Re: [PATCH 00/11] virtio: Support for hibernation (S4)

[Rusty Russell <rusty@rustcorp.com.au>]

On Sun, 2 Oct 2011 11:49:21 +0200, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Thu, Sep 29, 2011 at 08:55:56PM +0530, Amit Shah wrote:
> > Hello,
> > 
> > These patches add support for S4 to virtio (pci) and all drivers.  The
> > patches are based on the virtio-console patch series in Rusty's queue.
> > 
> > For each driver, all vqs are removed before hibernation, and then
> > re-created after restore.
> > 
> > All the drivers in testing work fine:
> > 
> > * virtio-blk is used for the only disk in the VM, IO works fine before
> >   and after.

I'm not familiar with the suspend code, but:

1) Does it already ensure there are no outstanding I/O requests?  If
   not, we want to restore them when we unfreeze.

2) Does it stop more I/O from reaching do_virtblk_request during freeze?
   If not, we need to.

If we need to save and restore requests, I don't think we should do this
on a per-driver basis, but try to do it in the core.

Thanks,
Rusty.