Re: [Qemu-ppc] [PATCH 0/5] Last minute ppc migration fixes

[David Gibson]

On Mon, Nov 21, 2016 at 03:58:31PM +1100, David Gibson wrote:
> Unfortunately, a bug already slipped into the qemu-2.7 release which
> breaks migration of the pseries-2.6 machine type from qemu v2.6.0 to
> qemu v2.7.0.  That bug also breaks migration from v2.6.0 to current
> master.  In addition there have been several more changes which have
> inadvertently broken migration from v2.7.0 to current master for both
> pseries-2.6 and pseries-2.7 machine types.
> 
> One of those was fixed - in a way - by 9b54ca0, however it was done in
> such a way as to break backwards migration from current master to
> v2.7.0.  It turns out that supporting backwards migration is more
> important than I realized at the time.
> 
> So, this series contains several fixes for migration.  Between them,
> they allow migration both forwards and backwards between qemu v2.6.0
> and current master (and therefore, I hope, v2.8.0).
> 
> Unfortunately, because of the already released bug, there's no
> reasonable way to fix migration from current master back to v2.7.0 as
> well, and, obviously, no way at all to fix the existing breakage
> between v2.6.0 and v2.7.0.  However, I'm also hoping to get patch 1/5
> of this series applied to the 2.7 stable branch.  If that happens, it
> should be possible to freely migrate between v2.6.0, v2.7.1 and
> current master / 2.8, which is about the best we can hope for.
> 
> I've done basic testing of these with all the combinations of source
> and destination being either v2.6.0, v2.7.0 + patch 1/5 and
> ppc-for-2.8 + this series, and with all the applicable machine types
> for each of those combinations.  Each test was with just a basic
> default hardware setup, running a RHEL7.3 guest, no fancier
> combinations.
> 
> Dave, could you please sanity check my compatibility sheanningans and
> send an R-b (and an acked-by for patch 2/5, which isn't strictly ppc
> related).
> 
> Michael, if you could test this on any combinations that occur to you,
> that would be most helpful.
> 
> I'm hoping to get some reviews and squeeze this into v2.8.0, which
> will mean a pull request within a couple of days.

Bother, just realised I left a chunk of debug code in there.  Will
resend momentarily.

> 
> David Gibson (5): target-ppc: Fix CPU migration from qemu-2.6 <->
>   later versions migration: Add VMSTATE_UINTTL_TEST() target-ppc:
>   Allow eventual removal of old migration mistakes Revert "spapr: Fix
>   migration of PCI host bridges from qemu-2.7" spapr: Fix 2.7<->2.8
>   migration of PCI host bridge
> 
>  hw/ppc/spapr.c              | 10 +++++++++
>  hw/ppc/spapr_pci.c          | 35 +++++++++++++++++++++--------
>  include/hw/pci-host/spapr.h |  6 +++++
>  include/migration/cpu.h     |  4 ++++
>  target-ppc/cpu.h            |  7 ++++++
>  target-ppc/machine.c        | 55 
> +++++++++++++++++++++++++++++++++++++++++----
>  target-ppc/translate_init.c |  6 +++++
>  7 files changed, 110 insertions(+), 13 deletions(-)
> 

-- 
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

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