From: Sean Christopherson <seanjc@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@kernel.org>,
"Ahmed S. Darwish" <darwi@linutronix.de>,
Ard Biesheuvel <ardb+git@google.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
Ard Biesheuvel <ardb@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Brian Gerst <brgerst@gmail.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>
Subject: Re: [PATCH v4 1/6] x86/cpu: Use a new feature flag for 5 level paging
Date: Thu, 22 May 2025 08:08:27 -0700 [thread overview]
Message-ID: <aC896zTw_z7Bx6I2@google.com> (raw)
In-Reply-To: <20250522075553.GG24938@noisy.programming.kicks-ass.net>
On Thu, May 22, 2025, Peter Zijlstra wrote:
> On Wed, May 21, 2025 at 05:23:37PM +0200, Thomas Gleixner wrote:
>
> > 4) Drivers having access to CPUID is just wrong. We've had issues
> > with that in the past because drivers evaluated CPUID themself and
> > missed that the core code had stuff disabled.
>
> I had this patch that read the module instructions and failed loading if
> they used 'fancy' instructions. Do you want me to revive that?
Unless you want to grant exceptions, that's not going to fly for KVM. KVM makes
heavy use of CPUID, the consumption/output of which is firmly entrenched in KVM's
ABI.
next prev parent reply other threads:[~2025-05-22 15:08 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-17 9:16 [PATCH v4 0/6] x86: Robustify pgtable_l5_enabled() Ard Biesheuvel
2025-05-17 9:16 ` [PATCH v4 1/6] x86/cpu: Use a new feature flag for 5 level paging Ard Biesheuvel
2025-05-17 14:28 ` Ard Biesheuvel
2025-05-19 8:35 ` Ingo Molnar
2025-05-19 9:40 ` Borislav Petkov
2025-05-19 9:46 ` Ard Biesheuvel
2025-05-19 12:15 ` Borislav Petkov
2025-05-19 12:24 ` Borislav Petkov
2025-05-19 12:25 ` Ard Biesheuvel
2025-05-19 13:08 ` Ingo Molnar
2025-05-19 13:19 ` Borislav Petkov
2025-05-21 15:23 ` Thomas Gleixner
2025-05-21 18:11 ` Borislav Petkov
2025-05-21 18:56 ` Thomas Gleixner
2025-05-21 19:29 ` Borislav Petkov
2025-05-21 19:41 ` Thomas Gleixner
2025-05-21 19:48 ` Borislav Petkov
2025-05-21 20:07 ` Thomas Gleixner
2025-05-22 7:55 ` Peter Zijlstra
2025-05-22 15:08 ` Sean Christopherson [this message]
2025-05-22 19:58 ` Thomas Gleixner
2025-05-22 22:15 ` Sean Christopherson
2025-05-19 12:55 ` [tip: x86/core] x86/cpu: Use a new feature flag for 5-level paging tip-bot2 for Ard Biesheuvel
2025-05-19 13:12 ` Ingo Molnar
2025-05-17 9:16 ` [PATCH v4 2/6] x86/cpu: Move CPU capability override arrays from BSS to __ro_after_init Ard Biesheuvel
2025-05-19 12:01 ` Brian Gerst
2025-05-17 9:16 ` [PATCH v4 3/6] x86/cpu: Allow caps to be set arbitrarily early Ard Biesheuvel
2025-05-17 9:16 ` [PATCH v4 4/6] x86/boot: Set 5-level paging CPU cap before entering C code Ard Biesheuvel
2025-05-17 9:16 ` [PATCH v4 5/6] x86/boot: Drop the early variant of pgtable_l5_enabled() Ard Biesheuvel
2025-05-17 9:16 ` [PATCH v4 6/6] x86/boot: Drop 5-level paging related variables and early updates Ard Biesheuvel
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=aC896zTw_z7Bx6I2@google.com \
--to=seanjc@google.com \
--cc=ardb+git@google.com \
--cc=ardb@kernel.org \
--cc=bp@alien8.de \
--cc=brgerst@gmail.com \
--cc=darwi@linutronix.de \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.