RE: [PATCH v2] x86/cpufeatures: Enable new SSE/AVX/AVX512 cpu features

[Yu, Fenghua]

> On Tuesday, October 31, 2017 11:03 AM, Yu, Fenghua wrote
> > On Tuesday, October 31, 2017 3:06 AM, Borislav Petkov wrote:
> > On Mon, Oct 30, 2017 at 06:20:29PM -0700, Gayatri Kammela wrote:
> > >  #define X86_FEATURE_AVX512VBMI  (16*32+ 1) /* AVX512 Vector Bit
> > Manipulation instructions*/
> >
> > So we have previous AVX512 feature bits which do not separate AVX512
> > with a "_" but the new ones do. I think we should unify this and the
> > SDM should be fixed too.
> 
> This patch exactly follows the names in the spec.
> 
> As you said, the legacy code doesn't follow spec naming strictly and the spec
> doesn't have uniform naming convention either. We are contacting spec
> author to see if we can follow the same naming convention in the future
> specs.

The spec author doesn't want to change the legacy names to insert "_" in order to have uniform names. The "_" in a name is just for readability. So in the future specs, there will be mixed names, some with "_" and some without "_".

We may need to send a patch to fix a few legacy names that don't match exactly specs, e.g. AVX512VBMI as you mentioned.

Thanks.

-Fenghua