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Commit eb259186 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Avi Kivity
Browse files

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: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 49edf878

arch/x86/kvm/mmu_audit.c

+69 −79
Original line number Diff line number Diff line
@@ -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];

		u64 *ent = sp->spt;



		if (is_shadow_present_pte(ent)) {

			if (!is_last_spte(ent, sp->role.level)) {

		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 & PT64_BASE_ADDR_MASK);

				__mmu_spte_walk(kvm, child, fn);

			} else

				fn(kvm, &sp->spt[i]);



			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;

}
@@ -75,15 +80,8 @@ 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;
@@ -111,8 +109,7 @@ static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte, 
		return;

	}



		if (!is_shadow_present_pte(*sptep) ||

		      !is_last_spte(*sptep, level))

	if (!is_shadow_present_pte(*sptep) || !is_last_spte(*sptep, level))

		return;



	gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
@@ -124,31 +121,14 @@ static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte, 
	}



	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",

				   "pfn %llx hpa %llx ent %llxn",

				   audit_msg, vcpu->arch.mmu.root_level,

					   va, pfn, hpa, *sptep);

	}

				   pfn, hpa, *sptep);

}



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);

}



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;