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Commit 8986ecc0 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Avi Kivity
Browse files

KVM: x86: check for cr3 validity in mmu_alloc_roots 



Verify the cr3 address stored in vcpu->arch.cr3 points to an existant
memslot. If not, inject a triple fault.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent b43b1901

arch/x86/kvm/mmu.c

+23 −4
Original line number Diff line number Diff line
@@ -1912,7 +1912,19 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu) 
	vcpu->arch.mmu.root_hpa = INVALID_PAGE;

}



static void mmu_alloc_roots(struct kvm_vcpu *vcpu)

static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)

{

	int ret = 0;



	if (!kvm_is_visible_gfn(vcpu->kvm, root_gfn)) {

		set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);

		ret = 1;

	}



	return ret;

}



static int mmu_alloc_roots(struct kvm_vcpu *vcpu)

{

	int i;

	gfn_t root_gfn;
@@ -1927,13 +1939,15 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu) 
		ASSERT(!VALID_PAGE(root));

		if (tdp_enabled)

			direct = 1;

		if (mmu_check_root(vcpu, root_gfn))

			return 1;

		sp = kvm_mmu_get_page(vcpu, root_gfn, 0,

				      PT64_ROOT_LEVEL, direct,

				      ACC_ALL, NULL);

		root = __pa(sp->spt);

		++sp->root_count;

		vcpu->arch.mmu.root_hpa = root;

		return;

		return 0;

	}

	direct = !is_paging(vcpu);

	if (tdp_enabled)
@@ -1950,6 +1964,8 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu) 
			root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;

		} else if (vcpu->arch.mmu.root_level == 0)

			root_gfn = 0;

		if (mmu_check_root(vcpu, root_gfn))

			return 1;

		sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,

				      PT32_ROOT_LEVEL, direct,

				      ACC_ALL, NULL);
@@ -1958,6 +1974,7 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu) 
		vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;

	}

	vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);

	return 0;

}



static void mmu_sync_roots(struct kvm_vcpu *vcpu)
@@ -1976,7 +1993,7 @@ static void mmu_sync_roots(struct kvm_vcpu *vcpu) 
	for (i = 0; i < 4; ++i) {

		hpa_t root = vcpu->arch.mmu.pae_root[i];



		if (root) {

		if (root && VALID_PAGE(root)) {

			root &= PT64_BASE_ADDR_MASK;

			sp = page_header(root);

			mmu_sync_children(vcpu, sp);
@@ -2311,9 +2328,11 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu) 
		goto out;

	spin_lock(&vcpu->kvm->mmu_lock);

	kvm_mmu_free_some_pages(vcpu);

	mmu_alloc_roots(vcpu);

	r = mmu_alloc_roots(vcpu);

	mmu_sync_roots(vcpu);

	spin_unlock(&vcpu->kvm->mmu_lock);

	if (r)

		goto out;

	kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);

	kvm_mmu_flush_tlb(vcpu);

out:

arch/x86/kvm/x86.c

+1 −0
Original line number Diff line number Diff line
@@ -4568,6 +4568,7 @@ int kvm_arch_set_memory_region(struct kvm *kvm, 
void kvm_arch_flush_shadow(struct kvm *kvm)

{

	kvm_mmu_zap_all(kvm);

	kvm_reload_remote_mmus(kvm);

}



int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)