KVM: MMU: fix sync of ptes addressed at owner pagetable

During page sync, if a pagetable contains a self referencing pte (that
points to the pagetable), the corresponding spte may be marked as
writable even though all mappings are supposed to be write protected.

Fix by clearing page unsync before syncing individual sptes.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f1983d9477cd163bc13de766f1edd8ffee4c720b..410ddbc1aa2eb0fc2dfa45de560c829df364aa81 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1038,13 +1038,13 @@ static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
        }
 
        rmap_write_protect(vcpu->kvm, sp->gfn);
+       kvm_unlink_unsync_page(vcpu->kvm, sp);
        if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
                kvm_mmu_zap_page(vcpu->kvm, sp);
                return 1;
        }
 
        kvm_mmu_flush_tlb(vcpu);
-       kvm_unlink_unsync_page(vcpu->kvm, sp);
        return 0;
 }