diff --git a/hw/usb-bus.c b/hw/usb-bus.c
index fc720185b7..2abce12de5 100644
--- a/hw/usb-bus.c
+++ b/hw/usb-bus.c
@@ -200,6 +200,11 @@ static int do_attach(USBDevice *dev)
     } else {
         port = QTAILQ_FIRST(&bus->free);
     }
+    if (!(port->speedmask & dev->speedmask)) {
+        error_report("Warning: speed mismatch trying to attach usb device %s to bus %s\n",
+                dev->product_desc, bus->qbus.name);
+        return -1;
+    }
 
     dev->attached++;
     QTAILQ_REMOVE(&bus->free, port, next);