diff options
Diffstat (limited to 'arch/x86/kvm/mmu')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 965 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/mmu_internal.h | 40 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/paging.h | 14 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/paging_tmpl.h | 126 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/spte.c | 43 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/spte.h | 38 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_iter.c | 15 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_iter.h | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 87 |
9 files changed, 888 insertions, 441 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 17252f39bd7c..3e1317325e1f 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -53,8 +53,6 @@ #include <asm/kvm_page_track.h> #include "trace.h" -#include "paging.h" - extern bool itlb_multihit_kvm_mitigation; int __read_mostly nx_huge_pages = -1; @@ -111,26 +109,6 @@ module_param(dbg, bool, 0644); #define PTE_PREFETCH_NUM 8 -#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 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)) - #include <trace/events/kvm.h> /* make pte_list_desc fit well in cache lines */ @@ -326,13 +304,6 @@ static int is_cpuid_PSE36(void) return 1; } -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) { @@ -432,7 +403,7 @@ static u64 __update_clear_spte_slow(u64 *sptep, u64 spte) * The idea using the light way get the spte on x86_32 guest is from * gup_get_pte (mm/gup.c). * - * An spte tlb flush may be pending, because kvm_set_pte_rmapp + * An spte tlb flush may be pending, because kvm_set_pte_rmap * coalesces them and we are running out of the MMU lock. Therefore * we need to protect against in-progress updates of the spte. * @@ -558,11 +529,12 @@ static bool mmu_spte_update(u64 *sptep, u64 new_spte) * state bits, it is used to clear the last level sptep. * Returns the old PTE. */ -static int mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep) +static u64 mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep) { kvm_pfn_t pfn; u64 old_spte = *sptep; int level = sptep_to_sp(sptep)->role.level; + struct page *page; if (!is_shadow_present_pte(old_spte) || !spte_has_volatile_bits(old_spte)) @@ -578,11 +550,13 @@ static int mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep) 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. + * KVM doesn't hold a reference to any pages mapped into the guest, and + * instead uses the mmu_notifier to ensure that KVM unmaps any pages + * before they are reclaimed. Sanity check that, if the pfn is backed + * by a refcounted page, the refcount is elevated. */ - WARN_ON(!kvm_is_reserved_pfn(pfn) && !page_count(pfn_to_page(pfn))); + page = kvm_pfn_to_refcounted_page(pfn); + WARN_ON(page && !page_count(page)); if (is_accessed_spte(old_spte)) kvm_set_pfn_accessed(pfn); @@ -682,7 +656,7 @@ static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect) if (r) return r; if (maybe_indirect) { - r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_gfn_array_cache, + r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_shadowed_info_cache, PT64_ROOT_MAX_LEVEL); if (r) return r; @@ -695,48 +669,79 @@ static void mmu_free_memory_caches(struct kvm_vcpu *vcpu) { kvm_mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache); kvm_mmu_free_memory_cache(&vcpu->arch.mmu_shadow_page_cache); - kvm_mmu_free_memory_cache(&vcpu->arch.mmu_gfn_array_cache); + kvm_mmu_free_memory_cache(&vcpu->arch.mmu_shadowed_info_cache); kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache); } -static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu) -{ - return kvm_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 bool sp_has_gptes(struct kvm_mmu_page *sp); + static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index) { if (sp->role.passthrough) return sp->gfn; if (!sp->role.direct) - return sp->gfns[index]; + return sp->shadowed_translation[index] >> PAGE_SHIFT; - return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS)); + return sp->gfn + (index << ((sp->role.level - 1) * SPTE_LEVEL_BITS)); } -static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn) +/* + * For leaf SPTEs, fetch the *guest* access permissions being shadowed. Note + * that the SPTE itself may have a more constrained access permissions that + * what the guest enforces. For example, a guest may create an executable + * huge PTE but KVM may disallow execution to mitigate iTLB multihit. + */ +static u32 kvm_mmu_page_get_access(struct kvm_mmu_page *sp, int index) { - if (sp->role.passthrough) { - WARN_ON_ONCE(gfn != sp->gfn); - return; - } + if (sp_has_gptes(sp)) + return sp->shadowed_translation[index] & ACC_ALL; - if (!sp->role.direct) { - sp->gfns[index] = gfn; + /* + * For direct MMUs (e.g. TDP or non-paging guests) or passthrough SPs, + * KVM is not shadowing any guest page tables, so the "guest access + * permissions" are just ACC_ALL. + * + * For direct SPs in indirect MMUs (shadow paging), i.e. when KVM + * is shadowing a guest huge page with small pages, the guest access + * permissions being shadowed are the access permissions of the huge + * page. + * + * In both cases, sp->role.access contains the correct access bits. + */ + return sp->role.access; +} + +static void kvm_mmu_page_set_translation(struct kvm_mmu_page *sp, int index, + gfn_t gfn, unsigned int access) +{ + if (sp_has_gptes(sp)) { + sp->shadowed_translation[index] = (gfn << PAGE_SHIFT) | access; return; } - if (WARN_ON(gfn != kvm_mmu_page_get_gfn(sp, index))) - pr_err_ratelimited("gfn mismatch under direct page %llx " - "(expected %llx, got %llx)\n", - sp->gfn, - kvm_mmu_page_get_gfn(sp, index), gfn); + WARN_ONCE(access != kvm_mmu_page_get_access(sp, index), + "access mismatch under %s page %llx (expected %u, got %u)\n", + sp->role.passthrough ? "passthrough" : "direct", + sp->gfn, kvm_mmu_page_get_access(sp, index), access); + + WARN_ONCE(gfn != kvm_mmu_page_get_gfn(sp, index), + "gfn mismatch under %s page %llx (expected %llx, got %llx)\n", + sp->role.passthrough ? "passthrough" : "direct", + sp->gfn, kvm_mmu_page_get_gfn(sp, index), gfn); +} + +static void kvm_mmu_page_set_access(struct kvm_mmu_page *sp, int index, + unsigned int access) +{ + gfn_t gfn = kvm_mmu_page_get_gfn(sp, index); + + kvm_mmu_page_set_translation(sp, index, gfn, access); } /* @@ -792,6 +797,9 @@ static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp) KVM_PAGE_TRACK_WRITE); kvm_mmu_gfn_disallow_lpage(slot, gfn); + + if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K)) + kvm_flush_remote_tlbs_with_address(kvm, gfn, 1); } void account_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp) @@ -855,7 +863,7 @@ gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn, /* * Returns the number of pointers in the rmap chain, not counting the new one. */ -static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, +static int pte_list_add(struct kvm_mmu_memory_cache *cache, u64 *spte, struct kvm_rmap_head *rmap_head) { struct pte_list_desc *desc; @@ -866,7 +874,7 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, rmap_head->val = (unsigned long)spte; } else if (!(rmap_head->val & 1)) { rmap_printk("%p %llx 1->many\n", spte, *spte); - desc = mmu_alloc_pte_list_desc(vcpu); + desc = kvm_mmu_memory_cache_alloc(cache); desc->sptes[0] = (u64 *)rmap_head->val; desc->sptes[1] = spte; desc->spte_count = 2; @@ -878,7 +886,7 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, while (desc->spte_count == PTE_LIST_EXT) { count += PTE_LIST_EXT; if (!desc->more) { - desc->more = mmu_alloc_pte_list_desc(vcpu); + desc->more = kvm_mmu_memory_cache_alloc(cache); desc = desc->more; desc->spte_count = 0; break; @@ -913,7 +921,7 @@ pte_list_desc_remove_entry(struct kvm_rmap_head *rmap_head, mmu_free_pte_list_desc(desc); } -static void __pte_list_remove(u64 *spte, struct kvm_rmap_head *rmap_head) +static void pte_list_remove(u64 *spte, struct kvm_rmap_head *rmap_head) { struct pte_list_desc *desc; struct pte_list_desc *prev_desc; @@ -949,15 +957,16 @@ static void __pte_list_remove(u64 *spte, struct kvm_rmap_head *rmap_head) } } -static void pte_list_remove(struct kvm *kvm, struct kvm_rmap_head *rmap_head, - u64 *sptep) +static void kvm_zap_one_rmap_spte(struct kvm *kvm, + struct kvm_rmap_head *rmap_head, u64 *sptep) { mmu_spte_clear_track_bits(kvm, sptep); - __pte_list_remove(sptep, rmap_head); + pte_list_remove(sptep, rmap_head); } -/* Return true if rmap existed, false otherwise */ -static bool pte_list_destroy(struct kvm *kvm, struct kvm_rmap_head *rmap_head) +/* Return true if at least one SPTE was zapped, false otherwise */ +static bool kvm_zap_all_rmap_sptes(struct kvm *kvm, + struct kvm_rmap_head *rmap_head) { struct pte_list_desc *desc, *next; int i; @@ -1030,7 +1039,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte) struct kvm_rmap_head *rmap_head; sp = sptep_to_sp(spte); - gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt); + gfn = kvm_mmu_page_get_gfn(sp, spte_index(spte)); /* * Unlike rmap_add, rmap_remove does not run in the context of a vCPU @@ -1042,7 +1051,7 @@ static void rmap_remove(struct kvm *kvm, u64 *spte) slot = __gfn_to_memslot(slots, gfn); rmap_head = gfn_to_rmap(gfn, sp->role.level, slot); - __pte_list_remove(spte, rmap_head); + pte_list_remove(spte, rmap_head); } /* @@ -1129,26 +1138,18 @@ static void drop_spte(struct kvm *kvm, u64 *sptep) rmap_remove(kvm, sptep); } - -static bool __drop_large_spte(struct kvm *kvm, u64 *sptep) +static void drop_large_spte(struct kvm *kvm, u64 *sptep, bool flush) { - if (is_large_pte(*sptep)) { - WARN_ON(sptep_to_sp(sptep)->role.level == PG_LEVEL_4K); - drop_spte(kvm, sptep); - return true; - } + struct kvm_mmu_page *sp; - return false; -} + sp = sptep_to_sp(sptep); + WARN_ON(sp->role.level == PG_LEVEL_4K); -static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) -{ - if (__drop_large_spte(vcpu->kvm, sptep)) { - struct kvm_mmu_page *sp = sptep_to_sp(sptep); + drop_spte(kvm, sptep); - kvm_flush_remote_tlbs_with_address(vcpu->kvm, sp->gfn, + if (flush) + kvm_flush_remote_tlbs_with_address(kvm, sp->gfn, KVM_PAGES_PER_HPAGE(sp->role.level)); - } } /* @@ -1383,22 +1384,22 @@ static bool kvm_vcpu_write_protect_gfn(struct kvm_vcpu *vcpu, u64 gfn) return kvm_mmu_slot_gfn_write_protect(vcpu->kvm, slot, gfn, PG_LEVEL_4K); } -static bool kvm_zap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, - const struct kvm_memory_slot *slot) +static bool __kvm_zap_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head, + const struct kvm_memory_slot *slot) { - return pte_list_destroy(kvm, rmap_head); + return kvm_zap_all_rmap_sptes(kvm, rmap_head); } -static bool kvm_unmap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, - struct kvm_memory_slot *slot, gfn_t gfn, int level, - pte_t unused) +static bool kvm_zap_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head, + struct kvm_memory_slot *slot, gfn_t gfn, int level, + pte_t unused) { - return kvm_zap_rmapp(kvm, rmap_head, slot); + return __kvm_zap_rmap(kvm, rmap_head, slot); } -static bool kvm_set_pte_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, - struct kvm_memory_slot *slot, gfn_t gfn, int level, - pte_t pte) +static bool kvm_set_pte_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head, + struct kvm_memory_slot *slot, gfn_t gfn, int level, + pte_t pte) { u64 *sptep; struct rmap_iterator iter; @@ -1417,7 +1418,7 @@ restart: need_flush = true; if (pte_write(pte)) { - pte_list_remove(kvm, rmap_head, sptep); + kvm_zap_one_rmap_spte(kvm, rmap_head, sptep); goto restart; } else { new_spte = kvm_mmu_changed_pte_notifier_make_spte( @@ -1529,7 +1530,7 @@ bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) bool flush = false; if (kvm_memslots_have_rmaps(kvm)) - flush = kvm_handle_gfn_range(kvm, range, kvm_unmap_rmapp); + flush = kvm_handle_gfn_range(kvm, range, kvm_zap_rmap); if (is_tdp_mmu_enabled(kvm)) flush = kvm_tdp_mmu_unmap_gfn_range(kvm, range, flush); @@ -1542,7 +1543,7 @@ bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) bool flush = false; if (kvm_memslots_have_rmaps(kvm)) - flush = kvm_handle_gfn_range(kvm, range, kvm_set_pte_rmapp); + flush = kvm_handle_gfn_range(kvm, range, kvm_set_pte_rmap); if (is_tdp_mmu_enabled(kvm)) flush |= kvm_tdp_mmu_set_spte_gfn(kvm, range); @@ -1550,9 +1551,9 @@ bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) return flush; } -static bool kvm_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, - struct kvm_memory_slot *slot, gfn_t gfn, int level, - pte_t unused) +static bool kvm_age_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head, + struct kvm_memory_slot *slot, gfn_t gfn, int level, + pte_t unused) { u64 *sptep; struct rmap_iterator iter; @@ -1564,9 +1565,9 @@ static bool kvm_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, return young; } -static bool kvm_test_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, - struct kvm_memory_slot *slot, gfn_t gfn, - int level, pte_t unused) +static bool kvm_test_age_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head, + struct kvm_memory_slot *slot, gfn_t gfn, + int level, pte_t unused) { u64 *sptep; struct rmap_iterator iter; @@ -1579,31 +1580,43 @@ static bool kvm_test_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, #define RMAP_RECYCLE_THRESHOLD 1000 -static void rmap_add(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, - u64 *spte, gfn_t gfn) +static void __rmap_add(struct kvm *kvm, + struct kvm_mmu_memory_cache *cache, + const struct kvm_memory_slot *slot, + u64 *spte, gfn_t gfn, unsigned int access) { struct kvm_mmu_page *sp; struct kvm_rmap_head *rmap_head; int rmap_count; sp = sptep_to_sp(spte); - kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn); + kvm_mmu_page_set_translation(sp, spte_index(spte), gfn, access); + kvm_update_page_stats(kvm, sp->role.level, 1); + rmap_head = gfn_to_rmap(gfn, sp->role.level, slot); - rmap_count = pte_list_add(vcpu, spte, rmap_head); + rmap_count = pte_list_add(cache, spte, rmap_head); if (rmap_count > RMAP_RECYCLE_THRESHOLD) { - kvm_unmap_rmapp(vcpu->kvm, rmap_head, NULL, gfn, sp->role.level, __pte(0)); + kvm_zap_all_rmap_sptes(kvm, rmap_head); kvm_flush_remote_tlbs_with_address( - vcpu->kvm, sp->gfn, KVM_PAGES_PER_HPAGE(sp->role.level)); + kvm, sp->gfn, KVM_PAGES_PER_HPAGE(sp->role.level)); } } +static void rmap_add(struct kvm_vcpu *vcpu, const struct kvm_memory_slot *slot, + u64 *spte, gfn_t gfn, unsigned int access) +{ + struct kvm_mmu_memory_cache *cache = &vcpu->arch.mmu_pte_list_desc_cache; + + __rmap_add(vcpu->kvm, cache, slot, spte, gfn, access); +} + bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) { bool young = false; if (kvm_memslots_have_rmaps(kvm)) - young = kvm_handle_gfn_range(kvm, range, kvm_age_rmapp); + young = kvm_handle_gfn_range(kvm, range, kvm_age_rmap); if (is_tdp_mmu_enabled(kvm)) young |= kvm_tdp_mmu_age_gfn_range(kvm, range); @@ -1616,7 +1629,7 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) bool young = false; if (kvm_memslots_have_rmaps(kvm)) - young = kvm_handle_gfn_range(kvm, range, kvm_test_age_rmapp); + young = kvm_handle_gfn_range(kvm, range, kvm_test_age_rmap); if (is_tdp_mmu_enabled(kvm)) young |= kvm_tdp_mmu_test_age_gfn(kvm, range); @@ -1652,14 +1665,14 @@ static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, long nr) percpu_counter_add(&kvm_total_used_mmu_pages, nr); } -static void kvm_mmu_free_page(struct kvm_mmu_page *sp) +static void kvm_mmu_free_shadow_page(struct kvm_mmu_page *sp) { MMU_WARN_ON(!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); + free_page((unsigned long)sp->shadowed_translation); kmem_cache_free(mmu_page_header_cache, sp); } @@ -1668,19 +1681,19 @@ static unsigned kvm_page_table_hashfn(gfn_t gfn) return hash_64(gfn, KVM_MMU_HASH_SHIFT); } -static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu, +static void mmu_page_add_parent_pte(struct kvm_mmu_memory_cache *cache, struct kvm_mmu_page *sp, u64 *parent_pte) { if (!parent_pte) return; - pte_list_add(vcpu, parent_pte, &sp->parent_ptes); + pte_list_add(cache, 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); + pte_list_remove(parent_pte, &sp->parent_ptes); } static void drop_parent_pte(struct kvm_mmu_page *sp, @@ -1690,27 +1703,6 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, mmu_spte_clear_no_track(parent_pte); } -static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct) -{ - struct kvm_mmu_page *sp; - - sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); - sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); - if (!direct) - sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); - set_page_private(virt_to_page(sp->spt), (unsigned long)sp); - - /* - * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() - * depends on valid pages being added to the head of the list. See - * comments in kvm_zap_obsolete_pages(). - */ - sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; - list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); - 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) { @@ -1725,11 +1717,9 @@ static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp) static void mark_unsync(u64 *spte) { struct kvm_mmu_page *sp; - unsigned int index; sp = sptep_to_sp(spte); - index = spte - sp->spt; - if (__test_and_set_bit(index, sp->unsync_child_bitmap)) + if (__test_and_set_bit(spte_index(spte), sp->unsync_child_bitmap)) return; if (sp->unsync_children++) return; @@ -1789,7 +1779,7 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp, continue; } - child = to_shadow_page(ent & PT64_BASE_ADDR_MASK); + child = to_shadow_page(ent & SPTE_BASE_ADDR_MASK); if (child->unsync_children) { if (mmu_pages_add(pvec, child, i)) @@ -2019,36 +2009,24 @@ static void clear_sp_write_flooding_count(u64 *spte) __clear_sp_write_flooding_count(sptep_to_sp(spte)); } -static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, - gfn_t gfn, - gva_t gaddr, - unsigned level, - int direct, - unsigned int access) +/* + * The vCPU is required when finding indirect shadow pages; the shadow + * page may already exist and syncing it needs the vCPU pointer in + * order to read guest page tables. Direct shadow pages are never + * unsync, thus @vcpu can be NULL if @role.direct is true. + */ +static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm *kvm, + struct kvm_vcpu *vcpu, + gfn_t gfn, + struct hlist_head *sp_list, + union kvm_mmu_page_role role) { - bool direct_mmu = vcpu->arch.mmu->root_role.direct; - union kvm_mmu_page_role role; - struct hlist_head *sp_list; - unsigned quadrant; struct kvm_mmu_page *sp; int ret; int collisions = 0; LIST_HEAD(invalid_list); - role = vcpu->arch.mmu->root_role; - role.level = level; - role.direct = direct; - role.access = access; - if (role.has_4_byte_gpte) { - quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level)); - quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1; - role.quadrant = quadrant; - } - if (level <= vcpu->arch.mmu->cpu_role.base.level) - role.passthrough = 0; - - sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; - for_each_valid_sp(vcpu->kvm, sp, sp_list) { + for_each_valid_sp(kvm, sp, sp_list) { if (sp->gfn != gfn) { collisions++; continue; @@ -2064,16 +2042,20 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, * Unsync pages must not be left as is, because the new * upper-level page will be write-protected. */ - if (level > PG_LEVEL_4K && sp->unsync) - kvm_mmu_prepare_zap_page(vcpu->kvm, sp, + if (role.level > PG_LEVEL_4K && sp->unsync) + kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); continue; } - if (direct_mmu) - goto trace_get_page; + /* unsync and write-flooding only apply to indirect SPs. */ + if (sp->role.direct) + goto out; if (sp->unsync) { + if (KVM_BUG_ON(!vcpu, kvm)) + break; + /* * The page is good, but is stale. kvm_sync_page does * get the latest guest state, but (unlike mmu_unsync_children) @@ -2092,37 +2074,160 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, WARN_ON(!list_empty(&invalid_list)); if (ret > 0) - kvm_flush_remote_tlbs(vcpu->kvm); + kvm_flush_remote_tlbs(kvm); } __clear_sp_write_flooding_count(sp); -trace_get_page: - trace_kvm_mmu_get_page(sp, false); goto out; } - ++vcpu->kvm->stat.mmu_cache_miss; + sp = NULL; + ++kvm->stat.mmu_cache_miss; + +out: + kvm_mmu_commit_zap_page(kvm, &invalid_list); + + if (collisions > kvm->stat.max_mmu_page_hash_collisions) + kvm->stat.max_mmu_page_hash_collisions = collisions; + return sp; +} + +/* Caches used when allocating a new shadow page. */ +struct shadow_page_caches { + struct kvm_mmu_memory_cache *page_header_cache; + struct kvm_mmu_memory_cache *shadow_page_cache; + struct kvm_mmu_memory_cache *shadowed_info_cache; +}; + +static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm *kvm, + struct shadow_page_caches *caches, + gfn_t gfn, + struct hlist_head *sp_list, + union kvm_mmu_page_role role) +{ + struct kvm_mmu_page *sp; + + sp = kvm_mmu_memory_cache_alloc(caches->page_header_cache); + sp->spt = kvm_mmu_memory_cache_alloc(caches->shadow_page_cache); + if (!role.direct) + sp->shadowed_translation = kvm_mmu_memory_cache_alloc(caches->shadowed_info_cache); + + set_page_private(virt_to_page(sp->spt), (unsigned long)sp); - sp = kvm_mmu_alloc_page(vcpu, direct); + /* + * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() + * depends on valid pages being added to the head of the list. See + * comments in kvm_zap_obsolete_pages(). + */ + sp->mmu_valid_gen = kvm->arch.mmu_valid_gen; + list_add(&sp->link, &kvm->arch.active_mmu_pages); + kvm_mod_used_mmu_pages(kvm, +1); sp->gfn = gfn; sp->role = role; hlist_add_head(&sp->hash_link, sp_list); - if (sp_has_gptes(sp)) { - account_shadowed(vcpu->kvm, sp); - if (level == PG_LEVEL_4K && kvm_vcpu_write_protect_gfn(vcpu, gfn)) - kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn, 1); + if (sp_has_gptes(sp)) + account_shadowed(kvm, sp); + + return sp; +} + +/* Note, @vcpu may be NULL if @role.direct is true; see kvm_mmu_find_shadow_page. */ +static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm *kvm, + struct kvm_vcpu *vcpu, + struct shadow_page_caches *caches, + gfn_t gfn, + union kvm_mmu_page_role role) +{ + struct hlist_head *sp_list; + struct kvm_mmu_page *sp; + bool created = false; + + sp_list = &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; + + sp = kvm_mmu_find_shadow_page(kvm, vcpu, gfn, sp_list, role); + if (!sp) { + created = true; + sp = kvm_mmu_alloc_shadow_page(kvm, caches, gfn, sp_list, role); } - trace_kvm_mmu_get_page(sp, true); -out: - kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); - if (collisions > vcpu->kvm->stat.max_mmu_page_hash_collisions) - vcpu->kvm->stat.max_mmu_page_hash_collisions = collisions; + trace_kvm_mmu_get_page(sp, created); return sp; } +static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, + gfn_t gfn, + union kvm_mmu_page_role role) +{ + struct shadow_page_caches caches = { + .page_header_cache = &vcpu->arch.mmu_page_header_cache, + .shadow_page_cache = &vcpu->arch.mmu_shadow_page_cache, + .shadowed_info_cache = &vcpu->arch.mmu_shadowed_info_cache, + }; + + return __kvm_mmu_get_shadow_page(vcpu->kvm, vcpu, &caches, gfn, role); +} + +static union kvm_mmu_page_role kvm_mmu_child_role(u64 *sptep, bool direct, + unsigned int access) +{ + struct kvm_mmu_page *parent_sp = sptep_to_sp(sptep); + union kvm_mmu_page_role role; + + role = parent_sp->role; + role.level--; + role.access = access; + role.direct = direct; + role.passthrough = 0; + + /* + * If the guest has 4-byte PTEs then that means it's using 32-bit, + * 2-level, non-PAE paging. KVM shadows such guests with PAE paging + * (i.e. 8-byte PTEs). The difference in PTE size means that KVM must + * shadow each guest page table with multiple shadow page tables, which + * requires extra bookkeeping in the role. + * + * Specifically, to shadow the guest's page directory (which covers a + * 4GiB address space), KVM uses 4 PAE page directories, each mapping + * 1GiB of the address space. @role.quadrant encodes which quarter of + * the address space each maps. + * + * To shadow the guest's page tables (which each map a 4MiB region), KVM + * uses 2 PAE page tables, each mapping a 2MiB region. For these, + * @role.quadrant encodes which half of the region they map. + * + * Concretely, a 4-byte PDE consumes bits 31:22, while an 8-byte PDE + * consumes bits 29:21. To consume bits 31:30, KVM's uses 4 shadow + * PDPTEs; those 4 PAE page directories are pre-allocated and their + * quadrant is assigned in mmu_alloc_root(). A 4-byte PTE consumes + * bits 21:12, while an 8-byte PTE consumes bits 20:12. To consume + * bit 21 in the PTE (the child here), KVM propagates that bit to the + * quadrant, i.e. sets quadrant to '0' or '1'. The parent 8-byte PDE + * covers bit 21 (see above), thus the quadrant is calculated from the + * _least_ significant bit of the PDE index. + */ + if (role.has_4_byte_gpte) { + WARN_ON_ONCE(role.level != PG_LEVEL_4K); + role.quadrant = spte_index(sptep) & 1; + } + + return role; +} + +static struct kvm_mmu_page *kvm_mmu_get_child_sp(struct kvm_vcpu *vcpu, + u64 *sptep, gfn_t gfn, + bool direct, unsigned int access) +{ + union kvm_mmu_page_role role; + + if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) + return ERR_PTR(-EEXIST); + + role = kvm_mmu_child_role(sptep, direct, access); + return kvm_mmu_get_shadow_page(vcpu, gfn, role); +} + static void shadow_walk_init_using_root(struct kvm_shadow_walk_iterator *iterator, struct kvm_vcpu *vcpu, hpa_t root, u64 addr) @@ -2145,7 +2250,7 @@ static void shadow_walk_init_using_root(struct kvm_shadow_walk_iterator *iterato iterator->shadow_addr = vcpu->arch.mmu->pae_root[(addr >> 30) & 3]; - iterator->shadow_addr &= PT64_BASE_ADDR_MASK; + iterator->shadow_addr &= SPTE_BASE_ADDR_MASK; --iterator->level; if (!iterator->shadow_addr) iterator->level = 0; @@ -2164,7 +2269,7 @@ static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator) if (iterator->level < PG_LEVEL_4K) return false; - iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level); + iterator->index = SPTE_INDEX(iterator->addr, iterator->level); iterator->sptep = ((u64 *)__va(iterator->shadow_addr)) + iterator->index; return true; } @@ -2177,7 +2282,7 @@ static void __shadow_walk_next(struct kvm_shadow_walk_iterator *iterator, return; } - iterator->shadow_addr = spte & PT64_BASE_ADDR_MASK; + iterator->shadow_addr = spte & SPTE_BASE_ADDR_MASK; --iterator->level; } @@ -2186,23 +2291,38 @@ static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator) __shadow_walk_next(iterator, *iterator->sptep); } -static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, - struct kvm_mmu_page *sp) +static void __link_shadow_page(struct kvm *kvm, + struct kvm_mmu_memory_cache *cache, u64 *sptep, + struct kvm_mmu_page *sp, bool flush) { u64 spte; BUILD_BUG_ON(VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK); + /* + * If an SPTE is present already, it must be a leaf and therefore + * a large one. Drop it, and flush the TLB if needed, before + * installing sp. + */ + if (is_shadow_present_pte(*sptep)) + drop_large_spte(kvm, sptep, flush); + spte = make_nonleaf_spte(sp->spt, sp_ad_disabled(sp)); mmu_spte_set(sptep, spte); - mmu_page_add_parent_pte(vcpu, sp, sptep); + mmu_page_add_parent_pte(cache, sp, sptep); if (sp->unsync_children || sp->unsync) mark_unsync(sptep); } +static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, + struct kvm_mmu_page *sp) +{ + __link_shadow_page(vcpu->kvm, &vcpu->arch.mmu_pte_list_desc_cache, sptep, sp, true); +} + static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned direct_access) { @@ -2216,7 +2336,7 @@ static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, * so we should update the spte at this point to get * a new sp with the correct access. */ - child = to_shadow_page(*sptep & PT64_BASE_ADDR_MASK); + child = to_shadow_page(*sptep & SPTE_BASE_ADDR_MASK); if (child->role.access == direct_access) return; @@ -2237,7 +2357,7 @@ static int mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp, if (is_last_spte(pte, sp->role.level)) { drop_spte(kvm, spte); } else { - child = to_shadow_page(pte & PT64_BASE_ADDR_MASK); + child = to_shadow_page(pte & SPTE_BASE_ADDR_MASK); drop_parent_pte(child, spte); /* @@ -2263,7 +2383,7 @@ static int kvm_mmu_page_unlink_children(struct kvm *kvm, int zapped = 0; unsigned i; - for (i = 0; i < PT64_ENT_PER_PAGE; ++i) + for (i = 0; i < SPTE_ENT_PER_PAGE; ++i) zapped += mmu_page_zap_pte(kvm, sp, sp->spt + i, invalid_list); return zapped; @@ -2396,7 +2516,7 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, list_for_each_entry_safe(sp, nsp, invalid_list, link) { WARN_ON(!sp->role.invalid || sp->root_count); - kvm_mmu_free_page(sp); + kvm_mmu_free_shadow_page(sp); } } @@ -2676,7 +2796,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, struct kvm_mmu_page *child; u64 pte = *sptep; - child = to_shadow_page(pte & PT64_BASE_ADDR_MASK); + child = to_shadow_page(pte & SPTE_BASE_ADDR_MASK); drop_parent_pte(child, sptep); flush = true; } else if (pfn != spte_to_pfn(*sptep)) { @@ -2711,8 +2831,10 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, if (!was_rmapped) { WARN_ON_ONCE(ret == RET_PF_SPURIOUS); - kvm_update_page_stats(vcpu->kvm, level, 1); - rmap_add(vcpu, slot, sptep, gfn); + rmap_add(vcpu, slot, sptep, gfn, pte_access); + } else { + /* Already rmapped but the pte_access bits may have changed. */ + kvm_mmu_page_set_access(sp, spte_index(sptep), pte_access); } return ret; @@ -2728,7 +2850,7 @@ static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu, int i, ret; gfn_t gfn; - gfn = kvm_mmu_page_get_gfn(sp, start - sp->spt); + gfn = kvm_mmu_page_get_gfn(sp, spte_index(start)); slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, access & ACC_WRITE_MASK); if (!slot) return -1; @@ -2754,7 +2876,7 @@ static void __direct_pte_prefetch(struct kvm_vcpu *vcpu, WARN_ON(!sp->role.direct); - i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1); + i = spte_index(sptep) & ~(PTE_PREFETCH_NUM - 1); spte = sp->spt + i; for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) { @@ -2798,20 +2920,42 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep) __direct_pte_prefetch(vcpu, sp, sptep); } -static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, +/* + * Lookup the mapping level for @gfn in the current mm. + * + * WARNING! Use of host_pfn_mapping_level() requires the caller and the end + * consumer to be tied into KVM's handlers for MMU notifier events! + * + * There are several ways to safely use this helper: + * + * - Check mmu_notifier_retry_hva() after grabbing the mapping level, before + * consuming it. In this case, mmu_lock doesn't need to be held during the + * lookup, but it does need to be held while checking the MMU notifier. + * + * - Hold mmu_lock AND ensure there is no in-progress MMU notifier invalidation + * event for the hva. This can be done by explicit checking the MMU notifier + * or by ensuring that KVM already has a valid mapping that covers the hva. + * + * - Do not use the result to install new mappings, e.g. use the host mapping + * level only to decide whether or not to zap an entry. In this case, it's + * not required to hold mmu_lock (though it's highly likely the caller will + * want to hold mmu_lock anyways, e.g. to modify SPTEs). + * + * Note! The lookup can still race with modifications to host page tables, but + * the above "rules" ensure KVM will not _consume_ the result of the walk if a + * race with the primary MMU occurs. + */ +static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, const struct kvm_memory_slot *slot) { + int level = PG_LEVEL_4K; unsigned long hva; unsigned long flags; - int level = PG_LEVEL_4K; pgd_t pgd; p4d_t p4d; pud_t pud; pmd_t pmd; - if (!PageCompound(pfn_to_page(pfn)) && !kvm_is_zone_device_pfn(pfn)) - return PG_LEVEL_4K; - /* * Note, using the already-retrieved memslot and __gfn_to_hva_memslot() * is not solely for performance, it's also necessary to avoid the @@ -2823,16 +2967,19 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, hva = __gfn_to_hva_memslot(slot, gfn); /* - * Lookup the mapping level in the current mm. The information - * may become stale soon, but it is safe to use as long as - * 1) mmu_notifier_retry was checked after taking mmu_lock, and - * 2) mmu_lock is taken now. - * - * We still need to disable IRQs to prevent concurrent tear down - * of page tables. + * Disable IRQs to prevent concurrent tear down of host page tables, + * e.g. if the primary MMU promotes a P*D to a huge page and then frees + * the original page table. */ local_irq_save(flags); + /* + * Read each entry once. As above, a non-leaf entry can be promoted to + * a huge page _during_ this walk. Re-reading the entry could send the + * walk into the weeks, e.g. p*d_large() returns false (sees the old + * value) and then p*d_offset() walks into the target huge page instead + * of the old page table (sees the new value). + */ pgd = READ_ONCE(*pgd_offset(kvm->mm, hva)); if (pgd_none(pgd)) goto out; @@ -2864,7 +3011,7 @@ out: int kvm_mmu_max_mapping_level(struct kvm *kvm, const struct kvm_memory_slot *slot, gfn_t gfn, - kvm_pfn_t pfn, int max_level) + int max_level) { struct kvm_lpage_info *linfo; int host_level; @@ -2879,7 +3026,7 @@ int kvm_mmu_max_mapping_level(struct kvm *kvm, if (max_level == PG_LEVEL_4K) return PG_LEVEL_4K; - host_level = host_pfn_mapping_level(kvm, gfn, pfn, slot); + host_level = host_pfn_mapping_level(kvm, gfn, slot); return min(host_level, max_level); } @@ -2893,7 +3040,7 @@ void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault if (unlikely(fault->max_level == PG_LEVEL_4K)) return; - if (is_error_noslot_pfn(fault->pfn) || kvm_is_reserved_pfn(fault->pfn)) + if (is_error_noslot_pfn(fault->pfn)) return; if (kvm_slot_dirty_track_enabled(slot)) @@ -2904,8 +3051,7 @@ void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault * level, which will be used to do precise, accurate accounting. */ fault->req_level = kvm_mmu_max_mapping_level(vcpu->kvm, slot, - fault->gfn, fault->pfn, - fault->max_level); + fault->gfn, fault->max_level); if (fault->req_level == PG_LEVEL_4K || fault->huge_page_disallowed) return; @@ -2961,13 +3107,10 @@ static int __direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) if (it.level == fault->goal_level) break; - drop_large_spte(vcpu, it.sptep); - if (is_shadow_present_pte(*it.sptep)) + sp = kvm_mmu_get_child_sp(vcpu, it.sptep, base_gfn, true, ACC_ALL); + if (sp == ERR_PTR(-EEXIST)) continue; - sp = kvm_mmu_get_page(vcpu, base_gfn, it.addr, - it.level - 1, true, ACC_ALL); - link_shadow_page(vcpu, it.sptep, sp); if (fault->is_tdp && fault->huge_page_disallowed && fault->req_level >= it.level) @@ -3095,7 +3238,7 @@ fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, * * Compare with set_spte where instead shadow_dirty_mask is set. */ - if (cmpxchg64(sptep, old_spte, new_spte) != old_spte) + if (!try_cmpxchg64(sptep, &old_spte, new_spte)) return false; if (is_writable_pte(new_spte) && !is_writable_pte(old_spte)) @@ -3265,7 +3408,7 @@ static void mmu_free_root_page(struct kvm *kvm, hpa_t *root_hpa, if (!VALID_PAGE(*root_hpa)) return; - sp = to_shadow_page(*root_hpa & PT64_BASE_ADDR_MASK); + sp = to_shadow_page(*root_hpa & SPTE_BASE_ADDR_MASK); if (WARN_ON(!sp)) return; @@ -3369,12 +3512,19 @@ static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn) return ret; } -static hpa_t mmu_alloc_root(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gva, - u8 level, bool direct) +static hpa_t mmu_alloc_root(struct kvm_vcpu *vcpu, gfn_t gfn, int quadrant, + u8 level) { + union kvm_mmu_page_role role = vcpu->arch.mmu->root_role; struct kvm_mmu_page *sp; - sp = kvm_mmu_get_page(vcpu, gfn, gva, level, direct, ACC_ALL); + role.level = level; + role.quadrant = quadrant; + + WARN_ON_ONCE(quadrant && !role.has_4_byte_gpte); + WARN_ON_ONCE(role.direct && role.has_4_byte_gpte); + + sp = kvm_mmu_get_shadow_page(vcpu, gfn, role); ++sp->root_count; return __pa(sp->spt); @@ -3397,7 +3547,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu) root = kvm_tdp_mmu_get_vcpu_root_hpa(vcpu); mmu->root.hpa = root; } else if (shadow_root_level >= PT64_ROOT_4LEVEL) { - root = mmu_alloc_root(vcpu, 0, 0, shadow_root_level, true); + root = mmu_alloc_root(vcpu, 0, 0, shadow_root_level); mmu->root.hpa = root; } else if (shadow_root_level == PT32E_ROOT_LEVEL) { if (WARN_ON_ONCE(!mmu->pae_root)) { @@ -3408,8 +3558,8 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu) for (i = 0; i < 4; ++i) { WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i])); - root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT), - i << 30, PT32_ROOT_LEVEL, true); + root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT), 0, + PT32_ROOT_LEVEL); mmu->pae_root[i] = root | PT_PRESENT_MASK | shadow_me_value; } @@ -3493,9 +3643,8 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) struct kvm_mmu *mmu = vcpu->arch.mmu; u64 pdptrs[4], pm_mask; gfn_t root_gfn, root_pgd; + int quadrant, i, r; hpa_t root; - unsigned i; - int r; root_pgd = mmu->get_guest_pgd(vcpu); root_gfn = root_pgd >> PAGE_SHIFT; @@ -3533,7 +3682,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) */ if (mmu->cpu_role.base.level >= PT64_ROOT_4LEVEL) { root = mmu_alloc_root(vcpu, root_gfn, 0, - mmu->root_role.level, false); + mmu->root_role.level); mmu->root.hpa = root; goto set_root_pgd; } @@ -3578,8 +3727,15 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) root_gfn = pdptrs[i] >> PAGE_SHIFT; } - root = mmu_alloc_root(vcpu, root_gfn, i << 30, - PT32_ROOT_LEVEL, false); + /* + * If shadowing 32-bit non-PAE page tables, each PAE page + * directory maps one quarter of the guest's non-PAE page + * directory. Othwerise each PAE page direct shadows one guest + * PAE page directory so that quadrant should be 0. + */ + quadrant = (mmu->cpu_role.base.level == PT32_ROOT_LEVEL) ? i : 0; + + root = mmu_alloc_root(vcpu, root_gfn, quadrant, PT32_ROOT_LEVEL); mmu->pae_root[i] = root | pm_mask; } @@ -3737,7 +3893,7 @@ void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu) hpa_t root = vcpu->arch.mmu->pae_root[i]; if (IS_VALID_PAE_ROOT(root)) { - root &= PT64_BASE_ADDR_MASK; + root &= SPTE_BASE_ADDR_MASK; sp = to_shadow_page(root); mmu_sync_children(vcpu, sp, true); } @@ -4155,14 +4311,26 @@ EXPORT_SYMBOL_GPL(kvm_handle_page_fault); int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) { - while (fault->max_level > PG_LEVEL_4K) { - int page_num = KVM_PAGES_PER_HPAGE(fault->max_level); - gfn_t base = (fault->addr >> PAGE_SHIFT) & ~(page_num - 1); - - if (kvm_mtrr_check_gfn_range_consistency(vcpu, base, page_num)) - break; + /* + * If the guest's MTRRs may be used to compute the "real" memtype, + * restrict the mapping level to ensure KVM uses a consistent memtype + * across the entire mapping. If the host MTRRs are ignored by TDP + * (shadow_memtype_mask is non-zero), and the VM has non-coherent DMA + * (DMA doesn't snoop CPU caches), KVM's ABI is to honor the memtype + * from the guest's MTRRs so that guest accesses to memory that is + * DMA'd aren't cached against the guest's wishes. + * + * Note, KVM may still ultimately ignore guest MTRRs for certain PFNs, + * e.g. KVM will force UC memtype for host MMIO. + */ + if (shadow_memtype_mask && kvm_arch_has_noncoherent_dma(vcpu->kvm)) { + for ( ; fault->max_level > PG_LEVEL_4K; --fault->max_level) { + int page_num = KVM_PAGES_PER_HPAGE(fault->max_level); + gfn_t base = (fault->addr >> PAGE_SHIFT) & ~(page_num - 1); - --fault->max_level; + if (kvm_mtrr_check_gfn_range_consistency(vcpu, base, page_num)) + break; + } } return direct_page_fault(vcpu, fault); @@ -4567,7 +4735,7 @@ reset_tdp_shadow_zero_bits_mask(struct kvm_mmu *context) if (boot_cpu_is_amd()) __reset_rsvds_bits_mask(shadow_zero_check, reserved_hpa_bits(), - context->root_role.level, false, + context->root_role.level, true, boot_cpu_has(X86_FEATURE_GBPAGES), false, true); else @@ -5199,11 +5367,11 @@ static bool need_remote_flush(u64 old, u64 new) return false; if (!is_shadow_present_pte(new)) return true; - if ((old ^ new) & PT64_BASE_ADDR_MASK) + if ((old ^ new) & SPTE_BASE_ADDR_MASK) return true; old ^= shadow_nx_mask; new ^= shadow_nx_mask; - return (old & ~new & PT64_PERM_MASK) != 0; + return (old & ~new & SPTE_PERM_MASK) != 0; } static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa, @@ -5328,13 +5496,6 @@ static void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes); - /* - * No need to care whether allocation memory is successful - * or not since pte prefetch is skipped if it does not have - * enough objects in the cache. - */ - mmu_topup_memory_caches(vcpu, true); - write_lock(&vcpu->kvm->mmu_lock); gentry = mmu_pte_write_fetch_gpte(vcpu, &gpa, &bytes); @@ -5819,9 +5980,25 @@ int kvm_mmu_init_vm(struct kvm *kvm) node->track_write = kvm_mmu_pte_write; node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot; kvm_page_track_register_notifier(kvm, node); + + kvm->arch.split_page_header_cache.kmem_cache = mmu_page_header_cache; + kvm->arch.split_page_header_cache.gfp_zero = __GFP_ZERO; + + kvm->arch.split_shadow_page_cache.gfp_zero = __GFP_ZERO; + + kvm->arch.split_desc_cache.kmem_cache = pte_list_desc_cache; + kvm->arch.split_desc_cache.gfp_zero = __GFP_ZERO; + return 0; } +static void mmu_free_vm_memory_caches(struct kvm *kvm) +{ + kvm_mmu_free_memory_cache(&kvm->arch.split_desc_cache); + kvm_mmu_free_memory_cache(&kvm->arch.split_page_header_cache); + kvm_mmu_free_memory_cache(&kvm->arch.split_shadow_page_cache); +} + void kvm_mmu_uninit_vm(struct kvm *kvm) { struct kvm_page_track_notifier_node *node = &kvm->arch.mmu_sp_tracker; @@ -5829,9 +6006,11 @@ void kvm_mmu_uninit_vm(struct kvm *kvm) kvm_page_track_unregister_notifier(kvm, node); kvm_mmu_uninit_tdp_mmu(kvm); + + mmu_free_vm_memory_caches(kvm); } -static bool __kvm_zap_rmaps(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) +static bool kvm_rmap_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) { const struct kvm_memory_slot *memslot; struct kvm_memslots *slots; @@ -5853,8 +6032,7 @@ static bool __kvm_zap_rmaps(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) if (WARN_ON_ONCE(start >= end)) continue; - flush = slot_handle_level_range(kvm, memslot, kvm_zap_rmapp, - + flush = slot_handle_level_range(kvm, memslot, __kvm_zap_rmap, PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL, start, end - 1, true, flush); } @@ -5879,7 +6057,7 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) kvm_inc_notifier_count(kvm, gfn_start, gfn_end); - flush = __kvm_zap_rmaps(kvm, gfn_start, gfn_end); + flush = kvm_rmap_zap_gfn_range(kvm, gfn_start, gfn_end); if (is_tdp_mmu_enabled(kvm)) { for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) @@ -5950,15 +6128,249 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, kvm_arch_flush_remote_tlbs_memslot(kvm, memslot); } +static inline bool need_topup(struct kvm_mmu_memory_cache *cache, int min) +{ + return kvm_mmu_memory_cache_nr_free_objects(cache) < min; +} + +static bool need_topup_split_caches_or_resched(struct kvm *kvm) +{ + if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) + return true; + + /* + * In the worst case, SPLIT_DESC_CACHE_MIN_NR_OBJECTS descriptors are needed + * to split a single huge page. Calculating how many are actually needed + * is possible but not worth the complexity. + */ + return need_topup(&kvm->arch.split_desc_cache, SPLIT_DESC_CACHE_MIN_NR_OBJECTS) || + need_topup(&kvm->arch.split_page_header_cache, 1) || + need_topup(&kvm->arch.split_shadow_page_cache, 1); +} + +static int topup_split_caches(struct kvm *kvm) +{ + /* + * Allocating rmap list entries when splitting huge pages for nested + * MMUs is uncommon as KVM needs to use a list if and only if there is + * more than one rmap entry for a gfn, i.e. requires an L1 gfn to be + * aliased by multiple L2 gfns and/or from multiple nested roots with + * different roles. Aliasing gfns when using TDP is atypical for VMMs; + * a few gfns are often aliased during boot, e.g. when remapping BIOS, + * but aliasing rarely occurs post-boot or for many gfns. If there is + * only one rmap entry, rmap->val points directly at that one entry and + * doesn't need to allocate a list. Buffer the cache by the default + * capacity so that KVM doesn't have to drop mmu_lock to topup if KVM + * encounters an aliased gfn or two. + */ + const int capacity = SPLIT_DESC_CACHE_MIN_NR_OBJECTS + + KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; + int r; + + lockdep_assert_held(&kvm->slots_lock); + + r = __kvm_mmu_topup_memory_cache(&kvm->arch.split_desc_cache, capacity, + SPLIT_DESC_CACHE_MIN_NR_OBJECTS); + if (r) + return r; + + r = kvm_mmu_topup_memory_cache(&kvm->arch.split_page_header_cache, 1); + if (r) + return r; + + return kvm_mmu_topup_memory_cache(&kvm->arch.split_shadow_page_cache, 1); +} + +static struct kvm_mmu_page *shadow_mmu_get_sp_for_split(struct kvm *kvm, u64 *huge_sptep) +{ + struct kvm_mmu_page *huge_sp = sptep_to_sp(huge_sptep); + struct shadow_page_caches caches = {}; + union kvm_mmu_page_role role; + unsigned int access; + gfn_t gfn; + + gfn = kvm_mmu_page_get_gfn(huge_sp, spte_index(huge_sptep)); + access = kvm_mmu_page_get_access(huge_sp, spte_index(huge_sptep)); + + /* + * Note, huge page splitting always uses direct shadow pages, regardless + * of whether the huge page itself is mapped by a direct or indirect + * shadow page, since the huge page region itself is being directly + * mapped with smaller pages. + */ + role = kvm_mmu_child_role(huge_sptep, /*direct=*/true, access); + + /* Direct SPs do not require a shadowed_info_cache. */ + caches.page_header_cache = &kvm->arch.split_page_header_cache; + caches.shadow_page_cache = &kvm->arch.split_shadow_page_cache; + + /* Safe to pass NULL for vCPU since requesting a direct SP. */ + return __kvm_mmu_get_shadow_page(kvm, NULL, &caches, gfn, role); +} + +static void shadow_mmu_split_huge_page(struct kvm *kvm, + const struct kvm_memory_slot *slot, + u64 *huge_sptep) + +{ + struct kvm_mmu_memory_cache *cache = &kvm->arch.split_desc_cache; + u64 huge_spte = READ_ONCE(*huge_sptep); + struct kvm_mmu_page *sp; + bool flush = false; + u64 *sptep, spte; + gfn_t gfn; + int index; + + sp = shadow_mmu_get_sp_for_split(kvm, huge_sptep); + + for (index = 0; index < SPTE_ENT_PER_PAGE; index++) { + sptep = &sp->spt[index]; + gfn = kvm_mmu_page_get_gfn(sp, index); + + /* + * The SP may already have populated SPTEs, e.g. if this huge + * page is aliased by multiple sptes with the same access + * permissions. These entries are guaranteed to map the same + * gfn-to-pfn translation since the SP is direct, so no need to + * modify them. + * + * However, if a given SPTE points to a lower level page table, + * that lower level page table may only be partially populated. + * Installing such SPTEs would effectively unmap a potion of the + * huge page. Unmapping guest memory always requires a TLB flush + * since a subsequent operation on the unmapped regions would + * fail to detect the need to flush. + */ + if (is_shadow_present_pte(*sptep)) { + flush |= !is_last_spte(*sptep, sp->role.level); + continue; + } + + spte = make_huge_page_split_spte(kvm, huge_spte, sp->role, index); + mmu_spte_set(sptep, spte); + __rmap_add(kvm, cache, slot, sptep, gfn, sp->role.access); + } + + __link_shadow_page(kvm, cache, huge_sptep, sp, flush); +} + +static int shadow_mmu_try_split_huge_page(struct kvm *kvm, + const struct kvm_memory_slot *slot, + u64 *huge_sptep) +{ + struct kvm_mmu_page *huge_sp = sptep_to_sp(huge_sptep); + int level, r = 0; + gfn_t gfn; + u64 spte; + + /* Grab information for the tracepoint before dropping the MMU lock. */ + gfn = kvm_mmu_page_get_gfn(huge_sp, spte_index(huge_sptep)); + level = huge_sp->role.level; + spte = *huge_sptep; + + if (kvm_mmu_available_pages(kvm) <= KVM_MIN_FREE_MMU_PAGES) { + r = -ENOSPC; + goto out; + } + + if (need_topup_split_caches_or_resched(kvm)) { + write_unlock(&kvm->mmu_lock); + cond_resched(); + /* + * If the topup succeeds, return -EAGAIN to indicate that the + * rmap iterator should be restarted because the MMU lock was + * dropped. + */ + r = topup_split_caches(kvm) ?: -EAGAIN; + write_lock(&kvm->mmu_lock); + goto out; + } + + shadow_mmu_split_huge_page(kvm, slot, huge_sptep); + +out: + trace_kvm_mmu_split_huge_page(gfn, spte, level, r); + return r; +} + +static bool shadow_mmu_try_split_huge_pages(struct kvm *kvm, + struct kvm_rmap_head *rmap_head, + const struct kvm_memory_slot *slot) +{ + struct rmap_iterator iter; + struct kvm_mmu_page *sp; + u64 *huge_sptep; + int r; + +restart: + for_each_rmap_spte(rmap_head, &iter, huge_sptep) { + sp = sptep_to_sp(huge_sptep); + + /* TDP MMU is enabled, so rmap only contains nested MMU SPs. */ + if (WARN_ON_ONCE(!sp->role.guest_mode)) + continue; + + /* The rmaps should never contain non-leaf SPTEs. */ + if (WARN_ON_ONCE(!is_large_pte(*huge_sptep))) + continue; + + /* SPs with level >PG_LEVEL_4K should never by unsync. */ + if (WARN_ON_ONCE(sp->unsync)) + continue; + + /* Don't bother splitting huge pages on invalid SPs. */ + if (sp->role.invalid) + continue; + + r = shadow_mmu_try_split_huge_page(kvm, slot, huge_sptep); + + /* + * The split succeeded or needs to be retried because the MMU + * lock was dropped. Either way, restart the iterator to get it + * back into a consistent state. + */ + if (!r || r == -EAGAIN) + goto restart; + + /* The split failed and shouldn't be retried (e.g. -ENOMEM). */ + break; + } + + return false; +} + +static void kvm_shadow_mmu_try_split_huge_pages(struct kvm *kvm, + const struct kvm_memory_slot *slot, + gfn_t start, gfn_t end, + int target_level) +{ + int level; + + /* + * Split huge pages starting with KVM_MAX_HUGEPAGE_LEVEL and working + * down to the target level. This ensures pages are recursively split + * all the way to the target level. There's no need to split pages + * already at the target level. + */ + for (level = KVM_MAX_HUGEPAGE_LEVEL; level > target_level; level--) { + slot_handle_level_range(kvm, slot, shadow_mmu_try_split_huge_pages, + level, level, start, end - 1, true, false); + } +} + /* Must be called with the mmu_lock held in write-mode. */ void kvm_mmu_try_split_huge_pages(struct kvm *kvm, const struct kvm_memory_slot *memslot, u64 start, u64 end, int target_level) { - if (is_tdp_mmu_enabled(kvm)) - kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, - target_level, false); + if (!is_tdp_mmu_enabled(kvm)) + return; + + if (kvm_memslots_have_rmaps(kvm)) + kvm_shadow_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level); + + kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level, false); /* * A TLB flush is unnecessary at this point for the same resons as in @@ -5973,12 +6385,19 @@ void kvm_mmu_slot_try_split_huge_pages(struct kvm *kvm, u64 start = memslot->base_gfn; u64 end = start + memslot->npages; - if (is_tdp_mmu_enabled(kvm)) { - read_lock(&kvm->mmu_lock); - kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level, true); - read_unlock(&kvm->mmu_lock); + if (!is_tdp_mmu_enabled(kvm)) + return; + + if (kvm_memslots_have_rmaps(kvm)) { + write_lock(&kvm->mmu_lock); + kvm_shadow_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level); + write_unlock(&kvm->mmu_lock); } + read_lock(&kvm->mmu_lock); + kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level, true); + read_unlock(&kvm->mmu_lock); + /* * No TLB flush is necessary here. KVM will flush TLBs after * write-protecting and/or clearing dirty on the newly split SPTEs to @@ -6012,10 +6431,10 @@ restart: * the guest, and the guest page table is using 4K page size * mapping if the indirect sp has level = 1. */ - if (sp->role.direct && !kvm_is_reserved_pfn(pfn) && + if (sp->role.direct && sp->role.level < kvm_mmu_max_mapping_level(kvm, slot, sp->gfn, - pfn, PG_LEVEL_NUM)) { - pte_list_remove(kvm, rmap_head, sptep); + PG_LEVEL_NUM)) { + kvm_zap_one_rmap_spte(kvm, rmap_head, sptep); if (kvm_available_flush_tlb_with_range()) kvm_flush_remote_tlbs_with_address(kvm, sp->gfn, @@ -6030,18 +6449,24 @@ restart: return need_tlb_flush; } +static void kvm_rmap_zap_collapsible_sptes(struct kvm *kvm, + const struct kvm_memory_slot *slot) +{ + /* + * Note, use KVM_MAX_HUGEPAGE_LEVEL - 1 since there's no need to zap + * pages that are already mapped at the maximum hugepage level. + */ + if (slot_handle_level(kvm, slot, kvm_mmu_zap_collapsible_spte, + PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL - 1, true)) + kvm_arch_flush_remote_tlbs_memslot(kvm, slot); +} + void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm, const struct kvm_memory_slot *slot) { if (kvm_memslots_have_rmaps(kvm)) { write_lock(&kvm->mmu_lock); - /* - * Zap only 4k SPTEs since the legacy MMU only supports dirty - * logging at a 4k granularity and never creates collapsible - * 2m SPTEs during dirty logging. - */ - if (slot_handle_level_4k(kvm, slot, kvm_mmu_zap_collapsible_spte, true)) - kvm_arch_flush_remote_tlbs_memslot(kvm, slot); + kvm_rmap_zap_collapsible_sptes(kvm, slot); write_unlock(&kvm->mmu_lock); } diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index bd2a26897b97..582def531d4d 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -20,6 +20,20 @@ extern bool dbg; #define MMU_WARN_ON(x) do { } while (0) #endif +/* Page table builder macros common to shadow (host) PTEs and guest PTEs. */ +#define __PT_LEVEL_SHIFT(level, bits_per_level) \ + (PAGE_SHIFT + ((level) - 1) * (bits_per_level)) +#define __PT_INDEX(address, level, bits_per_level) \ + (((address) >> __PT_LEVEL_SHIFT(level, bits_per_level)) & ((1 << (bits_per_level)) - 1)) + +#define __PT_LVL_ADDR_MASK(base_addr_mask, level, bits_per_level) \ + ((base_addr_mask) & ~((1ULL << (PAGE_SHIFT + (((level) - 1) * (bits_per_level)))) - 1)) + +#define __PT_LVL_OFFSET_MASK(base_addr_mask, level, bits_per_level) \ + ((base_addr_mask) & ((1ULL << (PAGE_SHIFT + (((level) - 1) * (bits_per_level)))) - 1)) + +#define __PT_ENT_PER_PAGE(bits_per_level) (1 << (bits_per_level)) + /* * Unlike regular MMU roots, PAE "roots", a.k.a. PDPTEs/PDPTRs, have a PRESENT * bit, and thus are guaranteed to be non-zero when valid. And, when a guest @@ -53,8 +67,21 @@ struct kvm_mmu_page { gfn_t gfn; u64 *spt; - /* hold the gfn of each spte inside spt */ - gfn_t *gfns; + + /* + * Stores the result of the guest translation being shadowed by each + * SPTE. KVM shadows two types of guest translations: nGPA -> GPA + * (shadow EPT/NPT) and GVA -> GPA (traditional shadow paging). In both + * cases the result of the translation is a GPA and a set of access + * constraints. + * + * The GFN is stored in the upper bits (PAGE_SHIFT) and the shadowed + * access permissions are stored in the lower bits. Note, for + * convenience and uniformity across guests, the access permissions are + * stored in KVM format (e.g. ACC_EXEC_MASK) not the raw guest format. + */ + u64 *shadowed_translation; + /* Currently serving as active root */ union { int root_count; @@ -141,9 +168,9 @@ void kvm_flush_remote_tlbs_with_address(struct kvm *kvm, unsigned int pte_list_count(struct kvm_rmap_head *rmap_head); extern int nx_huge_pages; -static inline bool is_nx_huge_page_enabled(void) +static inline bool is_nx_huge_page_enabled(struct kvm *kvm) { - return READ_ONCE(nx_huge_pages); + return READ_ONCE(nx_huge_pages) && !kvm->arch.disable_nx_huge_pages; } struct kvm_page_fault { @@ -242,7 +269,8 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, .user = err & PFERR_USER_MASK, .prefetch = prefetch, .is_tdp = likely(vcpu->arch.mmu->page_fault == kvm_tdp_page_fault), - .nx_huge_page_workaround_enabled = is_nx_huge_page_enabled(), + .nx_huge_page_workaround_enabled = + is_nx_huge_page_enabled(vcpu->kvm), .max_level = KVM_MAX_HUGEPAGE_LEVEL, .req_level = PG_LEVEL_4K, @@ -281,7 +309,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, int kvm_mmu_max_mapping_level(struct kvm *kvm, const struct kvm_memory_slot *slot, gfn_t gfn, - kvm_pfn_t pfn, int max_level); + int max_level); void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault); void disallowed_hugepage_adjust(struct kvm_page_fault *fault, u64 spte, int cur_level); diff --git a/arch/x86/kvm/mmu/paging.h b/arch/x86/kvm/mmu/paging.h deleted file mode 100644 index de8ab323bb70..000000000000 --- a/arch/x86/kvm/mmu/paging.h +++ /dev/null @@ -1,14 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ -/* Shadow paging constants/helpers that don't need to be #undef'd. */ -#ifndef __KVM_X86_PAGING_H -#define __KVM_X86_PAGING_H - -#define GUEST_PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1)) -#define PT64_LVL_ADDR_MASK(level) \ - (GUEST_PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \ - * PT64_LEVEL_BITS))) - 1)) -#define PT64_LVL_OFFSET_MASK(level) \ - (GUEST_PT64_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \ - * PT64_LEVEL_BITS))) - 1)) -#endif /* __KVM_X86_PAGING_H */ - diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index db80f7ccaa4e..f5958071220c 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -16,25 +16,21 @@ */ /* - * We need the mmu code to access both 32-bit and 64-bit guest ptes, - * so the code in this file is compiled twice, once per pte size. + * The MMU needs to be able to access/walk 32-bit and 64-bit guest page tables, + * as well as guest EPT tables, so the code in this file is compiled thrice, + * once per guest PTE type. The per-type defines are #undef'd at the end. */ #if PTTYPE == 64 #define pt_element_t u64 #define guest_walker guest_walker64 #define FNAME(name) paging##64_##name - #define PT_BASE_ADDR_MASK GUEST_PT64_BASE_ADDR_MASK - #define PT_LVL_ADDR_MASK(lvl) PT64_LVL_ADDR_MASK(lvl) - #define PT_LVL_OFFSET_MASK(lvl) PT64_LVL_OFFSET_MASK(lvl) - #define PT_INDEX(addr, level) PT64_INDEX(addr, level) - #define PT_LEVEL_BITS PT64_LEVEL_BITS + #define PT_LEVEL_BITS 9 #define PT_GUEST_DIRTY_SHIFT PT_DIRTY_SHIFT #define PT_GUEST_ACCESSED_SHIFT PT_ACCESSED_SHIFT #define PT_HAVE_ACCESSED_DIRTY(mmu) true #ifdef CONFIG_X86_64 #define PT_MAX_FULL_LEVELS PT64_ROOT_MAX_LEVEL - #define CMPXCHG "cmpxchgq" #else #define PT_MAX_FULL_LEVELS 2 #endif @@ -42,36 +38,35 @@ #define pt_element_t u32 #define guest_walker guest_walker32 #define FNAME(name) paging##32_##name - #define PT_BASE_ADDR_MASK PT32_BASE_ADDR_MASK - #define PT_LVL_ADDR_MASK(lvl) PT32_LVL_ADDR_MASK(lvl) - #define PT_LVL_OFFSET_MASK(lvl) PT32_LVL_OFFSET_MASK(lvl) - #define PT_INDEX(addr, level) PT32_INDEX(addr, level) - #define PT_LEVEL_BITS PT32_LEVEL_BITS + #define PT_LEVEL_BITS 10 #define PT_MAX_FULL_LEVELS 2 #define PT_GUEST_DIRTY_SHIFT PT_DIRTY_SHIFT #define PT_GUEST_ACCESSED_SHIFT PT_ACCESSED_SHIFT #define PT_HAVE_ACCESSED_DIRTY(mmu) true - #define CMPXCHG "cmpxchgl" + + #define PT32_DIR_PSE36_SIZE 4 + #define PT32_DIR_PSE36_SHIFT 13 + #define PT32_DIR_PSE36_MASK \ + (((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT) #elif PTTYPE == PTTYPE_EPT #define pt_element_t u64 #define guest_walker guest_walkerEPT #define FNAME(name) ept_##name - #define PT_BASE_ADDR_MASK GUEST_PT64_BASE_ADDR_MASK - #define PT_LVL_ADDR_MASK(lvl) PT64_LVL_ADDR_MASK(lvl) - #define PT_LVL_OFFSET_MASK(lvl) PT64_LVL_OFFSET_MASK(lvl) - #define PT_INDEX(addr, level) PT64_INDEX(addr, level) - #define PT_LEVEL_BITS PT64_LEVEL_BITS + #define PT_LEVEL_BITS 9 #define PT_GUEST_DIRTY_SHIFT 9 #define PT_GUEST_ACCESSED_SHIFT 8 #define PT_HAVE_ACCESSED_DIRTY(mmu) (!(mmu)->cpu_role.base.ad_disabled) - #ifdef CONFIG_X86_64 - #define CMPXCHG "cmpxchgq" - #endif #define PT_MAX_FULL_LEVELS PT64_ROOT_MAX_LEVEL #else #error Invalid PTTYPE value #endif +/* Common logic, but per-type values. These also need to be undefined. */ +#define PT_BASE_ADDR_MASK ((pt_element_t)(((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))) +#define PT_LVL_ADDR_MASK(lvl) __PT_LVL_ADDR_MASK(PT_BASE_ADDR_MASK, lvl, PT_LEVEL_BITS) +#define PT_LVL_OFFSET_MASK(lvl) __PT_LVL_OFFSET_MASK(PT_BASE_ADDR_MASK, lvl, PT_LEVEL_BITS) +#define PT_INDEX(addr, lvl) __PT_INDEX(addr, lvl, PT_LEVEL_BITS) + #define PT_GUEST_DIRTY_MASK (1 << PT_GUEST_DIRTY_SHIFT) #define PT_GUEST_ACCESSED_MASK (1 << PT_GUEST_ACCESSED_SHIFT) @@ -97,6 +92,15 @@ struct guest_walker { struct x86_exception fault; }; +#if PTTYPE == 32 +static inline gfn_t pse36_gfn_delta(u32 gpte) +{ + int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT; + + return (gpte & PT32_DIR_PSE36_MASK) << shift; +} +#endif + static gfn_t gpte_to_gfn_lvl(pt_element_t gpte, int lvl) { return (gpte & PT_LVL_ADDR_MASK(lvl)) >> PAGE_SHIFT; @@ -374,7 +378,7 @@ retry_walk: * information to fix the exit_qualification or exit_info_1 * fields. */ - if (unlikely(real_gpa == UNMAPPED_GVA)) + if (unlikely(real_gpa == INVALID_GPA)) return 0; host_addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gpa_to_gfn(real_gpa), @@ -421,11 +425,13 @@ retry_walk: gfn = gpte_to_gfn_lvl(pte, walker->level); gfn += (addr & PT_LVL_OFFSET_MASK(walker->level)) >> PAGE_SHIFT; - if (PTTYPE == 32 && walker->level > PG_LEVEL_4K && is_cpuid_PSE36()) +#if PTTYPE == 32 + if (walker->level > PG_LEVEL_4K && is_cpuid_PSE36()) gfn += pse36_gfn_delta(pte); +#endif real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(gfn), access, &walker->fault); - if (real_gpa == UNMAPPED_GVA) + if (real_gpa == INVALID_GPA) return 0; walker->gfn = real_gpa >> PAGE_SHIFT; @@ -589,7 +595,7 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw, if (sp->role.direct) return __direct_pte_prefetch(vcpu, sp, sptep); - i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1); + i = spte_index(sptep) & ~(PTE_PREFETCH_NUM - 1); spte = sp->spt + i; for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) { @@ -642,14 +648,13 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, gfn_t table_gfn; clear_sp_write_flooding_count(it.sptep); - drop_large_spte(vcpu, it.sptep); - - sp = NULL; - if (!is_shadow_present_pte(*it.sptep)) { - table_gfn = gw->table_gfn[it.level - 2]; - access = gw->pt_access[it.level - 2]; - sp = kvm_mmu_get_page(vcpu, table_gfn, fault->addr, - it.level-1, false, access); + + table_gfn = gw->table_gfn[it.level - 2]; + access = gw->pt_access[it.level - 2]; + sp = kvm_mmu_get_child_sp(vcpu, it.sptep, table_gfn, + false, access); + + if (sp != ERR_PTR(-EEXIST)) { /* * We must synchronize the pagetable before linking it * because the guest doesn't need to flush tlb when @@ -678,7 +683,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, if (FNAME(gpte_changed)(vcpu, gw, it.level - 1)) goto out_gpte_changed; - if (sp) + if (sp != ERR_PTR(-EEXIST)) link_shadow_page(vcpu, it.sptep, sp); } @@ -702,16 +707,15 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, validate_direct_spte(vcpu, it.sptep, direct_access); - drop_large_spte(vcpu, it.sptep); + sp = kvm_mmu_get_child_sp(vcpu, it.sptep, base_gfn, + true, direct_access); + if (sp == ERR_PTR(-EEXIST)) + continue; - if (!is_shadow_present_pte(*it.sptep)) { - sp = kvm_mmu_get_page(vcpu, base_gfn, fault->addr, - it.level - 1, true, direct_access); - link_shadow_page(vcpu, it.sptep, sp); - if (fault->huge_page_disallowed && - fault->req_level >= it.level) - account_huge_nx_page(vcpu->kvm, sp); - } + link_shadow_page(vcpu, it.sptep, sp); + if (fault->huge_page_disallowed && + fault->req_level >= it.level) + account_huge_nx_page(vcpu->kvm, sp); } if (WARN_ON_ONCE(it.level != fault->goal_level)) @@ -888,7 +892,7 @@ static gpa_t FNAME(get_level1_sp_gpa)(struct kvm_mmu_page *sp) WARN_ON(sp->role.level != PG_LEVEL_4K); if (PTTYPE == 32) - offset = sp->role.quadrant << PT64_LEVEL_BITS; + offset = sp->role.quadrant << SPTE_LEVEL_BITS; return gfn_to_gpa(sp->gfn) + offset * sizeof(pt_element_t); } @@ -929,7 +933,7 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa) break; pte_gpa = FNAME(get_level1_sp_gpa)(sp); - pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t); + pte_gpa += spte_index(sptep) * sizeof(pt_element_t); mmu_page_zap_pte(vcpu->kvm, sp, sptep, NULL); if (is_shadow_present_pte(old_spte)) @@ -958,7 +962,7 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, struct x86_exception *exception) { struct guest_walker walker; - gpa_t gpa = UNMAPPED_GVA; + gpa_t gpa = INVALID_GPA; int r; #ifndef CONFIG_X86_64 @@ -978,7 +982,8 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, } /* - * Using the cached information from sp->gfns is safe because: + * Using the information in sp->shadowed_translation (kvm_mmu_page_get_gfn()) is + * safe because: * - The spte has a reference to the struct page, so the pfn for a given gfn * can't change unless all sptes pointing to it are nuked first. * @@ -1023,7 +1028,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) first_pte_gpa = FNAME(get_level1_sp_gpa)(sp); - for (i = 0; i < PT64_ENT_PER_PAGE; i++) { + for (i = 0; i < SPTE_ENT_PER_PAGE; i++) { u64 *sptep, spte; struct kvm_memory_slot *slot; unsigned pte_access; @@ -1053,12 +1058,23 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) if (sync_mmio_spte(vcpu, &sp->spt[i], gfn, pte_access)) continue; - if (gfn != sp->gfns[i]) { + /* + * Drop the SPTE if the new protections would result in a RWX=0 + * SPTE or if the gfn is changing. The RWX=0 case only affects + * EPT with execute-only support, i.e. EPT without an effective + * "present" bit, as all other paging modes will create a + * read-only SPTE if pte_access is zero. + */ + if ((!pte_access && !shadow_present_mask) || + gfn != kvm_mmu_page_get_gfn(sp, i)) { drop_spte(vcpu->kvm, &sp->spt[i]); flush = true; continue; } + /* Update the shadowed access bits in case they changed. */ + kvm_mmu_page_set_access(sp, i, pte_access); + sptep = &sp->spt[i]; spte = *sptep; host_writable = spte & shadow_host_writable_mask; @@ -1070,6 +1086,15 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) flush |= mmu_spte_update(sptep, spte); } + /* + * Note, any flush is purely for KVM's correctness, e.g. when dropping + * an existing SPTE or clearing W/A/D bits to ensure an mmu_notifier + * unmap or dirty logging event doesn't fail to flush. The guest is + * responsible for flushing the TLB to ensure any changes in protection + * bits are recognized, i.e. until the guest flushes or page faults on + * a relevant address, KVM is architecturally allowed to let vCPUs use + * cached translations with the old protection bits. + */ return flush; } @@ -1084,7 +1109,6 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) #undef PT_MAX_FULL_LEVELS #undef gpte_to_gfn #undef gpte_to_gfn_lvl -#undef CMPXCHG #undef PT_GUEST_ACCESSED_MASK #undef PT_GUEST_DIRTY_MASK #undef PT_GUEST_DIRTY_SHIFT diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index b5960bbde7f7..7314d27d57a4 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -33,6 +33,7 @@ u64 __read_mostly shadow_mmio_value; u64 __read_mostly shadow_mmio_mask; u64 __read_mostly shadow_mmio_access_mask; u64 __read_mostly shadow_present_mask; +u64 __read_mostly shadow_memtype_mask; u64 __read_mostly shadow_me_value; u64 __read_mostly shadow_me_mask; u64 __read_mostly shadow_acc_track_mask; @@ -129,6 +130,8 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 spte = SPTE_MMU_PRESENT_MASK; bool wrprot = false; + WARN_ON_ONCE(!pte_access && !shadow_present_mask); + if (sp->role.ad_disabled) spte |= SPTE_TDP_AD_DISABLED_MASK; else if (kvm_mmu_page_ad_need_write_protect(sp)) @@ -145,7 +148,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, spte |= spte_shadow_accessed_mask(spte); if (level > PG_LEVEL_4K && (pte_access & ACC_EXEC_MASK) && - is_nx_huge_page_enabled()) { + is_nx_huge_page_enabled(vcpu->kvm)) { pte_access &= ~ACC_EXEC_MASK; } @@ -159,10 +162,10 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, if (level > PG_LEVEL_4K) spte |= PT_PAGE_SIZE_MASK; - if (tdp_enabled) - spte |= static_call(kvm_x86_get_mt_mask)(vcpu, gfn, - kvm_is_mmio_pfn(pfn)); + if (shadow_memtype_mask) + spte |= static_call(kvm_x86_get_mt_mask)(vcpu, gfn, + kvm_is_mmio_pfn(pfn)); if (host_writable) spte |= shadow_host_writable_mask; else @@ -244,10 +247,10 @@ static u64 make_spte_executable(u64 spte) * This is used during huge page splitting to build the SPTEs that make up the * new page table. */ -u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index) +u64 make_huge_page_split_spte(struct kvm *kvm, u64 huge_spte, union kvm_mmu_page_role role, + int index) { u64 child_spte; - int child_level; if (WARN_ON_ONCE(!is_shadow_present_pte(huge_spte))) return 0; @@ -256,23 +259,23 @@ u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index) return 0; child_spte = huge_spte; - child_level = huge_level - 1; /* * The child_spte already has the base address of the huge page being * split. So we just have to OR in the offset to the page at the next * lower level for the given index. */ - child_spte |= (index * KVM_PAGES_PER_HPAGE(child_level)) << PAGE_SHIFT; + child_spte |= (index * KVM_PAGES_PER_HPAGE(role.level)) << PAGE_SHIFT; - if (child_level == PG_LEVEL_4K) { + if (role.level == PG_LEVEL_4K) { child_spte &= ~PT_PAGE_SIZE_MASK; /* - * When splitting to a 4K page, mark the page executable as the - * NX hugepage mitigation no longer applies. + * When splitting to a 4K page where execution is allowed, mark + * the page executable as the NX hugepage mitigation no longer + * applies. */ - if (is_nx_huge_page_enabled()) + if ((role.access & ACC_EXEC_MASK) && is_nx_huge_page_enabled(kvm)) child_spte = make_spte_executable(child_spte); } @@ -299,7 +302,7 @@ u64 kvm_mmu_changed_pte_notifier_make_spte(u64 old_spte, kvm_pfn_t new_pfn) { u64 new_spte; - new_spte = old_spte & ~PT64_BASE_ADDR_MASK; + new_spte = old_spte & ~SPTE_BASE_ADDR_MASK; new_spte |= (u64)new_pfn << PAGE_SHIFT; new_spte &= ~PT_WRITABLE_MASK; @@ -389,6 +392,13 @@ void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only) shadow_nx_mask = 0ull; shadow_x_mask = VMX_EPT_EXECUTABLE_MASK; shadow_present_mask = has_exec_only ? 0ull : VMX_EPT_READABLE_MASK; + /* + * EPT overrides the host MTRRs, and so KVM must program the desired + * memtype directly into the SPTEs. Note, this mask is just the mask + * of all bits that factor into the memtype, the actual memtype must be + * dynamically calculated, e.g. to ensure host MMIO is mapped UC. + */ + shadow_memtype_mask = VMX_EPT_MT_MASK | VMX_EPT_IPAT_BIT; shadow_acc_track_mask = VMX_EPT_RWX_MASK; shadow_host_writable_mask = EPT_SPTE_HOST_WRITABLE; shadow_mmu_writable_mask = EPT_SPTE_MMU_WRITABLE; @@ -439,6 +449,13 @@ void kvm_mmu_reset_all_pte_masks(void) shadow_nx_mask = PT64_NX_MASK; shadow_x_mask = 0; shadow_present_mask = PT_PRESENT_MASK; + + /* + * For shadow paging and NPT, KVM uses PAT entry '0' to encode WB + * memtype in the SPTEs, i.e. relies on host MTRRs to provide the + * correct memtype (WB is the "weakest" memtype). + */ + shadow_memtype_mask = 0; shadow_acc_track_mask = 0; shadow_me_mask = 0; shadow_me_value = 0; diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index 0127bb6e3c7d..cabe3fbb4f39 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -36,12 +36,12 @@ extern bool __read_mostly enable_mmio_caching; static_assert(SPTE_TDP_AD_ENABLED_MASK == 0); #ifdef CONFIG_DYNAMIC_PHYSICAL_MASK -#define PT64_BASE_ADDR_MASK (physical_mask & ~(u64)(PAGE_SIZE-1)) +#define SPTE_BASE_ADDR_MASK (physical_mask & ~(u64)(PAGE_SIZE-1)) #else -#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1)) +#define SPTE_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1)) #endif -#define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | shadow_user_mask \ +#define SPTE_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | shadow_user_mask \ | shadow_x_mask | shadow_nx_mask | shadow_me_mask) #define ACC_EXEC_MASK 1 @@ -50,17 +50,13 @@ static_assert(SPTE_TDP_AD_ENABLED_MASK == 0); #define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK) /* The mask for the R/X bits in EPT PTEs */ -#define PT64_EPT_READABLE_MASK 0x1ull -#define PT64_EPT_EXECUTABLE_MASK 0x4ull +#define SPTE_EPT_READABLE_MASK 0x1ull +#define SPTE_EPT_EXECUTABLE_MASK 0x4ull -#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 SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level) +#define SPTE_LEVEL_BITS 9 +#define SPTE_LEVEL_SHIFT(level) __PT_LEVEL_SHIFT(level, SPTE_LEVEL_BITS) +#define SPTE_INDEX(address, level) __PT_INDEX(address, level, SPTE_LEVEL_BITS) +#define SPTE_ENT_PER_PAGE __PT_ENT_PER_PAGE(SPTE_LEVEL_BITS) /* * The mask/shift to use for saving the original R/X bits when marking the PTE @@ -69,8 +65,8 @@ static_assert(SPTE_TDP_AD_ENABLED_MASK == 0); * restored only when a write is attempted to the page. This mask obviously * must not overlap the A/D type mask. */ -#define SHADOW_ACC_TRACK_SAVED_BITS_MASK (PT64_EPT_READABLE_MASK | \ - PT64_EPT_EXECUTABLE_MASK) +#define SHADOW_ACC_TRACK_SAVED_BITS_MASK (SPTE_EPT_READABLE_MASK | \ + SPTE_EPT_EXECUTABLE_MASK) #define SHADOW_ACC_TRACK_SAVED_BITS_SHIFT 54 #define SHADOW_ACC_TRACK_SAVED_MASK (SHADOW_ACC_TRACK_SAVED_BITS_MASK << \ SHADOW_ACC_TRACK_SAVED_BITS_SHIFT) @@ -151,6 +147,7 @@ extern u64 __read_mostly shadow_mmio_value; extern u64 __read_mostly shadow_mmio_mask; extern u64 __read_mostly shadow_mmio_access_mask; extern u64 __read_mostly shadow_present_mask; +extern u64 __read_mostly shadow_memtype_mask; extern u64 __read_mostly shadow_me_value; extern u64 __read_mostly shadow_me_mask; @@ -194,6 +191,12 @@ static inline bool is_removed_spte(u64 spte) return spte == REMOVED_SPTE; } +/* Get an SPTE's index into its parent's page table (and the spt array). */ +static inline int spte_index(u64 *sptep) +{ + return ((unsigned long)sptep / sizeof(*sptep)) & (SPTE_ENT_PER_PAGE - 1); +} + /* * In some cases, we need to preserve the GFN of a non-present or reserved * SPTE when we usurp the upper five bits of the physical address space to @@ -282,7 +285,7 @@ static inline bool is_executable_pte(u64 spte) static inline kvm_pfn_t spte_to_pfn(u64 pte) { - return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT; + return (pte & SPTE_BASE_ADDR_MASK) >> PAGE_SHIFT; } static inline bool is_accessed_spte(u64 spte) @@ -425,7 +428,8 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn, u64 old_spte, bool prefetch, bool can_unsync, bool host_writable, u64 *new_spte); -u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index); +u64 make_huge_page_split_spte(struct kvm *kvm, u64 huge_spte, + union kvm_mmu_page_role role, int index); u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled); u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access); u64 mark_spte_for_access_track(u64 spte); diff --git a/arch/x86/kvm/mmu/tdp_iter.c b/arch/x86/kvm/mmu/tdp_iter.c index ee4802d7b36c..39b48e7d7d1a 100644 --- a/arch/x86/kvm/mmu/tdp_iter.c +++ b/arch/x86/kvm/mmu/tdp_iter.c @@ -11,7 +11,7 @@ static void tdp_iter_refresh_sptep(struct tdp_iter *iter) { iter->sptep = iter->pt_path[iter->level - 1] + - SHADOW_PT_INDEX(iter->gfn << PAGE_SHIFT, iter->level); + SPTE_INDEX(iter->gfn << PAGE_SHIFT, iter->level); iter->old_spte = kvm_tdp_mmu_read_spte(iter->sptep); } @@ -116,8 +116,8 @@ static bool try_step_side(struct tdp_iter *iter) * Check if the iterator is already at the end of the current page * table. */ - if (SHADOW_PT_INDEX(iter->gfn << PAGE_SHIFT, iter->level) == - (PT64_ENT_PER_PAGE - 1)) + if (SPTE_INDEX(iter->gfn << PAGE_SHIFT, iter->level) == + (SPTE_ENT_PER_PAGE - 1)) return false; iter->gfn += KVM_PAGES_PER_HPAGE(iter->level); @@ -146,15 +146,6 @@ static bool try_step_up(struct tdp_iter *iter) } /* - * Step the iterator back up a level in the paging structure. Should only be - * used when the iterator is below the root level. - */ -void tdp_iter_step_up(struct tdp_iter *iter) -{ - WARN_ON(!try_step_up(iter)); -} - -/* * Step to the next SPTE in a pre-order traversal of the paging structure. * To get to the next SPTE, the iterator either steps down towards the goal * GFN, if at a present, non-last-level SPTE, or over to a SPTE mapping a diff --git a/arch/x86/kvm/mmu/tdp_iter.h b/arch/x86/kvm/mmu/tdp_iter.h index adfca0cf94d3..f0af385c56e0 100644 --- a/arch/x86/kvm/mmu/tdp_iter.h +++ b/arch/x86/kvm/mmu/tdp_iter.h @@ -114,6 +114,5 @@ void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root, int min_level, gfn_t next_last_level_gfn); void tdp_iter_next(struct tdp_iter *iter); void tdp_iter_restart(struct tdp_iter *iter); -void tdp_iter_step_up(struct tdp_iter *iter); #endif /* __KVM_X86_MMU_TDP_ITER_H */ diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 7b9265d67131..bf2ccf9debca 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -425,7 +425,7 @@ static void handle_removed_pt(struct kvm *kvm, tdp_ptep_t pt, bool shared) tdp_mmu_unlink_sp(kvm, sp, shared); - for (i = 0; i < PT64_ENT_PER_PAGE; i++) { + for (i = 0; i < SPTE_ENT_PER_PAGE; i++) { tdp_ptep_t sptep = pt + i; gfn_t gfn = base_gfn + i * KVM_PAGES_PER_HPAGE(level); u64 old_spte; @@ -633,7 +633,6 @@ static inline int tdp_mmu_set_spte_atomic(struct kvm *kvm, u64 new_spte) { u64 *sptep = rcu_dereference(iter->sptep); - u64 old_spte; /* * The caller is responsible for ensuring the old SPTE is not a REMOVED @@ -649,17 +648,8 @@ static inline int tdp_mmu_set_spte_atomic(struct kvm *kvm, * Note, fast_pf_fix_direct_spte() can also modify TDP MMU SPTEs and * does not hold the mmu_lock. */ - old_spte = cmpxchg64(sptep, iter->old_spte, new_spte); - if (old_spte != iter->old_spte) { - /* - * The page table entry was modified by a different logical - * CPU. Refresh iter->old_spte with the current value so the - * caller operates on fresh data, e.g. if it retries - * tdp_mmu_set_spte_atomic(). - */ - iter->old_spte = old_spte; + if (!try_cmpxchg64(sptep, &iter->old_spte, new_spte)) return -EBUSY; - } __handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte, new_spte, iter->level, true); @@ -934,9 +924,6 @@ bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp) } /* - * Zap leafs SPTEs for the range of gfns, [start, end). Returns true if SPTEs - * have been cleared and a TLB flush is needed before releasing the MMU lock. - * * If can_yield is true, will release the MMU lock and reschedule if the * scheduler needs the CPU or there is contention on the MMU lock. If this * function cannot yield, it will not release the MMU lock or reschedule and @@ -979,10 +966,9 @@ static bool tdp_mmu_zap_leafs(struct kvm *kvm, struct kvm_mmu_page *root, } /* - * Tears down the mappings for the range of gfns, [start, end), and frees the - * non-root pages mapping GFNs strictly within that range. Returns true if - * SPTEs have been cleared and a TLB flush is needed before releasing the - * MMU lock. + * Zap leaf SPTEs for the range of gfns, [start, end), for all roots. Returns + * true if a TLB flush is needed before releasing the MMU lock, i.e. if one or + * more SPTEs were zapped since the MMU lock was last acquired. */ bool kvm_tdp_mmu_zap_leafs(struct kvm *kvm, int as_id, gfn_t start, gfn_t end, bool can_yield, bool flush) @@ -1487,8 +1473,8 @@ static int tdp_mmu_split_huge_page(struct kvm *kvm, struct tdp_iter *iter, * No need for atomics when writing to sp->spt since the page table has * not been linked in yet and thus is not reachable from any other CPU. */ - for (i = 0; i < PT64_ENT_PER_PAGE; i++) - sp->spt[i] = make_huge_page_split_spte(huge_spte, level, i); + for (i = 0; i < SPTE_ENT_PER_PAGE; i++) + sp->spt[i] = make_huge_page_split_spte(kvm, huge_spte, sp->role, i); /* * Replace the huge spte with a pointer to the populated lower level @@ -1507,7 +1493,7 @@ static int tdp_mmu_split_huge_page(struct kvm *kvm, struct tdp_iter *iter, * are overwriting from the page stats. But we have to manually update * the page stats with the new present child pages. */ - kvm_update_page_stats(kvm, level - 1, PT64_ENT_PER_PAGE); + kvm_update_page_stats(kvm, level - 1, SPTE_ENT_PER_PAGE); out: trace_kvm_mmu_split_huge_page(iter->gfn, huge_spte, level, ret); @@ -1731,10 +1717,6 @@ void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm, clear_dirty_pt_masked(kvm, root, gfn, mask, wrprot); } -/* - * Clear leaf entries which could be replaced by large mappings, for - * GFNs within the slot. - */ static void zap_collapsible_spte_range(struct kvm *kvm, struct kvm_mmu_page *root, const struct kvm_memory_slot *slot) @@ -1743,61 +1725,52 @@ static void zap_collapsible_spte_range(struct kvm *kvm, gfn_t end = start + slot->npages; struct tdp_iter iter; int max_mapping_level; - kvm_pfn_t pfn; rcu_read_lock(); - tdp_root_for_each_pte(iter, root, start, end) { + for_each_tdp_pte_min_level(iter, root, PG_LEVEL_2M, start, end) { +retry: if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true)) continue; - if (!is_shadow_present_pte(iter.old_spte) || - !is_last_spte(iter.old_spte, iter.level)) + if (iter.level > KVM_MAX_HUGEPAGE_LEVEL || + !is_shadow_present_pte(iter.old_spte)) continue; /* - * This is a leaf SPTE. Check if the PFN it maps can - * be mapped at a higher level. + * Don't zap leaf SPTEs, if a leaf SPTE could be replaced with + * a large page size, then its parent would have been zapped + * instead of stepping down. */ - pfn = spte_to_pfn(iter.old_spte); - - if (kvm_is_reserved_pfn(pfn)) + if (is_last_spte(iter.old_spte, iter.level)) continue; - max_mapping_level = kvm_mmu_max_mapping_level(kvm, slot, - iter.gfn, pfn, PG_LEVEL_NUM); - - WARN_ON(max_mapping_level < iter.level); - /* - * If this page is already mapped at the highest - * viable level, there's nothing more to do. + * If iter.gfn resides outside of the slot, i.e. the page for + * the current level overlaps but is not contained by the slot, + * then the SPTE can't be made huge. More importantly, trying + * to query that info from slot->arch.lpage_info will cause an + * out-of-bounds access. */ - if (max_mapping_level == iter.level) + if (iter.gfn < start || iter.gfn >= end) continue; - /* - * The page can be remapped at a higher level, so step - * up to zap the parent SPTE. - */ - while (max_mapping_level > iter.level) - tdp_iter_step_up(&iter); + max_mapping_level = kvm_mmu_max_mapping_level(kvm, slot, + iter.gfn, PG_LEVEL_NUM); + if (max_mapping_level < iter.level) + continue; /* Note, a successful atomic zap also does a remote TLB flush. */ - tdp_mmu_zap_spte_atomic(kvm, &iter); - - /* - * If the atomic zap fails, the iter will recurse back into - * the same subtree to retry. - */ + if (tdp_mmu_zap_spte_atomic(kvm, &iter)) + goto retry; } rcu_read_unlock(); } /* - * Clear non-leaf entries (and free associated page tables) which could - * be replaced by large mappings, for GFNs within the slot. + * Zap non-leaf SPTEs (and free their associated page tables) which could + * be replaced by huge pages, for GFNs within the slot. */ void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm, const struct kvm_memory_slot *slot) |