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

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>

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index b41a21cac5444131173b9adb7b357001c06dc3ed..510b833cbd39915c021db25d357cf0bedf777a43 100644 (file)
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -545,7 +545,6 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
                (svm->nested.ctl.int_ctl & int_ctl_vmcb12_bits) |
                (svm->vmcb01.ptr->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;