[hermon] Use Ethernet MAC as eIPoIB local EMAC

The eIPoIB local Ethernet MAC is currently constructed from the port
GUID.  Given a base GUID/MAC value of N, Mellanox seems to populate:

  Node GUID:   N + 0
  Port 1 GUID: N + 1
  Port 2 GUID: N + 2

and

  Port 1 MAC:  N + 0
  Port 2 MAC:  N + 1

This causes a duplicate local MAC address when port 1 is configured as
Infiniband and port 2 as Ethernet, since both will derive their MAC
address as (N + 1).

Fix by using the port's Ethernet MAC as the eIPoIB local EMAC.  This
is a behavioural change that could potentially break configurations
that rely on the local EMAC value, such as a DHCP server relying on
the chaddr field for DHCP reservations.

Signed-off-by: Christian Iversen <ci@iversenit.dk>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

2 files changed, 20 insertions, 17 deletions

diff --git a/src/drivers/infiniband/hermon.c b/src/drivers/infiniband/hermon.c
index e818b4d..d766ed5 100644
--- a/src/drivers/infiniband/hermon.c
+++ b/src/drivers/infiniband/hermon.c
@@ -3179,6 +3179,9 @@ static int hermon_register_ibdev ( struct hermon *hermon,
 	struct ib_device *ibdev = port->ibdev;
 	int rc;
 
+	/* Use Ethernet MAC as eIPoIB local EMAC */
+	memcpy ( ibdev->lemac, port->eth_mac.raw, ETH_ALEN );
+
 	/* Initialise parameters using SMC */
 	ib_smc_init ( ibdev, hermon_mad );
 
@@ -3495,24 +3498,10 @@ static int hermon_register_netdev ( struct hermon *hermon,
 				    struct hermon_port *port ) {
 	struct net_device *netdev = port->netdev;
 	struct ib_device *ibdev = port->ibdev;
-	struct hermonprm_query_port_cap query_port;
-	union {
-		uint8_t bytes[8];
-		uint32_t dwords[2];
-	} mac;
 	int rc;
 
-	/* Retrieve MAC address */
-	if ( ( rc = hermon_cmd_query_port ( hermon, ibdev->port,
-					    &query_port ) ) != 0 ) {
-		DBGC ( hermon, "Hermon %p port %d could not query port: %s\n",
-		       hermon, ibdev->port, strerror ( rc ) );
-		goto err_query_port;
-	}
-	mac.dwords[0] = htonl ( MLX_GET ( &query_port, mac_47_32 ) );
-	mac.dwords[1] = htonl ( MLX_GET ( &query_port, mac_31_0 ) );
-	memcpy ( netdev->hw_addr,
-		 &mac.bytes[ sizeof ( mac.bytes ) - ETH_ALEN ], ETH_ALEN );
+	/* Set MAC address */
+	memcpy ( netdev->hw_addr, port->eth_mac.raw, ETH_ALEN );
 
 	/* Register network device */
 	if ( ( rc = register_netdev ( netdev ) ) != 0 ) {
@@ -3536,7 +3525,6 @@ static int hermon_register_netdev ( struct hermon *hermon,
  err_register_nvo:
 	unregister_netdev ( netdev );
  err_register_netdev:
- err_query_port:
 	return rc;
 }
 
@@ -3674,6 +3662,10 @@ static int hermon_set_port_type ( struct hermon *hermon,
 	       ( ( ib_supported && eth_supported ) ? " and" : "" ),
 	       ( eth_supported ? " Ethernet" : "" ) );
 
+	/* Record Ethernet MAC address */
+	port->eth_mac.part.h = htons ( MLX_GET ( &query_port, mac_47_32 ) );
+	port->eth_mac.part.l = htonl ( MLX_GET ( &query_port, mac_31_0 ) );
+
 	/* Sense network, if applicable */
 	if ( ib_supported && eth_supported ) {
 
diff --git a/src/drivers/infiniband/hermon.h b/src/drivers/infiniband/hermon.h
index 8ac3562..381e2e4 100644
--- a/src/drivers/infiniband/hermon.h
+++ b/src/drivers/infiniband/hermon.h
@@ -822,6 +822,15 @@ struct hermon_port_type {
 				    struct hermon_port *port );
 };
 
+/** A Hermon port Ethernet MAC address */
+union hermon_port_mac {
+	struct {
+		uint16_t h;
+		uint32_t l;
+	} __attribute__ (( packed )) part;
+	uint8_t raw[ETH_ALEN];
+};
+
 /** A Hermon port */
 struct hermon_port {
 	/** Infiniband device */
@@ -832,6 +841,8 @@ struct hermon_port {
 	struct ib_completion_queue *eth_cq;
 	/** Ethernet queue pair */
 	struct ib_queue_pair *eth_qp;
+	/** Ethernet MAC */
+	union hermon_port_mac eth_mac;
 	/** Port type */
 	struct hermon_port_type *type;
 	/** Non-volatile option storage */