On Tue, 2014-06-24 at 14:55 -0300, Eduardo Habkost wrote: > On Tue, Jun 24, 2014 at 05:47:53PM +0100, Peter Maydell wrote: > > On 24 June 2014 17:44, Eduardo Habkost <ehabk...@redhat.com> wrote: > > > (I would go even further and say that no compat_props bit need to be > > > specific to a machine-type family, and they are simply tied to the code > > > included in a QEMU version. So every PC_COMPAT_* bit could go to a > > > common QEMU_COMPAT_<version> macro, that could be reusable by all > > > machine-types, and there's no need PC-specific compat macros.) > > > > What if different machines in a particular release had the > > property set to different defaults? > > I never saw that happen, and I don't think it is even likely: default > values set in instance_init, and compat_props are applied just after > instance_init, before object_new() returns. So a machine-type would need > to find a way to change fields after instance_init but before > compat_props are applied. > > Anyway, if a machine-type really needs that, it can still have its own > set of compat macros to implement machine-type-specific compat_props. My > point is that there's no need for that on the PC code today. > +1
As discussed in today's KVM call, compat props per version is the best approach. Thanks, Marcel
