Re: [PATCH 1/5] i386/sev: Add sev-emulated QOM object with TCG support

[Markus Armbruster <armbru@redhat.com>]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Fri, Mar 20, 2026 at 08:44:40AM +0100, Markus Armbruster wrote:
>> Daniel P. Berrangé <berrange@redhat.com> writes:
>> 
>> > On Tue, Mar 17, 2026 at 12:38:36PM +0100, Tommaso Califano wrote:
>> >> With this change it is possible to run a VM with the SEV CPUID active
>> >> adding:
>> >> 
>> >>     -accel tcg \
>> >>     -object sev-emulated,id=sev0,cbitpos=47,reduced-phys-bits=1 \
>> >>     -machine memory-encryption=sev0
>> >
>> > snip
>> >
>> >> diff --git a/qapi/qom.json b/qapi/qom.json
>> >> index c653248f85..35cda819ec 100644
>> >> --- a/qapi/qom.json
>> >> +++ b/qapi/qom.json
>> >> @@ -1057,6 +1057,19 @@
>> >>              '*handle': 'uint32',
>> >>              '*legacy-vm-type': 'OnOffAuto' } }
>> >>  
>> >> +##
>> >> +# @SevEmulatedProperties:
>> >> +#
>> >> +# Properties for sev-emulated objects.
>> >> +# This object functionally emulates AMD SEV hardware via TCG, so
>> >> +# it does not require real hardware to run.
>> >> +#
>> >> +# Since: 10.1.0
>> >> +##
>> >> +{ 'struct': 'SevEmulatedProperties',
>> >> +  'base': 'SevGuestProperties',
>> >> +  'data': {}}
>> >
>> > This is deriving 'sev-emulated' from 'sev-guest' which means it
>> > supports all the properties that 'sev-guest' does, which for
>> > the record is:
>> 
>> Uh, I somehow misread the base as SevCommonProperties!  Had I read
>> correctly, I would've had similar questions.
>
> Even SevCommonProperties has stuff that's irrelevant for
> emulation that I mentioned.

Yes.  I was too hasty.  Glad you spotted it!