virtio: add "use-started" property

In order to avoid migration issues, we introduce a "use-started"
property to the base virtio device to indicate whether use
"started" flag or not. This property will be true by default and
set to false when machine type <= 4.0.

Suggested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Xie Yongji <xieyongji@baidu.com>
Message-Id: <20190626023130.31315-2-xieyongji@baidu.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 7 insertions, 11 deletions

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index e1e90fc..c9a6ca0 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1162,10 +1162,8 @@ int virtio_set_status(VirtIODevice *vdev, uint8_t val)
             }
         }
     }
-    vdev->started = val & VIRTIO_CONFIG_S_DRIVER_OK;
-    if (unlikely(vdev->start_on_kick && vdev->started)) {
-        vdev->start_on_kick = false;
-    }
+
+    virtio_set_started(vdev, val & VIRTIO_CONFIG_S_DRIVER_OK);
 
     if (k->set_status) {
         k->set_status(vdev, val);
@@ -1536,8 +1534,7 @@ static bool virtio_queue_notify_aio_vq(VirtQueue *vq)
         ret = vq->handle_aio_output(vdev, vq);
 
         if (unlikely(vdev->start_on_kick)) {
-            vdev->started = true;
-            vdev->start_on_kick = false;
+            virtio_set_started(vdev, true);
         }
     }
 
@@ -1557,8 +1554,7 @@ static void virtio_queue_notify_vq(VirtQueue *vq)
         vq->handle_output(vdev, vq);
 
         if (unlikely(vdev->start_on_kick)) {
-            vdev->started = true;
-            vdev->start_on_kick = false;
+            virtio_set_started(vdev, true);
         }
     }
 }
@@ -1579,8 +1575,7 @@ void virtio_queue_notify(VirtIODevice *vdev, int n)
     }
 
     if (unlikely(vdev->start_on_kick)) {
-        vdev->started = true;
-        vdev->start_on_kick = false;
+        virtio_set_started(vdev, true);
     }
 }
 
@@ -2291,7 +2286,7 @@ static void virtio_vmstate_change(void *opaque, int running, RunState state)
     VirtIODevice *vdev = opaque;
     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
-    bool backend_run = running && vdev->started;
+    bool backend_run = running && virtio_device_started(vdev, vdev->status);
     vdev->vm_running = running;
 
     if (backend_run) {
@@ -2669,6 +2664,7 @@ static void virtio_device_instance_finalize(Object *obj)
 
 static Property virtio_properties[] = {
     DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
+    DEFINE_PROP_BOOL("use-started", VirtIODevice, use_started, true),
     DEFINE_PROP_END_OF_LIST(),
 };