On Tue, 2014-09-23 at 13:32 +0300, Michael S. Tsirkin wrote:

On restore, virtio pci does the following:
+ set features
+ init vqs etc - device can be used at this point!
+ set ACKNOWLEDGE,DRIVER and DRIVER_OK status bits

This is in violation of the virtio spec, which
requires the following order:
- ACKNOWLEDGE
- DRIVER
- init vqs
- DRIVER_OK

Cc: stable@vger.kernel.org
Cc: Amit Shah <redacted>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

[...]

What concrete problem does this fix, such that it should be applied to
stable branches?

Ben.

-- 
Ben Hutchings
Everything should be made as simple as possible, but not simpler.
                                                           - Albert Einstein