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Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS features

From Thomas Gleixner <tglx@linutronix.de>
Newsgroups linux.kernel
Subject Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS features
Date 2016-10-17 10:00 +0200
Message-ID <staZY-A3-3@gated-at.bofh.it> (permalink)
References <srw8x-7Wn-3@gated-at.bofh.it> <ssRND-59Z-23@gated-at.bofh.it> <ssUs9-6Vd-1@gated-at.bofh.it>
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On Sun, 16 Oct 2016, Borislav Petkov wrote:
> > The spec can be found in Intel Software Developer Manual or in
> > Instruction Set Extensions Programming Reference. See
> > https://software.intel.com/sites/default/files/managed/69/78/319433-025.pdf.
> 
> > +/* Intel-defined CPU features, CPUID level 0x00000007:0 (edx), word 18 */
> > +#define X86_FEATURE_AVX512_4VNNIW  (18*32+2) /* AVX-512 Neural Network Instructions */
> > +#define X86_FEATURE_AVX512_4FMAPS  (18*32+3) /* AVX-512 Multiply Accumulation Single precision */
> 
> This is getting ridiculous: we keep adding new leafs to
> ->x86_capability, thus bloating cpuinfo_x86 but then it is not even
> worth it - this patch defines only two bits.

What's worse is that the Instruction Set Extensions Programming Reference
manual says:

CPUID.(EAX=07H, ECX=0):EDX[bit 02] AVX512_4FMAPS
CPUID.(EAX=07H, ECX=0):EBX[bit 03] AVX512_4VNNIW

So AVX512_4VNNIW is in EBX not EDX. What's correct here? The manual or the patch?

I'm going to zap it.

Thanks,

	tglx

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[tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and  AVX512_4FMAPS features tip-bot for Piotr Luc <tipbot@zytor.com> - 2016-10-16 13:30 +0200
  Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and  AVX512_4FMAPS features Borislav Petkov <bp@alien8.de> - 2016-10-16 16:20 +0200
    Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS features hpa@zytor.com - 2016-10-16 18:10 +0200
      Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and  AVX512_4FMAPS features Borislav Petkov <bp@alien8.de> - 2016-10-16 18:40 +0200
        Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS features hpa@zytor.com - 2016-10-16 20:50 +0200
          Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and  AVX512_4FMAPS features Borislav Petkov <bp@alien8.de> - 2016-10-17 00:40 +0200
            Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and  AVX512_4FMAPS features "Luc, Piotr" <Piotr.Luc@intel.com> - 2016-10-17 12:00 +0200
    Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS  features Thomas Gleixner <tglx@linutronix.de> - 2016-10-17 10:00 +0200
      Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and  AVX512_4FMAPS features "Luc, Piotr" <Piotr.Luc@intel.com> - 2016-10-17 10:30 +0200
        Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and  AVX512_4FMAPS features Ingo Molnar <mingo@kernel.org> - 2016-10-17 10:50 +0200
          Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and  AVX512_4FMAPS features "Luc, Piotr" <Piotr.Luc@intel.com> - 2016-10-17 12:00 +0200
            Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS  features Thomas Gleixner <tglx@linutronix.de> - 2016-10-17 12:00 +0200
              [PATCH v2] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS features. Piotr Luc <piotr.luc@intel.com> - 2016-10-17 17:10 +0200
                Re: [v2] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS  features. "Luc, Piotr" <Piotr.Luc@intel.com> - 2016-10-18 15:10 +0200
                Re: [v2] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS  features. Ingo Molnar <mingo@kernel.org> - 2016-10-18 15:10 +0200
                [PATCH v3] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS features. Piotr Luc <piotr.luc@intel.com> - 2016-10-18 17:10 +0200
                [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and  AVX512_4FMAPS features tip-bot for Piotr Luc <tipbot@zytor.com> - 2016-10-19 17:50 +0200

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