diff options
Diffstat (limited to 'arch/x86/kvm/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 125 |
1 files changed, 109 insertions, 16 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 9cafbb4..f02b8ed 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -554,14 +554,18 @@ static int host_mapping_level(struct kvm *kvm, gfn_t gfn) return ret; } -static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn) +static bool mapping_level_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t large_gfn) { struct kvm_memory_slot *slot; - int host_level, level, max_level; - slot = gfn_to_memslot(vcpu->kvm, large_gfn); if (slot && slot->dirty_bitmap) - return PT_PAGE_TABLE_LEVEL; + return true; + return false; +} + +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); @@ -941,6 +945,35 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp, return young; } +static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp, + unsigned long data) +{ + u64 *spte; + int young = 0; + + /* + * If there's no access bit in the secondary pte set by the + * hardware it's up to gup-fast/gup to set the access bit in + * the primary pte or in the page structure. + */ + if (!shadow_accessed_mask) + goto out; + + spte = rmap_next(kvm, rmapp, NULL); + while (spte) { + u64 _spte = *spte; + BUG_ON(!(_spte & PT_PRESENT_MASK)); + young = _spte & PT_ACCESSED_MASK; + if (young) { + young = 1; + break; + } + spte = rmap_next(kvm, rmapp, spte); + } +out: + return young; +} + #define RMAP_RECYCLE_THRESHOLD 1000 static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn) @@ -961,6 +994,11 @@ int kvm_age_hva(struct kvm *kvm, unsigned long hva) return kvm_handle_hva(kvm, hva, 0, kvm_age_rmapp); } +int kvm_test_age_hva(struct kvm *kvm, unsigned long hva) +{ + return kvm_handle_hva(kvm, hva, 0, kvm_test_age_rmapp); +} + #ifdef MMU_DEBUG static int is_empty_shadow_page(u64 *spt) { @@ -2281,6 +2319,48 @@ static int kvm_handle_bad_page(struct kvm *kvm, gfn_t gfn, pfn_t pfn) return 1; } +static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu, + gfn_t *gfnp, pfn_t *pfnp, int *levelp) +{ + pfn_t pfn = *pfnp; + gfn_t gfn = *gfnp; + int level = *levelp; + + /* + * Check if it's a transparent hugepage. If this would be an + * hugetlbfs page, level wouldn't be set to + * PT_PAGE_TABLE_LEVEL and there would be no adjustment done + * here. + */ + if (!is_error_pfn(pfn) && !kvm_is_mmio_pfn(pfn) && + level == PT_PAGE_TABLE_LEVEL && + PageTransCompound(pfn_to_page(pfn)) && + !has_wrprotected_page(vcpu->kvm, gfn, PT_DIRECTORY_LEVEL)) { + unsigned long mask; + /* + * mmu_notifier_retry was successful and we hold the + * mmu_lock here, so the pmd can't become splitting + * from under us, and in turn + * __split_huge_page_refcount() can't run from under + * us and we can safely transfer the refcount from + * PG_tail to PG_head as we switch the pfn to tail to + * head. + */ + *levelp = level = PT_DIRECTORY_LEVEL; + mask = KVM_PAGES_PER_HPAGE(level) - 1; + VM_BUG_ON((gfn & mask) != (pfn & mask)); + if (pfn & mask) { + gfn &= ~mask; + *gfnp = gfn; + kvm_release_pfn_clean(pfn); + pfn &= ~mask; + if (!get_page_unless_zero(pfn_to_page(pfn))) + BUG(); + *pfnp = pfn; + } + } +} + static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, gva_t gva, pfn_t *pfn, bool write, bool *writable); @@ -2289,20 +2369,25 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn, { int r; int level; + int force_pt_level; pfn_t pfn; unsigned long mmu_seq; bool map_writable; - 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; + 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); + gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1); + } else + level = PT_PAGE_TABLE_LEVEL; mmu_seq = vcpu->kvm->mmu_notifier_seq; smp_rmb(); @@ -2318,6 +2403,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn, if (mmu_notifier_retry(vcpu, mmu_seq)) goto out_unlock; kvm_mmu_free_some_pages(vcpu); + if (likely(!force_pt_level)) + transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level); r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn, prefault); spin_unlock(&vcpu->kvm->mmu_lock); @@ -2655,6 +2742,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code, pfn_t pfn; int r; int level; + int force_pt_level; gfn_t gfn = gpa >> PAGE_SHIFT; unsigned long mmu_seq; int write = error_code & PFERR_WRITE_MASK; @@ -2667,9 +2755,12 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code, if (r) return r; - level = mapping_level(vcpu, gfn); - - gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1); + force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn); + if (likely(!force_pt_level)) { + level = mapping_level(vcpu, gfn); + gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1); + } else + level = PT_PAGE_TABLE_LEVEL; mmu_seq = vcpu->kvm->mmu_notifier_seq; smp_rmb(); @@ -2684,6 +2775,8 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code, if (mmu_notifier_retry(vcpu, mmu_seq)) goto out_unlock; kvm_mmu_free_some_pages(vcpu); + if (likely(!force_pt_level)) + transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level); r = __direct_map(vcpu, gpa, write, map_writable, level, gfn, pfn, prefault); spin_unlock(&vcpu->kvm->mmu_lock); |
