diff --git a/tools/ocaml/libs/xl/xl.ml b/tools/ocaml/libs/xl/xl.ml
index 0f665ae..1e3642f 100644
--- a/tools/ocaml/libs/xl/xl.ml
+++ b/tools/ocaml/libs/xl/xl.ml
@@ -13,6 +13,8 @@
  * GNU Lesser General Public License for more details.
  *)
 
+exception Error of string
+
 type create_info =
 {
 	hvm : bool;
@@ -207,3 +209,5 @@ external domain_sched_credit_set : domid -> sched_credit -> unit = "stub_xl_sche
 external send_trigger : domid -> string -> int -> unit = "stub_xl_send_trigger"
 external send_sysrq : domid -> char -> unit = "stub_xl_send_sysrq"
 external send_debug_keys : domid -> string -> unit = "stub_xl_send_debug_keys"
+
+let _ = Callback.register_exception "xl.error" (Error "register_callback")
diff --git a/tools/ocaml/libs/xl/xl.mli b/tools/ocaml/libs/xl/xl.mli
index 0f665ae..4193e59 100644
--- a/tools/ocaml/libs/xl/xl.mli
+++ b/tools/ocaml/libs/xl/xl.mli
@@ -13,6 +13,8 @@
  * GNU Lesser General Public License for more details.
  *)
 
+exception Error of string
+
 type create_info =
 {
 	hvm : bool;