Re: [PATCH v2 15/22] target/arm/kvm-rme: Add measurement algorithm property

[Markus Armbruster]

Jean-Philippe Brucker <jean-philippe@linaro.org> writes:

> This option selects which measurement algorithm to use for attestation.
> Supported values are SHA256 and SHA512. Default to SHA512 arbitrarily.
>
> SHA512 is generally faster on 64-bit architectures. On a few arm64 CPUs
> I tested SHA256 is much faster, but that's most likely because they only
> support acceleration via FEAT_SHA256 (Armv8.0) and not FEAT_SHA512
> (Armv8.2). Future CPUs supporting RME are likely to also support
> FEAT_SHA512.
>
> Cc: Eric Blake <eblake@redhat.com>
> Cc: Markus Armbruster <armbru@redhat.com>
> Cc: Daniel P. Berrangé <berrange@redhat.com>
> Cc: Eduardo Habkost <eduardo@habkost.net>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
> v1->v2: use enum, pick default
> ---
>  qapi/qom.json        | 18 +++++++++++++++++-
>  target/arm/kvm-rme.c | 39 ++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/qapi/qom.json b/qapi/qom.json
> index 91654aa267..84dce666b2 100644
> --- a/qapi/qom.json
> +++ b/qapi/qom.json
> @@ -931,18 +931,34 @@
>    'data': { '*cpu-affinity': ['uint16'],
>              '*node-affinity': ['uint16'] } }
>  
> +##
> +# @RmeGuestMeasurementAlgo:
> +#
> +# @sha256: Use the SHA256 algorithm

Let's have a blank line here.

> +# @sha512: Use the SHA512 algorithm
> +#
> +# Algorithm to use for realm measurements
> +#
> +# Since: FIXME

9.1

> +##
> +{ 'enum': 'RmeGuestMeasurementAlgo',
> +  'data': ['sha256', 'sha512'] }
> +
>  ##
>  # @RmeGuestProperties:
>  #
>  # Properties for rme-guest objects.
>  #
> +# @measurement-algo: Realm measurement algorithm (default: sha512)
> +#

We tend to avoid abbreviations in QMP: @measurement-algorithm.

May want to rename the type to RmeGuestMeasurementAlgorithm for
consistency.

>  # @personalization-value: Realm personalization value, as a 64-byte hex 
> string
>  #     (default: 0)
>  #
>  # Since: FIXME
>  ##
>  { 'struct': 'RmeGuestProperties',
> -  'data': { '*personalization-value': 'str' } }
> +  'data': { '*personalization-value': 'str',
> +            '*measurement-algo': 'RmeGuestMeasurementAlgo' } }
>  
>  ##
>  # @ObjectType:

With these issues addressed, QAPI schema
Acked-by: Markus Armbruster <armbru@redhat.com>

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