vdpa: move vhost reset after get vring base

The function vhost.c:vhost_dev_stop calls vhost operation
vhost_dev_start(false). In the case of vdpa it totally reset and wipes
the device, making the fetching of the vring base (virtqueue state) totally
useless.

The kernel backend does not use vhost_dev_start vhost op callback, but
vhost-user do. A patch to make vhost_user_dev_start more similar to vdpa
is desirable, but it can be added on top.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20230303172445.1089785-8-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 16 insertions, 6 deletions

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index aecc01c6a7..c9a82ce5e0 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -1146,14 +1146,23 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
     if (started) {
         memory_listener_register(&v->listener, &address_space_memory);
         return vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
-    } else {
-        vhost_vdpa_reset_device(dev);
-        vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE |
-                                   VIRTIO_CONFIG_S_DRIVER);
-        memory_listener_unregister(&v->listener);
+    }
 
-        return 0;
+    return 0;
+}
+
+static void vhost_vdpa_reset_status(struct vhost_dev *dev)
+{
+    struct vhost_vdpa *v = dev->opaque;
+
+    if (dev->vq_index + dev->nvqs != dev->vq_index_end) {
+        return;
     }
+
+    vhost_vdpa_reset_device(dev);
+    vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE |
+                               VIRTIO_CONFIG_S_DRIVER);
+    memory_listener_unregister(&v->listener);
 }
 
 static int vhost_vdpa_set_log_base(struct vhost_dev *dev, uint64_t base,
@@ -1337,4 +1346,5 @@ const VhostOps vdpa_ops = {
         .vhost_vq_get_addr = vhost_vdpa_vq_get_addr,
         .vhost_force_iommu = vhost_vdpa_force_iommu,
         .vhost_set_config_call = vhost_vdpa_set_config_call,
+        .vhost_reset_status = vhost_vdpa_reset_status,
 };