Re: [Qemu-devel] [Qemu-ppc] [PATCH] spapr: skip configuration section during migration of older machines

[David Gibson <david@gibson.dropbear.id.au>]

[-- Attachment #1: Type: text/plain, Size: 1894 bytes --]

On Wed, Feb 10, 2016 at 09:26:12PM +0100, Greg Kurz wrote:
> On Mon, 08 Feb 2016 16:59:47 +0100
> Greg Kurz <gkurz@linux.vnet.ibm.com> wrote:
> > Since QEMU 2.4, we have a configuration section in the migration stream.
> > This must be skipped for older machines, like it is already done for x86.
> > 
> 
> Ouch ! It is more complex than I thought... the migration of pseries-2.3
> machine is already broken between QEMU-2.3 and QEMU-2.4. So this patch
> fixes indeed migration of a pseries-2.3 machine from QEMU-2.3, but it
> breaks migration of the same machine from QEMU-2.4 and up.
> 
> Not sure how to deal with that... is it reasonable to assume that
> pseries-2.3 running with QEMU-2.3 is the common case ? If so, this
> patch would bring more help than harm.

Ouch.  I really have no idea what would be the more common case.  I
doubt there are many people using old upstream versions in anger, but
I can't be sure of course.

> 
> > Fixes: 61964c23e5ddd5a33f15699e45ce126f879e3e33
> > Cc: qemu-stable@nongnu.org
> > Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> > ---
> >  hw/ppc/spapr.c |    1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 5bd8fd3ef842..bca7cb8a5d27 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -2446,6 +2446,7 @@ static void spapr_machine_2_3_instance_options(MachineState *machine)
> >      spapr_machine_2_4_instance_options(machine);
> >      savevm_skip_section_footers();
> >      global_state_set_optional();
> > +    savevm_skip_configuration();
> >  }
> > 
> >  static void spapr_machine_2_3_class_options(MachineClass *mc)
> > 
> > 
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]