KVM: x86: nSVM: don't copy virt_ext from vmcb12

commit faf6b755629627f19feafa75b32e81cd7738f12d upstream.

These field correspond to features that we don't expose yet to L2

While currently there are no CVE worthy features in this field,
if AMD adds more features to this field, that could allow guest
escapes similar to CVE-2021-3653 and CVE-2021-3656.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210914154825.104886-6-mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index df17146e841fba1a36ff039ccdd41fea1b6456d8..f0946872f5e6d5f298db28d4327502f734ffc91b 100644 (file)
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -447,7 +447,6 @@ static void nested_prepare_vmcb_control(struct vcpu_svm *svm)
                (svm->nested.ctl.int_ctl & int_ctl_vmcb12_bits) |
                (svm->nested.hsave->control.int_ctl & int_ctl_vmcb01_bits);
 
-       svm->vmcb->control.virt_ext            = svm->nested.ctl.virt_ext;
        svm->vmcb->control.int_vector          = svm->nested.ctl.int_vector;
        svm->vmcb->control.int_state           = svm->nested.ctl.int_state;
        svm->vmcb->control.event_inj           = svm->nested.ctl.event_inj;