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KVM: MMU: improve spte audit
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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>
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Xiao Guangrong authored and Avi Kivity committed Oct 24, 2010
1 parent 49edf87 commit eb25918
Showing 1 changed file with 69 additions and 79 deletions.
148 changes: 69 additions & 79 deletions arch/x86/kvm/mmu_audit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
}
}
}
Expand All @@ -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;
}

Expand All @@ -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;
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand Down

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