KVM: MMU: improve spte audit

Both audit_mappings() and audit_sptes_have_rmaps() need to walk vcpu's page
table, so we can do these checking in a spte walking

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index 8becb86cd34833eb4413c5577c9f4fc6e73f6d33..3bde186409bfd9e2b5d65764519d3f02e93dbfe7 100644 (file)
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -19,23 +19,24 @@
 
 static const char *audit_msg;
 
-typedef void (*inspect_spte_fn) (struct kvm *kvm, u64 *sptep);
+typedef void (*inspect_spte_fn) (struct kvm_vcpu *vcpu, u64 *sptep, int level);
 
-static void __mmu_spte_walk(struct kvm *kvm, struct kvm_mmu_page *sp,
-                           inspect_spte_fn fn)
+static void __mmu_spte_walk(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
+                           inspect_spte_fn fn, int level)
 {
        int i;
 
        for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
-               u64 ent = sp->spt[i];
-
-               if (is_shadow_present_pte(ent)) {
-                       if (!is_last_spte(ent, sp->role.level)) {
-                               struct kvm_mmu_page *child;
-                               child = page_header(ent & PT64_BASE_ADDR_MASK);
-                               __mmu_spte_walk(kvm, child, fn);
-                       } else
-                               fn(kvm, &sp->spt[i]);
+               u64 *ent = sp->spt;
+
+               fn(vcpu, ent + i, level);
+
+               if (is_shadow_present_pte(ent[i]) &&
+                     !is_last_spte(ent[i], level)) {
+                       struct kvm_mmu_page *child;
+
+                       child = page_header(ent[i] & PT64_BASE_ADDR_MASK);
+                       __mmu_spte_walk(vcpu, child, fn, level - 1);
                }
        }
 }
@@ -47,21 +48,25 @@ static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn)
 
        if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
                return;
+
        if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
                hpa_t root = vcpu->arch.mmu.root_hpa;
+
                sp = page_header(root);
-               __mmu_spte_walk(vcpu->kvm, sp, fn);
+               __mmu_spte_walk(vcpu, sp, fn, PT64_ROOT_LEVEL);
                return;
        }
+
        for (i = 0; i < 4; ++i) {
                hpa_t root = vcpu->arch.mmu.pae_root[i];
 
                if (root && VALID_PAGE(root)) {
                        root &= PT64_BASE_ADDR_MASK;
                        sp = page_header(root);
-                       __mmu_spte_walk(vcpu->kvm, sp, fn);
+                       __mmu_spte_walk(vcpu, sp, fn, 2);
                }
        }
+
        return;
 }
 
@@ -75,80 +80,55 @@ static void walk_all_active_sps(struct kvm *kvm, sp_handler fn)
                fn(kvm, sp);
 }
 
-static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
-                               gva_t va, int level)
+static void audit_mappings(struct kvm_vcpu *vcpu, u64 *sptep, int level)
 {
-       u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
-       int i;
-       gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
-
-       for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
-               u64 *sptep = pt + i;
-               struct kvm_mmu_page *sp;
-               gfn_t gfn;
-               pfn_t pfn;
-               hpa_t hpa;
-
-               sp = page_header(__pa(sptep));
-
-               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 (*sptep == shadow_notrap_nonpresent_pte) {
-                               printk(KERN_ERR "audit: (%s) error: notrap spte in unsync sp: %p\n",
-                                               audit_msg, sp);
-                               return;
-                       }
-               }
+       struct kvm_mmu_page *sp;
+       gfn_t gfn;
+       pfn_t pfn;
+       hpa_t hpa;
 
-               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);
+       sp = page_header(__pa(sptep));
+
+       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_shadow_present_pte(*sptep) ||
-                     !is_last_spte(*sptep, level))
+               if (*sptep == shadow_notrap_nonpresent_pte) {
+                       printk(KERN_ERR "audit: (%s) error: notrap spte in unsync sp: %p\n",
+                               audit_msg, sp);
                        return;
+               }
+       }
 
-               gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
-               pfn = gfn_to_pfn_atomic(vcpu->kvm, gfn);
+       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_error_pfn(pfn)) {
-                       kvm_release_pfn_clean(pfn);
-                       return;
-               }
+       if (!is_shadow_present_pte(*sptep) || !is_last_spte(*sptep, level))
+               return;
 
-               hpa =  pfn << PAGE_SHIFT;
+       gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
+       pfn = gfn_to_pfn_atomic(vcpu->kvm, gfn);
 
-               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);
+       if (is_error_pfn(pfn)) {
+               kvm_release_pfn_clean(pfn);
+               return;
        }
-}
 
-static void audit_mappings(struct kvm_vcpu *vcpu)
-{
-       unsigned i;
-
-       if (vcpu->arch.mmu.root_level == 4)
-               audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
-       else
-               for (i = 0; i < 4; ++i)
-                       if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
-                               audit_mappings_page(vcpu,
-                                                   vcpu->arch.mmu.pae_root[i],
-                                                   i << 30,
-                                                   2);
+       hpa =  pfn << PAGE_SHIFT;
+       if ((*sptep & PT64_BASE_ADDR_MASK) != hpa)
+               printk(KERN_ERR "xx audit error: (%s) levels %d"
+                                  "pfn %llx hpa %llx ent %llxn",
+                                  audit_msg, vcpu->arch.mmu.root_level,
+                                  pfn, hpa, *sptep);
 }
 
-void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
+static void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
 {
        unsigned long *rmapp;
        struct kvm_mmu_page *rev_sp;
@@ -180,9 +160,10 @@ void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
        }
 }
 
-void audit_sptes_have_rmaps(struct kvm_vcpu *vcpu)
+static void audit_sptes_have_rmaps(struct kvm_vcpu *vcpu, u64 *sptep, int level)
 {
-       mmu_spte_walk(vcpu, inspect_spte_has_rmap);
+       if (is_shadow_present_pte(*sptep) && is_last_spte(*sptep, level))
+               inspect_spte_has_rmap(vcpu->kvm, sptep);
 }
 
 static void check_mappings_rmap(struct kvm *kvm, struct kvm_mmu_page *sp)
@@ -234,13 +215,22 @@ static void audit_all_active_sps(struct kvm *kvm)
        walk_all_active_sps(kvm, audit_sp);
 }
 
+static void audit_spte(struct kvm_vcpu *vcpu, u64 *sptep, int level)
+{
+       audit_sptes_have_rmaps(vcpu, sptep, level);
+       audit_mappings(vcpu, sptep, level);
+}
+
+static void audit_vcpu_spte(struct kvm_vcpu *vcpu)
+{
+       mmu_spte_walk(vcpu, audit_spte);
+}
+
 static void kvm_mmu_audit(void *ignore, struct kvm_vcpu *vcpu, int audit_point)
 {
        audit_msg = audit_point_name[audit_point];
        audit_all_active_sps(vcpu->kvm);
-       if (strcmp("pre pte write", audit_msg) != 0)
-               audit_mappings(vcpu);
-       audit_sptes_have_rmaps(vcpu);
+       audit_vcpu_spte(vcpu);
 }
 
 static bool mmu_audit;