VIRTIO_F_NOTIFICATION_DATA: extra data to devices

Some devices benefit from ability to find out the number of available
descriptors in the ring: for efficiency or as a debugging aid.

To help with these optimizations, add a new feature:
VIRTIO_F_NOTIFICATION_DATA. When negotiated, driver notifications to the
device include this extra information.

Fixes: https://github.com/oasis-tcs/virtio-spec/issues/26
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/notifications-be.c b/notifications-be.c
new file mode 100644
index 0000000..5be947e
--- /dev/null
+++ b/notifications-be.c
@@ -0,0 +1,5 @@
+be32 {
+	vqn : 16;
+	next_off : 15;
+	next_wrap : 1;
+};