diff --git a/src/include/ipxe/ib_mi.h b/src/include/ipxe/ib_mi.h
index c7c8143b..bd087cd3 100644
--- a/src/include/ipxe/ib_mi.h
+++ b/src/include/ipxe/ib_mi.h
@@ -127,8 +127,9 @@ ib_create_madx ( struct ib_device *ibdev, struct ib_mad_interface *mi,
 extern void ib_destroy_madx ( struct ib_device *ibdev,
 			      struct ib_mad_interface *mi,
 			      struct ib_mad_transaction *madx );
-extern struct ib_mad_interface * ib_create_mi ( struct ib_device *ibdev,
-						enum ib_queue_pair_type type );
+extern int ib_create_mi ( struct ib_device *ibdev,
+			  enum ib_queue_pair_type type,
+			  struct ib_mad_interface **new_mi );
 extern void ib_destroy_mi ( struct ib_device *ibdev,
 			    struct ib_mad_interface *mi );
 
diff --git a/src/net/infiniband.c b/src/net/infiniband.c
index fa45653e..3b79a660 100644
--- a/src/net/infiniband.c
+++ b/src/net/infiniband.c
@@ -666,10 +666,9 @@ int ib_open ( struct ib_device *ibdev ) {
 	}
 
 	/* Create subnet management interface */
-	ibdev->smi = ib_create_mi ( ibdev, IB_QPT_SMI );
-	if ( ! ibdev->smi ) {
-		DBGC ( ibdev, "IBDEV %s could not create SMI\n", ibdev->name );
-		rc = -ENOMEM;
+	if ( ( rc = ib_create_mi ( ibdev, IB_QPT_SMI, &ibdev->smi ) ) != 0 ) {
+		DBGC ( ibdev, "IBDEV %s could not create SMI: %s\n",
+		       ibdev->name, strerror ( rc ) );
 		goto err_create_smi;
 	}
 
@@ -681,10 +680,9 @@ int ib_open ( struct ib_device *ibdev ) {
 	}
 
 	/* Create general services interface */
-	ibdev->gsi = ib_create_mi ( ibdev, IB_QPT_GSI );
-	if ( ! ibdev->gsi ) {
-		DBGC ( ibdev, "IBDEV %s could not create GSI\n", ibdev->name );
-		rc = -ENOMEM;
+	if ( ( rc = ib_create_mi ( ibdev, IB_QPT_GSI, &ibdev->gsi ) ) != 0 ) {
+		DBGC ( ibdev, "IBDEV %s could not create GSI: %s\n",
+		       ibdev->name, strerror ( rc ) );
 		goto err_create_gsi;
 	}
 
diff --git a/src/net/infiniband/ib_mi.c b/src/net/infiniband/ib_mi.c
index 149c1e4d..781a3e2e 100644
--- a/src/net/infiniband/ib_mi.c
+++ b/src/net/infiniband/ib_mi.c
@@ -341,18 +341,21 @@ void ib_destroy_madx ( struct ib_device *ibdev __unused,
  *
  * @v ibdev		Infiniband device
  * @v type		Queue pair type
- * @ret mi		Management agent, or NULL
+ * @v new_mi		New management interface to fill in
+ * @ret rc		Return status code
  */
-struct ib_mad_interface * ib_create_mi ( struct ib_device *ibdev,
-					 enum ib_queue_pair_type type ) {
+int ib_create_mi ( struct ib_device *ibdev, enum ib_queue_pair_type type,
+		   struct ib_mad_interface **new_mi ) {
 	struct ib_mad_interface *mi;
 	const char *name;
 	int rc;
 
 	/* Allocate and initialise fields */
 	mi = zalloc ( sizeof ( *mi ) );
-	if ( ! mi )
+	if ( ! mi ) {
+		rc = -ENOMEM;
 		goto err_alloc;
+	}
 	mi->ibdev = ibdev;
 	INIT_LIST_HEAD ( &mi->madx );
 
@@ -387,7 +390,8 @@ struct ib_mad_interface * ib_create_mi ( struct ib_device *ibdev,
 
 	/* Fill receive ring */
 	ib_refill_recv ( ibdev, mi->qp );
-	return mi;
+	*new_mi = mi;
+	return 0;
 
  err_modify_qp:
 	ib_destroy_qp ( ibdev, mi->qp );
@@ -396,7 +400,7 @@ struct ib_mad_interface * ib_create_mi ( struct ib_device *ibdev,
  err_create_cq:
 	free ( mi );
  err_alloc:
-	return NULL;
+	return rc;
 }
 
 /**