On Thu, Oct 01, 2015 at 06:31:27PM -0400, Bandan Das wrote:
> >> @@ -514,7 +514,7 @@ static void skip_emulated_instruction(struct kvm_vcpu
> >> *vcpu)
> >> struct vcpu_svm *svm = to_svm(vcpu);
> >>
> >> if (svm->vmcb->control.next_rip != 0) {
> >> - WARN_ON(!static_cpu_has(X86_FEATURE_NRIPS));
> >> + WARN_ON_ONCE(!static_cpu_has(X86_FEATURE_NRIPS));
> >> svm->next_rip = svm->vmcb->control.next_rip;
> >> }
I looked again how this could possibly be triggered, and I am somewhat
confused now.
So svm->vmcb->control.next_rip is only written by hardware or in
svm_check_intercept(). Both cases write only to this field, if the
hardware supports X86_FEATURE_NRIPS. The write in nested_svm_vmexit only
targets the guests VMCB, and we don't use that one again.
So I can't see how the WARN_ON above could be triggered. Do I miss
something or might this also be a miscompilation of static_cpu_has?
Joerg
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