Re: [PATCH] arm64: Filter out SME hwcaps when FEAT_SME isn't implemented

From: Will Deacon
Date: Fri Jul 04 2025 - 13:45:07 EST


On Fri, 20 Jun 2025 12:28:48 +0100, Mark Brown wrote:
> We have a number of hwcaps for various SME subfeatures enumerated via
> ID_AA64SMFR0_EL1. Currently we advertise these without cross checking
> against the main SME feature, advertised in ID_AA64PFR1_EL1.SME which
> means that if the two are out of sync userspace can see a confusing
> situation where SME subfeatures are advertised without the base SME
> hwcap. This can be readily triggered by using the arm64.nosme override
> which only masks out ID_AA64PFR1_EL1.SME, and there have also been
> reports of VMMs which do the same thing.
>
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64: Filter out SME hwcaps when FEAT_SME isn't implemented
https://git.kernel.org/arm64/c/a75ad2fc76a2

Cheers,
--
Will

https://fixes.arm64.dev
https://next.arm64.dev
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