Re: [PATCH for-6.0] qapi: qom: do not use target-specific conditionals

[Paolo Bonzini]

On 26/03/21 11:57, Markus Armbruster wrote:
> >         'rng-random':                 'RngRandomProperties',
> >         'secret':                     'SecretProperties',
> >         'secret_keyring':             'SecretKeyringProperties',
> > -      'sev-guest':                  { 'type': 'SevGuestProperties',
> > -                                      'if': 'defined(CONFIG_SEV)' },
> > +      'sev-guest':                  'SevGuestProperties',
> >         'throttle-group':             'ThrottleGroupProperties',
> >         'tls-creds-anon':             'TlsCredsAnonProperties',
> >         'tls-creds-psk':              'TlsCredsPskProperties',
>
> No branch for tag value 'pef-guest', i.e. no tag-specific members.
> There are two more: can_bus, s390_pv_guest.  I assume this is
> intentional.

Yes, they have no properties.

> Links a bit of dead code into the other qemu-system-FOO, but that's
> okay.
>
> If we genuinely needed (or wanted) target-dependent -object, we'd split
> qom-target.json off qom.json, and put the target-dependent parts there,
> including the enum and the union, with the obvious ripple effects.  Not
> now, maybe not ever.
>
> Would adding "only for CONFIG_MUMBLE" to the doc comments make sense?
> It's what we did before we had 'if'.

In this specific case we had not documentation at all for objects.  We 
can add the information on relevant targets in the documentation for the 
*Properties types.

Paolo