linux-kernel - Re: [PATCH 01/13] x86/CPU/AMD: Add ZenX generations flags

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Date:   Thu, 30 Nov 2023 19:50:48 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Tom Lendacky <thomas.lendacky@....com>,
        Brian Gerst <brgerst@...il.com>
Cc:     X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 01/13] x86/CPU/AMD: Add ZenX generations flags

On Thu, Nov 30, 2023 at 12:17:02PM -0600, Tom Lendacky wrote:
> There are references to X86_FEATURE_ZEN in arch/x86/kernel/process.c and
> drivers/acpi/resource.c that should probably be vetted.
> 
> Maybe having X86_FEATURE_ZEN mean all ZEN (and set for anything family 17h
> or higher) and a separate per generation, e.g. X86_FEATURE_ZEN1, when you
> need to be specific, would work.

Yap, looks like it. Those process.c and resource.c things mean all Zen
- and perhaps that really should mean that - Zen and newer. This all
falls nicely into place anyway since Zen stopped using a family number
per generation so that's a natural cutoff point where we're going to
start using those synthetic feature flags for the generations and one
for all Zens.

And yap, the Zen1 stuff should probably be behind X86_FEATURE_ZEN1.

Yap, sounds good. Lemme cook up a patch tomorrow.

Thx to you and Brian for the suggestions.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette