linux-kernel - Re: [PATCH] x86: add hintable NOPs emulation

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: <ddfe73ac-177a-431f-8e6e-807ff0746213@orca.pet>
Date: Wed, 20 Aug 2025 12:21:40 +0200
From: Marcos Del Sol Vives <marcos@...a.pet>
To: Borislav Petkov <bp@...en8.de>
Cc: "Ahmed S. Darwish" <darwi@...utronix.de>, linux-kernel@...r.kernel.org,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
 "H. Peter Anvin" <hpa@...or.com>, Brian Gerst <brgerst@...il.com>,
 Uros Bizjak <ubizjak@...il.com>, Ard Biesheuvel <ardb@...nel.org>,
 David Kaplan <david.kaplan@....com>, Kees Cook <kees@...nel.org>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>,
 Andrew Cooper <andrew.cooper3@...rix.com>, Oleg Nesterov <oleg@...hat.com>,
 "Xin Li (Intel)" <xin@...or.com>, Sabyrzhan Tasbolatov <snovitoll@...il.com>
Subject: Re: [PATCH] x86: add hintable NOPs emulation

El 20/08/2025 a las 12:08, Borislav Petkov escribió:
> On Wed, Aug 20, 2025 at 12:01:30PM +0200, Marcos Del Sol Vives wrote:
>> Please define "once". Once per what? Per boot? Per executable? Per process?
> 
> pr_err_once(). Per boot.

Would a simple:

> pr_warn_once("Your processor does not correctly handle hintable NOPs.\n");
> pr_warn_once("The kernel will emulate them, but the performance will be impacted!\n");

work for you, then? With no thread information, as that might make the user
think there is only once binary impacted.