Re: [Qemu-devel] [PATCH qom-cpu 00/16 v10] target-i386: convert CPU features into properties

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 5 Feb 2014 17:52:16 +0100
Igor Mammedov <imammedo@redhat.com> wrote:

> On Wed, 05 Feb 2014 17:14:27 +0100
> Andreas Färber <afaerber@suse.de> wrote:
> 
> > Am 05.02.2014 15:40, schrieb Igor Mammedov:
> > > On Sun, 15 Dec 2013 23:50:47 +0100
> > > Andreas Färber <afaerber@suse.de> wrote:
> > > 
> > >> Am 27.11.2013 23:28, schrieb Igor Mammedov:
> > >>> Igor Mammedov (16):
> > >>>   target-i386: cleanup 'foo' feature handling'
> > >>>   target-i386: cleanup 'foo=val' feature handling
> > >>
> > >> Thanks, I've queued these on qom-cpu-next:
> > >> https://github.com/afaerber/qemu-cpu/commits/qom-cpu-next
> > >>
> > >>>   target-i386: cpu: convert 'level' to static property
> > >>>   target-i386: cpu: convert 'xlevel' to static property
> > >>>   target-i386: cpu: convert 'family' to static property
> > >>>   target-i386: cpu: convert 'model' to static property
> > >>>   target-i386: cpu: convert 'stepping' to static property
> > >>>   target-i386: cpu: convert 'vendor' to static property
> > >>>   target-i386: cpu: convert 'model-id' to static property
> > >>>   target-i386: cpu: convert 'tsc-frequency' to static property
> > >>
> > >> But I still don't see the utility of this conversion after all the
> > >> discussions we've had... :(
> > > It seems there is movement to make DEVICE self describing for purpose
> > > of QAPI schema introspection, where static properties would be used
> > > (dynamic ones are not suitable for this purpose)
> > 
> > Do you have a pointer to such a discussion? Sounds like I was not
> > involved and Anthony probably not either...
> Not at the moment, CCing people who might know more about the topic.
> 
> But just thinking about creating QAPI schema for devices, it's not really
> possible to generate one using dynamic properties (unless one resorts to
> creating every supported device instance), while arrays of static properties
> are there for every device and simplistically speaking just need conversion
> to schema format.

There is one more reason to use static properties for external user-settable
properties when it comes to device, i.e. to get list of properties user could
use command:
#qemu -device x86_64-cpu,?
x86_64-cpu.pmu=boolean
x86_64-cpu.hv-spinlocks=int
x86_64-cpu.hv-relaxed=boolean
x86_64-cpu.hv-vapic=boolean
x86_64-cpu.check=boolean
x86_64-cpu.enforce=boolean

which now yields only partial properties user is interested in, above
mentioned conversion patches make previously not available properties
visible to user via typical interface, perhaps eventually we could
drop list_cpu() interface in favor of -device foo-cpu,? command.

Taking in account Paolo's cleanup of legacy properties in static properties,
it might make them more suitable for moving concept to Object level.
(As far as I remember, Anthony objected to it due to existence of legacy
properties).
 

> > 
> > Andreas
> > 
> > -- 
> > SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
> > GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
> 
>