[Qemu-devel] Re: [SeaBIOS] [PATCH 0/8] option rom loading overhaul.

[Gerd Hoffmann]

On 12/18/09 17:42, Anthony Liguori wrote:
> > Do we need to do something for -M pc-0.11? Like loading the pci roms
> > via fw_cfg too so the guest doesn't see the new pci rom bar?
>
> Yes, we do. We can fix that problem as a stable-0.12 update though.
> Right now, migration with pc-0.11 is broken in other areas too.

Ok.  When it is fine to defer this to stable-0.12 then I have no 
objections to merge it for 0.12 (assuming the seabios folks ack+merge 
the seabios changes).

Note that I'll be offline for x-mas and newyear starting tomorrow, so I 
will not be able to work on that until January.

> It's really unclear to me the best way to handle live migration. The
> rom_offset is not enough because unfortunately it's not stable after
> invocations of qemu. I think we're going to have to actually save the
> some contents with the PCIDevices.

With hotplug this will become a issue indeed.

> > Is 0.11 -> 0.12 migration supposed to work? That could become quite
> > nasty too. But maybe that is impossible anyway due to the switch to
> > seabios?
>
> In theory, it should work. SeaBIOS should not be a guest visible change
> because the guest should not depend on what BIOS we're using.

Indeed.  In theory even the switch of the option rom loading should work 
just fine.  After migration old bios and roms are still in memory, the 
next reboot will be the world switch to new seabios, new roms, new way 
to deploy roms and everything.

Lets see how this works out in practice ...

cheers,
  Gerd