mlx4: Paravirtualize Node Guids for slaves

This is necessary in order to support > 1 VF/PF in a VM for software
that uses the node guid as a discriminator, such as librdmacm.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c
index 78fdbd6..90774b7 100644
--- a/drivers/net/ethernet/mellanox/mlx4/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c
@@ -696,6 +696,7 @@
 	struct ib_smp *outsmp = outbox->buf;
 	__be16 *outtab = (__be16 *)(outsmp->data);
 	__be32 slave_cap_mask;
+	__be64 slave_node_guid;
 	port = vhcr->in_modifier;
 
 	if (smp->base_version == 1 &&
@@ -755,6 +756,16 @@
 				}
 				return err;
 			}
+			if (smp->attr_id == IB_SMP_ATTR_NODE_INFO) {
+				err = mlx4_cmd_box(dev, inbox->dma, outbox->dma,
+					     vhcr->in_modifier, vhcr->op_modifier,
+					     vhcr->op, MLX4_CMD_TIME_CLASS_C, MLX4_CMD_NATIVE);
+				if (!err) {
+					slave_node_guid =  mlx4_get_slave_node_guid(dev, slave);
+					memcpy(outsmp->data + 12, &slave_node_guid, 8);
+				}
+				return err;
+			}
 		}
 	}
 	if (slave != mlx4_master_func_num(dev) &&