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Date: Thu, 4 Jul 2024 15:18:56 +0100
From: Catalin Marinas <catalin.marinas@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Fuad Tabba <tabba@google.com>, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev
Subject: Re: [PATCH v2 2/4] arm64/fpsimd: Discover maximum vector length
 implemented by any CPU
Message-ID: <ZoavUGcYLULHpVfg@arm.com>
References: <20240606-kvm-arm64-fix-pkvm-sve-vl-v2-0-c88f4eb4b14b@kernel.org>
 <20240606-kvm-arm64-fix-pkvm-sve-vl-v2-2-c88f4eb4b14b@kernel.org>
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In-Reply-To: <20240606-kvm-arm64-fix-pkvm-sve-vl-v2-2-c88f4eb4b14b@kernel.org>

On Thu, Jun 06, 2024 at 04:21:44PM +0100, Mark Brown wrote:
> When discovering the vector lengths for SVE and SME we do not currently
> record the maximum VL supported on any individual CPU.  This is expected
> to be the same for all CPUs but the architecture allows asymmetry, if we
> do encounter an asymmetric system then some CPUs may support VLs higher
> than the maximum Linux will use.  Since the pKVM hypervisor needs to
> support saving and restoring anything the host can physically set it
> needs to know the maximum value any CPU could have, add support for
> enumerating it and validation for late CPUs.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>

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

I guess the %lu suggested by Fuad can be done when applying the patch.