Re: [PATCH 1/2] Enumerate AVX Vector Neural Network instructions

Borislav Petkov
2021-01-05T12:15:56Z

On Tue, Jan 05, 2021 at 12:47:23PM +0100, Paolo Bonzini wrote:
> On 05/01/21 01:49, Yang Zhong wrote:
> > From: Kyung Min Park <kyung.min.park@intel.com>
> >
> > Add AVX version of the Vector Neural Network (VNNI) Instructions.
> >
> > A processor supports AVX VNNI instructions if CPUID.0x07.0x1:EAX[4] is
> > present. The following instructions are available when this feature is
> > present.
> > 1. VPDPBUS: Multiply and Add Unsigned and Signed Bytes
> > 2. VPDPBUSDS: Multiply and Add Unsigned and Signed Bytes with Saturation
> > 3. VPDPWSSD: Multiply and Add Signed Word Integers
> > 4. VPDPWSSDS: Multiply and Add Signed Integers with Saturation
> >
> > The only in-kernel usage of this is kvm passthrough. The CPU feature
> > flag is shown as "avx_vnni" in /proc/cpuinfo.
> >
> > This instruction is currently documented in the latest "extensions"
> > manual (ISE). It will appear in the "main" manual (SDM) in the future.
> >
> > Signed-off-by: Kyung Min Park <kyung.min.park@intel.com>
> > Signed-off-by: Yang Zhong <yang.zhong@intel.com>
> > Reviewed-by: Tony Luck <tony.luck@intel.com>
> > ---
> > arch/x86/include/asm/cpufeatures.h | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> > index f5ef2d5b9231..d10d9962bd9b 100644
> > --- a/arch/x86/include/asm/cpufeatures.h
> > +++ b/arch/x86/include/asm/cpufeatures.h
> > @@ -293,6 +293,7 @@
> > #define X86_FEATURE_PER_THREAD_MBA (11*32+ 7) /* "" Per-thread Memory Bandwidth Allocation */
> > /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
> > +#define X86_FEATURE_AVX_VNNI (12*32+ 4) /* AVX VNNI instructions */
> > #define X86_FEATURE_AVX512_BF16 (12*32+ 5) /* AVX512 BFLOAT16 instructions */
> > /* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */
> >
>
> Boris, is it possible to have a topic branch for this patch?

Just take it through your tree pls.

Acked-by: Borislav Petkov <bp@suse.de>

Thx.

--
Regards/Gruss,
Boris.