xen/kbdif: Add unique input device identifier

If frontend is configured to expose multiple input device instances
then backend may require a way to uniquely identify concrete input
device within the frontend. This is useful for use-cases where
virtual input device needs to be matched to physical input device.
Add XenBus "unique-id" node parameter, so this sort of use-cases can
be implemented.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Release-acked-by: Juergen Gross <jgross@suse.com>

diff --git a/xen/include/public/io/kbdif.h b/xen/include/public/io/kbdif.h
index a68da0f1a37f8f0271c3e185b29e25f1877344af..a6b01c52c79fde927b0bfd441f7c4df57a38be77 100644 (file)
--- a/xen/include/public/io/kbdif.h
+++ b/xen/include/public/io/kbdif.h
@@ -82,6 +82,15 @@
  *      for pointer devices should set this to 1. Raw (unscaled) values have
  *      a range of [0, 0x7fff].
  *
+ *-----------------------  Device Instance Parameters ------------------------
+ *
+ * unique-id
+ *      Values:         <string>
+ *
+ *      After device instance initialization it is assigned a unique ID,
+ *      so every instance of the frontend can be identified by the backend
+ *      by this ID. This can be UUID or such.
+ *
  *------------------------- Pointer Device Parameters ------------------------
  *
  * width
@@ -204,6 +213,7 @@
 #define XENKBD_FIELD_MT_WIDTH          "multi-touch-width"
 #define XENKBD_FIELD_MT_HEIGHT         "multi-touch-height"
 #define XENKBD_FIELD_MT_NUM_CONTACTS   "multi-touch-num-contacts"
+#define XENKBD_FIELD_UNIQUE_ID         "unique-id"
 
 /* OBSOLETE, not recommended for use */
 #define XENKBD_FIELD_RING_REF          "page-ref"