Re: [RFC PATCH v2 01/12] i386/sev: introduce "sev-common" type to encapsulate common SEV state

[Markus Armbruster]

Michael Roth <michael.roth@amd.com> writes:

> Currently all SEV/SEV-ES functionality is managed through a single
> 'sev-guest' QOM type. With upcoming support for SEV-SNP, taking this
> same approach won't work well since some of the properties/state
> managed by 'sev-guest' is not applicable to SEV-SNP, which will instead
> rely on a new QOM type with its own set of properties/state.
>
> To prepare for this, this patch moves common state into an abstract
> 'sev-common' parent type to encapsulate properties/state that is
> common to both SEV/SEV-ES and SEV-SNP, leaving only SEV/SEV-ES-specific
> properties/state in the current 'sev-guest' type. This should not
> affect current behavior or command-line options.
>
> As part of this patch, some related changes are also made:
>
>   - a static 'sev_guest' variable is currently used to keep track of
>     the 'sev-guest' instance. SEV-SNP would similarly introduce an
>     'sev_snp_guest' static variable. But these instances are now
>     available via qdev_get_machine()->cgs, so switch to using that
>     instead and drop the static variable.
>
>   - 'sev_guest' is currently used as the name for the static variable
>     holding a pointer to the 'sev-guest' instance. Re-purpose the name
>     as a local variable referring the 'sev-guest' instance, and use
>     that consistently throughout the code so it can be easily
>     distinguished from sev-common/sev-snp-guest instances.
>
>   - 'sev' is generally used as the name for local variables holding a
>     pointer to the 'sev-guest' instance. In cases where that now points
>     to common state, use the name 'sev_common'; in cases where that now
>     points to state specific to 'sev-guest' instance, use the name
>     'sev_guest'
>
> Signed-off-by: Michael Roth <michael.roth@amd.com>
> ---
>  qapi/qom.json     |  34 +++--
>  target/i386/sev.c | 329 +++++++++++++++++++++++++++-------------------
>  2 files changed, 214 insertions(+), 149 deletions(-)
>
> diff --git a/qapi/qom.json b/qapi/qom.json
> index a25616bc7a..211e083727 100644
> --- a/qapi/qom.json
> +++ b/qapi/qom.json
> @@ -735,12 +735,29 @@
>    'data': { '*filename': 'str' } }
>  
>  ##
> -# @SevGuestProperties:
> +# @SevCommonProperties:
>  #
> -# Properties for sev-guest objects.
> +# Properties common to objects that are derivatives of sev-common.
>  #
>  # @sev-device: SEV device to use (default: "/dev/sev")
>  #
> +# @cbitpos: C-bit location in page table entry (default: 0)
> +#
> +# @reduced-phys-bits: number of bits in physical addresses that become
> +#                     unavailable when SEV is enabled
> +#
> +# Since: 2.12
> +##
> +{ 'struct': 'SevCommonProperties',
> +  'data': { '*sev-device': 'str',
> +            '*cbitpos': 'uint32',
> +            'reduced-phys-bits': 'uint32' } }
> +
> +##
> +# @SevGuestProperties:
> +#
> +# Properties for sev-guest objects.
> +#
>  # @dh-cert-file: guest owners DH certificate (encoded with base64)
>  #
>  # @session-file: guest owners session parameters (encoded with base64)
> @@ -749,21 +766,14 @@
>  #
>  # @handle: SEV firmware handle (default: 0)
>  #
> -# @cbitpos: C-bit location in page table entry (default: 0)
> -#
> -# @reduced-phys-bits: number of bits in physical addresses that become
> -#                     unavailable when SEV is enabled
> -#
>  # Since: 2.12
>  ##
>  { 'struct': 'SevGuestProperties',
> -  'data': { '*sev-device': 'str',
> -            '*dh-cert-file': 'str',
> +  'base': 'SevCommonProperties',
> +  'data': { '*dh-cert-file': 'str',
>              '*session-file': 'str',
>              '*policy': 'uint32',
> -            '*handle': 'uint32',
> -            '*cbitpos': 'uint32',
> -            'reduced-phys-bits': 'uint32' } }
> +            '*handle': 'uint32' } }
>  
>  ##
>  # @ObjectType:

External interface remains unchanged, as far as I can tell.

For the QAPI schema:
Acked-by: Markus Armbruster <armbru@redhat.com>