| /* |
| * 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 <yaniv@qumranet.com> |
| * Avi Kivity <avi@qumranet.com> |
| * |
| * This work is licensed under the terms of the GNU GPL, version 2. See |
| * the COPYING file in the top-level directory. |
| * |
| */ |
| |
| #include "irq.h" |
| #include "mmu.h" |
| #include "x86.h" |
| #include "kvm_cache_regs.h" |
| |
| #include <linux/kvm_host.h> |
| #include <linux/types.h> |
| #include <linux/string.h> |
| #include <linux/mm.h> |
| #include <linux/highmem.h> |
| #include <linux/module.h> |
| #include <linux/swap.h> |
| #include <linux/hugetlb.h> |
| #include <linux/compiler.h> |
| #include <linux/srcu.h> |
| #include <linux/slab.h> |
| #include <linux/uaccess.h> |
| |
| #include <asm/page.h> |
| #include <asm/cmpxchg.h> |
| #include <asm/io.h> |
| #include <asm/vmx.h> |
| |
| /* |
| * 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 10 |
| #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 | shadow_user_mask \ |
| | shadow_x_mask | shadow_nx_mask) |
| |
| #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 <trace/events/kvm.h> |
| |
| #define CREATE_TRACE_POINTS |
| #include "mmutrace.h" |
| |
| #define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT) |
| #define SPTE_MMU_WRITEABLE (1ULL << (PT_FIRST_AVAIL_BITS_SHIFT + 1)) |
| |
| #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level) |
| |
| /* make pte_list_desc fit well in cache line */ |
| #define PTE_LIST_EXT 3 |
| |
| 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); |
| static void mmu_free_roots(struct kvm_vcpu *vcpu); |
| |
| void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask) |
| { |
| shadow_mmio_mask = mmio_mask; |
| } |
| EXPORT_SYMBOL_GPL(kvm_mmu_set_mmio_spte_mask); |
| |
| /* |
| * spte bits of bit 3 ~ bit 11 are used as low 9 bits of generation number, |
| * the bits of bits 52 ~ bit 61 are used as high 10 bits of generation |
| * number. |
| */ |
| #define MMIO_SPTE_GEN_LOW_SHIFT 3 |
| #define MMIO_SPTE_GEN_HIGH_SHIFT 52 |
| |
| #define MMIO_GEN_SHIFT 19 |
| #define MMIO_GEN_LOW_SHIFT 9 |
| #define MMIO_GEN_LOW_MASK ((1 << MMIO_GEN_LOW_SHIFT) - 1) |
| #define MMIO_GEN_MASK ((1 << MMIO_GEN_SHIFT) - 1) |
| #define MMIO_MAX_GEN ((1 << MMIO_GEN_SHIFT) - 1) |
| |
| static u64 generation_mmio_spte_mask(unsigned int gen) |
| { |
| u64 mask; |
| |
| WARN_ON(gen > MMIO_MAX_GEN); |
| |
| mask = (gen & MMIO_GEN_LOW_MASK) << MMIO_SPTE_GEN_LOW_SHIFT; |
| mask |= ((u64)gen >> MMIO_GEN_LOW_SHIFT) << MMIO_SPTE_GEN_HIGH_SHIFT; |
| return mask; |
| } |
| |
| static unsigned int get_mmio_spte_generation(u64 spte) |
| { |
| unsigned int gen; |
| |
| spte &= ~shadow_mmio_mask; |
| |
| gen = (spte >> MMIO_SPTE_GEN_LOW_SHIFT) & MMIO_GEN_LOW_MASK; |
| gen |= (spte >> MMIO_SPTE_GEN_HIGH_SHIFT) << MMIO_GEN_LOW_SHIFT; |
| return gen; |
| } |
| |
| static unsigned int kvm_current_mmio_generation(struct kvm *kvm) |
| { |
| /* |
| * Init kvm generation close to MMIO_MAX_GEN to easily test the |
| * code of handling generation number wrap-around. |
| */ |
| return (kvm_memslots(kvm)->generation + |
| MMIO_MAX_GEN - 150) & MMIO_GEN_MASK; |
| } |
| |
| static void mark_mmio_spte(struct kvm *kvm, u64 *sptep, u64 gfn, |
| unsigned access) |
| { |
| unsigned int gen = kvm_current_mmio_generation(kvm); |
| u64 mask = generation_mmio_spte_mask(gen); |
| |
| access &= ACC_WRITE_MASK | ACC_USER_MASK; |
| mask |= shadow_mmio_mask | access | gfn << PAGE_SHIFT; |
| |
| trace_mark_mmio_spte(sptep, gfn, access, gen); |
| mmu_spte_set(sptep, mask); |
| } |
| |
| static bool is_mmio_spte(u64 spte) |
| { |
| return (spte & shadow_mmio_mask) == shadow_mmio_mask; |
| } |
| |
| static gfn_t get_mmio_spte_gfn(u64 spte) |
| { |
| u64 mask = generation_mmio_spte_mask(MMIO_MAX_GEN) | shadow_mmio_mask; |
| return (spte & ~mask) >> PAGE_SHIFT; |
| } |
| |
| static unsigned get_mmio_spte_access(u64 spte) |
| { |
| u64 mask = generation_mmio_spte_mask(MMIO_MAX_GEN) | shadow_mmio_mask; |
| return (spte & ~mask) & ~PAGE_MASK; |
| } |
| |
| static bool set_mmio_spte(struct kvm *kvm, u64 *sptep, gfn_t gfn, |
| pfn_t pfn, unsigned access) |
| { |
| if (unlikely(is_noslot_pfn(pfn))) { |
| mark_mmio_spte(kvm, sptep, gfn, access); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static bool check_mmio_spte(struct kvm *kvm, u64 spte) |
| { |
| unsigned int kvm_gen, spte_gen; |
| |
| kvm_gen = kvm_current_mmio_generation(kvm); |
| spte_gen = get_mmio_spte_generation(spte); |
| |
| trace_check_mmio_spte(spte, kvm_gen, spte_gen); |
| return likely(kvm_gen == spte_gen); |
| } |
| |
| 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_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). |
| * |
| * An spte tlb flush may be pending, because kvm_set_pte_rmapp |
| * coalesces them and we are running out of the MMU lock. Therefore |
| * we need to protect against in-progress updates of the spte. |
| * |
| * Reading the spte while an update is in progress may get the old value |
| * for the high part of the spte. The race is fine for a present->non-present |
| * change (because the high part of the spte is ignored for non-present spte), |
| * but for a present->present change we must reread the spte. |
| * |
| * All such changes are done in two steps (present->non-present and |
| * non-present->present), hence it is enough to count the number of |
| * present->non-present updates: if it changed while reading the spte, |
| * we might have hit the race. This is done using clear_spte_count. |
| */ |
| 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_is_locklessly_modifiable(u64 spte) |
| { |
| return (spte & (SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE)) == |
| (SPTE_HOST_WRITEABLE | SPTE_MMU_WRITEABLE); |
| } |
| |
| static bool spte_has_volatile_bits(u64 spte) |
| { |
| /* |
| * Always atomicly update spte if it can be updated |
| * out of mmu-lock, it can ensure dirty bit is not lost, |
| * also, it can help us to get a stable is_writable_pte() |
| * to ensure tlb flush is not missed. |
| */ |
| if (spte_is_locklessly_modifiable(spte)) |
| return true; |
| |
| 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. |
| * |
| * Whenever 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, the return value indicates this |
| * case. |
| */ |
| static bool mmu_spte_update(u64 *sptep, u64 new_spte) |
| { |
| u64 old_spte = *sptep; |
| bool ret = false; |
| |
| WARN_ON(!is_rmap_spte(new_spte)); |
| |
| if (!is_shadow_present_pte(old_spte)) { |
| mmu_spte_set(sptep, new_spte); |
| return ret; |
| } |
| |
| if (!spte_has_volatile_bits(old_spte)) |
| __update_clear_spte_fast(sptep, new_spte); |
| else |
| old_spte = __update_clear_spte_slow(sptep, new_spte); |
| |
| /* |
| * For the spte updated out of mmu-lock is safe, since |
| * we always atomicly update it, see the comments in |
| * spte_has_volatile_bits(). |
| */ |
| if (is_writable_pte(old_spte) && !is_writable_pte(new_spte)) |
| ret = true; |
| |
| if (!shadow_accessed_mask) |
| return ret; |
| |
| 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)); |
| |
| return ret; |
| } |
| |
| /* |
| * 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); |
| |
| /* |
| * KVM does not hold the refcount of the page used by |
| * kvm mmu, before reclaiming the page, we should |
| * unmap it from mmu first. |
| */ |
| WARN_ON(!kvm_is_mmio_pfn(pfn) && !page_count(pfn_to_page(pfn))); |
| |
| 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) |
| { |
| /* |
| * Prevent page table teardown by making any free-er wait during |
| * kvm_flush_remote_tlbs() IPI to all active vcpus. |
| */ |
| local_irq_disable(); |
| vcpu->mode = READING_SHADOW_PAGE_TABLES; |
| /* |
| * Make sure a following spte read is not reordered ahead of the write |
| * to vcpu->mode. |
| */ |
| smp_mb(); |
| } |
| |
| static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu) |
| { |
| /* |
| * Make sure the write to vcpu->mode is not reordered in front of |
| * reads to sptes. If it does, kvm_commit_zap_page() can see us |
| * OUTSIDE_GUEST_MODE and proceed to free the shadow page table. |
| */ |
| smp_mb(); |
| vcpu->mode = OUTSIDE_GUEST_MODE; |
| local_irq_enable(); |
| } |
| |
| 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) |
| { |
| 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); |
| } |
| |
| 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_to_index(gfn, slot->base_gfn, level); |
| return &slot->arch.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 = min(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 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(gfn_t gfn, int level, |
| struct kvm_memory_slot *slot) |
| { |
| unsigned long idx; |
| |
| idx = gfn_to_index(gfn, slot->base_gfn, level); |
| return &slot->arch.rmap[level - PT_PAGE_TABLE_LEVEL][idx]; |
| } |
| |
| /* |
| * 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(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 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); |
| } |
| |
| /* |
| * Used by the following functions to iterate through the sptes linked by a |
| * rmap. All fields are private and not assumed to be used outside. |
| */ |
| struct rmap_iterator { |
| /* private fields */ |
| struct pte_list_desc *desc; /* holds the sptep if not NULL */ |
| int pos; /* index of the sptep */ |
| }; |
| |
| /* |
| * Iteration must be started by this function. This should also be used after |
| * removing/dropping sptes from the rmap link because in such cases the |
| * information in the itererator may not be valid. |
| * |
| * Returns sptep if found, NULL otherwise. |
| */ |
| static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator *iter) |
| { |
| if (!rmap) |
| return NULL; |
| |
| if (!(rmap & 1)) { |
| iter->desc = NULL; |
| return (u64 *)rmap; |
| } |
| |
| iter->desc = (struct pte_list_desc *)(rmap & ~1ul); |
| iter->pos = 0; |
| return iter->desc->sptes[iter->pos]; |
| } |
| |
| /* |
| * Must be used with a valid iterator: e.g. after rmap_get_first(). |
| * |
| * Returns sptep if found, NULL otherwise. |
| */ |
| static u64 *rmap_get_next(struct rmap_iterator *iter) |
| { |
| if (iter->desc) { |
| if (iter->pos < PTE_LIST_EXT - 1) { |
| u64 *sptep; |
| |
| ++iter->pos; |
| sptep = iter->desc->sptes[iter->pos]; |
| if (sptep) |
| return sptep; |
| } |
| |
| iter->desc = iter->desc->more; |
| |
| if (iter->desc) { |
| iter->pos = 0; |
| /* desc->sptes[0] cannot be NULL */ |
| return iter->desc->sptes[iter->pos]; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| static void drop_spte(struct kvm *kvm, u64 *sptep) |
| { |
| if (mmu_spte_clear_track_bits(sptep)) |
| rmap_remove(kvm, sptep); |
| } |
| |
| |
| static bool __drop_large_spte(struct kvm *kvm, u64 *sptep) |
| { |
| if (is_large_pte(*sptep)) { |
| WARN_ON(page_header(__pa(sptep))->role.level == |
| PT_PAGE_TABLE_LEVEL); |
| drop_spte(kvm, sptep); |
| --kvm->stat.lpages; |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) |
| { |
| if (__drop_large_spte(vcpu->kvm, sptep)) |
| kvm_flush_remote_tlbs(vcpu->kvm); |
| } |
| |
| /* |
| * Write-protect on the specified @sptep, @pt_protect indicates whether |
| * spte writ-protection is caused by protecting shadow page table. |
| * @flush indicates whether tlb need be flushed. |
| * |
| * Note: write protection is difference between drity logging and spte |
| * protection: |
| * - for dirty logging, the spte can be set to writable at anytime if |
| * its dirty bitmap is properly set. |
| * - for spte protection, the spte can be writable only after unsync-ing |
| * shadow page. |
| * |
| * Return true if the spte is dropped. |
| */ |
| static bool |
| spte_write_protect(struct kvm *kvm, u64 *sptep, bool *flush, bool pt_protect) |
| { |
| u64 spte = *sptep; |
| |
| if (!is_writable_pte(spte) && |
| !(pt_protect && spte_is_locklessly_modifiable(spte))) |
| return false; |
| |
| rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep); |
| |
| if (__drop_large_spte(kvm, sptep)) { |
| *flush |= true; |
| return true; |
| } |
| |
| if (pt_protect) |
| spte &= ~SPTE_MMU_WRITEABLE; |
| spte = spte & ~PT_WRITABLE_MASK; |
| |
| *flush |= mmu_spte_update(sptep, spte); |
| return false; |
| } |
| |
| static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, |
| bool pt_protect) |
| { |
| u64 *sptep; |
| struct rmap_iterator iter; |
| bool flush = false; |
| |
| for (sptep = rmap_get_first(*rmapp, &iter); sptep;) { |
| BUG_ON(!(*sptep & PT_PRESENT_MASK)); |
| if (spte_write_protect(kvm, sptep, &flush, pt_protect)) { |
| sptep = rmap_get_first(*rmapp, &iter); |
| continue; |
| } |
| |
| sptep = rmap_get_next(&iter); |
| } |
| |
| return flush; |
| } |
| |
| /** |
| * kvm_mmu_write_protect_pt_masked - write protect selected PT level pages |
| * @kvm: kvm instance |
| * @slot: slot to protect |
| * @gfn_offset: start of the BITS_PER_LONG pages we care about |
| * @mask: indicates which pages we should protect |
| * |
| * Used when we do not need to care about huge page mappings: e.g. during dirty |
| * logging we do not have any such mappings. |
| */ |
| void kvm_mmu_write_protect_pt_masked(struct kvm *kvm, |
| struct kvm_memory_slot *slot, |
| gfn_t gfn_offset, unsigned long mask) |
| { |
| unsigned long *rmapp; |
| |
| while (mask) { |
| rmapp = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask), |
| PT_PAGE_TABLE_LEVEL, slot); |
| __rmap_write_protect(kvm, rmapp, false); |
| |
| /* clear the first set bit */ |
| mask &= mask - 1; |
| } |
| } |
| |
| static bool rmap_write_protect(struct kvm *kvm, u64 gfn) |
| { |
| struct kvm_memory_slot *slot; |
| unsigned long *rmapp; |
| int i; |
| bool write_protected = false; |
| |
| slot = gfn_to_memslot(kvm, gfn); |
| |
| for (i = PT_PAGE_TABLE_LEVEL; |
| i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) { |
| rmapp = __gfn_to_rmap(gfn, i, slot); |
| write_protected |= __rmap_write_protect(kvm, rmapp, true); |
| } |
| |
| return write_protected; |
| } |
| |
| static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp, |
| struct kvm_memory_slot *slot, unsigned long data) |
| { |
| u64 *sptep; |
| struct rmap_iterator iter; |
| int need_tlb_flush = 0; |
| |
| while ((sptep = rmap_get_first(*rmapp, &iter))) { |
| BUG_ON(!(*sptep & PT_PRESENT_MASK)); |
| rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", sptep, *sptep); |
| |
| drop_spte(kvm, sptep); |
| need_tlb_flush = 1; |
| } |
| |
| return need_tlb_flush; |
| } |
| |
| static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp, |
| struct kvm_memory_slot *slot, unsigned long data) |
| { |
| u64 *sptep; |
| struct rmap_iterator iter; |
| int need_flush = 0; |
| u64 new_spte; |
| pte_t *ptep = (pte_t *)data; |
| pfn_t new_pfn; |
| |
| WARN_ON(pte_huge(*ptep)); |
| new_pfn = pte_pfn(*ptep); |
| |
| for (sptep = rmap_get_first(*rmapp, &iter); sptep;) { |
| BUG_ON(!is_shadow_present_pte(*sptep)); |
| rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", sptep, *sptep); |
| |
| need_flush = 1; |
| |
| if (pte_write(*ptep)) { |
| drop_spte(kvm, sptep); |
| sptep = rmap_get_first(*rmapp, &iter); |
| } else { |
| new_spte = *sptep & ~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(sptep); |
| mmu_spte_set(sptep, new_spte); |
| sptep = rmap_get_next(&iter); |
| } |
| } |
| |
| if (need_flush) |
| kvm_flush_remote_tlbs(kvm); |
| |
| return 0; |
| } |
| |
| static int kvm_handle_hva_range(struct kvm *kvm, |
| unsigned long start, |
| unsigned long end, |
| unsigned long data, |
| int (*handler)(struct kvm *kvm, |
| unsigned long *rmapp, |
| struct kvm_memory_slot *slot, |
| unsigned long data)) |
| { |
| int j; |
| int ret = 0; |
| struct kvm_memslots *slots; |
| struct kvm_memory_slot *memslot; |
| |
| slots = kvm_memslots(kvm); |
| |
| kvm_for_each_memslot(memslot, slots) { |
| unsigned long hva_start, hva_end; |
| gfn_t gfn_start, gfn_end; |
| |
| hva_start = max(start, memslot->userspace_addr); |
| hva_end = min(end, memslot->userspace_addr + |
| (memslot->npages << PAGE_SHIFT)); |
| if (hva_start >= hva_end) |
| continue; |
| /* |
| * {gfn(page) | page intersects with [hva_start, hva_end)} = |
| * {gfn_start, gfn_start+1, ..., gfn_end-1}. |
| */ |
| gfn_start = hva_to_gfn_memslot(hva_start, memslot); |
| gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot); |
| |
| for (j = PT_PAGE_TABLE_LEVEL; |
| j < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++j) { |
| unsigned long idx, idx_end; |
| unsigned long *rmapp; |
| |
| /* |
| * {idx(page_j) | page_j intersects with |
| * [hva_start, hva_end)} = {idx, idx+1, ..., idx_end}. |
| */ |
| idx = gfn_to_index(gfn_start, memslot->base_gfn, j); |
| idx_end = gfn_to_index(gfn_end - 1, memslot->base_gfn, j); |
| |
| rmapp = __gfn_to_rmap(gfn_start, j, memslot); |
| |
| for (; idx <= idx_end; ++idx) |
| ret |= handler(kvm, rmapp++, memslot, data); |
| } |
| } |
| |
| return ret; |
| } |
| |
| static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, |
| unsigned long data, |
| int (*handler)(struct kvm *kvm, unsigned long *rmapp, |
| struct kvm_memory_slot *slot, |
| unsigned long data)) |
| { |
| return kvm_handle_hva_range(kvm, hva, hva + 1, data, handler); |
| } |
| |
| int kvm_unmap_hva(struct kvm *kvm, unsigned long hva) |
| { |
| return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp); |
| } |
| |
| int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end) |
| { |
| return kvm_handle_hva_range(kvm, start, end, 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, |
| struct kvm_memory_slot *slot, unsigned long data) |
| { |
| u64 *sptep; |
| struct rmap_iterator uninitialized_var(iter); |
| int young = 0; |
| |
| /* |
| * In case of absence of EPT Access and Dirty Bits supports, |
| * 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) { |
| young = kvm_unmap_rmapp(kvm, rmapp, slot, data); |
| goto out; |
| } |
| |
| for (sptep = rmap_get_first(*rmapp, &iter); sptep; |
| sptep = rmap_get_next(&iter)) { |
| BUG_ON(!is_shadow_present_pte(*sptep)); |
| |
| if (*sptep & shadow_accessed_mask) { |
| young = 1; |
| clear_bit((ffs(shadow_accessed_mask) - 1), |
| (unsigned long *)sptep); |
| } |
| } |
| out: |
| /* @data has hva passed to kvm_age_hva(). */ |
| trace_kvm_age_page(data, slot, young); |
| return young; |
| } |
| |
| static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp, |
| struct kvm_memory_slot *slot, unsigned long data) |
| { |
| u64 *sptep; |
| struct rmap_iterator iter; |
| 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; |
| |
| for (sptep = rmap_get_first(*rmapp, &iter); sptep; |
| sptep = rmap_get_next(&iter)) { |
| BUG_ON(!is_shadow_present_pte(*sptep)); |
| |
| if (*sptep & shadow_accessed_mask) { |
| young = 1; |
| break; |
| } |
| } |
| 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, NULL, 0); |
| kvm_flush_remote_tlbs(vcpu->kvm); |
| } |
| |
| int kvm_age_hva(struct kvm *kvm, unsigned long hva) |
| { |
| return kvm_handle_hva(kvm, hva, hva, 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); |
| } |
| |
| static void kvm_mmu_free_page(struct kvm_mmu_page *sp) |
| { |
| ASSERT(is_empty_shadow_page(sp->spt)); |
| hlist_del(&sp->hash_link); |
| list_del(&sp->link); |
| free_page((unsigned long)sp->spt); |
| if (!sp->role.direct) |
| free_page((unsigned long)sp->gfns); |
| 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); |
| sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache); |
| if (!direct) |
| sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache); |
| set_page_private(virt_to_page(sp->spt), (unsigned long)sp); |
| |
| /* |
| * The active_mmu_pages list is the FIFO list, do not move the |
| * page until it is zapped. kvm_zap_obsolete_pages depends on |
| * this feature. See the comments in kvm_zap_obsolete_pages(). |
| */ |
| list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); |
| 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); |
| |
| /* |
| * NOTE: we should pay more attention on the zapped-obsolete page |
| * (is_obsolete_sp(sp) && sp->role.invalid) when you do hash list walk |
| * since it has been deleted from active_mmu_pages but still can be found |
| * at hast list. |
| * |
| * for_each_gfn_indirect_valid_sp has skipped that kind of page and |
| * kvm_mmu_get_page(), the only user of for_each_gfn_sp(), has skipped |
| * all the obsolete pages. |
| */ |
| #define for_each_gfn_sp(_kvm, _sp, _gfn) \ |
| hlist_for_each_entry(_sp, \ |
| &(_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) \ |
| for_each_gfn_sp(_kvm, _sp, _gfn) \ |
| if ((_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; |
| LIST_HEAD(invalid_list); |
| bool flush = false; |
| |
| for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) { |
| 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)) { |
| bool protected = false; |
| |
| 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 bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp) |
| { |
| return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen); |
| } |
| |
| 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; |
| 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) { |
| if (is_obsolete_sp(vcpu->kvm, sp)) |
| continue; |
| |
| 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); |
| } |
| sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; |
| 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, bool accessed) |
| { |
| u64 spte; |
| |
| BUILD_BUG_ON(VMX_EPT_READABLE_MASK != PT_PRESENT_MASK || |
| VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK); |
| |
| spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK | |
| shadow_user_mask | shadow_x_mask; |
| |
| if (accessed) |
| spte |= shadow_accessed_mask; |
| |
| mmu_spte_set(sptep, spte); |
| } |
| |
| 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 *sptep; |
| struct rmap_iterator iter; |
| |
| while ((sptep = rmap_get_first(sp->parent_ptes, &iter))) |
| drop_parent_pte(sp, sptep); |
| } |
| |
| 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); |
| |
| /* |
| * The obsolete pages can not be used on any vcpus. |
| * See the comments in kvm_mmu_invalidate_zap_all_pages(). |
| */ |
| if (!sp->role.invalid && !is_obsolete_sp(kvm, sp)) |
| kvm_reload_remote_mmus(kvm); |
| } |
| |
| sp->role.invalid = 1; |
| return ret; |
| } |
| |
| static void kvm_mmu_commit_zap_page(struct kvm *kvm, |
| struct list_head *invalid_list) |
| { |
| struct kvm_mmu_page *sp, *nsp; |
| |
| if (list_empty(invalid_list)) |
| return; |
| |
| /* |
| * wmb: make sure everyone sees our modifications to the page tables |
| * rmb: make sure we see changes to vcpu->mode |
| */ |
| smp_mb(); |
| |
| /* |
| * Wait for all vcpus to exit guest mode and/or lockless shadow |
| * page table walks. |
| */ |
| kvm_flush_remote_tlbs(kvm); |
| |
| list_for_each_entry_safe(sp, nsp, invalid_list, link) { |
| WARN_ON(!sp->role.invalid || sp->root_count); |
| kvm_mmu_free_page(sp); |
| } |
| } |
| |
| static bool prepare_zap_oldest_mmu_page(struct kvm *kvm, |
| struct list_head *invalid_list) |
| { |
| struct kvm_mmu_page *sp; |
| |
| if (list_empty(&kvm->arch.active_mmu_pages)) |
| return false; |
| |
| sp = list_entry(kvm->arch.active_mmu_pages.prev, |
| struct kvm_mmu_page, link); |
| kvm_mmu_prepare_zap_page(kvm, sp, invalid_list); |
| |
| return true; |
| } |
| |
| /* |
| * 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); |
| |
| spin_lock(&kvm->mmu_lock); |
| |
| if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) { |
| /* Need to free some mmu pages to achieve the goal. */ |
| while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) |
| if (!prepare_zap_oldest_mmu_page(kvm, &invalid_list)) |
| break; |
| |
| 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; |
| |
| spin_unlock(&kvm->mmu_lock); |
| } |
| |
| int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn) |
| { |
| struct kvm_mmu_page *sp; |
| 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) { |
| 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); |
| |
| /* |
| * 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; |
| |
| for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) { |
| 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; |
| bool need_unsync = false; |
| |
| for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) { |
| if (!can_unsync) |
| return 1; |
| |
| if (s->role.level != PT_PAGE_TABLE_LEVEL) |
| return 1; |
| |
| if (!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 level, |
| gfn_t gfn, pfn_t pfn, bool speculative, |
| bool can_unsync, bool host_writable) |
| { |
| u64 spte; |
| int ret = 0; |
| |
| if (set_mmio_spte(vcpu->kvm, 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) { |
| |
| /* |
| * Other vcpu creates new sp in the window between |
| * mapping_level() and acquiring mmu-lock. We can |
| * allow guest to retry the access, the mapping can |
| * be fixed if guest refault. |
| */ |
| if (level > PT_PAGE_TABLE_LEVEL && |
| has_wrprotected_page(vcpu->kvm, gfn, level)) |
| goto done; |
| |
| spte |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE; |
| |
| /* |
| * 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; |
| spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE); |
| } |
| } |
| |
| if (pte_access & ACC_WRITE_MASK) |
| mark_page_dirty(vcpu->kvm, gfn); |
| |
| set_pte: |
| if (mmu_spte_update(sptep, spte)) |
| kvm_flush_remote_tlbs(vcpu->kvm); |
| done: |
| return ret; |
| } |
| |
| static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, |
| unsigned pte_access, 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 write_fault %d gfn %llx\n", __func__, |
| *sptep, write_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, 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)) { |
| 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) |
| { |
| mmu_free_roots(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; |
| |
| slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log); |
| if (!slot) |
| return KVM_PFN_ERR_FAULT; |
| |
| return gfn_to_pfn_memslot_atomic(slot, gfn); |
| } |
| |
| 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, access, 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) { |
| mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, |
| 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); |
| |
| link_shadow_page(iterator.sptep, sp, true); |
| } |
| } |
| 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) |
| { |
| /* |
| * Do not cache the mmio info caused by writing the readonly gfn |
| * into the spte otherwise read access on readonly gfn also can |
| * caused mmio page fault and treat it as mmio access. |
| * Return 1 to tell kvm to emulate it. |
| */ |
| if (pfn == KVM_PFN_ERR_RO_FAULT) |
| return 1; |
| |
| if (pfn == KVM_PFN_ERR_HWPOISON) { |
| 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_noslot_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; |
| kvm_get_pfn(pfn); |
| *pfnp = 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_error_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 page_fault_can_be_fast(u32 error_code) |
| { |
| /* |
| * Do not fix the mmio spte with invalid generation number which |
| * need to be updated by slow page fault path. |
| */ |
| if (unlikely(error_code & PFERR_RSVD_MASK)) |
| return false; |
| |
| /* |
| * #PF can be fast only if the shadow page table is present and it |
| * is caused by write-protect, that means we just need change the |
| * W bit of the spte which can be done out of mmu-lock. |
| */ |
| if (!(error_code & PFERR_PRESENT_MASK) || |
| !(error_code & PFERR_WRITE_MASK)) |
| return false; |
| |
| return true; |
| } |
| |
| static bool |
| fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 spte) |
| { |
| struct kvm_mmu_page *sp = page_header(__pa(sptep)); |
| gfn_t gfn; |
| |
| WARN_ON(!sp->role.direct); |
| |
| /* |
| * The gfn of direct spte is stable since it is calculated |
| * by sp->gfn. |
| */ |
| gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt); |
| |
| if (cmpxchg64(sptep, spte, spte | PT_WRITABLE_MASK) == spte) |
| mark_page_dirty(vcpu->kvm, gfn); |
| |
| return true; |
| } |
| |
| /* |
| * Return value: |
| * - true: let the vcpu to access on the same address again. |
| * - false: let the real page fault path to fix it. |
| */ |
| static bool fast_page_fault(struct kvm_vcpu *vcpu, gva_t gva, int level, |
| u32 error_code) |
| { |
| struct kvm_shadow_walk_iterator iterator; |
| bool ret = false; |
| u64 spte = 0ull; |
| |
| if (!page_fault_can_be_fast(error_code)) |
| return false; |
| |
| walk_shadow_page_lockless_begin(vcpu); |
| for_each_shadow_entry_lockless(vcpu, gva, iterator, spte) |
| if (!is_shadow_present_pte(spte) || iterator.level < level) |
| break; |
| |
| /* |
| * If the mapping has been changed, let the vcpu fault on the |
| * same address again. |
| */ |
| if (!is_rmap_spte(spte)) { |
| ret = true; |
| goto exit; |
| } |
| |
| if (!is_last_spte(spte, level)) |
| goto exit; |
| |
| /* |
| * Check if it is a spurious fault caused by TLB lazily flushed. |
| * |
| * Need not check the access of upper level table entries since |
| * they are always ACC_ALL. |
| */ |
| if (is_writable_pte(spte)) { |
| ret = true; |
| goto exit; |
| } |
| |
| /* |
| * Currently, to simplify the code, only the spte write-protected |
| * by dirty-log can be fast fixed. |
| */ |
| if (!spte_is_locklessly_modifiable(spte)) |
| goto exit; |
| |
| /* |
| * Currently, fast page fault only works for direct mapping since |
| * the gfn is not stable for indirect shadow page. |
| * See Documentation/virtual/kvm/locking.txt to get more detail. |
| */ |
| ret = fast_pf_fix_direct_spte(vcpu, iterator.sptep, spte); |
| exit: |
| trace_fast_page_fault(vcpu, gva, error_code, iterator.sptep, |
| spte, ret); |
| walk_shadow_page_lockless_end(vcpu); |
| |
| 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 void make_mmu_pages_available(struct kvm_vcpu *vcpu); |
| |
| static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code, |
| gfn_t gfn, bool prefault) |
| { |
| int r; |
| int level; |
| int force_pt_level; |
| pfn_t pfn; |
| unsigned long mmu_seq; |
| bool map_writable, write = error_code & PFERR_WRITE_MASK; |
| |
| 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; |
| |
| if (fast_page_fault(vcpu, v, level, error_code)) |
| return 0; |
| |
| 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->kvm, mmu_seq)) |
| goto out_unlock; |
| make_mmu_pages_available(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; |
| |
| 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; |
| |
| spin_lock(&vcpu->kvm->mmu_lock); |
| 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); |
| } |
| spin_unlock(&vcpu->kvm->mmu_lock); |
| vcpu->arch.mmu.root_hpa = INVALID_PAGE; |
| return; |
| } |
| |
| spin_lock(&vcpu->kvm->mmu_lock); |
| 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); |
| make_mmu_pages_available(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); |
| make_mmu_pages_available(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); |
| make_mmu_pages_available(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); |
| |