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Message-ID: <20210112021321.GA9922@yangzhon-Virtual>
Date: Tue, 12 Jan 2021 10:13:21 +0800
From: Yang Zhong <yang.zhong@...el.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
hpa@...or.com, tony.luck@...el.com, seanjc@...gle.com,
vkuznets@...hat.com, wanpengli@...cent.com, jmattson@...gle.com,
joro@...tes.org, kyung.min.park@...el.com, x86@...nel.org,
yang.zhong@...el.com
Subject: Re: [PATCH 1/2] Enumerate AVX Vector Neural Network instructions
On Tue, Jan 05, 2021 at 01:14:56PM +0100, Borislav Petkov wrote:
> 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@...el.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@...el.com>
> > > Signed-off-by: Yang Zhong <yang.zhong@...el.com>
> > > Reviewed-by: Tony Luck <tony.luck@...el.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@...e.de>
>
Paolo, Boris has acked this kernel patch, and if i need send new patchset to add this
acked-by info ? or kvm tree will directly pull this patchset? thanks.
Yang
> Thx.
>
> --
> Regards/Gruss,
> Boris.
>
> https://people.kernel.org/tglx/notes-about-netiquette
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