lpage_info_slot(gfn, slot, i); linfo->write_count -= 1; WARN_ON(linfo->write_count < 0); } kvm->arch.indirect_shadow_pages--; } static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn, int level) { struct kvm_memory_slot *slot; struct kvm_lpage_info *linfo; slot = gfn_to_memslot(kvm, gfn); if (slot) { linfo = lpage_info_slot(gfn, slot, level); return linfo->write_count; } return 1; } static int host_mapping_level(struct kvm *kvm, gfn_t gfn) { unsigned long page_size; int i, ret = 0; page_size = kvm_host_page_size(kvm, gfn); for (i = PT_PAGE_TABLE_LEVEL; i < (PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES); ++i) { if (page_size >= KVM_HPAGE_SIZE(i)) ret = i; else break; } return ret; } static struct kvm_memory_slot * gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn, bool no_dirty_log) { struct kvm_memory_slot *slot; slot = gfn_to_memslot(vcpu->kvm, gfn); if (!slot || slot->flags & KVM_MEMSLOT_INVALID || (no_dirty_log && slot->dirty_bitmap)) slot = NULL; return slot; } static bool mapping_level_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t large_gfn) { return !gfn_to_memslot_dirty_bitmap(vcpu, large_gfn, true); } static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn) { int host_level, level, max_level; host_level = host_mapping_level(vcpu->kvm, large_gfn); if (host_level == PT_PAGE_TABLE_LEVEL) return host_level; max_level = kvm_x86_ops->get_lpage_level() < host_level ? kvm_x86_ops->get_lpage_level() : host_level; for (level = PT_DIRECTORY_LEVEL; level <= max_level; ++level) if (has_wrprotected_page(vcpu->kvm, large_gfn, level)) break; return level - 1; } /* * Pte mapping structures: * * If pte_list bit zero is zero, then pte_list point to the spte. * * If pte_list bit zero is one, (then pte_list & ~1) points to a struct * pte_list_desc containing more mappings. * * Returns the number of pte entries before the spte was added or zero if * the spte was not added. * */ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, unsigned long *pte_list) { struct pte_list_desc *desc; int i, count = 0; if (!*pte_list) { rmap_printk("pte_list_add: %p %llx 0->1\n", spte, *spte); *pte_list = (unsigned long)spte; } else if (!(*pte_list & 1)) { rmap_printk("pte_list_add: %p %llx 1->many\n", spte, *spte); desc = mmu_alloc_pte_list_desc(vcpu); desc->sptes[0] = (u64 *)*pte_list; desc->sptes[1] = spte; *pte_list = (unsigned long)desc | 1; ++count; } else { rmap_printk("pte_list_add: %p %llx many->many\n", spte, *spte); desc = (struct pte_list_desc *)(*pte_list & ~1ul); while (desc->sptes[PTE_LIST_EXT-1] && desc->more) { desc = desc->more; count += PTE_LIST_EXT; } if (desc->sptes[PTE_LIST_EXT-1]) { desc->more = mmu_alloc_pte_list_desc(vcpu); desc = desc->more; } for (i = 0; desc->sptes[i]; ++i) ++count; desc->sptes[i] = spte; } return count; } static u64 *pte_list_next(unsigned long *pte_list, u64 *spte) { struct pte_list_desc *desc; u64 *prev_spte; int i; if (!*pte_list) return NULL; else if (!(*pte_list & 1)) { if (!spte) return (u64 *)*pte_list; return NULL; } desc = (struct pte_list_desc *)(*pte_list & ~1ul); prev_spte = NULL; while (desc) { for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i) { if (prev_spte == spte) return desc->sptes[i]; prev_spte = desc->sptes[i]; } desc = desc->more; } return NULL; } static void pte_list_desc_remove_entry(unsigned long *pte_list, struct pte_list_desc *desc, int i, struct pte_list_desc *prev_desc) { int j; for (j = PTE_LIST_EXT - 1; !desc->sptes[j] && j > i; --j) ; desc->sptes[i] = desc->sptes[j]; desc->sptes[j] = NULL; if (j != 0) return; if (!prev_desc && !desc->more) *pte_list = (unsigned long)desc->sptes[0]; else if (prev_desc) prev_desc->more = desc->more; else *pte_list = (unsigned long)desc->more | 1; mmu_free_pte_list_desc(desc); } static void pte_list_remove(u64 *spte, unsigned long *pte_list) { struct pte_list_desc *desc; struct pte_list_desc *prev_desc; int i; if (!*pte_list) { printk(KERN_ERR "pte_list_remove: %p 0->BUG\n", spte); BUG(); } else if (!(*pte_list & 1)) { rmap_printk("pte_list_remove: %p 1->0\n", spte); if ((u64 *)*pte_list != spte) { printk(KERN_ERR "pte_list_remove: %p 1->BUG\n", spte); BUG(); } *pte_list = 0; } else { rmap_printk("pte_list_remove: %p many->many\n", spte); desc = (struct pte_list_desc *)(*pte_list & ~1ul); prev_desc = NULL; while (desc) { for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i) if (desc->sptes[i] == spte) { pte_list_desc_remove_entry(pte_list, desc, i, prev_desc); return; } prev_desc = desc; desc = desc->more; } pr_err("pte_list_remove: %p many->many\n", spte); BUG(); } } typedef void (*pte_list_walk_fn) (u64 *spte); static void pte_list_walk(unsigned long *pte_list, pte_list_walk_fn fn) { struct pte_list_desc *desc; int i; if (!*pte_list) return; if (!(*pte_list & 1)) return fn((u64 *)*pte_list); desc = (struct pte_list_desc *)(*pte_list & ~1ul); while (desc) { for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i) fn(desc->sptes[i]); desc = desc->more; } } static unsigned long *__gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level, struct kvm_memory_slot *slot) { struct kvm_lpage_info *linfo; if (likely(level == PT_PAGE_TABLE_LEVEL)) return &slot->rmap[gfn - slot->base_gfn]; linfo = lpage_info_slot(gfn, slot, level); return &linfo->rmap_pde; } /* * Take gfn and return the reverse mapping to it. */ static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level) { struct kvm_memory_slot *slot; slot = gfn_to_memslot(kvm, gfn); return __gfn_to_rmap(kvm, gfn, level, slot); } static bool rmap_can_add(struct kvm_vcpu *vcpu) { struct kvm_mmu_memory_cache *cache; cache = &vcpu->arch.mmu_pte_list_desc_cache; return mmu_memory_cache_free_objects(cache); } static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn) { struct kvm_mmu_page *sp; unsigned long *rmapp; sp = page_header(__pa(spte)); kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn); rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level); return pte_list_add(vcpu, spte, rmapp); } static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte) { return pte_list_next(rmapp, spte); } static void rmap_remove(struct kvm *kvm, u64 *spte) { struct kvm_mmu_page *sp; gfn_t gfn; unsigned long *rmapp; sp = page_header(__pa(spte)); gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt); rmapp = gfn_to_rmap(kvm, gfn, sp->role.level); pte_list_remove(spte, rmapp); } static void drop_spte(struct kvm *kvm, u64 *sptep) { if (mmu_spte_clear_track_bits(sptep)) rmap_remove(kvm, sptep); } int kvm_mmu_rmap_write_protect(struct kvm *kvm, u64 gfn, struct kvm_memory_slot *slot) { unsigned long *rmapp; u64 *spte; int i, write_protected = 0; rmapp = __gfn_to_rmap(kvm, gfn, PT_PAGE_TABLE_LEVEL, slot); spte = rmap_next(kvm, rmapp, NULL); while (spte) { BUG_ON(!(*spte & PT_PRESENT_MASK)); rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte); if (is_writable_pte(*spte)) { mmu_spte_update(spte, *spte & ~PT_WRITABLE_MASK); write_protected = 1; } spte = rmap_next(kvm, rmapp, spte); } /* check for huge page mappings */ for (i = PT_DIRECTORY_LEVEL; i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) { rmapp = __gfn_to_rmap(kvm, gfn, i, slot); spte = rmap_next(kvm, rmapp, NULL); while (spte) { BUG_ON(!(*spte & PT_PRESENT_MASK)); BUG_ON(!is_large_pte(*spte)); pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn); if (is_writable_pte(*spte)) { drop_spte(kvm, spte); --kvm->stat.lpages; spte = NULL; write_protected = 1; } spte = rmap_next(kvm, rmapp, spte); } } return write_protected; } static int rmap_write_protect(struct kvm *kvm, u64 gfn) { struct kvm_memory_slot *slot; slot = gfn_to_memslot(kvm, gfn); return kvm_mmu_rmap_write_protect(kvm, gfn, slot); } static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp, unsigned long data) { u64 *spte; int need_tlb_flush = 0; while ((spte = rmap_next(kvm, rmapp, NULL))) { BUG_ON(!(*spte & PT_PRESENT_MASK)); rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte); drop_spte(kvm, spte); need_tlb_flush = 1; } return need_tlb_flush; } static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp, unsigned long data) { int need_flush = 0; u64 *spte, new_spte; pte_t *ptep = (pte_t *)data; pfn_t new_pfn; WARN_ON(pte_huge(*ptep)); new_pfn = pte_pfn(*ptep); spte = rmap_next(kvm, rmapp, NULL); while (spte) { BUG_ON(!is_shadow_present_pte(*spte)); rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", spte, *spte); need_flush = 1; if (pte_write(*ptep)) { drop_spte(kvm, spte); spte = rmap_next(kvm, rmapp, NULL); } else { new_spte = *spte &~ (PT64_BASE_ADDR_MASK); new_spte |= (u64)new_pfn << PAGE_SHIFT; new_spte &= ~PT_WRITABLE_MASK; new_spte &= ~SPTE_HOST_WRITEABLE; new_spte &= ~shadow_accessed_mask; mmu_spte_clear_track_bits(spte); mmu_spte_set(spte, new_spte); spte = rmap_next(kvm, rmapp, spte); } } if (need_flush) kvm_flush_remote_tlbs(kvm); return 0; } static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, unsigned long data, int (*handler)(struct kvm *kvm, unsigned long *rmapp, unsigned long data)) { int j; int ret; int retval = 0; struct kvm_memslots *slots; struct kvm_memory_slot *memslot; slots = kvm_memslots(kvm); kvm_for_each_memslot(memslot, slots) { unsigned long start = memslot->userspace_addr; unsigned long end; end = start + (memslot->npages << PAGE_SHIFT); if (hva >= start && hva < end) { gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT; gfn_t gfn = memslot->base_gfn + gfn_offset; ret = handler(kvm, &memslot->rmap[gfn_offset], data); for (j = 0; j < KVM_NR_PAGE_SIZES - 1; ++j) { struct kvm_lpage_info *linfo; linfo = lpage_info_slot(gfn, memslot, PT_DIRECTORY_LEVEL + j); ret |= handler(kvm, &linfo->rmap_pde, data); } trace_kvm_age_page(hva, memslot, ret); retval |= ret; } } return retval; } int kvm_unmap_hva(struct kvm *kvm, unsigned long hva) { return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp); } void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte) { kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp); } static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp, unsigned long data) { u64 *spte; int young = 0; /* * Emulate the accessed bit for EPT, by checking if this page has * an EPT mapping, and clearing it if it does. On the next access, * a new EPT mapping will be established. * This has some overhead, but not as much as the cost of swapping * out actively used pages or breaking up actively used hugepages. */ if (!shadow_accessed_mask) return kvm_unmap_rmapp(kvm, rmapp, data); spte = rmap_next(kvm, rmapp, NULL); while (spte) { int _young; u64 _spte = *spte; BUG_ON(!(_spte & PT_PRESENT_MASK)); _young = _spte & PT_ACCESSED_MASK; if (_young) { young = 1; clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte); } spte = rmap_next(kvm, rmapp, spte); } return young; } static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp, unsigned long data) { u64 *spte; int young = 0; /* * If there's no access bit in the secondary pte set by the * hardware it's up to gup-fast/gup to set the access bit in * the primary pte or in the page structure. */ if (!shadow_accessed_mask) goto out; spte = rmap_next(kvm, rmapp, NULL); while (spte) { u64 _spte = *spte; BUG_ON(!(_spte & PT_PRESENT_MASK)); young = _spte & PT_ACCESSED_MASK; if (young) { young = 1; break; } spte = rmap_next(kvm, rmapp, spte); } out: return young; } #define RMAP_RECYCLE_THRESHOLD 1000 static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn) { unsigned long *rmapp; struct kvm_mmu_page *sp; sp = page_header(__pa(spte)); rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level); kvm_unmap_rmapp(vcpu->kvm, rmapp, 0); kvm_flush_remote_tlbs(vcpu->kvm); } int kvm_age_hva(struct kvm *kvm, unsigned long hva) { return kvm_handle_hva(kvm, hva, 0, kvm_age_rmapp); } int kvm_test_age_hva(struct kvm *kvm, unsigned long hva) { return kvm_handle_hva(kvm, hva, 0, kvm_test_age_rmapp); } #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 (is_shadow_present_pte(*pos)) { printk(KERN_ERR "%s: %p %llx\n", __func__, pos, *pos); return 0; } return 1; } #endif /* * This value is the sum of all of the kvm instances's * kvm->arch.n_used_mmu_pages values. We need a global, * aggregate version in order to make the slab shrinker * faster */ static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr) { kvm->arch.n_used_mmu_pages += nr; percpu_counter_add(&kvm_total_used_mmu_pages, nr); } /* * Remove the sp from shadow page cache, after call it, * we can not find this sp from the cache, and the shadow * page table is still valid. * It should be under the protection of mmu lock. */ static void kvm_mmu_isolate_page(struct kvm_mmu_page *sp) { ASSERT(is_empty_shadow_page(sp->spt)); hlist_del(&sp->hash_link); if (!sp->role.direct) free_page((unsigned long)sp->gfns); } /* * Free the shadow page table and the sp, we can do it * out of the protection of mmu lock. */ static void kvm_mmu_free_page(struct kvm_mmu_page *sp) { list_del(&sp->link); free_page((unsigned long)sp->spt); kmem_cache_free(mmu_page_header_cache, sp); } static unsigned kvm_page_table_hashfn(gfn_t gfn) { return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1); } static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 *parent_pte) { if (!parent_pte) return; pte_list_add(vcpu, parent_pte, &sp->parent_ptes); } static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp, u64 *parent_pte) { pte_list_remove(parent_pte, &sp->parent_ptes); } static void drop_parent_pte(struct kvm_mmu_page *sp, u64 *parent_pte) { mmu_page_remove_parent_pte(sp, parent_pte); mmu_spte_clear_no_track(parent_pte); } static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, u64 *parent_pte, int direct) { 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); if (!direct) 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); bitmap_zero(sp->slot_bitmap, KVM_MEM_SLOTS_NUM); sp->parent_ptes = 0; mmu_page_add_parent_pte(vcpu, sp, parent_pte); kvm_mod_used_mmu_pages(vcpu->kvm, +1); return sp; } static void mark_unsync(u64 *spte); static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp) { pte_list_walk(&sp->parent_ptes, mark_unsync); } static void mark_unsync(u64 *spte) { struct kvm_mmu_page *sp; unsigned int index; sp = page_header(__pa(spte)); index = spte - sp->spt; if (__test_and_set_bit(index, sp->unsync_child_bitmap)) return; if (sp->unsync_children++) return; kvm_mmu_mark_parents_unsync(sp); } static int nonpaging_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) { return 1; } static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva) { } static void nonpaging_update_pte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 *spte, const void *pte) { WARN_ON(1); } #define KVM_PAGE_ARRAY_NR 16 struct kvm_mmu_pages { struct mmu_page_and_offset { struct kvm_mmu_page *sp; unsigned int idx; } page[KVM_PAGE_ARRAY_NR]; unsigned int nr; }; static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp, int idx) { int i; if (sp->unsync) for (i=0; i < pvec->nr; i++) if (pvec->page[i].sp == sp) return 0; pvec->page[pvec->nr].sp = sp; pvec->page[pvec->nr].idx = idx; pvec->nr++; return (pvec->nr == KVM_PAGE_ARRAY_NR); } static int __mmu_unsync_walk(struct kvm_mmu_page *sp, struct kvm_mmu_pages *pvec) { int i, ret, nr_unsync_leaf = 0; for_each_set_bit(i, sp->unsync_child_bitmap, 512) { struct kvm_mmu_page *child; u64 ent = sp->spt[i]; if (!is_shadow_present_pte(ent) || is_large_pte(ent)) goto clear_child_bitmap; child = page_header(ent & PT64_BASE_ADDR_MASK); if (child->unsync_children) { if (mmu_pages_add(pvec, child, i)) return -ENOSPC; ret = __mmu_unsync_walk(child, pvec); if (!ret) goto clear_child_bitmap; else if (ret > 0) nr_unsync_leaf += ret; else return ret; } else if (child->unsync) { nr_unsync_leaf++; if (mmu_pages_add(pvec, child, i)) return -ENOSPC; } else goto clear_child_bitmap; continue; clear_child_bitmap: __clear_bit(i, sp->unsync_child_bitmap); sp->unsync_children--; WARN_ON((int)sp->unsync_children < 0); } return nr_unsync_leaf; } static int mmu_unsync_walk(struct kvm_mmu_page *sp, struct kvm_mmu_pages *pvec) { if (!sp->unsync_children) return 0; mmu_pages_add(pvec, sp, 0); return __mmu_unsync_walk(sp, pvec); } static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp) { WARN_ON(!sp->unsync); trace_kvm_mmu_sync_page(sp); sp->unsync = 0; --kvm->stat.mmu_unsync; } static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp, struct list_head *invalid_list); static void kvm_mmu_commit_zap_page(struct kvm *kvm, struct list_head *invalid_list); #define for_each_gfn_sp(kvm, sp, gfn, pos) \ hlist_for_each_entry(sp, pos, \ &(kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link) \ if ((sp)->gfn != (gfn)) {} else #define for_each_gfn_indirect_valid_sp(kvm, sp, gfn, pos) \ hlist_for_each_entry(sp, pos, \ &(kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link) \ if ((sp)->gfn != (gfn) || (sp)->role.direct || \ (sp)->role.invalid) {} else /* @sp->gfn should be write-protected at the call site */ static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, struct list_head *invalid_list, bool clear_unsync) { if (sp->role.cr4_pae != !!is_pae(vcpu)) { kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list); return 1; } if (clear_unsync) kvm_unlink_unsync_page(vcpu->kvm, sp); if (vcpu->arch.mmu.sync_page(vcpu, sp)) { kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list); return 1; } kvm_mmu_flush_tlb(vcpu); return 0; } static int kvm_sync_page_transient(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) { LIST_HEAD(invalid_list); int ret; ret = __kvm_sync_page(vcpu, sp, &invalid_list, false); if (ret) kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); return ret; } #ifdef CONFIG_KVM_MMU_AUDIT #include "mmu_audit.c" #else static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { } static void mmu_audit_disable(void) { } #endif static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, struct list_head *invalid_list) { return __kvm_sync_page(vcpu, sp, invalid_list, true); } /* @gfn should be write-protected at the call site */ static void kvm_sync_pages(struct kvm_vcpu *vcpu, gfn_t gfn) { struct kvm_mmu_page *s; struct hlist_node *node; LIST_HEAD(invalid_list); bool flush = false; for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) { if (!s->unsync) continue; WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL); kvm_unlink_unsync_page(vcpu->kvm, s); if ((s->role.cr4_pae != !!is_pae(vcpu)) || (vcpu->arch.mmu.sync_page(vcpu, s))) { kvm_mmu_prepare_zap_page(vcpu->kvm, s, &invalid_list); continue; } flush = true; } kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); if (flush) kvm_mmu_flush_tlb(vcpu); } struct mmu_page_path { struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1]; unsigned int idx[PT64_ROOT_LEVEL-1]; }; #define for_each_sp(pvec, sp, parents, i) \ for (i = mmu_pages_next(&pvec, &parents, -1), \ sp = pvec.page[i].sp; \ i < pvec.nr && ({ sp = pvec.page[i].sp; 1;}); \ i = mmu_pages_next(&pvec, &parents, i)) static int mmu_pages_next(struct kvm_mmu_pages *pvec, struct mmu_page_path *parents, int i) { int n; for (n = i+1; n < pvec->nr; n++) { struct kvm_mmu_page *sp = pvec->page[n].sp; if (sp->role.level == PT_PAGE_TABLE_LEVEL) { parents->idx[0] = pvec->page[n].idx; return n; } parents->parent[sp->role.level-2] = sp; parents->idx[sp->role.level-1] = pvec->page[n].idx; } return n; } static void mmu_pages_clear_parents(struct mmu_page_path *parents) { struct kvm_mmu_page *sp; unsigned int level = 0; do { unsigned int idx = parents->idx[level]; sp = parents->parent[level]; if (!sp) return; --sp->unsync_children; WARN_ON((int)sp->unsync_children < 0); __clear_bit(idx, sp->unsync_child_bitmap); level++; } while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children); } static void kvm_mmu_pages_init(struct kvm_mmu_page *parent, struct mmu_page_path *parents, struct kvm_mmu_pages *pvec) { parents->parent[parent->role.level-1] = NULL; pvec->nr = 0; } static void mmu_sync_children(struct kvm_vcpu *vcpu, struct kvm_mmu_page *parent) { int i; struct kvm_mmu_page *sp; struct mmu_page_path parents; struct kvm_mmu_pages pages; LIST_HEAD(invalid_list); kvm_mmu_pages_init(parent, &parents, &pages); while (mmu_unsync_walk(parent, &pages)) { int protected = 0; for_each_sp(pages, sp, parents, i) protected |= rmap_write_protect(vcpu->kvm, sp->gfn); if (protected) kvm_flush_remote_tlbs(vcpu->kvm); for_each_sp(pages, sp, parents, i) { kvm_sync_page(vcpu, sp, &invalid_list); mmu_pages_clear_parents(&parents); } kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); cond_resched_lock(&vcpu->kvm->mmu_lock); kvm_mmu_pages_init(parent, &parents, &pages); } } static void init_shadow_page_table(struct kvm_mmu_page *sp) { int i; for (i = 0; i < PT64_ENT_PER_PAGE; ++i) sp->spt[i] = 0ull; } static void __clear_sp_write_flooding_count(struct kvm_mmu_page *sp) { sp->write_flooding_count = 0; } static void clear_sp_write_flooding_count(u64 *spte) { struct kvm_mmu_page *sp = page_header(__pa(spte)); __clear_sp_write_flooding_count(sp); } static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gaddr, unsigned level, int direct, unsigned access, u64 *parent_pte) { union kvm_mmu_page_role role; unsigned quadrant; struct kvm_mmu_page *sp; struct hlist_node *node; bool need_sync = false; role = vcpu->arch.mmu.base_role; role.level = level; role.direct = direct; if (role.direct) role.cr4_pae = 0; role.access = access; if (!vcpu->arch.mmu.direct_map && 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; } for_each_gfn_sp(vcpu->kvm, sp, gfn, node) { if (!need_sync && sp->unsync) need_sync = true; if (sp->role.word != role.word) continue; if (sp->unsync && kvm_sync_page_transient(vcpu, sp)) break; mmu_page_add_parent_pte(vcpu, sp, parent_pte); if (sp->unsync_children) { kvm_make_request(KVM_REQ_MMU_SYNC, vcpu); kvm_mmu_mark_parents_unsync(sp); } else if (sp->unsync) kvm_mmu_mark_parents_unsync(sp); __clear_sp_write_flooding_count(sp); trace_kvm_mmu_get_page(sp, false); return sp; } ++vcpu->kvm->stat.mmu_cache_miss; sp = kvm_mmu_alloc_page(vcpu, parent_pte, direct); if (!sp) return sp; sp->gfn = gfn; sp->role = role; hlist_add_head(&sp->hash_link, &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]); if (!direct) { if (rmap_write_protect(vcpu->kvm, gfn)) kvm_flush_remote_tlbs(vcpu->kvm); if (level > PT_PAGE_TABLE_LEVEL && need_sync) kvm_sync_pages(vcpu, gfn); account_shadowed(vcpu->kvm, gfn); } init_shadow_page_table(sp); trace_kvm_mmu_get_page(sp, true); return sp; } static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator, struct kvm_vcpu *vcpu, u64 addr) { iterator->addr = addr; iterator->shadow_addr = vcpu->arch.mmu.root_hpa; iterator->level = vcpu->arch.mmu.shadow_root_level; if (iterator->level == PT64_ROOT_LEVEL && vcpu->arch.mmu.root_level < PT64_ROOT_LEVEL && !vcpu->arch.mmu.direct_map) --iterator->level; if (iterator->level == PT32E_ROOT_LEVEL) { iterator->shadow_addr = vcpu->arch.mmu.pae_root[(addr >> 30) & 3]; iterator->shadow_addr &= PT64_BASE_ADDR_MASK; --iterator->level; if (!iterator->shadow_addr) iterator->level = 0; } } static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator) { if (iterator->level < PT_PAGE_TABLE_LEVEL) return false; iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level); iterator->sptep = ((u64 *)__va(iterator->shadow_addr)) + iterator->index; return true; } static void __shadow_walk_next(struct kvm_shadow_walk_iterator *iterator, u64 spte) { if (is_last_spte(spte, iterator->level)) { iterator->level = 0; return; } iterator->shadow_addr = spte & PT64_BASE_ADDR_MASK; --iterator->level; } static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator) { return __shadow_walk_next(iterator, *iterator->sptep); } static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp) { u64 spte; spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK; mmu_spte_set(sptep, spte); } static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) { if (is_large_pte(*sptep)) { drop_spte(vcpu->kvm, sptep); --vcpu->kvm->stat.lpages; kvm_flush_remote_tlbs(vcpu->kvm); } } static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned direct_access) { if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) { struct kvm_mmu_page *child; /* * For the direct sp, if the guest pte's dirty bit * changed form clean to dirty, it will corrupt the * sp's access: allow writable in the read-only sp, * so we should update the spte at this point to get * a new sp with the correct access. */ child = page_header(*sptep & PT64_BASE_ADDR_MASK); if (child->role.access == direct_access) return; drop_parent_pte(child, sptep); kvm_flush_remote_tlbs(vcpu->kvm); } } static bool mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp, u64 *spte) { u64 pte; struct kvm_mmu_page *child; pte = *spte; if (is_shadow_present_pte(pte)) { if (is_last_spte(pte, sp->role.level)) { drop_spte(kvm, spte); if (is_large_pte(pte)) --kvm->stat.lpages; } else { child = page_header(pte & PT64_BASE_ADDR_MASK); drop_parent_pte(child, spte); } return true; } if (is_mmio_spte(pte)) mmu_spte_clear_no_track(spte); return false; } static void kvm_mmu_page_unlink_children(struct kvm *kvm, struct kvm_mmu_page *sp) { unsigned i; for (i = 0; i < PT64_ENT_PER_PAGE; ++i) mmu_page_zap_pte(kvm, sp, sp->spt + i); } 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_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp) { u64 *parent_pte; while ((parent_pte = pte_list_next(&sp->parent_ptes, NULL))) drop_parent_pte(sp, parent_pte); } static int mmu_zap_unsync_children(struct kvm *kvm, struct kvm_mmu_page *parent, struct list_head *invalid_list) { int i, zapped = 0; struct mmu_page_path parents; struct kvm_mmu_pages pages; if (parent->role.level == PT_PAGE_TABLE_LEVEL) return 0; kvm_mmu_pages_init(parent, &parents, &pages); while (mmu_unsync_walk(parent, &pages)) { struct kvm_mmu_page *sp; for_each_sp(pages, sp, parents, i) { kvm_mmu_prepare_zap_page(kvm, sp, invalid_list); mmu_pages_clear_parents(&parents); zapped++; } kvm_mmu_pages_init(parent, &parents, &pages); } return zapped; } static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp, struct list_head *invalid_list) { int ret; trace_kvm_mmu_prepare_zap_page(sp); ++kvm->stat.mmu_shadow_zapped; ret = mmu_zap_unsync_children(kvm, sp, invalid_list); kvm_mmu_page_unlink_children(kvm, sp); kvm_mmu_unlink_parents(kvm, sp); if (!sp->role.invalid && !sp->role.direct) unaccount_shadowed(kvm, sp->gfn); if (sp->unsync) kvm_unlink_unsync_page(kvm, sp); if (!sp->root_count) { /* Count self */ ret++; list_move(&sp->link, invalid_list); kvm_mod_used_mmu_pages(kvm, -1); } else { list_move(&sp->link, &kvm->arch.active_mmu_pages); kvm_reload_remote_mmus(kvm); } sp->role.invalid = 1; return ret; } static void kvm_mmu_isolate_pages(struct list_head *invalid_list) { struct kvm_mmu_page *sp; list_for_each_entry(sp, invalid_list, link) kvm_mmu_isolate_page(sp); } static void free_pages_rcu(struct rcu_head *head) { struct kvm_mmu_page *next, *sp; sp = container_of(head, struct kvm_mmu_page, rcu); while (sp) { if (!list_empty(&sp->link)) next = list_first_entry(&sp->link, struct kvm_mmu_page, link); else next = NULL; kvm_mmu_free_page(sp); sp = next; } } static void kvm_mmu_commit_zap_page(struct kvm *kvm, struct list_head *invalid_list) { struct kvm_mmu_page *sp; if (list_empty(invalid_list)) return; kvm_flush_remote_tlbs(kvm); if (atomic_read(&kvm->arch.reader_counter)) { kvm_mmu_isolate_pages(invalid_list); sp = list_first_entry(invalid_list, struct kvm_mmu_page, link); list_del_init(invalid_list); trace_kvm_mmu_delay_free_pages(sp); call_rcu(&sp->rcu, free_pages_rcu); return; } do { sp = list_first_entry(invalid_list, struct kvm_mmu_page, link); WARN_ON(!sp->role.invalid || sp->root_count); kvm_mmu_isolate_page(sp); kvm_mmu_free_page(sp); } while (!list_empty(invalid_list)); } /* * Changing the number of mmu pages allocated to the vm * Note: if goal_nr_mmu_pages is too small, you will get dead lock */ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages) { LIST_HEAD(invalid_list); /* * 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_used_mmu_pages > goal_nr_mmu_pages) { while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages && !list_empty(&kvm->arch.active_mmu_pages)) { struct kvm_mmu_page *page; page = container_of(kvm->arch.active_mmu_pages.prev, struct kvm_mmu_page, link); kvm_mmu_prepare_zap_page(kvm, page, &invalid_list); } kvm_mmu_commit_zap_page(kvm, &invalid_list); goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages; } kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages; } int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn) { struct kvm_mmu_page *sp; struct hlist_node *node; LIST_HEAD(invalid_list); int r; pgprintk("%s: looking for gfn %llx\n", __func__, gfn); r = 0; spin_lock(&kvm->mmu_lock); for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node) { pgprintk("%s: gfn %llx role %x\n", __func__, gfn, sp->role.word); r = 1; kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); } kvm_mmu_commit_zap_page(kvm, &invalid_list); spin_unlock(&kvm->mmu_lock); return r; } EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page); static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn) { int slot = memslot_id(kvm, gfn); struct kvm_mmu_page *sp = page_header(__pa(pte)); __set_bit(slot, sp->slot_bitmap); } /* * The function is based on mtrr_type_lookup() in * arch/x86/kernel/cpu/mtrr/generic.c */ static int get_mtrr_type(struct mtrr_state_type *mtrr_state, u64 start, u64 end) { int i; u64 base, mask; u8 prev_match, curr_match; int num_var_ranges = KVM_NR_VAR_MTRR; if (!mtrr_state->enabled) return 0xFF; /* Make end inclusive end, instead of exclusive */ end--; /* Look in fixed ranges. Just return the type as per start */ if (mtrr_state->have_fixed && (start < 0x100000)) { int idx; if (start < 0x80000) { idx = 0; idx += (start >> 16); return mtrr_state->fixed_ranges[idx]; } else if (start < 0xC0000) { idx = 1 * 8; idx += ((start - 0x80000) >> 14); return mtrr_state->fixed_ranges[idx]; } else if (start < 0x1000000) { idx = 3 * 8; idx += ((start - 0xC0000) >> 12); return mtrr_state->fixed_ranges[idx]; } } /* * Look in variable ranges * Look of multiple ranges matching this address and pick type * as per MTRR precedence */ if (!(mtrr_state->enabled & 2)) return mtrr_state->def_type; prev_match = 0xFF; for (i = 0; i < num_var_ranges; ++i) { unsigned short start_state, end_state; if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11))) continue; base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) + (mtrr_state->var_ranges[i].base_lo & PAGE_MASK); mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) + (mtrr_state->var_ranges[i].mask_lo & PAGE_MASK); start_state = ((start & mask) == (base & mask)); end_state = ((end & mask) == (base & mask)); if (start_state != end_state) return 0xFE; if ((start & mask) != (base & mask)) continue; curr_match = mtrr_state->var_ranges[i].base_lo & 0xff; if (prev_match == 0xFF) { prev_match = curr_match; continue; } if (prev_match == MTRR_TYPE_UNCACHABLE || curr_match == MTRR_TYPE_UNCACHABLE) return MTRR_TYPE_UNCACHABLE; if ((prev_match == MTRR_TYPE_WRBACK && curr_match == MTRR_TYPE_WRTHROUGH) || (prev_match == MTRR_TYPE_WRTHROUGH && curr_match == MTRR_TYPE_WRBACK)) { prev_match = MTRR_TYPE_WRTHROUGH; curr_match = MTRR_TYPE_WRTHROUGH; } if (prev_match != curr_match) return MTRR_TYPE_UNCACHABLE; } if (prev_match != 0xFF) return prev_match; return mtrr_state->def_type; } u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn) { u8 mtrr; mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT, (gfn << PAGE_SHIFT) + PAGE_SIZE); if (mtrr == 0xfe || mtrr == 0xff) mtrr = MTRR_TYPE_WRBACK; return mtrr; } EXPORT_SYMBOL_GPL(kvm_get_guest_memory_type); static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) { trace_kvm_mmu_unsync_page(sp); ++vcpu->kvm->stat.mmu_unsync; sp->unsync = 1; kvm_mmu_mark_parents_unsync(sp); } static void kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn) { struct kvm_mmu_page *s; struct hlist_node *node; for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) { if (s->unsync) continue; WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL); __kvm_unsync_page(vcpu, s); } } static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn, bool can_unsync) { struct kvm_mmu_page *s; struct hlist_node *node; bool need_unsync = false; for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) { if (!can_unsync) return 1; if (s->role.level != PT_PAGE_TABLE_LEVEL) return 1; if (!need_unsync && !s->unsync) { need_unsync = true; } } if (need_unsync) kvm_unsync_pages(vcpu, gfn); return 0; } static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, int user_fault, int write_fault, int level, gfn_t gfn, pfn_t pfn, bool speculative, bool can_unsync, bool host_writable) { u64 spte, entry = *sptep; int ret = 0; if (set_mmio_spte(sptep, gfn, pfn, pte_access)) return 0; spte = PT_PRESENT_MASK; if (!speculative) spte |= shadow_accessed_mask; if (pte_access & ACC_EXEC_MASK) spte |= shadow_x_mask; else spte |= shadow_nx_mask; if (pte_access & ACC_USER_MASK) spte |= shadow_user_mask; if (level > PT_PAGE_TABLE_LEVEL) spte |= PT_PAGE_SIZE_MASK; if (tdp_enabled) spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn, kvm_is_mmio_pfn(pfn)); if (host_writable) spte |= SPTE_HOST_WRITEABLE; else pte_access &= ~ACC_WRITE_MASK; spte |= (u64)pfn << PAGE_SHIFT; if ((pte_access & ACC_WRITE_MASK) || (!vcpu->arch.mmu.direct_map && write_fault && !is_write_protection(vcpu) && !user_fault)) { if (level > PT_PAGE_TABLE_LEVEL && has_wrprotected_page(vcpu->kvm, gfn, level)) { ret = 1; drop_spte(vcpu->kvm, sptep); goto done; } spte |= PT_WRITABLE_MASK; if (!vcpu->arch.mmu.direct_map && !(pte_access & ACC_WRITE_MASK)) { spte &= ~PT_USER_MASK; /* * If we converted a user page to a kernel page, * so that the kernel can write to it when cr0.wp=0, * then we should prevent the kernel from executing it * if SMEP is enabled. */ if (kvm_read_cr4_bits(vcpu, X86_CR4_SMEP)) spte |= PT64_NX_MASK; } /* * Optimization: for pte sync, if spte was writable the hash * lookup is unnecessary (and expensive). Write protection * is responsibility of mmu_get_page / kvm_sync_page. * Same reasoning can be applied to dirty page accounting. */ if (!can_unsync && is_writable_pte(*sptep)) goto set_pte; if (mmu_need_write_protect(vcpu, gfn, can_unsync)) { pgprintk("%s: found shadow page for %llx, marking ro\n", __func__, gfn); ret = 1; pte_access &= ~ACC_WRITE_MASK; if (is_writable_pte(spte)) spte &= ~PT_WRITABLE_MASK; } } if (pte_access & ACC_WRITE_MASK) mark_page_dirty(vcpu->kvm, gfn); set_pte: mmu_spte_update(sptep, spte); /* * If we overwrite a writable spte with a read-only one we * should flush remote TLBs. Otherwise rmap_write_protect * will find a read-only spte, even though the writable spte * might be cached on a CPU's TLB. */ if (is_writable_pte(entry) && !is_writable_pte(*sptep)) kvm_flush_remote_tlbs(vcpu->kvm); done: return ret; } static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pt_access, unsigned pte_access, int user_fault, int write_fault, int *emulate, int level, gfn_t gfn, pfn_t pfn, bool speculative, bool host_writable) { int was_rmapped = 0; int rmap_count; pgprintk("%s: spte %llx access %x write_fault %d" " user_fault %d gfn %llx\n", __func__, *sptep, pt_access, write_fault, user_fault, gfn); if (is_rmap_spte(*sptep)) { /* * If we overwrite a PTE page pointer with a 2MB PMD, unlink * the parent of the now unreachable PTE. */ if (level > PT_PAGE_TABLE_LEVEL && !is_large_pte(*sptep)) { struct kvm_mmu_page *child; u64 pte = *sptep; child = page_header(pte & PT64_BASE_ADDR_MASK); drop_parent_pte(child, sptep); kvm_flush_remote_tlbs(vcpu->kvm); } else if (pfn != spte_to_pfn(*sptep)) { pgprintk("hfn old %llx new %llx\n", spte_to_pfn(*sptep), pfn); drop_spte(vcpu->kvm, sptep); kvm_flush_remote_tlbs(vcpu->kvm); } else was_rmapped = 1; } if (set_spte(vcpu, sptep, pte_access, user_fault, write_fault, level, gfn, pfn, speculative, true, host_writable)) { if (write_fault) *emulate = 1; kvm_mmu_flush_tlb(vcpu); } if (unlikely(is_mmio_spte(*sptep) && emulate)) *emulate = 1; pgprintk("%s: setting spte %llx\n", __func__, *sptep); pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n", is_large_pte(*sptep)? "2MB" : "4kB", *sptep & PT_PRESENT_MASK ?"RW":"R", gfn, *sptep, sptep); if (!was_rmapped && is_large_pte(*sptep)) ++vcpu->kvm->stat.lpages; if (is_shadow_present_pte(*sptep)) { page_header_update_slot(vcpu->kvm, sptep, gfn); if (!was_rmapped) { rmap_count = rmap_add(vcpu, sptep, gfn); if (rmap_count > RMAP_RECYCLE_THRESHOLD) rmap_recycle(vcpu, sptep, gfn); } } kvm_release_pfn_clean(pfn); } static void nonpaging_new_cr3(struct kvm_vcpu *vcpu) { } static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn, bool no_dirty_log) { struct kvm_memory_slot *slot; unsigned long hva; slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log); if (!slot) { get_page(fault_page); return page_to_pfn(fault_page); } hva = gfn_to_hva_memslot(slot, gfn); return hva_to_pfn_atomic(vcpu->kvm, hva); } static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 *start, u64 *end) { struct page *pages[PTE_PREFETCH_NUM]; unsigned access = sp->role.access; int i, ret; gfn_t gfn; gfn = kvm_mmu_page_get_gfn(sp, start - sp->spt); if (!gfn_to_memslot_dirty_bitmap(vcpu, gfn, access & ACC_WRITE_MASK)) return -1; ret = gfn_to_page_many_atomic(vcpu->kvm, gfn, pages, end - start); if (ret <= 0) return -1; for (i = 0; i < ret; i++, gfn++, start++) mmu_set_spte(vcpu, start, ACC_ALL, access, 0, 0, NULL, sp->role.level, gfn, page_to_pfn(pages[i]), true, true); return 0; } static void __direct_pte_prefetch(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 *sptep) { u64 *spte, *start = NULL; int i; WARN_ON(!sp->role.direct); i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1); spte = sp->spt + i; for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) { if (is_shadow_present_pte(*spte) || spte == sptep) { if (!start) continue; if (direct_pte_prefetch_many(vcpu, sp, start, spte) < 0) break; start = NULL; } else if (!start) start = spte; } } static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep) { struct kvm_mmu_page *sp; /* * Since it's no accessed bit on EPT, it's no way to * distinguish between actually accessed translations * and prefetched, so disable pte prefetch if EPT is * enabled. */ if (!shadow_accessed_mask) return; sp = page_header(__pa(sptep)); if (sp->role.level > PT_PAGE_TABLE_LEVEL) return; __direct_pte_prefetch(vcpu, sp, sptep); } static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, int map_writable, int level, gfn_t gfn, pfn_t pfn, bool prefault) { struct kvm_shadow_walk_iterator iterator; struct kvm_mmu_page *sp; int emulate = 0; gfn_t pseudo_gfn; for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { if (iterator.level == level) { unsigned pte_access = ACC_ALL; mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, pte_access, 0, write, &emulate, level, gfn, pfn, prefault, map_writable); direct_pte_prefetch(vcpu, iterator.sptep); ++vcpu->stat.pf_fixed; break; } if (!is_shadow_present_pte(*iterator.sptep)) { u64 base_addr = iterator.addr; base_addr &= PT64_LVL_ADDR_MASK(iterator.level); pseudo_gfn = base_addr >> PAGE_SHIFT; sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr, iterator.level - 1, 1, ACC_ALL, iterator.sptep); if (!sp) { pgprintk("nonpaging_map: ENOMEM\n"); kvm_release_pfn_clean(pfn); return -ENOMEM; } mmu_spte_set(iterator.sptep, __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK | shadow_user_mask | shadow_x_mask | shadow_accessed_mask); } } return emulate; } static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *tsk) { siginfo_t info; info.si_signo = SIGBUS; info.si_errno = 0; info.si_code = BUS_MCEERR_AR; info.si_addr = (void __user *)address; info.si_addr_lsb = PAGE_SHIFT; send_sig_info(SIGBUS, &info, tsk); } static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, pfn_t pfn) { kvm_release_pfn_clean(pfn); if (is_hwpoison_pfn(pfn)) { kvm_send_hwpoison_signal(gfn_to_hva(vcpu->kvm, gfn), current); return 0; } return -EFAULT; } static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu, gfn_t *gfnp, pfn_t *pfnp, int *levelp) { pfn_t pfn = *pfnp; gfn_t gfn = *gfnp; int level = *levelp; /* * Check if it's a transparent hugepage. If this would be an * hugetlbfs page, level wouldn't be set to * PT_PAGE_TABLE_LEVEL and there would be no adjustment done * here. */ if (!is_error_pfn(pfn) && !kvm_is_mmio_pfn(pfn) && level == PT_PAGE_TABLE_LEVEL && PageTransCompound(pfn_to_page(pfn)) && !has_wrprotected_page(vcpu->kvm, gfn, PT_DIRECTORY_LEVEL)) { unsigned long mask; /* * mmu_notifier_retry was successful and we hold the * mmu_lock here, so the pmd can't become splitting * from under us, and in turn * __split_huge_page_refcount() can't run from under * us and we can safely transfer the refcount from * PG_tail to PG_head as we switch the pfn to tail to * head. */ *levelp = level = PT_DIRECTORY_LEVEL; mask = KVM_PAGES_PER_HPAGE(level) - 1; VM_BUG_ON((gfn & mask) != (pfn & mask)); if (pfn & mask) { gfn &= ~mask; *gfnp = gfn; kvm_release_pfn_clean(pfn); pfn &= ~mask; if (!get_page_unless_zero(pfn_to_page(pfn))) BUG(); *pfnp = pfn; } } } static bool mmu_invalid_pfn(pfn_t pfn) { return unlikely(is_invalid_pfn(pfn)); } static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, pfn_t pfn, unsigned access, int *ret_val) { bool ret = true; /* The pfn is invalid, report the error! */ if (unlikely(is_invalid_pfn(pfn))) { *ret_val = kvm_handle_bad_page(vcpu, gfn, pfn); goto exit; } if (unlikely(is_noslot_pfn(pfn))) vcpu_cache_mmio_info(vcpu, gva, gfn, access); ret = false; exit: return ret; } static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, gva_t gva, pfn_t *pfn, bool write, bool *writable); static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn, bool prefault) { int r; int level; int force_pt_level; pfn_t pfn; unsigned long mmu_seq; bool map_writable; force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn); if (likely(!force_pt_level)) { level = mapping_level(vcpu, gfn); /* * This path builds a PAE pagetable - so we can map * 2mb pages at maximum. Therefore check if the level * is larger than that. */ if (level > PT_DIRECTORY_LEVEL) level = PT_DIRECTORY_LEVEL; gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1); } else level = PT_PAGE_TABLE_LEVEL; mmu_seq = vcpu->kvm->mmu_notifier_seq; smp_rmb(); if (try_async_pf(vcpu, prefault, gfn, v, &pfn, write, &map_writable)) return 0; if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r)) return r; spin_lock(&vcpu->kvm->mmu_lock); if (mmu_notifier_retry(vcpu, mmu_seq)) goto out_unlock; kvm_mmu_free_some_pages(vcpu); if (likely(!force_pt_level)) transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level); r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn, prefault); spin_unlock(&vcpu->kvm->mmu_lock); return r; out_unlock: spin_unlock(&vcpu->kvm->mmu_lock); kvm_release_pfn_clean(pfn); return 0; } static void mmu_free_roots(struct kvm_vcpu *vcpu) { int i; struct kvm_mmu_page *sp; LIST_HEAD(invalid_list); if (!VALID_PAGE(vcpu->arch.mmu.root_hpa)) return; spin_lock(&vcpu->kvm->mmu_lock); if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL && (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL || vcpu->arch.mmu.direct_map)) { hpa_t root = vcpu->arch.mmu.root_hpa; sp = page_header(root); --sp->root_count; if (!sp->root_count && sp->role.invalid) { kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list); kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); } vcpu->arch.mmu.root_hpa = INVALID_PAGE; spin_unlock(&vcpu->kvm->mmu_lock); return; } 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; if (!sp->root_count && sp->role.invalid) kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list); } vcpu->arch.mmu.pae_root[i] = INVALID_PAGE; } kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); spin_unlock(&vcpu->kvm->mmu_lock); vcpu->arch.mmu.root_hpa = INVALID_PAGE; } static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn) { int ret = 0; if (!kvm_is_visible_gfn(vcpu->kvm, root_gfn)) { kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu); ret = 1; } return ret; } static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu) { struct kvm_mmu_page *sp; unsigned i; if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) { spin_lock(&vcpu->kvm->mmu_lock); kvm_mmu_free_some_pages(vcpu); sp = kvm_mmu_get_page(vcpu, 0, 0, PT64_ROOT_LEVEL, 1, ACC_ALL, NULL); ++sp->root_count; spin_unlock(&vcpu->kvm->mmu_lock); vcpu->arch.mmu.root_hpa = __pa(sp->spt); } else if (vcpu->arch.mmu.shadow_root_level == PT32E_ROOT_LEVEL) { for (i = 0; i < 4; ++i) { hpa_t root = vcpu->arch.mmu.pae_root[i]; ASSERT(!VALID_PAGE(root)); spin_lock(&vcpu->kvm->mmu_lock); kvm_mmu_free_some_pages(vcpu); sp = kvm_mmu_get_page(vcpu, i << (30 - PAGE_SHIFT), i << 30, PT32_ROOT_LEVEL, 1, ACC_ALL, NULL); root = __pa(sp->spt); ++sp->root_count; spin_unlock(&vcpu->kvm->mmu_lock); vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK; } vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root); } else BUG(); return 0; } static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) { struct kvm_mmu_page *sp; u64 pdptr, pm_mask; gfn_t root_gfn; int i; root_gfn = vcpu->arch.mmu.get_cr3(vcpu) >> PAGE_SHIFT; if (mmu_check_root(vcpu, root_gfn)) return 1; /* * Do we shadow a long mode page table? If so we need to * write-protect the guests page table root. */ if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) { hpa_t root = vcpu->arch.mmu.root_hpa; ASSERT(!VALID_PAGE(root)); spin_lock(&vcpu->kvm->mmu_lock); kvm_mmu_free_some_pages(vcpu); sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL, 0, ACC_ALL, NULL); root = __pa(sp->spt); ++sp->root_count; spin_unlock(&vcpu->kvm->mmu_lock); vcpu->arch.mmu.root_hpa = root; return 0; } /* * We shadow a 32 bit page table. This may be a legacy 2-level * or a PAE 3-level page table. In either case we need to be aware that * the shadow page table may be a PAE or a long mode page table. */ pm_mask = PT_PRESENT_MASK; if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK; 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) { pdptr = vcpu->arch.mmu.get_pdptr(vcpu, i); if (!is_present_gpte(pdptr)) { vcpu->arch.mmu.pae_root[i] = 0; continue; } root_gfn = pdptr >> PAGE_SHIFT; if (mmu_check_root(vcpu, root_gfn)) return 1; } spin_lock(&vcpu->kvm->mmu_lock); kvm_mmu_free_some_pages(vcpu); sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30, PT32_ROOT_LEVEL, 0, ACC_ALL, NULL); root = __pa(sp->spt); ++sp->root_count; spin_unlock(&vcpu->kvm->mmu_lock); vcpu->arch.mmu.pae_root[i] = root | pm_mask; } vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root); /* * If we shadow a 32 bit page table with a long mode page * table we enter this path. */ if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) { if (vcpu->arch.mmu.lm_root == NULL) { /* * The additional page necessary for this is only * allocated on demand. */ u64 *lm_root; lm_root = (void*)get_zeroed_page(GFP_KERNEL); if (lm_root == NULL) return 1; lm_root[0] = __pa(vcpu->arch.mmu.pae_root) | pm_mask; vcpu->arch.mmu.lm_root = lm_root; } vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.lm_root); } return 0; } static int mmu_alloc_roots(struct kvm_vcpu *vcpu) { if (vcpu->arch.mmu.direct_map) return mmu_alloc_direct_roots(vcpu); else return mmu_alloc_shadow_roots(vcpu); } static void mmu_sync_roots(struct kvm_vcpu *vcpu) { int i; struct kvm_mmu_page *sp; if (vcpu->arch.mmu.direct_map) return; if (!VALID_PAGE(vcpu->arch.mmu.root_hpa)) return; vcpu_clear_mmio_info(vcpu, ~0ul); kvm_mmu_audit(vcpu, AUDIT_PRE_SYNC); if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) { hpa_t root = vcpu->arch.mmu.root_hpa; sp = page_header(root); mmu_sync_children(vcpu, sp); kvm_mmu_audit(vcpu, AUDIT_POST_SYNC); return; } for (i = 0; i < 4; ++i) { hpa_t root = vcpu->arch.mmu.pae_root[i]; if (root && VALID_PAGE(root)) { root &= PT64_BASE_ADDR_MASK; sp = page_header(root); mmu_sync_children(vcpu, sp); } } kvm_mmu_audit(vcpu, AUDIT_POST_SYNC); } void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu) { spin_lock(&vcpu->kvm->mmu_lock); mmu_sync_roots(vcpu); spin_unlock(&vcpu->kvm->mmu_lock); } static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr, u32 access, struct x86_exception *exception) { if (exception) exception->error_code = 0; return vaddr; } static gpa_t nonpaging_gva_to_gpa_nested(struct kvm_vcpu *vcpu, gva_t vaddr, u32 access, struct x86_exception *exception) { if (exception) exception->error_code = 0; return vcpu->arch.nested_mmu.translate_gpa(vcpu, vaddr, access); } static bool quickly_check_mmio_pf(struct kvm_vcpu *vcpu, u64 addr, bool direct) { if (direct) return vcpu_match_mmio_gpa(vcpu, addr); return vcpu_match_mmio_gva(vcpu, addr); } /* * On direct hosts, the last spte is only allows two states * for mmio page fault: * - It is the mmio spte * - It is zapped or it is being zapped. * * This function completely checks the spte when the last spte * is not the mmio spte. */ static bool check_direct_spte_mmio_pf(u64 spte) { return __check_direct_spte_mmio_pf(spte); } static u64 walk_shadow_page_get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr) { struct kvm_shadow_walk_iterator iterator; u64 spte = 0ull; walk_shadow_page_lockless_begin(vcpu); for_each_shadow_entry_lockless(vcpu, addr, iterator, spte) if (!is_shadow_present_pte(spte)) break; walk_shadow_page_lockless_end(vcpu); return spte; } /* * If it is a real mmio page fault, return 1 and emulat the instruction * directly, return 0 to let CPU fault again on the address, -1 is * returned if bug is detected. */ int handle_mmio_page_fault_common(struct kvm_vcpu *vcpu, u64 addr, bool direct) { u64 spte; if (quickly_check_mmio_pf(vcpu, addr, direct)) return 1; spte = walk_shadow_page_get_mmio_spte(vcpu, addr); if (is_mmio_spte(spte)) { gfn_t gfn = get_mmio_spte_gfn(spte); unsigned access = get_mmio_spte_access(spte); if (direct) addr = 0; trace_handle_mmio_page_fault(addr, gfn, access); vcpu_cache_mmio_info(vcpu, addr, gfn, access); return 1; } /* * It's ok if the gva is remapped by other cpus on shadow guest, * it's a BUG if the gfn is not a mmio page. */ if (direct && !check_direct_spte_mmio_pf(spte)) return -1; /* * If the page table is zapped by other cpus, let CPU fault again on * the address. */ return 0; } EXPORT_SYMBOL_GPL(handle_mmio_page_fault_common); static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, u32 error_code, bool direct) { int ret; ret = handle_mmio_page_fault_common(vcpu, addr, direct); WARN_ON(ret < 0); return ret; } static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva, u32 error_code, bool prefault) { gfn_t gfn; int r; pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code); if (unlikely(error_code & PFERR_RSVD_MASK)) return handle_mmio_page_fault(vcpu, gva, error_code, true); 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, prefault); } static int kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn) { struct kvm_arch_async_pf arch; arch.token = (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id; arch.gfn = gfn; arch.direct_map = vcpu->arch.mmu.direct_map; arch.cr3 = vcpu->arch.mmu.get_cr3(vcpu); return kvm_setup_async_pf(vcpu, gva, gfn, &arch); } static bool can_do_async_pf(struct kvm_vcpu *vcpu) { if (unlikely(!irqchip_in_kernel(vcpu->kvm) || kvm_event_needs_reinjection(vcpu))) return false; return kvm_x86_ops->interrupt_allowed(vcpu); } static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, gva_t gva, pfn_t *pfn, bool write, bool *writable) { bool async; *pfn = gfn_to_pfn_async(vcpu->kvm, gfn, &async, write, writable); if (!async) return false; /* *pfn has correct page already */ put_page(pfn_to_page(*pfn)); if (!prefault && can_do_async_pf(vcpu)) { trace_kvm_try_async_get_page(gva, gfn); if (kvm_find_async_pf_gfn(vcpu, gfn)) { trace_kvm_async_pf_doublefault(gva, gfn); kvm_make_request(KVM_REQ_APF_HALT, vcpu); return true; } else if (kvm_arch_setup_async_pf(vcpu, gva, gfn)) return true; } *pfn = gfn_to_pfn_prot(vcpu->kvm, gfn, write, writable); return false; } static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code, bool prefault) { pfn_t pfn; int r; int level; int force_pt_level; gfn_t gfn = gpa >> PAGE_SHIFT; unsigned long mmu_seq; int write = error_code & PFERR_WRITE_MASK; bool map_writable; ASSERT(vcpu); ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa)); if (unlikely(error_code & PFERR_RSVD_MASK)) return handle_mmio_page_fault(vcpu, gpa, error_code, true); r = mmu_topup_memory_caches(vcpu); if (r) return r; force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn); if (likely(!force_pt_level)) { level = mapping_level(vcpu, gfn); gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1); } else level = PT_PAGE_TABLE_LEVEL; mmu_seq = vcpu->kvm->mmu_notifier_seq; smp_rmb(); if (try_async_pf(vcpu, prefault, gfn, gpa, &pfn, write, &map_writable)) return 0; if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r)) return r; spin_lock(&vcpu->kvm->mmu_lock); if (mmu_notifier_retry(vcpu, mmu_seq)) goto out_unlock; kvm_mmu_free_some_pages(vcpu); if (likely(!force_pt_level)) transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level); r = __direct_map(vcpu, gpa, write, map_writable, level, gfn, pfn, prefault); spin_unlock(&vcpu->kvm->mmu_lock); return r; out_unlock: spin_unlock(&vcpu->kvm->mmu_lock); kvm_release_pfn_clean(pfn); return 0; } 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) { 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->sync_page = nonpaging_sync_page; context->invlpg = nonpaging_invlpg; context->update_pte = nonpaging_update_pte; context->root_level = 0; context->shadow_root_level = PT32E_ROOT_LEVEL; context->root_hpa = INVALID_PAGE; context->direct_map = true; context->nx = false; return 0; } void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu) { ++vcpu->stat.tlb_flush; kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu); } static void paging_new_cr3(struct kvm_vcpu *vcpu) { pgprintk("%s: cr3 %lx\n", __func__, kvm_read_cr3(vcpu)); mmu_free_roots(vcpu); } static unsigned long get_cr3(struct kvm_vcpu *vcpu) { return kvm_read_cr3(vcpu); } static void inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) { vcpu->arch.mmu.inject_page_fault(vcpu, fault); } static void paging_free(struct kvm_vcpu *vcpu) { nonpaging_free(vcpu); } static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level) { int bit7; bit7 = (gpte >> 7) & 1; return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) != 0; } static bool sync_mmio_spte(u64 *sptep, gfn_t gfn, unsigned access, int *nr_present) { if (unlikely(is_mmio_spte(*sptep))) { if (gfn != get_mmio_spte_gfn(*sptep)) { mmu_spte_clear_no_track(sptep); return true; } (*nr_present)++; mark_mmio_spte(sptep, gfn, access); return true; } return false; } #define PTTYPE 64 #include "paging_tmpl.h" #undef PTTYPE #define PTTYPE 32 #include "paging_tmpl.h" #undef PTTYPE static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context, int level) { int maxphyaddr = cpuid_maxphyaddr(vcpu); u64 exb_bit_rsvd = 0; if (!context->nx) exb_bit_rsvd = rsvd_bits(63, 63); switch (level) { case PT32_ROOT_LEVEL: /* no rsvd bits for 2 level 4K page table entries */ context->rsvd_bits_mask[0][1] = 0; context->rsvd_bits_mask[0][0] = 0; context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0]; if (!is_pse(vcpu)) { context->rsvd_bits_mask[1][1] = 0; break; } if (is_cpuid_PSE36()) /* 36bits PSE 4MB page */ context->rsvd_bits_mask[1][1] = rsvd_bits(17, 21); else /* 32 bits PSE 4MB page */ context->rsvd_bits_mask[1][1] = rsvd_bits(13, 21); break; case PT32E_ROOT_LEVEL: context->rsvd_bits_mask[0][2] = rsvd_bits(maxphyaddr, 63) | rsvd_bits(7, 8) | rsvd_bits(1, 2); /* PDPTE */ context->rsvd_bits_mask[0][1] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 62); /* PDE */ context->rsvd_bits_mask[0][0] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 62); /* PTE */ context->rsvd_bits_mask[1][1] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 62) | rsvd_bits(13, 20); /* large page */ context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0]; break; case PT64_ROOT_LEVEL: context->rsvd_bits_mask[0][3] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8); context->rsvd_bits_mask[0][2] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8); context->rsvd_bits_mask[0][1] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 51); context->rsvd_bits_mask[0][0] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 51); context->rsvd_bits_mask[1][3] = context->rsvd_bits_mask[0][3]; context->rsvd_bits_mask[1][2] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 51) | rsvd_bits(13, 29); context->rsvd_bits_mask[1][1] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 51) | rsvd_bits(13, 20); /* large page */ context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0]; break; } } static int paging64_init_context_common(struct kvm_vcpu *vcpu, struct kvm_mmu *context, int level) { context->nx = is_nx(vcpu); reset_rsvds_bits_mask(vcpu, context, level); 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->sync_page = paging64_sync_page; context->invlpg = paging64_invlpg; context->update_pte = paging64_update_pte; context->free = paging_free; context->root_level = level; context->shadow_root_level = level; context->root_hpa = INVALID_PAGE; context->direct_map = false; return 0; } static int paging64_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context) { return paging64_init_context_common(vcpu, context, PT64_ROOT_LEVEL); } static int paging32_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context) { context->nx = false; reset_rsvds_bits_mask(vcpu, context, PT32_ROOT_LEVEL); 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->sync_page = paging32_sync_page; context->invlpg = paging32_invlpg; context->update_pte = paging32_update_pte; context->root_level = PT32_ROOT_LEVEL; context->shadow_root_level = PT32E_ROOT_LEVEL; context->root_hpa = INVALID_PAGE; context->direct_map = false; return 0; } static int paging32E_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context) { return paging64_init_context_common(vcpu, context, PT32E_ROOT_LEVEL); } static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu) { struct kvm_mmu *context = vcpu->arch.walk_mmu; context->base_role.word = 0; context->new_cr3 = nonpaging_new_cr3; context->page_fault = tdp_page_fault; context->free = nonpaging_free; context->sync_page = nonpaging_sync_page; context->invlpg = nonpaging_invlpg; context->update_pte = nonpaging_update_pte; context->shadow_root_level = kvm_x86_ops->get_tdp_level(); context->root_hpa = INVALID_PAGE; context->direct_map = true; context->set_cr3 = kvm_x86_ops->set_tdp_cr3; context->get_cr3 = get_cr3; context->get_pdptr = kvm_pdptr_read; context->inject_page_fault = kvm_inject_page_fault; context->nx = is_nx(vcpu); if (!is_paging(vcpu)) { context->nx = false; context->gva_to_gpa = nonpaging_gva_to_gpa; context->root_level = 0; } else if (is_long_mode(vcpu)) { context->nx = is_nx(vcpu); reset_rsvds_bits_mask(vcpu, context, PT64_ROOT_LEVEL); context->gva_to_gpa = paging64_gva_to_gpa; context->root_level = PT64_ROOT_LEVEL; } else if (is_pae(vcpu)) { context->nx = is_nx(vcpu); reset_rsvds_bits_mask(vcpu, context, PT32E_ROOT_LEVEL); context->gva_to_gpa = paging64_gva_to_gpa; context->root_level = PT32E_ROOT_LEVEL; } else { context->nx = false; reset_rsvds_bits_mask(vcpu, context, PT32_ROOT_LEVEL); context->gva_to_gpa = paging32_gva_to_gpa; context->root_level = PT32_ROOT_LEVEL; } return 0; } int kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context) { int r; bool smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP); ASSERT(vcpu); ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa)); if (!is_paging(vcpu)) r = nonpaging_init_context(vcpu, context); else if (is_long_mode(vcpu)) r = paging64_init_context(vcpu, context); else if (is_pae(vcpu)) r = paging32E_init_context(vcpu, context); else r = paging32_init_context(vcpu, context); vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu); vcpu->arch.mmu.base_role.cr0_wp = is_write_protection(vcpu); vcpu->arch.mmu.base_role.smep_andnot_wp = smep && !is_write_protection(vcpu); return r; } EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu); static int init_kvm_softmmu(struct kvm_vcpu *vcpu) { int r = kvm_init_shadow_mmu(vcpu, vcpu->arch.walk_mmu); vcpu->arch.walk_mmu->set_cr3 = kvm_x86_ops->set_cr3; vcpu->arch.walk_mmu->get_cr3 = get_cr3; vcpu->arch.walk_mmu->get_pdptr = kvm_pdptr_read; vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault; return r; } static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu) { struct kvm_mmu *g_context = &vcpu->arch.nested_mmu; g_context->get_cr3 = get_cr3; g_context->get_pdptr = kvm_pdptr_read; g_context->inject_page_fault = kvm_inject_page_fault; /* * Note that arch.mmu.gva_to_gpa translates l2_gva to l1_gpa. The * translation of l2_gpa to l1_gpa addresses is done using the * arch.nested_mmu.gva_to_gpa function. Basically the gva_to_gpa * functions between mmu and nested_mmu are swapped. */ if (!is_paging(vcpu)) { g_context->nx = false; g_context->root_level = 0; g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested; } else if (is_long_mode(vcpu)) { g_context->nx = is_nx(vcpu); reset_rsvds_bits_mask(vcpu, g_context, PT64_ROOT_LEVEL); g_context->root_level = PT64_ROOT_LEVEL; g_context->gva_to_gpa = paging64_gva_to_gpa_nested; } else if (is_pae(vcpu)) { g_context->nx = is_nx(vcpu); reset_rsvds_bits_mask(vcpu, g_context, PT32E_ROOT_LEVEL); g_context->root_level = PT32E_ROOT_LEVEL; g_context->gva_to_gpa = paging64_gva_to_gpa_nested; } else { g_context->nx = false; reset_rsvds_bits_mask(vcpu, g_context, PT32_ROOT_LEVEL); g_context->root_level = PT32_ROOT_LEVEL; g_context->gva_to_gpa = paging32_gva_to_gpa_nested; } return 0; } static int init_kvm_mmu(struct kvm_vcpu *vcpu) { if (mmu_is_nested(vcpu)) return init_kvm_nested_mmu(vcpu); else if (tdp_enabled) return init_kvm_tdp_mmu(vcpu); else return init_kvm_softmmu(vcpu); } static void destroy_kvm_mmu(struct kvm_vcpu *vcpu) { ASSERT(vcpu); if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) /* mmu.free() should set root_hpa = INVALID_PAGE */ vcpu->arch.mmu.free(vcpu); } 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; r = mmu_alloc_roots(vcpu); spin_lock(&vcpu->kvm->mmu_lock); mmu_sync_roots(vcpu); spin_unlock(&vcpu->kvm->mmu_lock); if (r) goto out; /* set_cr3() should ensure TLB has been flushed */ vcpu->arch.mmu.set_cr3(vcpu, vcpu->arch.mmu.root_hpa); out: return r; } EXPORT_SYMBOL_GPL(kvm_mmu_load); void kvm_mmu_unload(struct kvm_vcpu *vcpu) { mmu_free_roots(vcpu); } EXPORT_SYMBOL_GPL(kvm_mmu_unload); static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 *spte, const void *new) { if (sp->role.level != PT_PAGE_TABLE_LEVEL) { ++vcpu->kvm->stat.mmu_pde_zapped; return; } ++vcpu->kvm->stat.mmu_pte_updated; vcpu->arch.mmu.update_pte(vcpu, sp, spte, new); } 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, bool zap_page, bool remote_flush, bool local_flush) { if (zap_page) return; if (remote_flush) kvm_flush_remote_tlbs(vcpu->kvm); else if (local_flush) kvm_mmu_flush_tlb(vcpu); } static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa, const u8 *new, int *bytes) { u64 gentry; int r; /* * Assume that the pte write on a page table of the same type * as the current vcpu paging mode since we update the sptes only * when they have the same mode. */ if (is_pae(vcpu) && *bytes == 4) { /* Handle a 32-bit guest writing two halves of a 64-bit gpte */ *gpa &= ~(gpa_t)7; *bytes = 8; r = kvm_read_guest(vcpu->kvm, *gpa, &gentry, min(*bytes, 8)); if (r) gentry = 0; new = (const u8 *)&gentry; } switch (*bytes) { case 4: gentry = *(const u32 *)new; break; case 8: gentry = *(const u64 *)new; break; default: gentry = 0; break; } return gentry; } /* * 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. */ static bool detect_write_flooding(struct kvm_mmu_page *sp) { /* * Skip write-flooding detected for the sp whose level is 1, because * it can become unsync, then the guest page is not write-protected. */ if (sp->role.level == 1) return false; return ++sp->write_flooding_count >= 3; } /* * Misaligned accesses are too much trouble to fix up; also, they usually * indicate a page is not used as a page table. */ static bool detect_write_misaligned(struct kvm_mmu_page *sp, gpa_t gpa, int bytes) { unsigned offset, pte_size, misaligned; pgprintk("misaligned: gpa %llx bytes %d role %x\n", gpa, bytes, sp->role.word); offset = offset_in_page(gpa); pte_size = sp->role.cr4_pae ? 8 : 4; /* * Sometimes, the OS only writes the last one bytes to update status * bits, for example, in linux, andb instruction is used in clear_bit(). */ if (!(offset & (pte_size - 1)) && bytes == 1) return false; misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1); misaligned |= bytes < 4; return misaligned; } static u64 *get_written_sptes(struct kvm_mmu_page *sp, gpa_t gpa, int *nspte) { unsigned page_offset, quadrant; u64 *spte; int level; page_offset = offset_in_page(gpa); level = sp->role.level; *nspte = 1; if (!sp->role.cr4_pae) { 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; *nspte = 2; } quadrant = page_offset >> PAGE_SHIFT; page_offset &= ~PAGE_MASK; if (quadrant != sp->role.quadrant) return NULL; } spte = &sp->spt[page_offset / sizeof(*spte)]; return spte; } void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, int bytes) { gfn_t gfn = gpa >> PAGE_SHIFT; union kvm_mmu_page_role mask = { .word = 0 }; struct kvm_mmu_page *sp; struct hlist_node *node; LIST_HEAD(invalid_list); u64 entry, gentry, *spte; int npte; bool remote_flush, local_flush, zap_page; /* * If we don't have indirect shadow pages, it means no page is * write-protected, so we can exit simply. */ if (!ACCESS_ONCE(vcpu->kvm->arch.indirect_shadow_pages)) return; zap_page = remote_flush = local_flush = false; pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes); gentry = mmu_pte_write_fetch_gpte(vcpu, &gpa, new, &bytes); /* * No need to care whether allocation memory is successful * or not since pte prefetch is skiped if it does not have * enough objects in the cache. */ mmu_topup_memory_caches(vcpu); spin_lock(&vcpu->kvm->mmu_lock); ++vcpu->kvm->stat.mmu_pte_write; kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE); mask.cr0_wp = mask.cr4_pae = mask.nxe = 1; for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn, node) { if (detect_write_misaligned(sp, gpa, bytes) || detect_write_flooding(sp)) { zap_page |= !!kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list); ++vcpu->kvm->stat.mmu_flooded; continue; } spte = get_written_sptes(sp, gpa, &npte); if (!spte) continue; local_flush = true; while (npte--) { entry = *spte; mmu_page_zap_pte(vcpu->kvm, sp, spte); if (gentry && !((sp->role.word ^ vcpu->arch.mmu.base_role.word) & mask.word) && rmap_can_add(vcpu)) mmu_pte_write_new_pte(vcpu, sp, spte, &gentry); if (!remote_flush && need_remote_flush(entry, *spte)) remote_flush = true; ++spte; } } mmu_pte_write_flush_tlb(vcpu, zap_page, remote_flush, local_flush); kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE); spin_unlock(&vcpu->kvm->mmu_lock); } int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva) { gpa_t gpa; int r; if (vcpu->arch.mmu.direct_map) return 0; gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL); r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT); return r; } EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt); void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) { LIST_HEAD(invalid_list); while (kvm_mmu_available_pages(vcpu->kvm) < KVM_REFILL_PAGES && !list_empty(&vcpu->kvm->arch.active_mmu_pages)) { struct kvm_mmu_page *sp; sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev, struct kvm_mmu_page, link); kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list); ++vcpu->kvm->stat.mmu_recycled; } kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); } static bool is_mmio_page_fault(struct kvm_vcpu *vcpu, gva_t addr) { if (vcpu->arch.mmu.direct_map || mmu_is_nested(vcpu)) return vcpu_match_mmio_gpa(vcpu, addr); return vcpu_match_mmio_gva(vcpu, addr); } int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code, void *insn, int insn_len) { int r, emulation_type = EMULTYPE_RETRY; enum emulation_result er; r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code, false); if (r < 0) goto out; if (!r) { r = 1; goto out; } if (is_mmio_page_fault(vcpu, cr2)) emulation_type = 0; er = x86_emulate_instruction(vcpu, cr2, emulation_type, insn, insn_len); switch (er) { case EMULATE_DONE: return 1; case EMULATE_DO_MMIO: ++vcpu->stat.mmio_exits; /* fall through */ case EMULATE_FAIL: return 0; default: BUG(); } out: return r; } EXPORT_SYMBOL_GPL(kvm_mmu_page_fault); void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva) { vcpu->arch.mmu.invlpg(vcpu, gva); kvm_mmu_flush_tlb(vcpu); ++vcpu->stat.invlpg; } EXPORT_SYMBOL_GPL(kvm_mmu_invlpg); void kvm_enable_tdp(void) { tdp_enabled = true; } EXPORT_SYMBOL_GPL(kvm_enable_tdp); void kvm_disable_tdp(void) { tdp_enabled = false; } EXPORT_SYMBOL_GPL(kvm_disable_tdp); static void free_mmu_pages(struct kvm_vcpu *vcpu) { free_page((unsigned long)vcpu->arch.mmu.pae_root); if (vcpu->arch.mmu.lm_root != NULL) free_page((unsigned long)vcpu->arch.mmu.lm_root); } static int alloc_mmu_pages(struct kvm_vcpu *vcpu) { struct page *page; int i; ASSERT(vcpu); /* * 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) return -ENOMEM; vcpu->arch.mmu.pae_root = page_address(page); for (i = 0; i < 4; ++i) vcpu->arch.mmu.pae_root[i] = INVALID_PAGE; return 0; } int kvm_mmu_create(struct kvm_vcpu *vcpu) { ASSERT(vcpu); vcpu->arch.walk_mmu = &vcpu->arch.mmu; vcpu->arch.mmu.root_hpa = INVALID_PAGE; vcpu->arch.mmu.translate_gpa = translate_gpa; vcpu->arch.nested_mmu.translate_gpa = translate_nested_gpa; 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_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) { if (!is_shadow_present_pte(pt[i]) || !is_last_spte(pt[i], sp->role.level)) continue; if (is_large_pte(pt[i])) { drop_spte(kvm, &pt[i]); --kvm->stat.lpages; continue; } /* avoid RMW */ if (is_writable_pte(pt[i])) mmu_spte_update(&pt[i], pt[i] & ~PT_WRITABLE_MASK); } } kvm_flush_remote_tlbs(kvm); } void kvm_mmu_zap_all(struct kvm *kvm) { struct kvm_mmu_page *sp, *node; LIST_HEAD(invalid_list); spin_lock(&kvm->mmu_lock); restart: list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link) if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list)) goto restart; kvm_mmu_commit_zap_page(kvm, &invalid_list); spin_unlock(&kvm->mmu_lock); } static void kvm_mmu_remove_some_alloc_mmu_pages(struct kvm *kvm, struct list_head *invalid_list) { struct kvm_mmu_page *page; page = container_of(kvm->arch.active_mmu_pages.prev, struct kvm_mmu_page, link); kvm_mmu_prepare_zap_page(kvm, page, invalid_list); } static int mmu_shrink(struct shrinker *shrink, struct shrink_control *sc) { struct kvm *kvm; struct kvm *kvm_freed = NULL; int nr_to_scan = sc->nr_to_scan; if (nr_to_scan == 0) goto out; raw_spin_lock(&kvm_lock); list_for_each_entry(kvm, &vm_list, vm_list) { int idx; LIST_HEAD(invalid_list); idx = srcu_read_lock(&kvm->srcu); spin_lock(&kvm->mmu_lock); if (!kvm_freed && nr_to_scan > 0 && kvm->arch.n_used_mmu_pages > 0) { kvm_mmu_remove_some_alloc_mmu_pages(kvm, &invalid_list); kvm_freed = kvm; } nr_to_scan--; kvm_mmu_commit_zap_page(kvm, &invalid_list); spin_unlock(&kvm->mmu_lock); srcu_read_unlock(&kvm->srcu, idx); } if (kvm_freed) list_move_tail(&kvm_freed->vm_list, &vm_list); raw_spin_unlock(&kvm_lock); out: return percpu_counter_read_positive(&kvm_total_used_mmu_pages); } static struct shrinker mmu_shrinker = { .shrink = mmu_shrink, .seeks = DEFAULT_SEEKS * 10, }; static void mmu_destroy_caches(void) { if (pte_list_desc_cache) kmem_cache_destroy(pte_list_desc_cache); if (mmu_page_header_cache) kmem_cache_destroy(mmu_page_header_cache); } int kvm_mmu_module_init(void) { pte_list_desc_cache = kmem_cache_create("pte_list_desc", sizeof(struct pte_list_desc), 0, 0, NULL); if (!pte_list_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; if (percpu_counter_init(&kvm_total_used_mmu_pages, 0)) goto nomem; register_shrinker(&mmu_shrinker); return 0; nomem: mmu_destroy_caches(); return -ENOMEM; } /* * Caculate mmu pages needed for kvm. */ unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm) { unsigned int nr_mmu_pages; unsigned int nr_pages = 0; struct kvm_memslots *slots; struct kvm_memory_slot *memslot; slots = kvm_memslots(kvm); kvm_for_each_memslot(memslot, slots) nr_pages += memslot->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; } int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4]) { struct kvm_shadow_walk_iterator iterator; u64 spte; int nr_sptes = 0; walk_shadow_page_lockless_begin(vcpu); for_each_shadow_entry_lockless(vcpu, addr, iterator, spte) { sptes[iterator.level-1] = spte; nr_sptes++; if (!is_shadow_present_pte(spte)) break; } walk_shadow_page_lockless_end(vcpu); return nr_sptes; } EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy); 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_module_exit(void) { mmu_destroy_caches(); percpu_counter_destroy(&kvm_total_used_mmu_pages); unregister_shrinker(&mmu_shrinker); mmu_audit_disable(); }