Commit 8c6de56a authored by Boris Ostrovsky's avatar Boris Ostrovsky Committed by Paolo Bonzini

x86/kvm: Be careful not to clear KVM_VCPU_FLUSH_TLB bit

kvm_steal_time_set_preempted() may accidentally clear KVM_VCPU_FLUSH_TLB
bit if it is called more than once while VCPU is preempted.

This is part of CVE-2019-3016.

(This bug was also independently discovered by Jim Mattson
<jmattson@google.com>)
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: default avatarJoao Martins <joao.m.martins@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ae608821
...@@ -3504,6 +3504,9 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) ...@@ -3504,6 +3504,9 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu)
if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
return; return;
if (vcpu->arch.st.steal.preempted)
return;
vcpu->arch.st.steal.preempted = KVM_VCPU_PREEMPTED; vcpu->arch.st.steal.preempted = KVM_VCPU_PREEMPTED;
kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime, kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime,
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment