[Qemu-devel] [PATCH master/0.14] virtio-serial: Disallow generic ports at id 0

[Amit Shah <amit.shah@redhat.com>]

It was found libvirt was using port 0 for generic ports.  It has been
fixed in libvirt commit 8e28c5d40200b4c5d483bd585d237b9d870372e5.

Port 0 is reserved for virtconsole devices for backward compatibility
with the old -virtioconsole (from qemu 0.12) device type.

Ensure we don't allow instantiating a port at id 0 as well.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-console.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-console.c b/hw/virtio-console.c
index 62624ec..3560db3 100644
--- a/hw/virtio-console.c
+++ b/hw/virtio-console.c
@@ -11,6 +11,7 @@
  */
 
 #include "qemu-char.h"
+#include "qemu-error.h"
 #include "virtio-serial.h"
 
 typedef struct VirtConsole {
@@ -118,6 +119,14 @@ static int virtserialport_initfn(VirtIOSerialDevice *dev)
     VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);
     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
 
+    if (port->id == 0) {
+        /*
+         * Disallow a generic port at id 0, that's reserved for
+         * console ports.
+         */
+        error_report("Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility.");
+        return -1;
+    }
     return generic_port_init(vcon, dev);
 }
 
-- 
1.7.3.5