Merge pull request #2294 from vivianQizhu/block_hotplug

block_devices_plug: Fix 2 hotplug issues

provider/block_devices_plug.py

@@ -275,6 +275,7 @@ class BlockDevicesPlug(object):
         with _LOCK:
             self.vm.devices.set_dirty()
 
+        qdev_out = ''
         if isinstance(device, qdevices.QDevice):
             dev_bus = device.get_param('bus')
             if bus is None:
@@ -378,7 +379,11 @@ class BlockDevicesPlug(object):
         """ Plug devices. """
         for img, devices in devices_dict.items():
             for device in devices:
-                args = (device, monitor) if bus is None else (device, monitor, bus)
+                args = (device, monitor)
+                if (isinstance(device, qdevices.QDevice) and
+                        bus is not None and
+                        self.vm.devices.is_pci_device(device['driver'])):
+                    args += (bus,)
                 _QMP_OUTPUT[device.get_qid()] = getattr(
                     self, '_%s_atomic' % action)(*args)
                 time.sleep(self._interval)