Re: [PATCH 0/2] KVM: x86: Propagate AMD-specific IBRS bits to guests

Paolo Bonzini
2023-03-06T21:26:23Z

On 3/6/23 22:16, Sean Christopherson wrote:
>> Not harmless - cpufeatures.h should contain flags which the kernel uses
>> and not*every* CPUID bit out there.
>
> I thought that the consensus was that adding unused-by-the-kernel flags to
> cpufeatures.h is ok so long as the feature is hidden from /proc/cpuinfo and the
> kernel already dedicates a word to the CPUID leaf?
Yeah, I understand adding no new CPUID leaf just for KVM, but you don't
gain anything really from not having X86_FEATURE_* defines.

Paolo