diff --git a/src/drivers/infiniband/arbel.c b/src/drivers/infiniband/arbel.c
index 5937c524..129ec574 100644
--- a/src/drivers/infiniband/arbel.c
+++ b/src/drivers/infiniband/arbel.c
@@ -396,7 +396,7 @@ arbel_cmd_write_mgm ( struct arbel *arbel, unsigned int index,
 }
 
 static inline int
-arbel_cmd_mgid_hash ( struct arbel *arbel, const struct ib_gid *gid,
+arbel_cmd_mgid_hash ( struct arbel *arbel, const union ib_gid *gid,
 		      struct arbelprm_mgm_hash *hash ) {
 	return arbel_cmd ( arbel,
 			   ARBEL_HCR_INOUT_CMD ( ARBEL_HCR_MGID_HASH,
@@ -998,8 +998,8 @@ static void arbel_ring_doorbell ( struct arbel *arbel,
 }
 
 /** GID used for GID-less send work queue entries */
-static const struct ib_gid arbel_no_gid = {
-	{ { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0 } }
+static const union ib_gid arbel_no_gid = {
+	.bytes = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0 },
 };
 
 /**
@@ -1023,7 +1023,7 @@ static int arbel_post_send ( struct ib_device *ibdev,
 	struct arbelprm_ud_send_wqe *wqe;
 	struct arbelprm_qp_db_record *qp_db_rec;
 	union arbelprm_doorbell_register db_reg;
-	const struct ib_gid *gid;
+	const union ib_gid *gid;
 	unsigned int wqe_idx_mask;
 	size_t nds;
 
@@ -1565,7 +1565,7 @@ static void arbel_close ( struct ib_device *ibdev ) {
  */
 static int arbel_mcast_attach ( struct ib_device *ibdev,
 				struct ib_queue_pair *qp,
-				struct ib_gid *gid ) {
+				union ib_gid *gid ) {
 	struct arbel *arbel = ib_get_drvdata ( ibdev );
 	struct arbelprm_mgm_hash hash;
 	struct arbelprm_mgm_entry mgm;
@@ -1620,7 +1620,7 @@ static int arbel_mcast_attach ( struct ib_device *ibdev,
  */
 static void arbel_mcast_detach ( struct ib_device *ibdev,
 				 struct ib_queue_pair *qp __unused,
-				 struct ib_gid *gid ) {
+				 union ib_gid *gid ) {
 	struct arbel *arbel = ib_get_drvdata ( ibdev );
 	struct arbelprm_mgm_hash hash;
 	struct arbelprm_mgm_entry mgm;
diff --git a/src/drivers/infiniband/hermon.c b/src/drivers/infiniband/hermon.c
index f074386f..8b5c2487 100644
--- a/src/drivers/infiniband/hermon.c
+++ b/src/drivers/infiniband/hermon.c
@@ -474,7 +474,7 @@ hermon_cmd_write_mcg ( struct hermon *hermon, unsigned int index,
 }
 
 static inline int
-hermon_cmd_mgid_hash ( struct hermon *hermon, const struct ib_gid *gid,
+hermon_cmd_mgid_hash ( struct hermon *hermon, const union ib_gid *gid,
 		       struct hermonprm_mgm_hash *hash ) {
 	return hermon_cmd ( hermon,
 			    HERMON_HCR_INOUT_CMD ( HERMON_HCR_MGID_HASH,
@@ -2012,7 +2012,7 @@ static int hermon_inform_sma ( struct ib_device *ibdev,
  */
 static int hermon_mcast_attach ( struct ib_device *ibdev,
 				 struct ib_queue_pair *qp,
-				 struct ib_gid *gid ) {
+				 union ib_gid *gid ) {
 	struct hermon *hermon = ib_get_drvdata ( ibdev );
 	struct hermonprm_mgm_hash hash;
 	struct hermonprm_mcg_entry mcg;
@@ -2066,7 +2066,7 @@ static int hermon_mcast_attach ( struct ib_device *ibdev,
  */
 static void hermon_mcast_detach ( struct ib_device *ibdev,
 				  struct ib_queue_pair *qp __unused,
-				  struct ib_gid *gid ) {
+				  union ib_gid *gid ) {
 	struct hermon *hermon = ib_get_drvdata ( ibdev );
 	struct hermonprm_mgm_hash hash;
 	struct hermonprm_mcg_entry mcg;
diff --git a/src/drivers/infiniband/linda.c b/src/drivers/infiniband/linda.c
index 83d473c7..12a09a04 100644
--- a/src/drivers/infiniband/linda.c
+++ b/src/drivers/infiniband/linda.c
@@ -1456,7 +1456,7 @@ static void linda_close ( struct ib_device *ibdev ) {
  */
 static int linda_mcast_attach ( struct ib_device *ibdev,
 				struct ib_queue_pair *qp,
-				struct ib_gid *gid ) {
+				union ib_gid *gid ) {
 	struct linda *linda = ib_get_drvdata ( ibdev );
 
 	( void ) linda;
@@ -1474,7 +1474,7 @@ static int linda_mcast_attach ( struct ib_device *ibdev,
  */
 static void linda_mcast_detach ( struct ib_device *ibdev,
 				 struct ib_queue_pair *qp,
-				 struct ib_gid *gid ) {
+				 union ib_gid *gid ) {
 	struct linda *linda = ib_get_drvdata ( ibdev );
 
 	( void ) linda;
@@ -1631,22 +1631,19 @@ static int linda_init_i2c ( struct linda *linda ) {
  * @v guid		GUID to fill in
  * @ret rc		Return status code
  */
-static int linda_read_eeprom ( struct linda *linda,
-			       struct ib_gid_half *guid ) {
+static int linda_read_eeprom ( struct linda *linda, union ib_guid *guid ) {
 	struct i2c_interface *i2c = &linda->i2c.i2c;
 	int rc;
 
 	/* Read GUID */
 	if ( ( rc = i2c->read ( i2c, &linda->eeprom, LINDA_EEPROM_GUID_OFFSET,
-				guid->u.bytes, sizeof ( *guid ) ) ) != 0 ) {
+				guid->bytes, sizeof ( *guid ) ) ) != 0 ) {
 		DBGC ( linda, "Linda %p could not read GUID: %s\n",
 		       linda, strerror ( rc ) );
 		return rc;
 	}
-	DBGC2 ( linda, "Linda %p has GUID %02x:%02x:%02x:%02x:%02x:%02x:"
-		"%02x:%02x\n", linda, guid->u.bytes[0], guid->u.bytes[1],
-		guid->u.bytes[2], guid->u.bytes[3], guid->u.bytes[4],
-		guid->u.bytes[5], guid->u.bytes[6], guid->u.bytes[7] );
+	DBGC2 ( linda, "Linda %p has GUID " IB_GUID_FMT "\n",
+		linda, IB_GUID_ARGS ( guid ) );
 
 	/* Read serial number (debug only) */
 	if ( DBG_LOG ) {
@@ -2367,7 +2364,7 @@ static int linda_probe ( struct pci_device *pci,
 		goto err_init_i2c;
 
 	/* Read EEPROM parameters */
-	if ( ( rc = linda_read_eeprom ( linda, &ibdev->gid.u.half[1] ) ) != 0 )
+	if ( ( rc = linda_read_eeprom ( linda, &ibdev->gid.s.guid ) ) != 0 )
 		goto err_read_eeprom;
 
 	/* Initialise send datapath */
diff --git a/src/drivers/infiniband/qib7322.c b/src/drivers/infiniband/qib7322.c
index e8b41a47..b1902cfa 100644
--- a/src/drivers/infiniband/qib7322.c
+++ b/src/drivers/infiniband/qib7322.c
@@ -118,7 +118,7 @@ struct qib7322 {
 	struct i2c_device eeprom;
 
 	/** Base GUID */
-	struct ib_gid_half guid;
+	union ib_guid guid;
 	/** Infiniband devices */
 	struct ib_device *ibdev[QIB7322_MAX_PORTS];
 };
@@ -1770,7 +1770,7 @@ static void qib7322_close ( struct ib_device *ibdev ) {
  */
 static int qib7322_mcast_attach ( struct ib_device *ibdev,
 				  struct ib_queue_pair *qp,
-				  struct ib_gid *gid ) {
+				  union ib_gid *gid ) {
 	struct qib7322 *qib7322 = ib_get_drvdata ( ibdev );
 
 	( void ) qib7322;
@@ -1788,7 +1788,7 @@ static int qib7322_mcast_attach ( struct ib_device *ibdev,
  */
 static void qib7322_mcast_detach ( struct ib_device *ibdev,
 				   struct ib_queue_pair *qp,
-				   struct ib_gid *gid ) {
+				   union ib_gid *gid ) {
 	struct qib7322 *qib7322 = ib_get_drvdata ( ibdev );
 
 	( void ) qib7322;
@@ -1946,21 +1946,19 @@ static int qib7322_init_i2c ( struct qib7322 *qib7322 ) {
  */
 static int qib7322_read_eeprom ( struct qib7322 *qib7322 ) {
 	struct i2c_interface *i2c = &qib7322->i2c.i2c;
-	struct ib_gid_half *guid = &qib7322->guid;
+	union ib_guid *guid = &qib7322->guid;
 	int rc;
 
 	/* Read GUID */
 	if ( ( rc = i2c->read ( i2c, &qib7322->eeprom,
-				QIB7322_EEPROM_GUID_OFFSET, guid->u.bytes,
+				QIB7322_EEPROM_GUID_OFFSET, guid->bytes,
 				sizeof ( *guid ) ) ) != 0 ) {
 		DBGC ( qib7322, "QIB7322 %p could not read GUID: %s\n",
 		       qib7322, strerror ( rc ) );
 		return rc;
 	}
-	DBGC2 ( qib7322, "QIB7322 %p has GUID %02x:%02x:%02x:%02x:%02x:%02x:"
-		"%02x:%02x\n", qib7322, guid->u.bytes[0], guid->u.bytes[1],
-		guid->u.bytes[2], guid->u.bytes[3], guid->u.bytes[4],
-		guid->u.bytes[5], guid->u.bytes[6], guid->u.bytes[7] );
+	DBGC2 ( qib7322, "QIB7322 %p has GUID " IB_GUID_FMT "\n",
+		qib7322, IB_GUID_ARGS ( guid ) );
 
 	/* Read serial number (debug only) */
 	if ( DBG_LOG ) {
@@ -2359,10 +2357,10 @@ static int qib7322_probe ( struct pci_device *pci,
 			IB_LINK_WIDTH_4X; /* 1x does not work */
 		ibdev->link_speed_enabled = ibdev->link_speed_supported =
 			IB_LINK_SPEED_SDR; /* to avoid need for link tuning */
-		memcpy ( &ibdev->gid.u.half[1], &qib7322->guid,
-			 sizeof ( ibdev->gid.u.half[1] ) );
-		assert ( ( ibdev->gid.u.half[1].u.bytes[7] & i ) == 0 );
-		ibdev->gid.u.half[1].u.bytes[7] |= i;
+		memcpy ( &ibdev->gid.s.guid, &qib7322->guid,
+			 sizeof ( ibdev->gid.s.guid ) );
+		assert ( ( ibdev->gid.s.guid.bytes[7] & i ) == 0 );
+		ibdev->gid.s.guid.bytes[7] |= i;
 		ib_set_drvdata ( ibdev, qib7322 );
 	}
 
diff --git a/src/drivers/net/ipoib.c b/src/drivers/net/ipoib.c
index 82d7ca99..52ac5f03 100644
--- a/src/drivers/net/ipoib.c
+++ b/src/drivers/net/ipoib.c
@@ -72,8 +72,8 @@ struct ipoib_device {
 /** Broadcast IPoIB address */
 static struct ipoib_mac ipoib_broadcast = {
 	.flags__qpn = htonl ( IB_QPN_BROADCAST ),
-	.gid.u.bytes = 	{ 0xff, 0x12, 0x40, 0x1b, 0x00, 0x00, 0x00, 0x00,
-			  0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff },
+	.gid.bytes = { 0xff, 0x12, 0x40, 0x1b, 0x00, 0x00, 0x00, 0x00,
+		       0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff },
 };
 
 /** Link status for "broadcast join in progress" */
@@ -266,11 +266,11 @@ static int ipoib_pull ( struct net_device *netdev,
  * @v ll_addr		Link-layer address
  */
 static void ipoib_init_addr ( const void *hw_addr, void *ll_addr ) {
-	const struct ib_gid_half *guid = hw_addr;
+	const union ib_guid *guid = hw_addr;
 	struct ipoib_mac *mac = ll_addr;
 
 	memset ( mac, 0, sizeof ( *mac ) );
-	memcpy ( &mac->gid.u.half[1], guid, sizeof ( mac->gid.u.half[1] ) );
+	memcpy ( &mac->gid.s.guid, guid, sizeof ( mac->gid.s.guid ) );
 }
 
 /**
@@ -284,10 +284,10 @@ const char * ipoib_ntoa ( const void *ll_addr ) {
 	const struct ipoib_mac *mac = ll_addr;
 
 	snprintf ( buf, sizeof ( buf ), "%08x:%08x:%08x:%08x:%08x",
-		   htonl ( mac->flags__qpn ), htonl ( mac->gid.u.dwords[0] ),
-		   htonl ( mac->gid.u.dwords[1] ),
-		   htonl ( mac->gid.u.dwords[2] ),
-		   htonl ( mac->gid.u.dwords[3] ) );
+		   htonl ( mac->flags__qpn ), htonl ( mac->gid.dwords[0] ),
+		   htonl ( mac->gid.dwords[1] ),
+		   htonl ( mac->gid.dwords[2] ),
+		   htonl ( mac->gid.dwords[3] ) );
 	return buf;
 }
 
@@ -312,14 +312,14 @@ static int ipoib_mc_hash ( unsigned int af __unused,
  * @v ll_addr		Link-layer address
  * @v eth_addr		Ethernet-compatible address to fill in
  */
-static int ipoib_mlx_eth_addr ( const struct ib_gid_half *guid,
+static int ipoib_mlx_eth_addr ( const union ib_guid *guid,
 				uint8_t *eth_addr ) {
-	eth_addr[0] = ( ( guid->u.bytes[3] == 2 ) ? 0x00 : 0x02 );
-	eth_addr[1] = guid->u.bytes[1];
-	eth_addr[2] = guid->u.bytes[2];
-	eth_addr[3] = guid->u.bytes[5];
-	eth_addr[4] = guid->u.bytes[6];
-	eth_addr[5] = guid->u.bytes[7];
+	eth_addr[0] = ( ( guid->bytes[3] == 2 ) ? 0x00 : 0x02 );
+	eth_addr[1] = guid->bytes[1];
+	eth_addr[2] = guid->bytes[2];
+	eth_addr[3] = guid->bytes[5];
+	eth_addr[4] = guid->bytes[6];
+	eth_addr[5] = guid->bytes[7];
 	return 0;
 }
 
@@ -330,7 +330,7 @@ struct ipoib_eth_addr_handler {
 	/** GUID byte 2 */
 	uint8_t byte2;
 	/** Handler */
-	int ( * eth_addr ) ( const struct ib_gid_half *guid,
+	int ( * eth_addr ) ( const union ib_guid *guid,
 			     uint8_t *eth_addr );
 };
 
@@ -347,15 +347,15 @@ static struct ipoib_eth_addr_handler ipoib_eth_addr_handlers[] = {
  */
 static int ipoib_eth_addr ( const void *ll_addr, void *eth_addr ) {
 	const struct ipoib_mac *ipoib_addr = ll_addr;
-	const struct ib_gid_half *guid = &ipoib_addr->gid.u.half[1];
+	const union ib_guid *guid = &ipoib_addr->gid.s.guid;
 	struct ipoib_eth_addr_handler *handler;
 	unsigned int i;
 
 	for ( i = 0 ; i < ( sizeof ( ipoib_eth_addr_handlers ) /
 			    sizeof ( ipoib_eth_addr_handlers[0] ) ) ; i++ ) {
 		handler = &ipoib_eth_addr_handlers[i];
-		if ( ( handler->byte1 == guid->u.bytes[1] ) &&
-		     ( handler->byte2 == guid->u.bytes[2] ) ) {
+		if ( ( handler->byte1 == guid->bytes[1] ) &&
+		     ( handler->byte2 == guid->bytes[2] ) ) {
 			return handler->eth_addr ( guid, eth_addr );
 		}
 	}
@@ -366,7 +366,7 @@ static int ipoib_eth_addr ( const void *ll_addr, void *eth_addr ) {
 struct ll_protocol ipoib_protocol __ll_protocol = {
 	.name		= "IPoIB",
 	.ll_proto	= htons ( ARPHRD_INFINIBAND ),
-	.hw_addr_len	= sizeof ( struct ib_gid_half ),
+	.hw_addr_len	= sizeof ( union ib_guid ),
 	.ll_addr_len	= IPOIB_ALEN,
 	.ll_header_len	= IPOIB_HLEN,
 	.push		= ipoib_push,
@@ -612,11 +612,11 @@ static void ipoib_link_state_changed ( struct ib_device *ibdev ) {
 	ipoib_leave_broadcast_group ( ipoib );
 
 	/* Update MAC address based on potentially-new GID prefix */
-	memcpy ( &mac->gid.u.half[0], &ibdev->gid.u.half[0],
-		 sizeof ( mac->gid.u.half[0] ) );
+	memcpy ( &mac->gid.s.prefix, &ibdev->gid.s.prefix,
+		 sizeof ( mac->gid.s.prefix ) );
 
 	/* Update broadcast GID based on potentially-new partition key */
-	ipoib->broadcast.gid.u.words[2] =
+	ipoib->broadcast.gid.words[2] =
 		htons ( ibdev->pkey | IB_PKEY_FULL );
 
 	/* Set net device link state to reflect Infiniband link state */
@@ -750,8 +750,8 @@ static int ipoib_probe ( struct ib_device *ibdev ) {
 	ipoib->ibdev = ibdev;
 
 	/* Extract hardware address */
-	memcpy ( netdev->hw_addr, &ibdev->gid.u.half[1],
-		 sizeof ( ibdev->gid.u.half[1] ) );
+	memcpy ( netdev->hw_addr, &ibdev->gid.s.guid,
+		 sizeof ( ibdev->gid.s.guid ) );
 
 	/* Set default broadcast address */
 	memcpy ( &ipoib->broadcast, &ipoib_broadcast,
diff --git a/src/include/ipxe/ib_cm.h b/src/include/ipxe/ib_cm.h
index 136e4943..7d08cd9b 100644
--- a/src/include/ipxe/ib_cm.h
+++ b/src/include/ipxe/ib_cm.h
@@ -42,7 +42,7 @@ struct ib_connection {
 	/** Remote communication ID */
 	uint32_t remote_id;
 	/** Target service ID */
-	struct ib_gid_half service_id;
+	union ib_guid service_id;
 	/** Connection operations */
 	struct ib_connection_operations *op;
 
@@ -62,7 +62,7 @@ struct ib_connection {
 
 extern struct ib_connection *
 ib_create_conn ( struct ib_device *ibdev, struct ib_queue_pair *qp,
-		 struct ib_gid *dgid, struct ib_gid_half *service_id,
+		 union ib_gid *dgid, union ib_guid *service_id,
 		 void *req_private_data, size_t req_private_data_len,
 		 struct ib_connection_operations *op );
 extern void ib_destroy_conn ( struct ib_device *ibdev,
diff --git a/src/include/ipxe/ib_cmrc.h b/src/include/ipxe/ib_cmrc.h
index 4f2eae69..47ad27fa 100644
--- a/src/include/ipxe/ib_cmrc.h
+++ b/src/include/ipxe/ib_cmrc.h
@@ -14,7 +14,7 @@ FILE_LICENCE ( BSD2 );
 
 extern int ib_cmrc_open ( struct interface *xfer,
 			  struct ib_device *ibdev,
-			  struct ib_gid *dgid,
-			  struct ib_gid_half *service_id );
+			  union ib_gid *dgid,
+			  union ib_guid *service_id );
 
 #endif /* _IPXE_IB_CMRC_H */
diff --git a/src/include/ipxe/ib_mad.h b/src/include/ipxe/ib_mad.h
index 23c2657c..b8694833 100644
--- a/src/include/ipxe/ib_mad.h
+++ b/src/include/ipxe/ib_mad.h
@@ -75,9 +75,9 @@ struct ib_node_info {
 	uint8_t class_version;
 	uint8_t node_type;
 	uint8_t num_ports;
-	struct ib_gid_half sys_guid;
-	struct ib_gid_half node_guid;
-	struct ib_gid_half port_guid;
+	union ib_guid sys_guid;
+	union ib_guid node_guid;
+	union ib_guid port_guid;
 	uint16_t partition_cap;
 	uint16_t device_id;
 	uint32_t revision;
@@ -221,8 +221,8 @@ struct ib_sa_hdr {
 
 struct ib_path_record {
 	uint32_t reserved0[2];
-	struct ib_gid dgid;
-	struct ib_gid sgid;
+	union ib_gid dgid;
+	union ib_gid sgid;
 	uint16_t dlid;
 	uint16_t slid;
 	uint32_t hop_limit__flow_label__raw_traffic;
@@ -239,8 +239,8 @@ struct ib_path_record {
 #define IB_SA_PATH_REC_SGID			(1<<3)
 
 struct ib_mc_member_record {
-	struct ib_gid mgid;
-	struct ib_gid port_gid;
+	union ib_gid mgid;
+	union ib_gid port_gid;
 	uint32_t qkey;
 	uint16_t mlid;
 	uint8_t mtu_selector__mtu;
@@ -320,9 +320,9 @@ struct ib_cm_path {
 	/** Remote port LID */
 	uint16_t remote_lid;
 	/** Local port GID */
-	struct ib_gid local_gid;
+	union ib_gid local_gid;
 	/** Remote port GID */
-	struct ib_gid remote_gid;
+	union ib_gid remote_gid;
 	/** Flow label and rate */
 	uint32_t flow_label__rate;
 	/** Traffic class */
@@ -345,9 +345,9 @@ struct ib_cm_connect_request {
 	/** Reserved */
 	uint32_t reserved0[1];
 	/** Service ID */
-	struct ib_gid_half service_id;
+	union ib_guid service_id;
 	/** Local CA GUID */
-	struct ib_gid_half local_ca;
+	union ib_guid local_ca;
 	/** Reserved */
 	uint32_t reserved1[1];
 	/** Local queue key */
@@ -433,7 +433,7 @@ struct ib_cm_connect_reply {
 	/** RNR retry count, SRQ */
 	uint8_t rnr_retry__srq;
 	/** Local CA GUID */
-	struct ib_gid_half local_ca;
+	union ib_guid local_ca;
 	/** Private data */
 	uint8_t private_data[196];
 } __attribute__ (( packed ));
diff --git a/src/include/ipxe/ib_mcast.h b/src/include/ipxe/ib_mcast.h
index 86d57090..a5c22a03 100644
--- a/src/include/ipxe/ib_mcast.h
+++ b/src/include/ipxe/ib_mcast.h
@@ -18,7 +18,7 @@ struct ib_mc_membership {
 	/** Queue pair */
 	struct ib_queue_pair *qp;
 	/** Multicast GID */
-	struct ib_gid gid;
+	union ib_gid gid;
 	/** Multicast group join transaction */
 	struct ib_mad_transaction *madx;
 	/** Handle join success/failure
@@ -36,7 +36,7 @@ struct ib_mc_membership {
 
 extern int ib_mcast_join ( struct ib_device *ibdev, struct ib_queue_pair *qp,
 			   struct ib_mc_membership *membership,
-			   struct ib_gid *gid,
+			   union ib_gid *gid,
 			   void ( * joined ) ( struct ib_device *ibdev,
 					       struct ib_queue_pair *qp,
 					       struct ib_mc_membership *memb,
diff --git a/src/include/ipxe/ib_packet.h b/src/include/ipxe/ib_packet.h
index 09042957..4bd33576 100644
--- a/src/include/ipxe/ib_packet.h
+++ b/src/include/ipxe/ib_packet.h
@@ -14,25 +14,38 @@ struct ib_queue_pair;
 struct ib_address_vector;
 struct io_buffer;
 
-/** Half of an Infiniband Global Identifier */
-struct ib_gid_half {
-	union {
-		uint8_t bytes[8];
-		uint16_t words[4];
-		uint32_t dwords[2];
-	} u;
+/** An Infiniband Globally Unique Identifier */
+union ib_guid {
+	uint8_t bytes[8];
+	uint16_t words[4];
+	uint32_t dwords[2];
 };
 
+/** Infiniband Globally Unique Identifier debug message format */
+#define IB_GUID_FMT "%08x:%08x"
+
+/** Infiniband Globally Unique Identifier debug message arguments */
+#define IB_GUID_ARGS( guid ) \
+	ntohl ( (guid)->dwords[0] ), ntohl ( (guid)->dwords[1] )
+
 /** An Infiniband Global Identifier */
-struct ib_gid {
-	union {
-		uint8_t bytes[16];
-		uint16_t words[8];
-		uint32_t dwords[4];
-		struct ib_gid_half half[2];
-	} u;
+union ib_gid {
+	uint8_t bytes[16];
+	uint16_t words[8];
+	uint32_t dwords[4];
+	struct {
+		union ib_guid prefix;
+		union ib_guid guid;
+	} s;
 };
 
+/** Infiniband Global Identifier debug message format */
+#define IB_GID_FMT IB_GUID_FMT ":" IB_GUID_FMT
+
+/** Infiniband Global Identifier debug message arguments */
+#define IB_GID_ARGS( gid ) \
+	IB_GUID_ARGS ( &(gid)->s.prefix ), IB_GUID_ARGS ( &(gid)->s.guid )
+
 /** An Infiniband Local Route Header */
 struct ib_local_route_header {
 	/** Virtual lane and link version */
@@ -83,9 +96,9 @@ struct ib_global_route_header {
 	/** Hop limit */
 	uint8_t hoplmt;
 	/** Source GID */
-	struct ib_gid sgid;
+	union ib_gid sgid;
 	/** Destiniation GID */
-	struct ib_gid dgid;
+	union ib_gid dgid;
 } __attribute__ (( packed ));
 
 #define IB_GRH_IPVER_IPv6 0x06
diff --git a/src/include/ipxe/ib_srp.h b/src/include/ipxe/ib_srp.h
index 902bef56..ad407b0c 100644
--- a/src/include/ipxe/ib_srp.h
+++ b/src/include/ipxe/ib_srp.h
@@ -20,9 +20,9 @@ union ib_srp_initiator_port_id {
 	/** Infiniband version of port identifier */
 	struct {
 		/** Identifier extension */
-		struct ib_gid_half id_ext;
+		union ib_guid id_ext;
 		/** IB channel adapter GUID */
-		struct ib_gid_half hca_guid;
+		union ib_guid hca_guid;
 	} __attribute__ (( packed )) ib;
 };
 
@@ -33,9 +33,9 @@ union ib_srp_target_port_id {
 	/** Infiniband version of port identifier */
 	struct {
 		/** Identifier extension */
-		struct ib_gid_half id_ext;
+		union ib_guid id_ext;
 		/** I/O controller GUID */
-		struct ib_gid_half ioc_guid;
+		union ib_guid ioc_guid;
 	} __attribute__ (( packed )) ib;
 };
 
@@ -44,11 +44,11 @@ union ib_srp_target_port_id {
  */
 struct sbft_ib_subtable {
 	/** Source GID */
-	struct ib_gid sgid;
+	union ib_gid sgid;
 	/** Destination GID */
-	struct ib_gid dgid;
+	union ib_gid dgid;
 	/** Service ID */
-	struct ib_gid_half service_id;
+	union ib_guid service_id;
 	/** Partition key */
 	uint16_t pkey;
 	/** Reserved */
diff --git a/src/include/ipxe/infiniband.h b/src/include/ipxe/infiniband.h
index edcce371..aa67dd4a 100644
--- a/src/include/ipxe/infiniband.h
+++ b/src/include/ipxe/infiniband.h
@@ -88,7 +88,7 @@ struct ib_address_vector {
 	/** GID is present */
 	unsigned int gid_present;
 	/** GID, if present */
-	struct ib_gid gid;
+	union ib_gid gid;
 };
 
 /** An Infiniband Work Queue */
@@ -126,7 +126,7 @@ struct ib_multicast_gid {
 	/** List of multicast GIDs on this QP */
 	struct list_head list;
 	/** Multicast GID */
-	struct ib_gid gid;
+	union ib_gid gid;
 };
 
 /** An Infiniband queue pair type */
@@ -338,7 +338,7 @@ struct ib_device_operations {
 	 */
 	int ( * mcast_attach ) ( struct ib_device *ibdev,
 				 struct ib_queue_pair *qp,
-				 struct ib_gid *gid );
+				 union ib_gid *gid );
 	/** Detach from multicast group
 	 *
 	 * @v ibdev		Infiniband device
@@ -347,7 +347,7 @@ struct ib_device_operations {
 	 */
 	void ( * mcast_detach ) ( struct ib_device *ibdev,
 				  struct ib_queue_pair *qp,
-				  struct ib_gid *gid );
+				  union ib_gid *gid );
 	/** Set port information
 	 *
 	 * @v ibdev		Infiniband device
@@ -405,7 +405,7 @@ struct ib_device {
 	/** Link speed active */
 	uint8_t link_speed_active;
 	/** Port GID */
-	struct ib_gid gid;
+	union ib_gid gid;
 	/** Port LID */
 	uint16_t lid;
 	/** Subnet manager LID */
@@ -479,7 +479,7 @@ extern void ib_destroy_qp ( struct ib_device *ibdev,
 extern struct ib_queue_pair * ib_find_qp_qpn ( struct ib_device *ibdev,
 					       unsigned long qpn );
 extern struct ib_queue_pair * ib_find_qp_mgid ( struct ib_device *ibdev,
-						struct ib_gid *gid );
+						union ib_gid *gid );
 extern struct ib_work_queue * ib_find_wq ( struct ib_completion_queue *cq,
 					   unsigned long qpn, int is_send );
 extern int ib_post_send ( struct ib_device *ibdev, struct ib_queue_pair *qp,
@@ -500,17 +500,17 @@ extern int ib_open ( struct ib_device *ibdev );
 extern void ib_close ( struct ib_device *ibdev );
 extern int ib_link_rc ( struct ib_device *ibdev );
 extern int ib_mcast_attach ( struct ib_device *ibdev, struct ib_queue_pair *qp,
-			     struct ib_gid *gid );
+			     union ib_gid *gid );
 extern void ib_mcast_detach ( struct ib_device *ibdev,
-			      struct ib_queue_pair *qp, struct ib_gid *gid );
+			      struct ib_queue_pair *qp, union ib_gid *gid );
 extern int ib_get_hca_info ( struct ib_device *ibdev,
-			     struct ib_gid_half *hca_guid );
+			     union ib_guid *hca_guid );
 extern int ib_set_port_info ( struct ib_device *ibdev, union ib_mad *mad );
 extern int ib_set_pkey_table ( struct ib_device *ibdev, union ib_mad *mad );
 extern struct ib_device * alloc_ibdev ( size_t priv_size );
 extern int register_ibdev ( struct ib_device *ibdev );
 extern void unregister_ibdev ( struct ib_device *ibdev );
-extern struct ib_device * find_ibdev ( struct ib_gid *gid );
+extern struct ib_device * find_ibdev ( union ib_gid *gid );
 extern struct ib_device * last_opened_ibdev ( void );
 extern void ib_link_state_changed ( struct ib_device *ibdev );
 extern void ib_poll_eq ( struct ib_device *ibdev );
diff --git a/src/include/ipxe/ipoib.h b/src/include/ipxe/ipoib.h
index 6a3fd607..e8f12dc5 100644
--- a/src/include/ipxe/ipoib.h
+++ b/src/include/ipxe/ipoib.h
@@ -22,7 +22,7 @@ struct ipoib_mac {
 	 */
 	uint32_t flags__qpn;
 	/** Port GID */
-	struct ib_gid gid;
+	union ib_gid gid;
 } __attribute__ (( packed ));
 
 /** IPoIB link-layer header length */
diff --git a/src/net/infiniband.c b/src/net/infiniband.c
index 76fce3bd..d7cbf697 100644
--- a/src/net/infiniband.c
+++ b/src/net/infiniband.c
@@ -341,7 +341,7 @@ struct ib_queue_pair * ib_find_qp_qpn ( struct ib_device *ibdev,
  * @ret qp		Queue pair, or NULL
  */
 struct ib_queue_pair * ib_find_qp_mgid ( struct ib_device *ibdev,
-					 struct ib_gid *gid ) {
+					 union ib_gid *gid ) {
 	struct ib_queue_pair *qp;
 	struct ib_multicast_gid *mgid;
 
@@ -703,7 +703,7 @@ void ib_close ( struct ib_device *ibdev ) {
  * the multicast group on the subnet.
  */
 int ib_mcast_attach ( struct ib_device *ibdev, struct ib_queue_pair *qp,
-		      struct ib_gid *gid ) {
+		      union ib_gid *gid ) {
 	struct ib_multicast_gid *mgid;
 	int rc;
 
@@ -737,7 +737,7 @@ int ib_mcast_attach ( struct ib_device *ibdev, struct ib_queue_pair *qp,
  * @v gid		Multicast GID
  */
 void ib_mcast_detach ( struct ib_device *ibdev, struct ib_queue_pair *qp,
-		       struct ib_gid *gid ) {
+		       union ib_gid *gid ) {
 	struct ib_multicast_gid *mgid;
 
 	/* Remove from hardware multicast GID list */
@@ -767,8 +767,7 @@ void ib_mcast_detach ( struct ib_device *ibdev, struct ib_queue_pair *qp,
  * @ret hca_guid	HCA GUID
  * @ret num_ports	Number of ports
  */
-int ib_get_hca_info ( struct ib_device *ibdev,
-		      struct ib_gid_half *hca_guid ) {
+int ib_get_hca_info ( struct ib_device *ibdev, union ib_guid *hca_guid ) {
 	struct ib_device *tmp;
 	int num_ports = 0;
 
@@ -779,7 +778,7 @@ int ib_get_hca_info ( struct ib_device *ibdev,
 		if ( tmp->dev != ibdev->dev )
 			continue;
 		if ( num_ports == 0 ) {
-			memcpy ( hca_guid, &tmp->gid.u.half[1],
+			memcpy ( hca_guid, &tmp->gid.s.guid,
 				 sizeof ( *hca_guid ) );
 		}
 		num_ports++;
@@ -969,7 +968,7 @@ void unregister_ibdev ( struct ib_device *ibdev ) {
  * @v gid		GID
  * @ret ibdev		Infiniband device, or NULL
  */
-struct ib_device * find_ibdev ( struct ib_gid *gid ) {
+struct ib_device * find_ibdev ( union ib_gid *gid ) {
 	struct ib_device *ibdev;
 
 	for_each_ibdev ( ibdev ) {
diff --git a/src/net/infiniband/ib_cm.c b/src/net/infiniband/ib_cm.c
index cac0a983..bbba5727 100644
--- a/src/net/infiniband/ib_cm.c
+++ b/src/net/infiniband/ib_cm.c
@@ -432,7 +432,7 @@ static struct ib_path_operations ib_cm_path_op = {
  */
 struct ib_connection *
 ib_create_conn ( struct ib_device *ibdev, struct ib_queue_pair *qp,
-		 struct ib_gid *dgid, struct ib_gid_half *service_id,
+		 union ib_gid *dgid, union ib_guid *service_id,
 		 void *private_data, size_t private_data_len,
 		 struct ib_connection_operations *op ) {
 	struct ib_connection *conn;
@@ -463,11 +463,8 @@ ib_create_conn ( struct ib_device *ibdev, struct ib_queue_pair *qp,
 
 	DBGC ( conn, "CM %p created for IBDEV %p QPN %lx\n",
 	       conn, ibdev, qp->qpn );
-	DBGC ( conn, "CM %p connecting to %08x:%08x:%08x:%08x %08x:%08x\n",
-	       conn, ntohl ( dgid->u.dwords[0] ), ntohl ( dgid->u.dwords[1] ),
-	       ntohl ( dgid->u.dwords[2] ), ntohl ( dgid->u.dwords[3] ),
-	       ntohl ( service_id->u.dwords[0] ),
-	       ntohl ( service_id->u.dwords[1] ) );
+	DBGC ( conn, "CM %p connecting to " IB_GID_FMT " " IB_GUID_FMT "\n",
+	       conn, IB_GID_ARGS ( dgid ), IB_GUID_ARGS ( service_id ) );
 
 	return conn;
 
diff --git a/src/net/infiniband/ib_cmrc.c b/src/net/infiniband/ib_cmrc.c
index f596c36d..011ff3e0 100644
--- a/src/net/infiniband/ib_cmrc.c
+++ b/src/net/infiniband/ib_cmrc.c
@@ -80,9 +80,9 @@ struct ib_cmrc_connection {
 	/** Connection */
 	struct ib_connection *conn;
 	/** Destination GID */
-	struct ib_gid dgid;
+	union ib_gid dgid;
 	/** Service ID */
-	struct ib_gid_half service_id;
+	union ib_guid service_id;
 	/** QP is connected */
 	int connected;
 	/** Shutdown process */
@@ -357,7 +357,7 @@ static struct interface_descriptor ib_cmrc_xfer_desc =
  * @ret rc		Returns status code
  */
 int ib_cmrc_open ( struct interface *xfer, struct ib_device *ibdev,
-		   struct ib_gid *dgid, struct ib_gid_half *service_id ) {
+		   union ib_gid *dgid, union ib_guid *service_id ) {
 	struct ib_cmrc_connection *cmrc;
 	int rc;
 
diff --git a/src/net/infiniband/ib_mcast.c b/src/net/infiniband/ib_mcast.c
index 9eff1899..0f03b54a 100644
--- a/src/net/infiniband/ib_mcast.c
+++ b/src/net/infiniband/ib_mcast.c
@@ -41,7 +41,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
  * @v join		Join (rather than leave) group
  * @v mad		MAD to fill in
  */
-static void ib_mcast_mad ( struct ib_device *ibdev, struct ib_gid *gid,
+static void ib_mcast_mad ( struct ib_device *ibdev, union ib_gid *gid,
 			   int join, union ib_mad *mad ) {
 	struct ib_mad_sa *sa = &mad->sa;
 
@@ -79,7 +79,7 @@ static void ib_mcast_complete ( struct ib_device *ibdev,
 				struct ib_address_vector *av __unused ) {
 	struct ib_mc_membership *membership = ib_madx_get_ownerdata ( madx );
 	struct ib_queue_pair *qp = membership->qp;
-	struct ib_gid *gid = &membership->gid;
+	union ib_gid *gid = &membership->gid;
 	struct ib_mc_member_record *mc_member_record =
 		&mad->sa.sa_data.mc_member_record;
 	int joined;
@@ -97,11 +97,9 @@ static void ib_mcast_complete ( struct ib_device *ibdev,
 	/* Extract values from MAD */
 	joined = ( mad->hdr.method == IB_MGMT_METHOD_GET_RESP );
 	qkey = ntohl ( mc_member_record->qkey );
-	DBGC ( ibdev, "IBDEV %p QPN %lx %s %08x:%08x:%08x:%08x qkey %lx\n",
+	DBGC ( ibdev, "IBDEV %p QPN %lx %s " IB_GID_FMT " qkey %lx\n",
 	       ibdev, qp->qpn, ( joined ? "joined" : "left" ),
-	       ntohl ( gid->u.dwords[0] ), ntohl ( gid->u.dwords[1] ),
-	       ntohl ( gid->u.dwords[2] ), ntohl ( gid->u.dwords[3] ),
-	       qkey );
+	       IB_GID_ARGS ( gid ), qkey );
 
 	/* Set queue key */
 	qp->qkey = qkey;
@@ -136,7 +134,7 @@ static struct ib_mad_transaction_operations ib_mcast_op = {
  * @ret rc		Return status code
  */
 int ib_mcast_join ( struct ib_device *ibdev, struct ib_queue_pair *qp,
-		    struct ib_mc_membership *membership, struct ib_gid *gid,
+		    struct ib_mc_membership *membership, union ib_gid *gid,
 		    void ( * complete ) ( struct ib_device *ibdev,
 					  struct ib_queue_pair *qp,
 					  struct ib_mc_membership *membership,
@@ -144,10 +142,8 @@ int ib_mcast_join ( struct ib_device *ibdev, struct ib_queue_pair *qp,
 	union ib_mad mad;
 	int rc;
 
-	DBGC ( ibdev, "IBDEV %p QPN %lx joining %08x:%08x:%08x:%08x\n",
-	       ibdev, qp->qpn, ntohl ( gid->u.dwords[0] ),
-	       ntohl ( gid->u.dwords[1] ), ntohl ( gid->u.dwords[2] ),
-	       ntohl ( gid->u.dwords[3] ) );
+	DBGC ( ibdev, "IBDEV %p QPN %lx joining " IB_GID_FMT "\n",
+	       ibdev, qp->qpn, IB_GID_ARGS ( gid ) );
 
 	/* Initialise structure */
 	membership->qp = qp;
@@ -191,14 +187,12 @@ int ib_mcast_join ( struct ib_device *ibdev, struct ib_queue_pair *qp,
  */
 void ib_mcast_leave ( struct ib_device *ibdev, struct ib_queue_pair *qp,
 		      struct ib_mc_membership *membership ) {
-	struct ib_gid *gid = &membership->gid;
+	union ib_gid *gid = &membership->gid;
 	union ib_mad mad;
 	int rc;
 
-	DBGC ( ibdev, "IBDEV %p QPN %lx leaving %08x:%08x:%08x:%08x\n",
-	       ibdev, qp->qpn, ntohl ( gid->u.dwords[0] ),
-	       ntohl ( gid->u.dwords[1] ), ntohl ( gid->u.dwords[2] ),
-	       ntohl ( gid->u.dwords[3] ) );
+	DBGC ( ibdev, "IBDEV %p QPN %lx leaving " IB_GID_FMT "\n",
+	       ibdev, qp->qpn, IB_GID_ARGS ( gid ) );
 
 	/* Detach from multicast GID */
 	ib_mcast_detach ( ibdev, qp, &membership->gid );
diff --git a/src/net/infiniband/ib_packet.c b/src/net/infiniband/ib_packet.c
index 943f3957..d58e0ad4 100644
--- a/src/net/infiniband/ib_packet.c
+++ b/src/net/infiniband/ib_packet.c
@@ -215,11 +215,8 @@ int ib_pull ( struct ib_device *ibdev, struct io_buffer *iobuf,
 		if ( IB_LID_MULTICAST ( lid ) && grh ) {
 			if ( ! ( *qp = ib_find_qp_mgid ( ibdev, &grh->dgid ))){
 				DBGC ( ibdev, "IBDEV %p RX for unknown MGID "
-				       "%08x:%08x:%08x:%08x\n", ibdev,
-				       ntohl ( grh->dgid.u.dwords[0] ),
-				       ntohl ( grh->dgid.u.dwords[1] ),
-				       ntohl ( grh->dgid.u.dwords[2] ),
-				       ntohl ( grh->dgid.u.dwords[3] ) );
+				       IB_GID_FMT "\n",
+				       ibdev, IB_GID_ARGS ( &grh->dgid ) );
 				return -ENODEV;
 			}
 		} else {
diff --git a/src/net/infiniband/ib_pathrec.c b/src/net/infiniband/ib_pathrec.c
index e1fa5306..7b914654 100644
--- a/src/net/infiniband/ib_pathrec.c
+++ b/src/net/infiniband/ib_pathrec.c
@@ -49,18 +49,16 @@ static void ib_path_complete ( struct ib_device *ibdev,
 			       int rc, union ib_mad *mad,
 			       struct ib_address_vector *av __unused ) {
 	struct ib_path *path = ib_madx_get_ownerdata ( madx );
-	struct ib_gid *dgid = &path->av.gid;
+	union ib_gid *dgid = &path->av.gid;
 	struct ib_path_record *pathrec = &mad->sa.sa_data.path_record;
 
 	/* Report failures */
 	if ( ( rc == 0 ) && ( mad->hdr.status != htons ( IB_MGMT_STATUS_OK ) ))
 		rc = -ENETUNREACH;
 	if ( rc != 0 ) {
-		DBGC ( ibdev, "IBDEV %p path lookup for %08x:%08x:%08x:%08x "
-		       "failed: %s\n", ibdev, htonl ( dgid->u.dwords[0] ),
-		       htonl ( dgid->u.dwords[1] ),
-		       htonl ( dgid->u.dwords[2] ),
-		       htonl ( dgid->u.dwords[3] ), strerror ( rc ) );
+		DBGC ( ibdev, "IBDEV %p path lookup for " IB_GID_FMT
+		       " failed: %s\n",
+		       ibdev, IB_GID_ARGS ( dgid ), strerror ( rc ) );
 		goto out;
 	}
 
@@ -68,10 +66,8 @@ static void ib_path_complete ( struct ib_device *ibdev,
 	path->av.lid = ntohs ( pathrec->dlid );
 	path->av.sl = ( pathrec->reserved__sl & 0x0f );
 	path->av.rate = ( pathrec->rate_selector__rate & 0x3f );
-	DBGC ( ibdev, "IBDEV %p path to %08x:%08x:%08x:%08x is %04x sl %d "
-	       "rate %d\n", ibdev, htonl ( dgid->u.dwords[0] ),
-	       htonl ( dgid->u.dwords[1] ), htonl ( dgid->u.dwords[2] ),
-	       htonl ( dgid->u.dwords[3] ), path->av.lid, path->av.sl,
+	DBGC ( ibdev, "IBDEV %p path to " IB_GID_FMT " is %04x sl %d rate "
+	       "%d\n", ibdev, IB_GID_ARGS ( dgid ), path->av.lid, path->av.sl,
 	       path->av.rate );
 
  out:
@@ -179,7 +175,7 @@ static unsigned int ib_path_cache_idx;
  * @ret path		Path cache entry, or NULL
  */
 static struct ib_cached_path *
-ib_find_path_cache_entry ( struct ib_device *ibdev, struct ib_gid *dgid ) {
+ib_find_path_cache_entry ( struct ib_device *ibdev, union ib_gid *dgid ) {
 	struct ib_cached_path *cached;
 	unsigned int i;
 
@@ -240,14 +236,14 @@ static struct ib_path_operations ib_cached_path_op = {
  * cache similar to ARP.
  */
 int ib_resolve_path ( struct ib_device *ibdev, struct ib_address_vector *av ) {
-	struct ib_gid *gid = &av->gid;
+	union ib_gid *gid = &av->gid;
 	struct ib_cached_path *cached;
 	unsigned int cache_idx;
 
 	/* Sanity check */
 	if ( ! av->gid_present ) {
-		DBGC ( ibdev, "IBDEV %p attempt to look up path "
-		       "without GID\n", ibdev );
+		DBGC ( ibdev, "IBDEV %p attempt to look up path without GID\n",
+		       ibdev );
 		return -EINVAL;
 	}
 
@@ -258,16 +254,12 @@ int ib_resolve_path ( struct ib_device *ibdev, struct ib_address_vector *av ) {
 		av->lid = cached->path->av.lid;
 		av->rate = cached->path->av.rate;
 		av->sl = cached->path->av.sl;
-		DBGC2 ( ibdev, "IBDEV %p cache hit for %08x:%08x:%08x:%08x\n",
-			ibdev, htonl ( gid->u.dwords[0] ),
-			htonl ( gid->u.dwords[1] ), htonl ( gid->u.dwords[2] ),
-			htonl ( gid->u.dwords[3] ) );
+		DBGC2 ( ibdev, "IBDEV %p cache hit for " IB_GID_FMT "\n",
+			ibdev, IB_GID_ARGS ( gid ) );
 		return 0;
 	}
-	DBGC ( ibdev, "IBDEV %p cache miss for %08x:%08x:%08x:%08x%s\n",
-	       ibdev, htonl ( gid->u.dwords[0] ), htonl ( gid->u.dwords[1] ),
-	       htonl ( gid->u.dwords[2] ), htonl ( gid->u.dwords[3] ),
-	       ( cached ? " (in progress)" : "" ) );
+	DBGC ( ibdev, "IBDEV %p cache miss for " IB_GID_FMT "%s\n", ibdev,
+	       IB_GID_ARGS ( gid ), ( cached ? " (in progress)" : "" ) );
 
 	/* If lookup is already in progress, do nothing */
 	if ( cached )
diff --git a/src/net/infiniband/ib_sma.c b/src/net/infiniband/ib_sma.c
index b8327355..45a1e446 100644
--- a/src/net/infiniband/ib_sma.c
+++ b/src/net/infiniband/ib_sma.c
@@ -61,7 +61,7 @@ static void ib_sma_node_info ( struct ib_device *ibdev,
 	node_info->num_ports = ib_get_hca_info ( ibdev, &node_info->sys_guid );
 	memcpy ( &node_info->node_guid, &node_info->sys_guid,
 		 sizeof ( node_info->node_guid ) );
-	memcpy ( &node_info->port_guid, &ibdev->gid.u.half[1],
+	memcpy ( &node_info->port_guid, &ibdev->gid.s.guid,
 		 sizeof ( node_info->port_guid ) );
 	node_info->partition_cap = htons ( 1 );
 	node_info->local_port_num = ibdev->port;
@@ -88,7 +88,7 @@ static void ib_sma_node_desc ( struct ib_device *ibdev,
 			       union ib_mad *mad,
 			       struct ib_address_vector *av ) {
 	struct ib_node_desc *node_desc = &mad->smp.smp_data.node_desc;
-	struct ib_gid_half guid;
+	union ib_guid guid;
 	char hostname[ sizeof ( node_desc->node_string ) ];
 	int hostname_len;
 	int rc;
@@ -101,9 +101,9 @@ static void ib_sma_node_desc ( struct ib_device *ibdev,
 	snprintf ( node_desc->node_string, sizeof ( node_desc->node_string ),
 		   "iPXE %s%s%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x (%s)",
 		   hostname, ( ( hostname_len >= 0 ) ? " " : "" ),
-		   guid.u.bytes[0], guid.u.bytes[1], guid.u.bytes[2],
-		   guid.u.bytes[3], guid.u.bytes[4], guid.u.bytes[5],
-		   guid.u.bytes[6], guid.u.bytes[7], ibdev->dev->name );
+		   guid.bytes[0], guid.bytes[1], guid.bytes[2], guid.bytes[3],
+		   guid.bytes[4], guid.bytes[5], guid.bytes[6], guid.bytes[7],
+		   ibdev->dev->name );
 
 	/* Send GetResponse */
 	mad->hdr.method = IB_MGMT_METHOD_GET_RESP;
@@ -131,7 +131,7 @@ static void ib_sma_guid_info ( struct ib_device *ibdev,
 
 	/* Fill in information */
 	memset ( guid_info, 0, sizeof ( *guid_info ) );
-	memcpy ( guid_info->guid[0], &ibdev->gid.u.half[1],
+	memcpy ( guid_info->guid[0], &ibdev->gid.s.guid,
 		 sizeof ( guid_info->guid[0] ) );
 
 	/* Send GetResponse */
@@ -160,8 +160,8 @@ static int ib_sma_set_port_info ( struct ib_device *ibdev,
 	int rc;
 
 	/* Set parameters */
-	memcpy ( &ibdev->gid.u.half[0], port_info->gid_prefix,
-		 sizeof ( ibdev->gid.u.half[0] ) );
+	memcpy ( &ibdev->gid.s.prefix, port_info->gid_prefix,
+		 sizeof ( ibdev->gid.s.prefix ) );
 	ibdev->lid = ntohs ( port_info->lid );
 	ibdev->sm_lid = ntohs ( port_info->mastersm_lid );
 	if ( ( link_width_enabled = port_info->link_width_enabled ) )
@@ -210,7 +210,7 @@ static void ib_sma_port_info ( struct ib_device *ibdev,
 
 	/* Fill in information */
 	memset ( port_info, 0, sizeof ( *port_info ) );
-	memcpy ( port_info->gid_prefix, &ibdev->gid.u.half[0],
+	memcpy ( port_info->gid_prefix, &ibdev->gid.s.prefix,
 		 sizeof ( port_info->gid_prefix ) );
 	port_info->lid = ntohs ( ibdev->lid );
 	port_info->mastersm_lid = ntohs ( ibdev->sm_lid );
diff --git a/src/net/infiniband/ib_smc.c b/src/net/infiniband/ib_smc.c
index 7d596359..5eef8255 100644
--- a/src/net/infiniband/ib_smc.c
+++ b/src/net/infiniband/ib_smc.c
@@ -141,8 +141,8 @@ int ib_smc_update ( struct ib_device *ibdev, ib_local_mad_t local_mad ) {
 	 */
 	if ( ( rc = ib_smc_get_port_info ( ibdev, local_mad, &mad ) ) != 0 )
 		return rc;
-	memcpy ( &ibdev->gid.u.half[0], port_info->gid_prefix,
-		 sizeof ( ibdev->gid.u.half[0] ) );
+	memcpy ( &ibdev->gid.s.prefix, port_info->gid_prefix,
+		 sizeof ( ibdev->gid.s.prefix ) );
 	ibdev->lid = ntohs ( port_info->lid );
 	ibdev->sm_lid = ntohs ( port_info->mastersm_lid );
 	ibdev->link_width_enabled = port_info->link_width_enabled;
@@ -161,19 +161,16 @@ int ib_smc_update ( struct ib_device *ibdev, ib_local_mad_t local_mad ) {
 	/* GUID info gives us the second half of the port GID */
 	if ( ( rc = ib_smc_get_guid_info ( ibdev, local_mad, &mad ) ) != 0 )
 		return rc;
-	memcpy ( &ibdev->gid.u.half[1], guid_info->guid[0],
-		 sizeof ( ibdev->gid.u.half[1] ) );
+	memcpy ( &ibdev->gid.s.guid, guid_info->guid[0],
+		 sizeof ( ibdev->gid.s.guid ) );
 
 	/* Get partition key */
 	if ( ( rc = ib_smc_get_pkey_table ( ibdev, local_mad, &mad ) ) != 0 )
 		return rc;
 	ibdev->pkey = ntohs ( pkey_table->pkey[0] );
 
-	DBGC ( ibdev, "IBDEV %p port GID is %08x:%08x:%08x:%08x\n", ibdev,
-	       htonl ( ibdev->gid.u.dwords[0] ),
-	       htonl ( ibdev->gid.u.dwords[1] ),
-	       htonl ( ibdev->gid.u.dwords[2] ),
-	       htonl ( ibdev->gid.u.dwords[3] ) );
+	DBGC ( ibdev, "IBDEV %p port GID is " IB_GID_FMT "\n",
+	       ibdev, IB_GID_ARGS ( &ibdev->gid ) );
 
 	return 0;
 }
diff --git a/src/net/infiniband/ib_srp.c b/src/net/infiniband/ib_srp.c
index 41416a20..7b2b2b4e 100644
--- a/src/net/infiniband/ib_srp.c
+++ b/src/net/infiniband/ib_srp.c
@@ -81,9 +81,9 @@ struct ib_srp_device {
 	struct ib_device *ibdev;
 
 	/** Destination GID (for boot firmware table) */
-	struct ib_gid dgid;
+	union ib_gid dgid;
 	/** Service ID (for boot firmware table) */
-	struct ib_gid_half service_id;
+	union ib_guid service_id;
 };
 
 /**
@@ -184,7 +184,7 @@ static struct interface_descriptor ib_srp_srp_desc =
  * @ret rc		Return status code
  */
 static int ib_srp_open ( struct interface *block, struct ib_device *ibdev,
-			 struct ib_gid *dgid, struct ib_gid_half *service_id,
+			 union ib_gid *dgid, union ib_guid *service_id,
 			 union srp_port_id *initiator,
 			 union srp_port_id *target, struct scsi_lun *lun ) {
 	struct ib_srp_device *ib_srp;
@@ -200,11 +200,8 @@ static int ib_srp_open ( struct interface *block, struct ib_device *ibdev,
 	intf_init ( &ib_srp->srp, &ib_srp_srp_desc, &ib_srp->refcnt );
 	intf_init ( &ib_srp->cmrc, &ib_srp_cmrc_desc, &ib_srp->refcnt );
 	ib_srp->ibdev = ibdev_get ( ibdev );
-	DBGC ( ib_srp, "IBSRP %p created for %08x%08x%08x%08x:%08x%08x\n",
-	       ib_srp, ntohl ( dgid->u.dwords[0] ),
-	       ntohl ( dgid->u.dwords[1] ), ntohl ( dgid->u.dwords[2] ),
-	       ntohl ( dgid->u.dwords[3] ), ntohl ( service_id->u.dwords[0] ),
-	       ntohl ( service_id->u.dwords[1] ) );
+	DBGC ( ib_srp, "IBSRP %p for " IB_GID_FMT " " IB_GUID_FMT "\n",
+	       ib_srp, IB_GID_ARGS ( dgid ), IB_GUID_ARGS ( service_id ) );
 
 	/* Preserve parameters required for boot firmware table */
 	memcpy ( &ib_srp->dgid, dgid, sizeof ( ib_srp->dgid ) );
@@ -256,15 +253,15 @@ enum ib_srp_parse_flags {
 /** IB SRP root path parameters */
 struct ib_srp_root_path {
 	/** Source GID */
-	struct ib_gid sgid;
+	union ib_gid sgid;
 	/** Initiator port ID */
 	union ib_srp_initiator_port_id initiator;
 	/** Destination GID */
-	struct ib_gid dgid;
+	union ib_gid dgid;
 	/** Partition key */
 	uint16_t pkey;
 	/** Service ID */
-	struct ib_gid_half service_id;
+	union ib_guid service_id;
 	/** SCSI LUN */
 	struct scsi_lun lun;
 	/** Target port ID */
@@ -337,7 +334,7 @@ static int ib_srp_parse_sgid ( const char *rp_comp,
 	if ( ( ibdev = last_opened_ibdev() ) != NULL )
 		memcpy ( &rp->sgid, &ibdev->gid, sizeof ( rp->sgid ) );
 
-	return ib_srp_parse_byte_string ( rp_comp, rp->sgid.u.bytes,
+	return ib_srp_parse_byte_string ( rp_comp, rp->sgid.bytes,
 					  ( sizeof ( rp->sgid ) |
 					    IB_SRP_PARSE_OPTIONAL ) );
 }
@@ -353,7 +350,7 @@ static int ib_srp_parse_initiator_id_ext ( const char *rp_comp,
 					   struct ib_srp_root_path *rp ) {
 	union ib_srp_initiator_port_id *port_id = &rp->initiator;
 
-	return ib_srp_parse_byte_string ( rp_comp, port_id->ib.id_ext.u.bytes,
+	return ib_srp_parse_byte_string ( rp_comp, port_id->ib.id_ext.bytes,
 					  ( sizeof ( port_id->ib.id_ext ) |
 					    IB_SRP_PARSE_OPTIONAL ) );
 }
@@ -370,10 +367,10 @@ static int ib_srp_parse_initiator_hca_guid ( const char *rp_comp,
 	union ib_srp_initiator_port_id *port_id = &rp->initiator;
 
 	/* Default to the GUID portion of the source GID */
-	memcpy ( &port_id->ib.hca_guid, &rp->sgid.u.half[1],
+	memcpy ( &port_id->ib.hca_guid, &rp->sgid.s.guid,
 		 sizeof ( port_id->ib.hca_guid ) );
 
-	return ib_srp_parse_byte_string ( rp_comp, port_id->ib.hca_guid.u.bytes,
+	return ib_srp_parse_byte_string ( rp_comp, port_id->ib.hca_guid.bytes,
 					  ( sizeof ( port_id->ib.hca_guid ) |
 					    IB_SRP_PARSE_OPTIONAL ) );
 }
@@ -387,7 +384,7 @@ static int ib_srp_parse_initiator_hca_guid ( const char *rp_comp,
  */
 static int ib_srp_parse_dgid ( const char *rp_comp,
 			       struct ib_srp_root_path *rp ) {
-	return ib_srp_parse_byte_string ( rp_comp, rp->dgid.u.bytes,
+	return ib_srp_parse_byte_string ( rp_comp, rp->dgid.bytes,
 					  ( sizeof ( rp->dgid ) |
 					    IB_SRP_PARSE_REQUIRED ) );
 }
@@ -418,7 +415,7 @@ static int ib_srp_parse_pkey ( const char *rp_comp,
  */
 static int ib_srp_parse_service_id ( const char *rp_comp,
 				     struct ib_srp_root_path *rp ) {
-	return ib_srp_parse_byte_string ( rp_comp, rp->service_id.u.bytes,
+	return ib_srp_parse_byte_string ( rp_comp, rp->service_id.bytes,
 					  ( sizeof ( rp->service_id ) |
 					    IB_SRP_PARSE_REQUIRED ) );
 }
@@ -446,7 +443,7 @@ static int ib_srp_parse_target_id_ext ( const char *rp_comp,
 					struct ib_srp_root_path *rp ) {
 	union ib_srp_target_port_id *port_id = &rp->target;
 
-	return ib_srp_parse_byte_string ( rp_comp, port_id->ib.id_ext.u.bytes,
+	return ib_srp_parse_byte_string ( rp_comp, port_id->ib.id_ext.bytes,
 					  ( sizeof ( port_id->ib.id_ext ) |
 					    IB_SRP_PARSE_REQUIRED ) );
 }
@@ -462,7 +459,7 @@ static int ib_srp_parse_target_ioc_guid ( const char *rp_comp,
 					  struct ib_srp_root_path *rp ) {
 	union ib_srp_target_port_id *port_id = &rp->target;
 
-	return ib_srp_parse_byte_string ( rp_comp, port_id->ib.ioc_guid.u.bytes,
+	return ib_srp_parse_byte_string ( rp_comp, port_id->ib.ioc_guid.bytes,
 					  ( sizeof ( port_id->ib.ioc_guid ) |
 					    IB_SRP_PARSE_REQUIRED ) );
 }