virtio-serial-bus: Add ability to hot-unplug ports

Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/virtio-serial-bus.c

@@ -520,6 +520,8 @@ static int virtser_port_qdev_exit(DeviceState *qdev)
     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);
     VirtIOSerial *vser = port->vser;
 
+    send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1);
+
     /*
      * Don't decrement nr_ports here; thus we keep a linearly
      * increasing port id. Not utilising an id again saves us a couple

hw/virtio-serial.h

@@ -51,6 +51,7 @@ struct virtio_console_control {
 #define VIRTIO_CONSOLE_RESIZE		2
 #define VIRTIO_CONSOLE_PORT_OPEN	3
 #define VIRTIO_CONSOLE_PORT_NAME	4
+#define VIRTIO_CONSOLE_PORT_REMOVE	5
 
 /* == In-qemu interface == */