linux-kernel - Re: [PATCH v4 1/6] x86: move ZMM exclusion list into CPU feature flag

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Message-ID: <20250210211710.GCZ6ps1pNklAXyqD0p@fat_crate.local>
Date: Mon, 10 Feb 2025 22:17:10 +0100
From: Borislav Petkov <bp@...en8.de>
To: Eric Biggers <ebiggers@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-crypto@...r.kernel.org,
	x86@...nel.org, linux-block@...r.kernel.org,
	Ard Biesheuvel <ardb@...nel.org>, Keith Busch <kbusch@...nel.org>,
	Kent Overstreet <kent.overstreet@...ux.dev>,
	"Martin K . Petersen" <martin.petersen@...cle.com>,
	Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH v4 1/6] x86: move ZMM exclusion list into CPU feature flag

On Mon, Feb 10, 2025 at 01:01:03PM -0800, Eric Biggers wrote:
> I see that cpu_feature_enabled() uses code patching while boot_cpu_has() does
> not.  All these checks occur once at module load time, though, so code patching
> wouldn't be beneficial.

We want to convert all code to use a single interface for testing CPU features
- cpu_feature_enabled() - and the implementation shouldn't be important to
users - it should just work.

Since you're adding new code, you might as well use the proper interface. As
to converting crypto/ and the rest of the tree, that should happen at some
point... eventually...

Thx.

-- 
Regards/Gruss,
    Boris.

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