Re: [PATCH] ppc: function to setup latest class options

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Feb 07, 2020 at 12:12:09PM +0100, Greg Kurz wrote:
> On Fri, 7 Feb 2020 11:35:47 +0100
> Philippe Mathieu-Daudé <philmd@redhat.com> wrote:
> 
> > On 2/7/20 7:48 AM, Michael S. Tsirkin wrote:
> > > We are going to add more init for the latest machine, so move the setup
> > > to a function so we don't have to change the DEFINE_SPAPR_MACHINE macro
> > > each time.
> > > 
> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > ---
> > >   hw/ppc/spapr.c | 9 +++++++--
> > >   1 file changed, 7 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > > index 02cf53fc5b..4cf2a992a5 100644
> > > --- a/hw/ppc/spapr.c
> > > +++ b/hw/ppc/spapr.c
> > > @@ -4428,6 +4428,12 @@ static const TypeInfo spapr_machine_info = {
> > >       },
> > >   };
> > >   
> > > +static void spapr_machine_latest_class_options(MachineClass *mc)
> > > +{
> > > +    mc->alias = "pseries";
> > > +    mc->is_default = 1;
> > 
> > But we can have only 1 default per QEMU binary... How PPC manage having 
> > multiple defaults? The first or last listed is choosen as default?
> > 
> 
> IIUC it isn't about putting multiple defaults here. It is about putting
> any additional init for the default machine type that we cannot put in
> spapr_machine_class_init(), instead of putting it in the versioned
> init function, eg. spapr_machine_5_0_class_options(). Otherwise this
> would force us to carry the change when we add a new machine version.

Maybe it's cleaner to pass the latest flag to
spapr_machine_latest_class_options? Rename it spapr_machine_default_class_options?
This way we don't need to bother clearing is_default in other
machine types, we'll only set it for the latest one.

> > > +}
> > > +
> > >   #define DEFINE_SPAPR_MACHINE(suffix, verstr, latest)                 \
> > >       static void spapr_machine_##suffix##_class_init(ObjectClass *oc, \
> > >                                                       void *data)      \
> > > @@ -4435,8 +4441,7 @@ static const TypeInfo spapr_machine_info = {
> > >           MachineClass *mc = MACHINE_CLASS(oc);                        \
> > >           spapr_machine_##suffix##_class_options(mc);                  \
> > >           if (latest) {                                                \
> > > -            mc->alias = "pseries";                                   \
> > > -            mc->is_default = 1;                                      \
> > > +            spapr_machine_latest_class_options(mc);                  \
> > >           }                                                            \
> > >       }                                                                \
> > >       static const TypeInfo spapr_machine_##suffix##_info = {          \
> > > 
> > 
> >