From 365fb3fdf6769d3553999d8eb6cc2a8c56c747c1 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Sat, 28 Aug 2010 19:24:13 +0800 Subject: [PATCH] KVM: MMU: rewrite audit_mappings_page() function There is a bugs in this function, we call gfn_to_pfn() and kvm_mmu_gva_to_gpa_read() in atomic context(kvm_mmu_audit() is called under the spinlock(mmu_lock)'s protection). This patch fix it by: - introduce gfn_to_pfn_atomic instead of gfn_to_pfn - get the mapping gfn from kvm_mmu_page_get_gfn() And it adds 'notrap' ptes check in unsync/direct sps Signed-off-by: Xiao Guangrong Signed-off-by: Avi Kivity --- arch/x86/kvm/mmu.c | 75 +++++++++++++++++++++------------------- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 15 ++++++-- 3 files changed, 54 insertions(+), 37 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 68575dc32ec..0d91f60af1a 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3487,15 +3487,6 @@ EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy); static const char *audit_msg; -static gva_t canonicalize(gva_t gva) -{ -#ifdef CONFIG_X86_64 - gva = (long long)(gva << 16) >> 16; -#endif - return gva; -} - - typedef void (*inspect_spte_fn) (struct kvm *kvm, u64 *sptep); static void __mmu_spte_walk(struct kvm *kvm, struct kvm_mmu_page *sp, @@ -3550,39 +3541,53 @@ static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte, gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1)); for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) { - u64 ent = pt[i]; + u64 *sptep = pt + i; + struct kvm_mmu_page *sp; + gfn_t gfn; + pfn_t pfn; + hpa_t hpa; - if (ent == shadow_trap_nonpresent_pte) - continue; + sp = page_header(__pa(sptep)); - va = canonicalize(va); - if (is_shadow_present_pte(ent) && !is_last_spte(ent, level)) - audit_mappings_page(vcpu, ent, va, level - 1); - else { - gpa_t gpa = kvm_mmu_gva_to_gpa_read(vcpu, va, NULL); - gfn_t gfn = gpa >> PAGE_SHIFT; - pfn_t pfn = gfn_to_pfn(vcpu->kvm, gfn); - hpa_t hpa = (hpa_t)pfn << PAGE_SHIFT; + if (sp->unsync) { + if (level != PT_PAGE_TABLE_LEVEL) { + printk(KERN_ERR "audit: (%s) error: unsync sp: %p level = %d\n", + audit_msg, sp, level); + return; + } - if (is_error_pfn(pfn)) { - kvm_release_pfn_clean(pfn); - continue; + if (*sptep == shadow_notrap_nonpresent_pte) { + printk(KERN_ERR "audit: (%s) error: notrap spte in unsync sp: %p\n", + audit_msg, sp); + return; } + } - if (is_shadow_present_pte(ent) - && (ent & PT64_BASE_ADDR_MASK) != hpa) - printk(KERN_ERR "xx audit error: (%s) levels %d" - " gva %lx gpa %llx hpa %llx ent %llx %d\n", - audit_msg, vcpu->arch.mmu.root_level, - va, gpa, hpa, ent, - is_shadow_present_pte(ent)); - else if (ent == shadow_notrap_nonpresent_pte - && !is_error_hpa(hpa)) - printk(KERN_ERR "audit: (%s) notrap shadow," - " valid guest gva %lx\n", audit_msg, va); - kvm_release_pfn_clean(pfn); + if (sp->role.direct && *sptep == shadow_notrap_nonpresent_pte) { + printk(KERN_ERR "audit: (%s) error: notrap spte in direct sp: %p\n", + audit_msg, sp); + return; + } + + if (!is_shadow_present_pte(*sptep) || + !is_last_spte(*sptep, level)) + return; + + gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt); + pfn = gfn_to_pfn_atomic(vcpu->kvm, gfn); + if (is_error_pfn(pfn)) { + kvm_release_pfn_clean(pfn); + return; } + + hpa = pfn << PAGE_SHIFT; + + if ((*sptep & PT64_BASE_ADDR_MASK) != hpa) + printk(KERN_ERR "xx audit error: (%s) levels %d" + " gva %lx pfn %llx hpa %llx ent %llxn", + audit_msg, vcpu->arch.mmu.root_level, + va, pfn, hpa, *sptep); } } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index b837ec80885..f2ecdd52032 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -300,6 +300,7 @@ void kvm_set_page_dirty(struct page *page); void kvm_set_page_accessed(struct page *page); pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr); +pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn); pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn); pfn_t gfn_to_pfn_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2eb0b7500a2..c7a57b4feb3 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -999,7 +999,7 @@ pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr) } EXPORT_SYMBOL_GPL(hva_to_pfn_atomic); -pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) +static pfn_t __gfn_to_pfn(struct kvm *kvm, gfn_t gfn, bool atomic) { unsigned long addr; @@ -1009,7 +1009,18 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) return page_to_pfn(bad_page); } - return hva_to_pfn(kvm, addr, false); + return hva_to_pfn(kvm, addr, atomic); +} + +pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn) +{ + return __gfn_to_pfn(kvm, gfn, true); +} +EXPORT_SYMBOL_GPL(gfn_to_pfn_atomic); + +pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn) +{ + return __gfn_to_pfn(kvm, gfn, false); } EXPORT_SYMBOL_GPL(gfn_to_pfn); -- 2.39.2