Re: [tip: perf/urgent] x86/cpufeatures: Add dedicated feature word for CPUID leaf 0x80000022[EAX]
From: Borislav Petkov
Date: Tue Mar 19 2024 - 09:01:19 EST
On Tue, Mar 19, 2024 at 10:36:01AM -0000, tip-bot2 for Sandipan Das wrote:
> The following commit has been merged into the perf/urgent branch of tip:
>
> Commit-ID: f0a22ea644717fa21698a32d342fcd307e53a935
> Gitweb: https://git.kernel.org/tip/f0a22ea644717fa21698a32d342fcd307e53a935
> Author: Sandipan Das <sandipan.das@xxxxxxx>
> AuthorDate: Tue, 19 Mar 2024 13:48:16 +05:30
> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> CommitterDate: Tue, 19 Mar 2024 11:23:47 +01:00
>
> x86/cpufeatures: Add dedicated feature word for CPUID leaf 0x80000022[EAX]
>
> Move the existing scattered performance monitoring related feature bits
> from CPUID leaf 0x80000022[EAX] into a dedicated word since additional
> bits will be defined from the same leaf in the future. This includes
> X86_FEATURE_PERFMON_V2 and X86_FEATURE_AMD_LBR_V2.
That CPUID leaf has a whopping three bits defined and the rest is
reserved. You should do a dedicated leaf when we use at least 50% of the
bits in the leaf. But not like this.
Please do simply another synthetic leaf and put your bits there.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette