linux-kernel - Re: [PATCH v9 04/30] arm64/fpsimd: Check enable bit for FA64 when saving EFI state

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Message-ID: <87wm1072ex.fsf@draig.linaro.org>
Date: Thu, 29 Jan 2026 17:29:42 +0000
From: Alex Bennée <alex.bennee@...aro.org>
To: Mark Brown <broonie@...nel.org>
Cc: Marc Zyngier <maz@...nel.org>,  Joey Gouly <joey.gouly@....com>,
  Catalin Marinas <catalin.marinas@....com>,  Suzuki K Poulose
 <suzuki.poulose@....com>,  Will Deacon <will@...nel.org>,  Paolo Bonzini
 <pbonzini@...hat.com>,  Jonathan Corbet <corbet@....net>,  Shuah Khan
 <shuah@...nel.org>,  Oliver Upton <oupton@...nel.org>,  Dave Martin
 <Dave.Martin@....com>,  Fuad Tabba <tabba@...gle.com>,  Mark Rutland
 <mark.rutland@....com>,  Ben Horgan <ben.horgan@....com>,
  linux-arm-kernel@...ts.infradead.org,  kvmarm@...ts.linux.dev,
  linux-kernel@...r.kernel.org,  kvm@...r.kernel.org,
  linux-doc@...r.kernel.org,  linux-kselftest@...r.kernel.org,  Peter
 Maydell <peter.maydell@...aro.org>,  Eric Auger <eric.auger@...hat.com>
Subject: Re: [PATCH v9 04/30] arm64/fpsimd: Check enable bit for FA64 when
 saving EFI state

Mark Brown <broonie@...nel.org> writes:

> On Thu, Jan 29, 2026 at 04:39:33PM +0000, Alex Bennée wrote:
>> Mark Brown <broonie@...nel.org> writes:
>
>> > Currently when deciding if we need to save FFR when in streaming mode prior
>> > to EFI calls we check if FA64 is supported by the system. Since KVM guest
>> > support will mean that FA64 might be enabled and disabled at runtime switch
>> > to checking if traps for FA64 are enabled in SMCR_EL1 instead.
>
>> This is conflicting with the now merged 63de2b3859ba1 (arm64/efi: Remove
>> unneeded SVE/SME fallback preserve/store handling) so I think this patch
>> can now be dropped?
>
> Yes, this should go away in the next rebase.

Everything else applies cleanly though so thats good ;-)

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro