virtio: Allow guest to defer VIRTIO_F_NOTIFY_ON_EMPTY (Alex Williamson)
commit97b83deb557679c909465456acaa723c2ba34948
authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>
Fri, 20 Mar 2009 16:13:50 +0000 (20 16:13 +0000)
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>
Fri, 20 Mar 2009 16:13:50 +0000 (20 16:13 +0000)
tree01584249ce6bc8cae70e98db04499d53b44652dd
parentbf16cc8f97ff57db191eec73346ba0333ade342b
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/trunk@6865 c046a42c-6fe2-441c-8c8c-71466251a162
hw/virtio.c