Re: [Qemu-devel] [PATCH RFC 1/8] virtio: add subsections to the migration stream

[Fam Zheng]

On Thu, 05/15 12:08, Greg Kurz wrote:
> > > The main problem I see is that virtio sucks: as you see in patch 8, we 
> > > have
> > > to be careful not to call vring or virtqueue stuff before the device knows
> > > its endianness or it breaks... I need to study how the virtio-bus gets
> > > migrated to ensure the endian section is streamed before the devices.
> > 
> > There is no ordering guarantee. The state needs to be migrated in the
> > device or bus where it sits, if post-load processing is required; i.e.,
> > if it's in VirtIODevice then something like this series, if it were on
> > VirtioBus exclusively (device asking bus for its endianness each time
> > and does not do post-load stuff) then endianness could be migrated as a
> > new bus section. Not sure if that would help the "broken" state though?
> > 
> 
> IIRW the "broken" state was proposed as a per-device property...

Yes.

> 
> Fam,
> 
> Do you have plans about the "broken" property ? Is it still needed ?

It is on my todo list. We will need it. I hope the next revision of virtio
specification has a proper device status bit that the "broken" property can
utilize.

Thanks,
Fam