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 <20240412084213.1733764-1-steven.price@arm.com> <20240412084213.1733764-15-steven.price@arm.com>
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From: Thomas Fossati <thomas.fossati@linaro.org>
Date: Wed, 24 Apr 2024 15:06:04 +0200
Message-ID: <CA+1=6ydMVk4Vcouc2ag8G7tfqZy80VWFxWHSHEKF1JaABd=A7A@mail.gmail.com>
Subject: Re: [PATCH v2 14/14] virt: arm-cca-guest: TSM_REPORT support for realms
To: Steven Price <steven.price@arm.com>
Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, 
	Sami Mujawar <sami.mujawar@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, 
	Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>, James Morse <james.morse@arm.com>, 
	Oliver Upton <oliver.upton@linux.dev>, Suzuki K Poulose <suzuki.poulose@arm.com>, 
	Zenghui Yu <yuzenghui@huawei.com>, linux-arm-kernel@lists.infradead.org, 
	linux-kernel@vger.kernel.org, Joey Gouly <joey.gouly@arm.com>, 
	Alexandru Elisei <alexandru.elisei@arm.com>, Christoffer Dall <christoffer.dall@arm.com>, 
	Fuad Tabba <tabba@google.com>, linux-coco@lists.linux.dev, 
	Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
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Hi Steven, Sami,

On Fri, 12 Apr 2024 at 10:47, Steven Price <steven.price@arm.com> wrote:
> +/**
> + * arm_cca_report_new - Generate a new attestation token.
> + *
> + * @report: pointer to the TSM report context information.
> + * @data:  pointer to the context specific data for this module.
> + *
> + * Initialise the attestation token generation using the challenge data
> + * passed in the TSM decriptor.

Here, it'd be good to document two interesting facts about challenge data:
1. It must be at least 32 bytes, and
2. If its size is less than 64 bytes, it will be zero-padded.

cheers!