[PATCH] vhost-user-blk: fix the resize crash

[Li Feng]

If the os is not installed and doesn't have the virtio guest driver,
the vhost dev isn't started, so the dev->vdev is NULL.

Reproduce: mount a Win 2019 iso, go into the install ui, then resize
the virtio-blk device, qemu crash.

Signed-off-by: Li Feng <fengli@smartx.com>
---
 hw/block/vhost-user-blk.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index 9117222456..db30bb754f 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -95,6 +95,10 @@ static int vhost_user_blk_handle_config_change(struct 
vhost_dev *dev)
     VHostUserBlk *s = VHOST_USER_BLK(dev->vdev);
     Error *local_err = NULL;
 
+    if (!dev->started) {
+        return 0;
+    }
+
     ret = vhost_dev_get_config(dev, (uint8_t *)&blkcfg,
                                sizeof(struct virtio_blk_config),
                                &local_err);
-- 
2.37.3