linux-kernel - Re: [PATCH RFC v1 00/11] x86: Support Intel Advanced Performance Extensions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <64be7980-644d-4b16-a8c1-5598ea63aeef@intel.com>
Date: Thu, 27 Feb 2025 11:36:57 -0800
From: Dave Hansen <dave.hansen@...el.com>
To: Ingo Molnar <mingo@...nel.org>, "Chang S. Bae" <chang.seok.bae@...el.com>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org, tglx@...utronix.de,
 mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
 Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH RFC v1 00/11] x86: Support Intel Advanced Performance
 Extensions

On 2/27/25 11:15, Ingo Molnar wrote:
>> by userspace applications, with no intended use in kernel mode. More
>                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> details on its use cases can be found in the published documentation [1].
> I strongly suspect this won't remain so, unless there's some horrible 
> ISA limitation or other quirk that makes APX unsuitable for kernel use.

I think Chang was trying to say that this series is completely focused
on userspace AMX and basically ignores the idea of using it in the kernel.

That said, we honestly talk all the time about using it in the kernel. A
kernel compiled to use APX everywhere obviously won't run on older CPUs
but it _should_ have some really nice advantages. I completely expect
the kernel to be able to be compiled to use APX at _some_ point.