virtio: Allow guest to defer VIRTIO_F_NOTIFY_ON_EMPTY (Alex Williamson)
commit7c14db42cb46625283828d47bbc157548fc3a751
authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>
Fri, 20 Mar 2009 16:18:45 +0000 (20 16:18 +0000)
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>
Fri, 20 Mar 2009 16:18:45 +0000 (20 16:18 +0000)
treeb5a1b60ba9847b8417fdd8eb3415b42f4abd8221
parente58843d0f117b2a30d27552b509d7cf24a0c4ba6
virtio: Allow guest to defer VIRTIO_F_NOTIFY_ON_EMPTY (Alex Williamson)

There may be cases where the guest does not want the avail queue
interrupt, even when it's empty.  For the virtio-net case, the
guest may use a different buffering scheme or decide polling for
used buffers is more efficient.  This can be accomplished by simply
checking for whether the guest has acknowledged the existing notify
on empty flag.

Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/branches/stable_0_10_0@6868 c046a42c-6fe2-441c-8c8c-71466251a162
hw/virtio.c