Re: [PATCH v3 1/2] x86: KVM: Advertise FSRS and FSRC on AMD to userspace

Borislav Petkov
2025-04-11T09:42:30Z

On Wed, Dec 04, 2024 at 04:43:44PM +0300, Maksim Davydov wrote:
> Fast short REP STOSB and fast short CMPSB support on AMD processors are
> provided in other CPUID function in comparison with Intel processors:
> * FSRS: 10 bit in 0x80000021_EAX
> * FSRC: 11 bit in 0x80000021_EAX
>
> AMD bit numbers differ from existing definition of FSRC and
> FSRS. So, the new appropriate values have to be added with new names.
>
> It's safe to advertise these features to userspace because they are a part
> of CPU model definition and they can't be disabled (as existing Intel
> features).
>
> Fixes: 2a4209d6a9cb ("KVM: x86: Advertise fast REP string features inherent to the CPU")

Why is there a Fixes tag here?

--
Regards/Gruss,
Boris.