vhost: support event index

Support the new event index feature. When acked,
utilize it to reduce the # of interrupts sent to the guest.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 14 insertions, 7 deletions

diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index b3363ae38518..8e03379dd30f 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -84,6 +84,12 @@ struct vhost_virtqueue {
         /* Used flags */
         u16 used_flags;
 
+        /* Last used index value we have signalled on */
+        u16 signalled_used;
+
+        /* Last used index value we have signalled on */
+        bool signalled_used_valid;
+
         /* Log writes to used structure. */
         bool log_used;
         u64 log_addr;
@@ -149,8 +155,8 @@ void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
                                struct vring_used_elem *heads, unsigned count);
 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
-void vhost_disable_notify(struct vhost_virtqueue *);
-bool vhost_enable_notify(struct vhost_virtqueue *);
+void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
+bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 
 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
                     unsigned int log_num, u64 len);
@@ -162,11 +168,12 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
         } while (0)
 
 enum {
-        VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) |
-                         (1 << VIRTIO_RING_F_INDIRECT_DESC) |
-                         (1 << VHOST_F_LOG_ALL) |
-                         (1 << VHOST_NET_F_VIRTIO_NET_HDR) |
-                         (1 << VIRTIO_NET_F_MRG_RXBUF),
+        VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
+                         (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
+                         (1ULL << VIRTIO_RING_F_EVENT_IDX) |
+                         (1ULL << VHOST_F_LOG_ALL) |
+                         (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
+                         (1ULL << VIRTIO_NET_F_MRG_RXBUF),
 };
 
 static inline int vhost_has_feature(struct vhost_dev *dev, int bit)