From: Christoph Hellwig <hch@lst.de>
To: Eric Biggers <ebiggers@kernel.org>
Cc: x86@kernel.org, linux-um@lists.infradead.org,
linux-raid@vger.kernel.org, linux-crypto@vger.kernel.org,
linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/8] x86/fpu: Check for missing AVX and AVX-512 xstate bits
Date: Fri, 26 Jun 2026 07:39:55 +0200 [thread overview]
Message-ID: <20260626053955.GA9629@lst.de> (raw)
In-Reply-To: <20260626043731.319287-2-ebiggers@kernel.org>
On Thu, Jun 25, 2026 at 09:37:24PM -0700, Eric Biggers wrote:
> If the CPU declares AVX or AVX-512 support, verify that the
> corresponding xstate bits are also set. If not, warn and clear them.
>
> This eliminates the perceived need for AVX and AVX-512 optimized code in
> the kernel to call cpu_has_xfeatures(). That has never been universally
> done, which strongly suggests that it has never really been needed in
> practice, but this should remove any remaining doubt.
I'll leave it to the x86-experts if the low-level details are right,
but the model behind this makes life so much easier, thanks a lot!
next prev parent reply other threads:[~2026-06-26 5:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-26 4:37 [PATCH 0/8] x86: Remove cpu_has_xfeatures() and add AVX-512 xor_gen() Eric Biggers
2026-06-26 4:37 ` [PATCH 1/8] x86/fpu: Check for missing AVX and AVX-512 xstate bits Eric Biggers
2026-06-26 5:39 ` Christoph Hellwig [this message]
2026-06-26 4:37 ` [PATCH 2/8] um: " Eric Biggers
2026-06-26 7:41 ` David Laight
2026-06-26 8:21 ` Anton Ivanov
2026-06-26 10:49 ` David Laight
2026-06-26 4:37 ` [PATCH 3/8] crypto: x86 - Stop using cpu_has_xfeatures() Eric Biggers
2026-06-26 4:37 ` [PATCH 4/8] lib/crypto: x86: " Eric Biggers
2026-06-26 4:37 ` [PATCH 5/8] lib/crc: " Eric Biggers
2026-06-26 4:37 ` [PATCH 6/8] x86/fpu: Remove cpu_has_xfeatures() Eric Biggers
2026-06-26 4:37 ` [PATCH 7/8] lib/raid/xor: x86: Remove redundant X86_FEATURE_OSXSAVE check Eric Biggers
2026-06-26 5:40 ` Christoph Hellwig
2026-06-26 4:37 ` [PATCH 8/8] lib/raid/xor: x86: Add AVX-512 optimized xor_gen() Eric Biggers
2026-06-26 5:47 ` Christoph Hellwig
2026-06-26 5:47 ` Christoph Hellwig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260626053955.GA9629@lst.de \
--to=hch@lst.de \
--cc=akpm@linux-foundation.org \
--cc=ebiggers@kernel.org \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-raid@vger.kernel.org \
--cc=linux-um@lists.infradead.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox