Re: [Qemu-devel] [RFC PATCH 0/4] Fix subsection ambiguity in the migration format

[Dor Laor]

On 07/31/2011 09:46 PM, Christoph Hellwig wrote:
> On Sun, Jul 31, 2011 at 02:45:07PM +0300, Dor Laor wrote:
> > > No, definitely not. I think most people using non-x86 architectures
> > > don't use the vmsave/vmload/migration features at all, but would
> > > be annoyed if the perfectly functional device models they were
> > > using got deleted...
> >
> > I didn't mean to erase the entire device, just the code for save/load which
> > as you say, might not be used at all.
>
> Like the one in virtio?

/me caught off guard. I wonder why it wasn't converted to VMSTATE 
before?  virtio is one of the key devices, it's not just random 
forgotten one that might not care about migration.

It's worth to utilize this discussion to realize whether vmstate is 
significant enough.
From my brief browsing it looks like vmstate helps to reduce some plain 
errors with double save/load coding, ease the field encoding and handles 
subsections (which imho is the most important).

It's true that we need to introduce capabilities to the live migration 
protocol and some other goodies but we might be able to do that with
the existing method of gradual enhancement for VMSTATE to whatever form 
it may be.