Re: Kernel 6.9 regression: X86: Bogus messages from topology detection

[Linux regression tracking (Thorsten Leemhuis)]

On 31.05.24 10:42, Thomas Gleixner wrote:
> On Fri, May 31 2024 at 10:33, Thomas Gleixner wrote:

> ---
> Subject: x86/topology/intel: Unlock CPUID before evaluating anything
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Date: Thu, 30 May 2024 17:29:18 +0200
> 
> Intel CPUs have a MSR bit to limit CPUID enumeration to leaf two. If this
> bit is set by the BIOS then CPUID evaluation including topology enumeration
> does not work correctly as the evaluation code does not try to analyze any
> leaf greater than two.
> [...]

TWIMC, I noticed a bug report with a "12 × 12th Gen Intel® Core™
i7-1255U" where the reporter also noticed a lot of messages like these:

archlinux kernel: [Firmware Bug]: CPU4: Topology domain 1 shift 7 != 6
archlinux kernel: [Firmware Bug]: CPU4: Topology domain 2 shift 7 != 6
archlinux kernel: [Firmware Bug]: CPU4: Topology domain 3 shift 7 != 6

Asked the reporter to test this patch. For details see:
https://bugzilla.kernel.org/show_bug.cgi?id=218879

Ciao, Thorsten

#regzbot fix: x86/topology/intel: Unlock CPUID before evaluating anything