[Qemu-devel] [RFC 1/5] vhost: send virtio device status update to the backend

[Maxime Coquelin <maxime.coquelin@redhat.com>]

This patch adds a function to notify the vhost backend with
virtio device status updates.

Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 hw/virtio/vhost.c                 | 11 +++++++++++
 include/hw/virtio/vhost-backend.h |  3 +++
 include/hw/virtio/vhost.h         |  3 +++
 3 files changed, 17 insertions(+)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 338e4395b7..95981e5a32 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1546,6 +1546,17 @@ void vhost_dev_set_config_notifier(struct vhost_dev *hdev,
     hdev->config_ops = ops;
 }
 
+int vhost_dev_set_virtio_status(struct vhost_dev *hdev, uint8_t status)
+{
+    const VhostOps *vhost_ops = hdev->vhost_ops;
+
+    if (vhost_ops && vhost_ops->vhost_set_virtio_status) {
+        return vhost_ops->vhost_set_virtio_status(hdev, status);
+    }
+
+    return 0;
+}
+
 /* Host notifiers must be enabled at this point. */
 int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
 {
diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
index 592254f40d..45f6b8f6c5 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -94,6 +94,8 @@ typedef int (*vhost_set_config_op)(struct vhost_dev *dev, const uint8_t *data,
                                    uint32_t flags);
 typedef int (*vhost_get_config_op)(struct vhost_dev *dev, uint8_t *config,
                                    uint32_t config_len);
+typedef int (*vhost_set_virtio_status_op)(struct vhost_dev *dev,
+                                          uint8_t status);
 
 typedef struct VhostOps {
     VhostBackendType backend_type;
@@ -130,6 +132,7 @@ typedef struct VhostOps {
     vhost_send_device_iotlb_msg_op vhost_send_device_iotlb_msg;
     vhost_get_config_op vhost_get_config;
     vhost_set_config_op vhost_set_config;
+    vhost_set_virtio_status_op vhost_set_virtio_status;
 } VhostOps;
 
 extern const VhostOps user_ops;
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index 1dc2d73d76..fe055b2bd5 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -121,4 +121,7 @@ int vhost_dev_set_config(struct vhost_dev *dev, const uint8_t *data,
  */
 void vhost_dev_set_config_notifier(struct vhost_dev *dev,
                                    const VhostDevConfigOps *ops);
+
+int vhost_dev_set_virtio_status(struct vhost_dev *hdev, uint8_t status);
+
 #endif
-- 
2.14.3