vhost: backend masking support

Support backend guest notifier masking in vhost-net:
create eventfd at device init, when masked,
make vhost use that as eventfd instead of
sending an interrupt.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/hw/vhost.h b/hw/vhost.h
index 6f6a906..44c61a5 100644
--- a/hw/vhost.h
+++ b/hw/vhost.h
@@ -18,6 +18,7 @@ struct vhost_virtqueue {
     void *ring;
     unsigned long long ring_phys;
     unsigned ring_size;
+    EventNotifier masked_notifier;
 };
 
 typedef unsigned long vhost_log_chunk_t;
@@ -53,4 +54,13 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev);
 int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev);
 void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev);
 
+/* Test and clear masked event pending status.
+ * Should be called after unmask to avoid losing events.
+ */
+bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n);
+
+/* Mask/unmask events from this vq.
+ */
+void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n,
+                          bool mask);
 #endif