From: no-reply@sashiko.virtuozzo.com
To: Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>,
Konstantin Khorenko <khorenko@virtuozzo.com>,
Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: devel@openvz.org
Subject: Re: [Devel] [PATCH hci-8.1 v5 4/5] x86/traps: decode the faulting CPUID with the instruction decoder
Date: Tue, 6 Oct 2026 23:01:17 +0000 [thread overview]
Message-ID: <010701a113732dd6-92580627-9c67-4f56-892d-9351412bab84-000000@eu-central-1.amazonses.com> (raw)
In-Reply-To: <20261007-b4-prep-khorenko-vstor-148656-cpuid-v5-4-652c5c9e56da@virtuozzo.com>
> check_cpuid_fault() reads two bytes at the faulting ip and emulates
> only when they are 0f a2, the bare CPUID encoding.
>
> CPUID has no operands, so the CPU accepts and ignores every legacy
> and REX prefix in front of it. All of these are valid CPUID and raise
> the same #GP(0) when CPUID faulting is on:
>
> 0f a2 cpuid
> 66 0f a2 data16 cpuid (operand-size override)
> f3 0f a2 repz cpuid
> 2e 0f a2 cs cpuid (segment override)
> 48 0f a2 rex.W cpuid
>
> Only the first one is recognised. For the others the handler reads
> the prefix byte instead of the opcode, declines, and the task is
> [ ... ]
> Fixes: 1033fe455434 ("arch/x86: introduce cpuid override")
> https://virtuozzo.atlassian.net/browse/VSTOR-148843
>
> Feature: x86: cpu pools (cpuid override)
> Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.vzint.dev/#/patchset/20261007-b4-prep-khorenko-vstor-148656-cpuid-v5-0-652c5c9e56da@virtuozzo.com?part=4
_______________________________________________
Devel mailing list
Devel@openvz.org
https://lists.openvz.org/mailman/listinfo/devel
next prev parent reply other threads:[~2026-10-06 23:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-06 22:54 [Devel] [PATCH hci-8.1 v5 0/5] x86/ve: CPUID override follow-ups: arm at once, prefixes, selftests Konstantin Khorenko
2026-10-06 22:54 ` [Devel] [PATCH hci-8.1 v5 1/5] selftests/ve: check CPUID override emulation for VE tasks Konstantin Khorenko
2026-10-06 23:03 ` no-reply
2026-10-06 22:54 ` [Devel] [PATCH hci-8.1 v5 2/5] x86/ve: enable CPUID faulting at once when the current task enters a VE Konstantin Khorenko
2026-10-06 22:59 ` no-reply
2026-10-06 22:54 ` [Devel] [PATCH hci-8.1 v5 3/5] selftests/ve: check CPUID override right after entering " Konstantin Khorenko
2026-10-06 23:00 ` no-reply
2026-10-06 22:54 ` [Devel] [PATCH hci-8.1 v5 4/5] x86/traps: decode the faulting CPUID with the instruction decoder Konstantin Khorenko
2026-10-06 23:01 ` no-reply [this message]
2026-10-06 22:54 ` [Devel] [PATCH hci-8.1 v5 5/5] selftests/ve: check CPUID override emulation for a prefixed CPUID Konstantin Khorenko
2026-10-06 23:03 ` no-reply
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=010701a113732dd6-92580627-9c67-4f56-892d-9351412bab84-000000@eu-central-1.amazonses.com \
--to=no-reply@sashiko.virtuozzo.com \
--cc=devel@openvz.org \
--cc=khorenko@virtuozzo.com \
--cc=ptikhomirov@virtuozzo.com \
--cc=vasileios.almpanis@virtuozzo.com \
/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