[PATCH] hw/s390x: Emit a warning if user tried to enable USB

[Thomas Huth <thuth@redhat.com>]

There is no USB on s390x, so running qemu-system-s390x with
"-machine ...,usb=on" is certainly wrong. Emit a warning to make
the users aware of their misconfiguration.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 After a year or two, we could finally turn this into a hard error,
 but I think we should give the users some time to fix their command
 lines first, so I'm initially only emitting a warning here.

 hw/s390x/s390-virtio-ccw.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index d3edeef0ad..af8c4c0daf 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -243,6 +243,10 @@ static void ccw_init(MachineState *machine)
     VirtualCssBus *css_bus;
     DeviceState *dev;
 
+    if (machine->usb) {
+        warn_report("This machine does not support USB");
+    }
+
     s390_sclp_init();
     /* init memory + setup max page size. Required for the CPU model */
     s390_memory_init(machine->ram_size);
-- 
2.18.1