vhost-user: support registering external host notifiers

This patch introduces VHOST_USER_PROTOCOL_F_HOST_NOTIFIER.
With this feature negotiated, vhost-user backend can register
memory region based host notifiers. And it will allow the guest
driver in the VM to notify the hardware accelerator at the
vhost-user backend directly.

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h
index eb8bc0d90d..fd660393a0 100644
--- a/include/hw/virtio/vhost-user.h
+++ b/include/hw/virtio/vhost-user.h
@@ -9,9 +9,17 @@
 #define HW_VIRTIO_VHOST_USER_H
 
 #include "chardev/char-fe.h"
+#include "hw/virtio/virtio.h"
+
+typedef struct VhostUserHostNotifier {
+    MemoryRegion mr;
+    void *addr;
+    bool set;
+} VhostUserHostNotifier;
 
 typedef struct VhostUserState {
     CharBackend *chr;
+    VhostUserHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostUserState;
 
 VhostUserState *vhost_user_init(void);