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Subject[PATCH 3/4] 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>
---
arch/x86/kvm/mmu_debug.c | 148 +++++++++++++++++++++------------------------
1 files changed, 69 insertions(+), 79 deletions(-)
diff --git a/arch/x86/kvm/mmu_debug.c b/arch/x86/kvm/mmu_debug.c
index 812d6dc..c4ebe6a 100644
--- a/arch/x86/kvm/mmu_debug.c
+++ b/arch/x86/kvm/mmu_debug.c
@@ -24,23 +24,24 @@ static bool mmu_debug;

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);
}
}
}
@@ -52,19 +53,21 @@ 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;
@@ -80,80 +83,56 @@ 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;
@@ -185,9 +164,10 @@ 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)
@@ -239,13 +219,23 @@ 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, const char *msg)
{
audit_msg = msg;
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 void mmu_debug_enable(void)
--
1.7.0.4


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