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Date:   Mon, 12 Apr 2021 16:31:39 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Florian Weimer <fweimer@redhat.com>
Cc:     Andy Lutomirski <luto@kernel.org>,
        "Bae, Chang Seok" <chang.seok.bae@intel.com>,
        Dave Hansen <dave.hansen@intel.com>, X86 ML <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, linux-abi@vger.kernel.org,
        "libc-alpha@sourceware.org" <libc-alpha@sourceware.org>,
        Rich Felker <dalias@libc.org>, Kyle Huey <me@kylehuey.com>,
        Keno Fischer <keno@juliacomputing.com>
Subject: Re: Candidate Linux ABI for Intel AMX and hypothetical new related
 features
Message-ID: <20210412143139.GE24283@zn.tnic>
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On Mon, Apr 12, 2021 at 04:19:29PM +0200, Florian Weimer wrote:
> Maybe we could have done this in 2016 when I reported this for the first
> time.  Now it is too late, as more and more software is using
> CPUID-based detection for AVX-512.

So as I said on another mail today, I don't think a library should rely
solely on CPUID-based detection of features especially if those features
need kernel support too. IOW, it should ask whether the kernel can
handle those too, first.

And the CPUID-faulting thing would solve stuff like that because then
the kernel can *actually* get involved into answering something where it
has a say in, too.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette