Add kbd_mouse_has_absolute()

kbd_mouse_is_absolute tells us whether the current mouse handler is an absolute
device.  kbd_mouse_has_absolute tells us whether we have any device that is
capable of absolute input.

This lets us tell a user that they have configured an absolute device but that
the guest is not currently using it.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

console.h

@@ -53,8 +53,13 @@ void qemu_remove_led_event_handler(QEMUPutLEDEntry *entry);
 void kbd_put_keycode(int keycode);
 void kbd_put_ledstate(int ledstate);
 void kbd_mouse_event(int dx, int dy, int dz, int buttons_state);
+
+/* Does the current mouse generate absolute events */
 int kbd_mouse_is_absolute(void);
 
+/* Of all the mice, is there one that generates absolute events */
+int kbd_mouse_has_absolute(void);
+
 struct MouseTransformInfo {
     /* Touchscreen resolution */
     int x;

input.c

@@ -153,6 +153,19 @@ int kbd_mouse_is_absolute(void)
     return QTAILQ_FIRST(&mouse_handlers)->qemu_put_mouse_event_absolute;
 }
 
+int kbd_mouse_has_absolute(void)
+{
+    QEMUPutMouseEntry *entry;
+
+    QTAILQ_FOREACH(entry, &mouse_handlers, node) {
+        if (entry->qemu_put_mouse_event_absolute) {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
 static void info_mice_iter(QObject *data, void *opaque)
 {
     QDict *mouse;