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Date:   Mon, 21 Feb 2022 18:12:36 +0000
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Mark Brown <broonie@kernel.org>
Cc:     Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Shuah Khan <shuah@kernel.org>,
        Alan Hayward <alan.hayward@arm.com>,
        Luis Machado <luis.machado@arm.com>,
        Salil Akerkar <Salil.Akerkar@arm.com>,
        Basant Kumar Dwivedi <Basant.KumarDwivedi@arm.com>,
        Szabolcs Nagy <szabolcs.nagy@arm.com>,
        James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        linux-arm-kernel@lists.infradead.org,
        linux-kselftest@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v11 15/40] arm64/sme: Implement SVCR context switching
Message-ID: <YhPWFMkjLYT06uYT@arm.com>
References: <20220207152109.197566-1-broonie@kernel.org>
 <20220207152109.197566-16-broonie@kernel.org>
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On Mon, Feb 07, 2022 at 03:20:44PM +0000, Mark Brown wrote:
> In SME the use of both streaming SVE mode and ZA are tracked through
> PSTATE.SM and PSTATE.ZA, visible through the system register SVCR.  In
> order to context switch the floating point state for SME we need to
> context switch the contents of this register as part of context
> switching the floating point state.
> 
> Since changing the vector length exits streaming SVE mode and disables
> ZA we also make sure we update SVCR appropriately when setting vector
> length, and similarly ensure that new threads have streaming SVE mode
> and ZA disabled.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>