Re: [PATCH 3/3] KVM: SVM: enable LBRV virtualization

Avi Kivity
2008-02-13T10:20:07Z

Joerg Roedel wrote:
>>>
>>>
>> This still has the same issue as the previous patchset: if the guest enables some other bit
>> in MSR_IA32_DEBUCTLMSR, we silently ignore it. We should either pr_unimpl() on such bits or
>> not handle them (ultimately injecting a #GP).
>>
>
> Thats not true. The patch saves the MSR value in vmcb->save.dbgctl. This
> value is returned on reads of that MSR. So no bit is ignored. This value
> in the VMCB is also used as the guests copy of that MSR if LBR
> virtualization is enabled.

Right, my mistake.

--
Any sufficiently difficult bug is indistinguishable from a feature.