Re: [PATCH v2 3/8] crypto: x86 - Stop using cpu_has_xfeatures()

[Eric Biggers <ebiggers@kernel.org>]

On Tue, Jul 28, 2026 at 10:30:18AM +0100, David Laight wrote:
> On Mon, 27 Jul 2026 19:15:58 -0700
> Eric Biggers <ebiggers@kernel.org> wrote:
> 
> > Checking both boot_cpu_has(X86_FEATURE_AVX*) and cpu_has_xfeatures() has
> > never really been needed in practice, and it's never been universally
> > done (e.g., lib/raid/ omits cpu_has_xfeatures()).  Nevertheless, both
> > x86 and UML now explicitly clear the AVX and AVX-512 flags if their
> > xfeatures are missing, which should remove any remaining doubts.
> > 
> > Thus, remove all the calls to cpu_has_xfeatures(), as well as the
> > related checks of boot_cpu_has(X86_FEATURE_OSXSAVE).
> > 
> > In a few cases there was no corresponding boot_cpu_has(X86_FEATURE_AVX*)
> > check, so add the missing ones.
> > 
> > Signed-off-by: Eric Biggers <ebiggers@kernel.org>
> > ---
> ...
> > --- a/arch/x86/crypto/aria_gfni_avx512_glue.c
> > +++ b/arch/x86/crypto/aria_gfni_avx512_glue.c
> > @@ -196,24 +196,15 @@ static struct skcipher_alg aria_algs[] = {
> >  
> >  static int __init aria_avx512_init(void)
> >  {
> > -	const char *feature_name;
> > -
> >  	if (!boot_cpu_has(X86_FEATURE_AVX) ||
> >  	    !boot_cpu_has(X86_FEATURE_AVX2) ||
> 
> Doesn't AVX2 require AVX support?
> 
> >  	    !boot_cpu_has(X86_FEATURE_AVX512F) ||
> >  	    !boot_cpu_has(X86_FEATURE_AVX512VL) ||
> 
> And (less sure) AVX512xxx require AVX2?
> 
> So the extra checks could be reduced.

Yes, but this patch is just intended to clean up the xfeatures and
OSXSAVE checks.  Further cleanups would be separate patches.

- Eric