diff -r d4a3479e68ce tools/ioemu/hw/xenfb.c
--- a/tools/ioemu/hw/xenfb.c	Fri Dec 07 18:24:33 2007 +0000
+++ b/tools/ioemu/hw/xenfb.c	Sat Dec 08 13:00:49 2007 -0700
@@ -592,7 +592,7 @@ static int xenfb_send_key(struct xenfb *
 }
 
 /* Send a relative mouse movement event */
-static int xenfb_send_motion(struct xenfb *xenfb, int rel_x, int rel_y)
+static int xenfb_send_motion(struct xenfb *xenfb, int rel_x, int rel_y, int rel_z)
 {
 	union xenkbd_in_event event;
 
@@ -600,12 +600,13 @@ static int xenfb_send_motion(struct xenf
 	event.type = XENKBD_TYPE_MOTION;
 	event.motion.rel_x = rel_x;
 	event.motion.rel_y = rel_y;
+	event.motion.rel_z = rel_z;
 
 	return xenfb_kbd_event(xenfb, &event);
 }
 
 /* Send an absolute mouse movement event */
-static int xenfb_send_position(struct xenfb *xenfb, int abs_x, int abs_y)
+static int xenfb_send_position(struct xenfb *xenfb, int abs_x, int abs_y, int abs_z)
 {
 	union xenkbd_in_event event;
 
@@ -613,6 +614,7 @@ static int xenfb_send_position(struct xe
 	event.type = XENKBD_TYPE_POS;
 	event.pos.abs_x = abs_x;
 	event.pos.abs_y = abs_y;
+	event.pos.abs_z = abs_z;
 
 	return xenfb_kbd_event(xenfb, &event);
 }
@@ -1043,9 +1045,10 @@ static void xenfb_mouse_event(void *opaq
     if (xenfb->abs_pointer_wanted)
 	    xenfb_send_position(xenfb,
 				dx * xenfb->ds->width / 0x7fff,
-				dy * xenfb->ds->height / 0x7fff);
+				dy * xenfb->ds->height / 0x7fff,
+				dz);
     else
-	    xenfb_send_motion(xenfb, dx, dy);
+	    xenfb_send_motion(xenfb, dx, dy, dz);
 
     for (i = 0 ; i < 8 ; i++) {
 	    int lastDown = xenfb->button_state & (1 << i);
diff -r d4a3479e68ce xen/include/public/io/kbdif.h
--- a/xen/include/public/io/kbdif.h	Fri Dec 07 18:24:33 2007 +0000
+++ b/xen/include/public/io/kbdif.h	Sat Dec 08 12:56:46 2007 -0700
@@ -50,6 +50,7 @@ struct xenkbd_motion
     uint8_t type;        /* XENKBD_TYPE_MOTION */
     int32_t rel_x;       /* relative X motion */
     int32_t rel_y;       /* relative Y motion */
+    int32_t rel_z;       /* relative Z motion (wheel) */
 };
 
 struct xenkbd_key
@@ -64,6 +65,7 @@ struct xenkbd_position
     uint8_t type;        /* XENKBD_TYPE_POS */
     int32_t abs_x;       /* absolute X position (in FB pixels) */
     int32_t abs_y;       /* absolute Y position (in FB pixels) */
+    int32_t abs_z;       /* absolute Z position (wheel) */
 };
 
 #define XENKBD_IN_EVENT_SIZE 40