Re: [Qemu-ppc] [PATCH v5 2/3] xics: directly register ICPState objects to vmstate

[Greg Kurz]

On Wed, 14 Jun 2017 16:04:12 +0200
Laurent Vivier <address@hidden> wrote:

> On 14/06/2017 15:29, Greg Kurz wrote:
> > The ICPState objects are currently registered to vmstate as qdev objects.
> > Their instance ids are hence computed automatically in the migration code,
> > and thus depends on the order the CPU cores were plugged.
> > 
> > If the destination had its CPU cores plugged in a different order than the
> > source, then ICPState objects will have different instance_ids and load
> > the wrong state.
> > 
> > Since CPU objects have a reliable cpu_index which is already used as
> > instance_id in vmstate, let's use it for ICPState as well.
> > 
> > Please note that this doesn't break migration. Older machine types used to
> > allocate and realize all ICPState objects at machine init time, for the 
> > whole
> > lifetime of the machine. The qdev instance ids are thus 0,1,2... nr_servers
> > and happen to map to the vCPU indexes.
> > 
> > Signed-off-by: Greg Kurz <address@hidden>  
> 
> Reviewed-by: Laurent Vivier <address@hidden>
> 
> CC: dgilbert
> 

Oops, I had planned to Cc: dgilbert and I fumbled just before the
goal... of course. :P

Thanks Laurent !

> > ---
> > v5: - explain why it doesn't break migration in the changelog
> > ---
> >  hw/intc/xics.c |    5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/intc/xics.c b/hw/intc/xics.c
> > index 7ccfb53c55a0..faa5c631f655 100644
> > --- a/hw/intc/xics.c
> > +++ b/hw/intc/xics.c
> > @@ -344,10 +344,14 @@ static void icp_realize(DeviceState *dev, Error 
> > **errp)
> >      }
> >  
> >      qemu_register_reset(icp_reset, dev);
> > +    vmstate_register(NULL, icp->cs->cpu_index, &vmstate_icp_server, icp);
> >  }
> >  
> >  static void icp_unrealize(DeviceState *dev, Error **errp)
> >  {
> > +    ICPState *icp = ICP(dev);
> > +
> > +    vmstate_unregister(NULL, &vmstate_icp_server, icp);
> >      qemu_unregister_reset(icp_reset, dev);
> >  }
> >  
> > @@ -355,7 +359,6 @@ static void icp_class_init(ObjectClass *klass, void 
> > *data)
> >  {
> >      DeviceClass *dc = DEVICE_CLASS(klass);
> >  
> > -    dc->vmsd = &vmstate_icp_server;
> >      dc->realize = icp_realize;
> >      dc->unrealize = icp_unrealize;
> >  }
> >   
>

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