| Message ID | 20210914154825.104886-8-mlevitsk@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [01/14] KVM: x86: nSVM: restore int_vector in svm_clear_vintr | expand |
On 14/09/21 17:48, Maxim Levitsky wrote: > Just in case, add a warning ensuring that on guest entry, > either both VMLOAD and VMSAVE intercept is enabled or > vVMLOAD/VMSAVE is enabled. > > Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> > --- > arch/x86/kvm/svm/svm.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index 861ac9f74331..deeebd05f682 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -3784,6 +3784,12 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) > > WARN_ON_ONCE(kvm_apicv_activated(vcpu->kvm) != kvm_vcpu_apicv_active(vcpu)); > > + /* Check that CVE-2021-3656 can't happen again */ > + if (!svm_is_intercept(svm, INTERCEPT_VMSAVE) || > + !svm_is_intercept(svm, INTERCEPT_VMSAVE)) > + WARN_ON(!(svm->vmcb->control.virt_ext & > + VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK)); > + > sync_lapic_to_cr8(vcpu); > > if (unlikely(svm->asid != svm->vmcb->control.asid)) { > While it's nice to be "proactive", this does adds some extra work. Maybe it should be under CONFIG_DEBUG_KERNEL. It could be useful to make it into its own function so we can add similar intercept invariants in the same place. Paolo
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 861ac9f74331..deeebd05f682 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3784,6 +3784,12 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) WARN_ON_ONCE(kvm_apicv_activated(vcpu->kvm) != kvm_vcpu_apicv_active(vcpu)); + /* Check that CVE-2021-3656 can't happen again */ + if (!svm_is_intercept(svm, INTERCEPT_VMSAVE) || + !svm_is_intercept(svm, INTERCEPT_VMSAVE)) + WARN_ON(!(svm->vmcb->control.virt_ext & + VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK)); + sync_lapic_to_cr8(vcpu); if (unlikely(svm->asid != svm->vmcb->control.asid)) {
Just in case, add a warning ensuring that on guest entry, either both VMLOAD and VMSAVE intercept is enabled or vVMLOAD/VMSAVE is enabled. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> --- arch/x86/kvm/svm/svm.c | 6 ++++++ 1 file changed, 6 insertions(+)