Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <CAJvTdK=evAofQRcmt_iwtYx2f_wTGUDpXzvjuiVwgZZ6BZV_Qg@mail.gmail.com>
 <E8BCA270-4F23-4E1B-BAD6-917DBE36F5F6@amacapital.net> <CAJvTdK=Lqbzy6bs8qiE8MZ5LSzyZJ-FMUTcNPD4MxYJGEMBW3g@mail.gmail.com>
 <20210331225226.GC11673@zn.tnic>
In-Reply-To: <20210331225226.GC11673@zn.tnic>
From:   Len Brown <lenb@kernel.org>
Date:   Fri, 9 Apr 2021 16:55:30 -0400
Message-ID: <CAJvTdKm_sa869Xn-GVFPnka_B+-otf1FwoMtA-8PAYOaN99BnA@mail.gmail.com>
Subject: Re: Candidate Linux ABI for Intel AMX and hypothetical new related features
To:     Borislav Petkov <bp@alien8.de>
Cc:     Andy Lutomirski <luto@amacapital.net>,
        David Laight <David.Laight@aculab.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        "Bae, Chang Seok" <chang.seok.bae@intel.com>,
        X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        libc-alpha <libc-alpha@sourceware.org>,
        Florian Weimer <fweimer@redhat.com>,
        Rich Felker <dalias@libc.org>, Kyle Huey <me@kylehuey.com>,
        Keno Fischer <keno@juliacomputing.com>,
        Linux API <linux-api@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Wed, Mar 31, 2021 at 6:54 PM Borislav Petkov <bp@alien8.de> wrote:
>
> On Wed, Mar 31, 2021 at 06:28:27PM -0400, Len Brown wrote:
> > dynamic XCR0 breaks the installed base, I thought we had established
> > that.
>
> We should do a clear cut and have legacy stuff which has its legacy
> expectations on the XSTATE layout and not touch those at all.
>
> And then all new apps which will use these new APIs can go and request
> whatever fancy new state constellations we support. Including how they
> want their signals handled, etc.
>
> Fat states like avx512, amx etc will be off by default and apps
> explicitly requesting those, can get them.
>
> That's it.

100% agreement from me!  (does anybody disagree?)

thanks,
Len Brown, Intel Open Source Technology Center