Re: [Qemu-devel] [PATCH] Migration compatibility for serial

[Michael S. Tsirkin]

On Wed, Jun 17, 2015 at 01:53:11PM +0200, Paolo Bonzini wrote:
> 
> 
> On 17/06/2015 13:45, Michael S. Tsirkin wrote:
> >> > Where, in the specific case of migration?
> > Just look at hour compat flags.
> > 
> > For example (intentionally using serial here):
> >         {\
> >             .driver   = "pci-serial",\
> >             .property = "prog_if",\
> >             .value    = stringify(0),\
> >         },\
> >         {\
> >             .driver   = "pci-serial-2x",\
> >             .property = "prog_if",\
> >             .value    = stringify(0),\
> >         },\
> >         {\
> >             .driver   = "pci-serial-4x",\
> >             .property = "prog_if",\
> >             .value    = stringify(0),\
> >         },\
> > 
> > apparently some clients check the specific prog if
> > value, completely breaking if the value was incorrect.
> > So we fixed it for new machine types but not old ones.
> 
> That has nothing to do with migration.
> 
> Paolo

If you change prog_if migration fails.

-- 
MST