On Thu, Nov 17, 2011 at 05:59:20PM +0530, Amit Shah wrote: > On (Thu) 17 Nov 2011 [14:25:08], Michael S. Tsirkin wrote: > > On Thu, Nov 17, 2011 at 05:27:42PM +0530, Amit Shah wrote: > > > Delete the vqs on the freeze callback to prepare for hibernation. > > > Re-create the vqs in the restore callback to resume normal function. > > > > > > Signed-off-by: Amit Shah <[email protected]> > > > --- > > > drivers/virtio/virtio_balloon.c | 20 ++++++++++++++++++++ > > > 1 files changed, 20 insertions(+), 0 deletions(-) > > > > > > diff --git a/drivers/virtio/virtio_balloon.c > > > b/drivers/virtio/virtio_balloon.c > > > index 1ff3cf4..90149d1 100644 > > > --- a/drivers/virtio/virtio_balloon.c > > > +++ b/drivers/virtio/virtio_balloon.c > > > @@ -363,6 +363,22 @@ static void __devexit virtballoon_remove(struct > > > virtio_device *vdev) > > > kfree(vb); > > > } > > > > > > +#ifdef CONFIG_PM > > > +static int virtballoon_freeze(struct virtio_device *vdev) > > > +{ > > > + /* Now we reset the device so we can clean up the queues. */ > > > + vdev->config->reset(vdev); > > > + > > > > This is a weird thing to do. We normally delete vqs then reset. > > No, all the drivers first reset, then delete.
BTW, reset does not flush callbacks at the moment. It probably should. > > For example, I don't know whether we guarantee what happens > > to MSI-X vectors assigned meanwhile if you reset. > > IIRC qemu doesn't use MSI-X for the balloon, but nothing > > prevents it. > > > > > + vdev->config->del_vqs(vdev); > > > > What prevents requests being submitted at this point? > > I see all kind of handling of freezing in the balloon thread ... > > maybe that gives us some guarantees, but if yes > > it makes sense to add a comment to point this out. > > Once reset, the host won't write anything to the vqs anyway.. > > Amit But thread might have already been scheduled, handling previous requests. -- MST _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
