Re: [Qemu-devel] [PATCH] [RFC] Add machine type pc-1.0-qemu-kvm for live migrate compatibility with qemu-kvm

[Paolo Bonzini <pbonzini@redhat.com>]

Il 29/07/2014 15:27, Serge Hallyn ha scritto:
> Quoting Paolo Bonzini (pbonzini@redhat.com):
>> Il 29/07/2014 15:03, Serge E. Hallyn ha scritto:
>>>
>>> And from there I think the thing to do will be to introduce a transient
>>> alternate package that has the pc-1.0 alias pointing ot pc-1.0-qemu-kvm
>>
>> This should be done in the main package, too.
> 
> That seems like a problem, unless I"m misunderstanding something.  If we do
> that in the main package, then anyone running a pc-1.0 system under the
> qemu package won't be able to migrate.  Wouldn't it be better to have
> pc-1.0 alias by default point to the pc-1.0-qemu machine type?

You'd break that for people who have already upgraded from 12.04 and
14.04 and are keeping the old machine type.  You'd fix it for people who
are upgrading now.

I think providing a smoother upgrade path is worthwhile, even if it
annoys someone else.

Unfortunately the only solution is a lot of testing *before* a release,
and in fact this is why 2.1 was delayed by a migration problem.  Once
the release is out, you'll have to make someone unhappy.

>>> and depends on the legacy pxe rom.
>>
>> If you can make the pxe-virtio.rom file 64k or less, then that would be
>> a good idea for 14.04 in general.  Newer machine types use
>> efi-virtio.rom, so you won't break "-M pc" migration.
> 
> Hm.  No idea offhand how I'd do that, but it sounds worth looking into.

I'm not sure either.  You could simply package the 12.04 ipxe ROMs into
14.04, and add a note about getting the sources for GPL friendliness.

Paolo