Re: [Qemu-devel] [PATCH 2/2] qxl: change rom size to 8192

[Gerd Hoffmann]

  Hi,

>> foo.img generated with stock qemu 1.3.1, migration fails with git
>> head, still
>> fails after reverting the seabios 1.7.2 update which supposedly
>> causes other
>> migrate issues (commit 3588185b8396eb97fd9efd41c2b97775465f67c4)
> 
> So this is by design - that patch changes the rom size for revision 4 (which 
> is the default for qemu 1.3.1) from 16384 bytes to 8192. This breaks 
> migration from previously created revision 4 images... But it unbreaks 
> migration from other revisions. Different things that could be done: do a 
> special migration hook to copy from src 16384 byte rom bar to dst 8192 byte 
> rom bar. Gerd, what do you think?

So the change making the rpm 16k was before 1.3, the fix thereafter, and
now we have migration 1.2 -> 1.3 broken (maybe masked by -M 1.2
defaulting to qxl rev 3), 1.3 -> 1.4 broken and 1.2 -> 1.4 working, correct?

So a compat property changing the rom size to 16k for pc-1.3 should do
the trick I think.

cheers,
  Gerd