Commit 995decb6 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
Browse files

KVM: x86: take as_id into account when checking PGD 



OVMF booted guest running on shadow pages crashes on TRIPLE FAULT after
enabling paging from SMM. The crash is triggered from mmu_check_root() and
is caused by kvm_is_visible_gfn() searching through memslots with as_id = 0
while vCPU may be in a different context (address space).

Introduce kvm_vcpu_is_visible_gfn() and use it from mmu_check_root().

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200708140023.1476020-1-vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 5668821a

arch/x86/kvm/mmu/mmu.c

+1 −1
Original line number Diff line number Diff line
@@ -3693,7 +3693,7 @@ 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)) {

	if (!kvm_vcpu_is_visible_gfn(vcpu, root_gfn)) {

		kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);

		ret = 1;

	}

include/linux/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -774,6 +774,7 @@ int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len); 
int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len);

struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn);

bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn);

bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn);

unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn);

void mark_page_dirty(struct kvm *kvm, gfn_t gfn);

virt/kvm/kvm_main.c

+8 −0
Original line number Diff line number Diff line
@@ -1626,6 +1626,14 @@ bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn) 
}

EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);



bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)

{

	struct kvm_memory_slot *memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);



	return kvm_is_visible_memslot(memslot);

}

EXPORT_SYMBOL_GPL(kvm_vcpu_is_visible_gfn);



unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn)

{

	struct vm_area_struct *vma;