ipxe/src/net/infiniband.c

/*
 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <byteswap.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/list.h>
#include <ipxe/errortab.h>
#include <ipxe/if_arp.h>
#include <ipxe/netdevice.h>
#include <ipxe/iobuf.h>
#include <ipxe/process.h>
#include <ipxe/infiniband.h>
#include <ipxe/ib_mi.h>
#include <ipxe/ib_sma.h>

/** @file
 *
 * Infiniband protocol
 *
 */

/** List of Infiniband devices */
struct list_head ib_devices = LIST_HEAD_INIT ( ib_devices );

/** List of open Infiniband devices, in reverse order of opening */
static struct list_head open_ib_devices = LIST_HEAD_INIT ( open_ib_devices );

/* Disambiguate the various possible EINPROGRESSes */
#define EINPROGRESS_INIT __einfo_error ( EINFO_EINPROGRESS_INIT )
#define EINFO_EINPROGRESS_INIT __einfo_uniqify \
	( EINFO_EINPROGRESS, 0x01, "Initialising" )
#define EINPROGRESS_ARMED __einfo_error ( EINFO_EINPROGRESS_ARMED )
#define EINFO_EINPROGRESS_ARMED __einfo_uniqify \
	( EINFO_EINPROGRESS, 0x02, "Armed" )

/** Human-readable message for the link statuses */
struct errortab infiniband_errors[] __errortab = {
	__einfo_errortab ( EINFO_EINPROGRESS_INIT ),
	__einfo_errortab ( EINFO_EINPROGRESS_ARMED ),
};

/***************************************************************************
 *
 * Completion queues
 *
 ***************************************************************************
 */

/**
 * Create completion queue
 *
 * @v ibdev		Infiniband device
 * @v num_cqes		Number of completion queue entries
 * @v op		Completion queue operations
 * @ret cq		New completion queue
 */
struct ib_completion_queue *
ib_create_cq ( struct ib_device *ibdev, unsigned int num_cqes,
	       struct ib_completion_queue_operations *op ) {
	struct ib_completion_queue *cq;
	int rc;

	DBGC ( ibdev, "IBDEV %p creating completion queue\n", ibdev );

	/* Allocate and initialise data structure */
	cq = zalloc ( sizeof ( *cq ) );
	if ( ! cq )
		goto err_alloc_cq;
	cq->ibdev = ibdev;
	list_add ( &cq->list, &ibdev->cqs );
	cq->num_cqes = num_cqes;
	INIT_LIST_HEAD ( &cq->work_queues );
	cq->op = op;

	/* Perform device-specific initialisation and get CQN */
	if ( ( rc = ibdev->op->create_cq ( ibdev, cq ) ) != 0 ) {
		DBGC ( ibdev, "IBDEV %p could not initialise completion "
		       "queue: %s\n", ibdev, strerror ( rc ) );
		goto err_dev_create_cq;
	}

	DBGC ( ibdev, "IBDEV %p created %d-entry completion queue %p (%p) "
	       "with CQN %#lx\n", ibdev, num_cqes, cq,
	       ib_cq_get_drvdata ( cq ), cq->cqn );
	return cq;

	ibdev->op->destroy_cq ( ibdev, cq );
 err_dev_create_cq:
	list_del ( &cq->list );
	free ( cq );
 err_alloc_cq:
	return NULL;
}

/**
 * Destroy completion queue
 *
 * @v ibdev		Infiniband device
 * @v cq		Completion queue
 */
void ib_destroy_cq ( struct ib_device *ibdev,
		     struct ib_completion_queue *cq ) {
	DBGC ( ibdev, "IBDEV %p destroying completion queue %#lx\n",
	       ibdev, cq->cqn );
	assert ( list_empty ( &cq->work_queues ) );
	ibdev->op->destroy_cq ( ibdev, cq );
	list_del ( &cq->list );
	free ( cq );
}

/**
 * Poll completion queue
 *
 * @v ibdev		Infiniband device
 * @v cq		Completion queue
 */
void ib_poll_cq ( struct ib_device *ibdev,
		  struct ib_completion_queue *cq ) {
	struct ib_work_queue *wq;

	/* Poll completion queue */
	ibdev->op->poll_cq ( ibdev, cq );

	/* Refill receive work queues */
	list_for_each_entry ( wq, &cq->work_queues, list ) {
		if ( ! wq->is_send )
			ib_refill_recv ( ibdev, wq->qp );
	}
}

/***************************************************************************
 *
 * Work queues
 *
 ***************************************************************************
 */

/**
 * Create queue pair
 *
 * @v ibdev		Infiniband device
 * @v type		Queue pair type
 * @v num_send_wqes	Number of send work queue entries
 * @v send_cq		Send completion queue
 * @v num_recv_wqes	Number of receive work queue entries
 * @v recv_cq		Receive completion queue
 * @v op		Queue pair operations
 * @ret qp		Queue pair
 *
 * The queue pair will be left in the INIT state; you must call
 * ib_modify_qp() before it is ready to use for sending and receiving.
 */
struct ib_queue_pair * ib_create_qp ( struct ib_device *ibdev,
				      enum ib_queue_pair_type type,
				      unsigned int num_send_wqes,
				      struct ib_completion_queue *send_cq,
				      unsigned int num_recv_wqes,
				      struct ib_completion_queue *recv_cq,
				      struct ib_queue_pair_operations *op ) {
	struct ib_queue_pair *qp;
	size_t total_size;
	int rc;

	DBGC ( ibdev, "IBDEV %p creating queue pair\n", ibdev );

	/* Allocate and initialise data structure */
	total_size = ( sizeof ( *qp ) +
		       ( num_send_wqes * sizeof ( qp->send.iobufs[0] ) ) +
		       ( num_recv_wqes * sizeof ( qp->recv.iobufs[0] ) ) );
	qp = zalloc ( total_size );
	if ( ! qp )
		goto err_alloc_qp;
	qp->ibdev = ibdev;
	list_add ( &qp->list, &ibdev->qps );
	qp->type = type;
	qp->send.qp = qp;
	qp->send.is_send = 1;
	qp->send.cq = send_cq;
	list_add ( &qp->send.list, &send_cq->work_queues );
	qp->send.psn = ( random() & 0xffffffUL );
	qp->send.num_wqes = num_send_wqes;
	qp->send.iobufs = ( ( ( void * ) qp ) + sizeof ( *qp ) );
	qp->recv.qp = qp;
	qp->recv.cq = recv_cq;
	list_add ( &qp->recv.list, &recv_cq->work_queues );
	qp->recv.psn = ( random() & 0xffffffUL );
	qp->recv.num_wqes = num_recv_wqes;
	qp->recv.iobufs = ( ( ( void * ) qp ) + sizeof ( *qp ) +
			    ( num_send_wqes * sizeof ( qp->send.iobufs[0] ) ));
	INIT_LIST_HEAD ( &qp->mgids );
	qp->op = op;

	/* Perform device-specific initialisation and get QPN */
	if ( ( rc = ibdev->op->create_qp ( ibdev, qp ) ) != 0 ) {
		DBGC ( ibdev, "IBDEV %p could not initialise queue pair: "
		       "%s\n", ibdev, strerror ( rc ) );
		goto err_dev_create_qp;
	}
	DBGC ( ibdev, "IBDEV %p created queue pair %p (%p) with QPN %#lx\n",
	       ibdev, qp, ib_qp_get_drvdata ( qp ), qp->qpn );
	DBGC ( ibdev, "IBDEV %p QPN %#lx has %d send entries at [%p,%p)\n",
	       ibdev, qp->qpn, num_send_wqes, qp->send.iobufs,
	       qp->recv.iobufs );
	DBGC ( ibdev, "IBDEV %p QPN %#lx has %d receive entries at [%p,%p)\n",
	       ibdev, qp->qpn, num_recv_wqes, qp->recv.iobufs,
	       ( ( ( void * ) qp ) + total_size ) );

	/* Calculate externally-visible QPN */
	switch ( type ) {
	case IB_QPT_SMI:
		qp->ext_qpn = IB_QPN_SMI;
		break;
	case IB_QPT_GSI:
		qp->ext_qpn = IB_QPN_GSI;
		break;
	default:
		qp->ext_qpn = qp->qpn;
		break;
	}
	if ( qp->ext_qpn != qp->qpn ) {
		DBGC ( ibdev, "IBDEV %p QPN %#lx has external QPN %#lx\n",
		       ibdev, qp->qpn, qp->ext_qpn );
	}

	return qp;

	ibdev->op->destroy_qp ( ibdev, qp );
 err_dev_create_qp:
	list_del ( &qp->send.list );
	list_del ( &qp->recv.list );
	list_del ( &qp->list );
	free ( qp );
 err_alloc_qp:
	return NULL;
}

/**
 * Modify queue pair
 *
 * @v ibdev		Infiniband device
 * @v qp		Queue pair
 * @ret rc		Return status code
 */
int ib_modify_qp ( struct ib_device *ibdev, struct ib_queue_pair *qp ) {
	int rc;

	DBGC ( ibdev, "IBDEV %p modifying QPN %#lx\n", ibdev, qp->qpn );

	if ( ( rc = ibdev->op->modify_qp ( ibdev, qp ) ) != 0 ) {
		DBGC ( ibdev, "IBDEV %p could not modify QPN %#lx: %s\n",
		       ibdev, qp->qpn, strerror ( rc ) );
		return rc;
	}

	return 0;
}

/**
 * Destroy queue pair
 *
 * @v ibdev		Infiniband device
 * @v qp		Queue pair
 */
void ib_destroy_qp ( struct ib_device *ibdev, struct ib_queue_pair *qp ) {
	struct io_buffer *iobuf;
	unsigned int i;

	DBGC ( ibdev, "IBDEV %p destroying QPN %#lx\n",
	       ibdev, qp->qpn );

	assert ( list_empty ( &qp->mgids ) );

	/* Perform device-specific destruction */
	ibdev->op->destroy_qp ( ibdev, qp );

	/* Complete any remaining I/O buffers with errors */
	for ( i = 0 ; i < qp->send.num_wqes ; i++ ) {
		if ( ( iobuf = qp->send.iobufs[i] ) != NULL )
			ib_complete_send ( ibdev, qp, iobuf, -ECANCELED );
	}
	for ( i = 0 ; i < qp->recv.num_wqes ; i++ ) {
		if ( ( iobuf = qp->recv.iobufs[i] ) != NULL ) {
			ib_complete_recv ( ibdev, qp, NULL, NULL, iobuf,
					   -ECANCELED );
		}
	}

	/* Remove work queues from completion queue */
	list_del ( &qp->send.list );
	list_del ( &qp->recv.list );

	/* Free QP */
	list_del ( &qp->list );
	free ( qp );
}

/**
 * Find queue pair by QPN
 *
 * @v ibdev		Infiniband device
 * @v qpn		Queue pair number
 * @ret qp		Queue pair, or NULL
 */
struct ib_queue_pair * ib_find_qp_qpn ( struct ib_device *ibdev,
					unsigned long qpn ) {
	struct ib_queue_pair *qp;

	list_for_each_entry ( qp, &ibdev->qps, list ) {
		if ( ( qpn == qp->qpn ) || ( qpn == qp->ext_qpn ) )
			return qp;
	}
	return NULL;
}

/**
 * Find queue pair by multicast GID
 *
 * @v ibdev		Infiniband device
 * @v gid		Multicast GID
 * @ret qp		Queue pair, or NULL
 */
struct ib_queue_pair * ib_find_qp_mgid ( struct ib_device *ibdev,
					 union ib_gid *gid ) {
	struct ib_queue_pair *qp;
	struct ib_multicast_gid *mgid;

	list_for_each_entry ( qp, &ibdev->qps, list ) {
		list_for_each_entry ( mgid, &qp->mgids, list ) {
			if ( memcmp ( &mgid->gid, gid,
				      sizeof ( mgid->gid ) ) == 0 ) {
				return qp;
			}
		}
	}
	return NULL;
}

/**
 * Find work queue belonging to completion queue
 *
 * @v cq		Completion queue
 * @v qpn		Queue pair number
 * @v is_send		Find send work queue (rather than receive)
 * @ret wq		Work queue, or NULL if not found
 */
struct ib_work_queue * ib_find_wq ( struct ib_completion_queue *cq,
				    unsigned long qpn, int is_send ) {
	struct ib_work_queue *wq;

	list_for_each_entry ( wq, &cq->work_queues, list ) {
		if ( ( wq->qp->qpn == qpn ) && ( wq->is_send == is_send ) )
			return wq;
	}
	return NULL;
}

/**
 * Post send work queue entry
 *
 * @v ibdev		Infiniband device
 * @v qp		Queue pair
 * @v dest		Destination address vector
 * @v iobuf		I/O buffer
 * @ret rc		Return status code
 */
int ib_post_send ( struct ib_device *ibdev, struct ib_queue_pair *qp,
		   struct ib_address_vector *dest,
		   struct io_buffer *iobuf ) {
	struct ib_address_vector dest_copy;
	int rc;

	/* Check queue fill level */
	if ( qp->send.fill >= qp->send.num_wqes ) {
		DBGC ( ibdev, "IBDEV %p QPN %#lx send queue full\n",
		       ibdev, qp->qpn );
		return -ENOBUFS;
	}

	/* Use default address vector if none specified */
	if ( ! dest )
		dest = &qp->av;

	/* Make modifiable copy of address vector */
	memcpy ( &dest_copy, dest, sizeof ( dest_copy ) );
	dest = &dest_copy;

	/* Fill in optional parameters in address vector */
	if ( ! dest->qkey )
		dest->qkey = qp->qkey;
	if ( ! dest->rate )
		dest->rate = IB_RATE_2_5;

	/* Post to hardware */
	if ( ( rc = ibdev->op->post_send ( ibdev, qp, dest, iobuf ) ) != 0 ) {
		DBGC ( ibdev, "IBDEV %p QPN %#lx could not post send WQE: "
		       "%s\n", ibdev, qp->qpn, strerror ( rc ) );
		return rc;
	}

	qp->send.fill++;
	return 0;
}

/**
 * Post receive work queue entry
 *
 * @v ibdev		Infiniband device
 * @v qp		Queue pair
 * @v iobuf		I/O buffer
 * @ret rc		Return status code
 */
int ib_post_recv ( struct ib_device *ibdev, struct ib_queue_pair *qp,
		   struct io_buffer *iobuf ) {
	int rc;

	/* Check packet length */
	if ( iob_tailroom ( iobuf ) < IB_MAX_PAYLOAD_SIZE ) {
		DBGC ( ibdev, "IBDEV %p QPN %#lx wrong RX buffer size (%zd)\n",
		       ibdev, qp->qpn, iob_tailroom ( iobuf ) );
		return -EINVAL;
	}

	/* Check queue fill level */
	if ( qp->recv.fill >= qp->recv.num_wqes ) {
		DBGC ( ibdev, "IBDEV %p QPN %#lx receive queue full\n",
		       ibdev, qp->qpn );
		return -ENOBUFS;
	}

	/* Post to hardware */
	if ( ( rc = ibdev->op->post_recv ( ibdev, qp, iobuf ) ) != 0 ) {
		DBGC ( ibdev, "IBDEV %p QPN %#lx could not post receive WQE: "
		       "%s\n", ibdev, qp->qpn, strerror ( rc ) );
		return rc;
	}

	qp->recv.fill++;
	return 0;
}

/**
 * Complete send work queue entry
 *
 * @v ibdev		Infiniband device
 * @v qp		Queue pair
 * @v iobuf		I/O buffer
 * @v rc		Completion status code
 */
void ib_complete_send ( struct ib_device *ibdev, struct ib_queue_pair *qp,
			struct io_buffer *iobuf, int rc ) {

	if ( qp->send.cq->op->complete_send ) {
		qp->send.cq->op->complete_send ( ibdev, qp, iobuf, rc );
	} else {
		free_iob ( iobuf );
	}
	qp->send.fill--;
}

/**
 * Complete receive work queue entry
 *
 * @v ibdev		Infiniband device
 * @v qp		Queue pair
 * @v dest		Destination address vector, or NULL
 * @v source		Source address vector, or NULL
 * @v iobuf		I/O buffer
 * @v rc		Completion status code
 */
void ib_complete_recv ( struct ib_device *ibdev, struct ib_queue_pair *qp,
			struct ib_address_vector *dest,
			struct ib_address_vector *source,
			struct io_buffer *iobuf, int rc ) {

	if ( qp->recv.cq->op->complete_recv ) {
		qp->recv.cq->op->complete_recv ( ibdev, qp, dest, source,
						 iobuf, rc );
	} else {
		free_iob ( iobuf );
	}
	qp->recv.fill--;
}

/**
 * Refill receive work queue
 *
 * @v ibdev		Infiniband device
 * @v qp		Queue pair
 */
void ib_refill_recv ( struct ib_device *ibdev, struct ib_queue_pair *qp ) {
	struct io_buffer *iobuf;
	int rc;

	/* Keep filling while unfilled entries remain */
	while ( qp->recv.fill < qp->recv.num_wqes ) {

		/* Allocate I/O buffer */
		iobuf = qp->op->alloc_iob ( IB_MAX_PAYLOAD_SIZE );
		if ( ! iobuf ) {
			/* Non-fatal; we will refill on next attempt */
			return;
		}

		/* Post I/O buffer */
		if ( ( rc = ib_post_recv ( ibdev, qp, iobuf ) ) != 0 ) {
			DBGC ( ibdev, "IBDEV %p could not refill: %s\n",
			       ibdev, strerror ( rc ) );
			free_iob ( iobuf );
			/* Give up */
			return;
		}
	}
}

/***************************************************************************
 *
 * Link control
 *
 ***************************************************************************
 */

/**
 * Get link state
 *
 * @v ibdev		Infiniband device
 * @ret rc		Link status code
 */
int ib_link_rc ( struct ib_device *ibdev ) {
	switch ( ibdev->port_state ) {
	case IB_PORT_STATE_DOWN:	return -ENOTCONN;
	case IB_PORT_STATE_INIT:	return -EINPROGRESS_INIT;
	case IB_PORT_STATE_ARMED:	return -EINPROGRESS_ARMED;
	case IB_PORT_STATE_ACTIVE:	return 0;
	default:			return -EINVAL;
	}
}

/**
 * Textual representation of Infiniband link state
 *
 * @v ibdev		Infiniband device
 * @ret link_text	Link state text
 */
static const char * ib_link_state_text ( struct ib_device *ibdev ) {
	switch ( ibdev->port_state ) {
	case IB_PORT_STATE_DOWN:	return "DOWN";
	case IB_PORT_STATE_INIT:	return "INIT";
	case IB_PORT_STATE_ARMED:	return "ARMED";
	case IB_PORT_STATE_ACTIVE:	return "ACTIVE";
	default:			return "UNKNOWN";
	}
}

/**
 * Notify drivers of Infiniband device or link state change
 *
 * @v ibdev		Infiniband device
 */
static void ib_notify ( struct ib_device *ibdev ) {
	struct ib_driver *driver;

	for_each_table_entry ( driver, IB_DRIVERS )
		driver->notify ( ibdev );
}

/**
 * Notify of Infiniband link state change
 *
 * @v ibdev		Infiniband device
 */
void ib_link_state_changed ( struct ib_device *ibdev ) {

	DBGC ( ibdev, "IBDEV %p link state is %s\n",
	       ibdev, ib_link_state_text ( ibdev ) );

	/* Notify drivers of link state change */
	ib_notify ( ibdev );
}

/**
 * Open port
 *
 * @v ibdev		Infiniband device
 * @ret rc		Return status code
 */
int ib_open ( struct ib_device *ibdev ) {
	int rc;

	/* Increment device open request counter */
	if ( ibdev->open_count++ > 0 ) {
		/* Device was already open; do nothing */
		return 0;
	}

	/* Open device */
	if ( ( rc = ibdev->op->open ( ibdev ) ) != 0 ) {
		DBGC ( ibdev, "IBDEV %p could not open: %s\n",
		       ibdev, strerror ( rc ) );
		goto err_open;
	}

	/* Create subnet management interface */
	ibdev->smi = ib_create_mi ( ibdev, IB_QPT_SMI );
	if ( ! ibdev->smi ) {
		DBGC ( ibdev, "IBDEV %p could not create SMI\n", ibdev );
		rc = -ENOMEM;
		goto err_create_smi;
	}

	/* Create subnet management agent */
	if ( ( rc = ib_create_sma ( ibdev, ibdev->smi ) ) != 0 ) {
		DBGC ( ibdev, "IBDEV %p could not create SMA: %s\n",
		       ibdev, strerror ( rc ) );
		goto err_create_sma;
	}

	/* Create general services interface */
	ibdev->gsi = ib_create_mi ( ibdev, IB_QPT_GSI );
	if ( ! ibdev->gsi ) {
		DBGC ( ibdev, "IBDEV %p could not create GSI\n", ibdev );
		rc = -ENOMEM;
		goto err_create_gsi;
	}

	/* Add to head of open devices list */
	list_add ( &ibdev->open_list, &open_ib_devices );

	/* Notify drivers of device state change */
	ib_notify ( ibdev );

	assert ( ibdev->open_count == 1 );
	return 0;

	ib_destroy_mi ( ibdev, ibdev->gsi );
 err_create_gsi:
	ib_destroy_sma ( ibdev, ibdev->smi );
 err_create_sma:
	ib_destroy_mi ( ibdev, ibdev->smi );
 err_create_smi:
	ibdev->op->close ( ibdev );
 err_open:
	assert ( ibdev->open_count == 1 );
	ibdev->open_count = 0;
	return rc;
}

/**
 * Close port
 *
 * @v ibdev		Infiniband device
 */
void ib_close ( struct ib_device *ibdev ) {

	/* Decrement device open request counter */
	ibdev->open_count--;

	/* Close device if this was the last remaining requested opening */
	if ( ibdev->open_count == 0 ) {
		ib_notify ( ibdev );
		list_del ( &ibdev->open_list );
		ib_destroy_mi ( ibdev, ibdev->gsi );
		ib_destroy_sma ( ibdev, ibdev->smi );
		ib_destroy_mi ( ibdev, ibdev->smi );
		ibdev->op->close ( ibdev );
		ibdev->port_state = IB_PORT_STATE_DOWN;
	}
}

/***************************************************************************
 *
 * Multicast
 *
 ***************************************************************************
 */

/**
 * Attach to multicast group
 *
 * @v ibdev		Infiniband device
 * @v qp		Queue pair
 * @v gid		Multicast GID
 * @ret rc		Return status code
 *
 * Note that this function handles only the local device's attachment
 * to the multicast GID; it does not issue the relevant MADs to join
 * the multicast group on the subnet.
 */
int ib_mcast_attach ( struct ib_device *ibdev, struct ib_queue_pair *qp,
		      union ib_gid *gid ) {
	struct ib_multicast_gid *mgid;
	int rc;

	/* Add to software multicast GID list */
	mgid = zalloc ( sizeof ( *mgid ) );
	if ( ! mgid ) {
		rc = -ENOMEM;
		goto err_alloc_mgid;
	}
	memcpy ( &mgid->gid, gid, sizeof ( mgid->gid ) );
	list_add ( &mgid->list, &qp->mgids );

	/* Add to hardware multicast GID list */
	if ( ( rc = ibdev->op->mcast_attach ( ibdev, qp, gid ) ) != 0 )
		goto err_dev_mcast_attach;

	return 0;

 err_dev_mcast_attach:
	list_del ( &mgid->list );
	free ( mgid );
 err_alloc_mgid:
	return rc;
}

/**
 * Detach from multicast group
 *
 * @v ibdev		Infiniband device
 * @v qp		Queue pair
 * @v gid		Multicast GID
 */
void ib_mcast_detach ( struct ib_device *ibdev, struct ib_queue_pair *qp,
		       union ib_gid *gid ) {
	struct ib_multicast_gid *mgid;

	/* Remove from hardware multicast GID list */
	ibdev->op->mcast_detach ( ibdev, qp, gid );

	/* Remove from software multicast GID list */
	list_for_each_entry ( mgid, &qp->mgids, list ) {
		if ( memcmp ( &mgid->gid, gid, sizeof ( mgid->gid ) ) == 0 ) {
			list_del ( &mgid->list );
			free ( mgid );
			break;
		}
	}
}

/***************************************************************************
 *
 * Miscellaneous
 *
 ***************************************************************************
 */

/**
 * Count Infiniband HCA ports
 *
 * @v ibdev		Infiniband device
 * @ret num_ports	Number of ports
 */
int ib_count_ports ( struct ib_device *ibdev ) {
	struct ib_device *tmp;
	int num_ports = 0;

	/* Search for IB devices with the same physical device to
	 * identify port count.
	 */
	for_each_ibdev ( tmp ) {
		if ( tmp->dev == ibdev->dev )
			num_ports++;
	}
	return num_ports;
}

/**
 * Set port information
 *
 * @v ibdev		Infiniband device
 * @v mad		Set port information MAD
 */
int ib_set_port_info ( struct ib_device *ibdev, union ib_mad *mad ) {
	int rc;

	/* Adapters with embedded SMAs do not need to support this method */
	if ( ! ibdev->op->set_port_info ) {
		DBGC ( ibdev, "IBDEV %p does not support setting port "
		       "information\n", ibdev );
		return -ENOTSUP;
	}

	if ( ( rc = ibdev->op->set_port_info ( ibdev, mad ) ) != 0 ) {
		DBGC ( ibdev, "IBDEV %p could not set port information: %s\n",
		       ibdev, strerror ( rc ) );
		return rc;
	}

	return 0;
};

/**
 * Set partition key table
 *
 * @v ibdev		Infiniband device
 * @v mad		Set partition key table MAD
 */
int ib_set_pkey_table ( struct ib_device *ibdev, union ib_mad *mad ) {
	int rc;

	/* Adapters with embedded SMAs do not need to support this method */
	if ( ! ibdev->op->set_pkey_table ) {
		DBGC ( ibdev, "IBDEV %p does not support setting partition "
		       "key table\n", ibdev );
		return -ENOTSUP;
	}

	if ( ( rc = ibdev->op->set_pkey_table ( ibdev, mad ) ) != 0 ) {
		DBGC ( ibdev, "IBDEV %p could not set partition key table: "
		       "%s\n", ibdev, strerror ( rc ) );
		return rc;
	}

	return 0;
};

/***************************************************************************
 *
 * Event queues
 *
 ***************************************************************************
 */

/**
 * Poll event queue
 *
 * @v ibdev		Infiniband device
 */
void ib_poll_eq ( struct ib_device *ibdev ) {
	struct ib_completion_queue *cq;

	/* Poll device's event queue */
	ibdev->op->poll_eq ( ibdev );

	/* Poll all completion queues */
	list_for_each_entry ( cq, &ibdev->cqs, list )
		ib_poll_cq ( ibdev, cq );
}

/**
 * Single-step the Infiniband event queue
 *
 * @v process		Infiniband event queue process
 */
static void ib_step ( struct process *process __unused ) {
	struct ib_device *ibdev;

	list_for_each_entry ( ibdev, &open_ib_devices, open_list )
		ib_poll_eq ( ibdev );
}

/** Infiniband event queue process */
PERMANENT_PROCESS ( ib_process, ib_step );

/***************************************************************************
 *
 * Infiniband device creation/destruction
 *
 ***************************************************************************
 */

/**
 * Allocate Infiniband device
 *
 * @v priv_size		Size of driver private data area
 * @ret ibdev		Infiniband device, or NULL
 */
struct ib_device * alloc_ibdev ( size_t priv_size ) {
	struct ib_device *ibdev;
	void *drv_priv;
	size_t total_len;

	total_len = ( sizeof ( *ibdev ) + priv_size );
	ibdev = zalloc ( total_len );
	if ( ibdev ) {
		drv_priv = ( ( ( void * ) ibdev ) + sizeof ( *ibdev ) );
		ib_set_drvdata ( ibdev, drv_priv );
		INIT_LIST_HEAD ( &ibdev->list );
		INIT_LIST_HEAD ( &ibdev->open_list );
		INIT_LIST_HEAD ( &ibdev->cqs );
		INIT_LIST_HEAD ( &ibdev->qps );
		ibdev->port_state = IB_PORT_STATE_DOWN;
		ibdev->lid = IB_LID_NONE;
		ibdev->pkey = IB_PKEY_DEFAULT;
	}
	return ibdev;
}

/**
 * Register Infiniband device
 *
 * @v ibdev		Infiniband device
 * @ret rc		Return status code
 */
int register_ibdev ( struct ib_device *ibdev ) {
	struct ib_driver *driver;
	int rc;

	/* Add to device list */
	ibdev_get ( ibdev );
	list_add_tail ( &ibdev->list, &ib_devices );
	DBGC ( ibdev, "IBDEV %p registered (phys %s)\n", ibdev,
	       ibdev->dev->name );

	/* Probe device */
	for_each_table_entry ( driver, IB_DRIVERS ) {
		if ( ( rc = driver->probe ( ibdev ) ) != 0 ) {
			DBGC ( ibdev, "IBDEV %p could not add %s device: %s\n",
			       ibdev, driver->name, strerror ( rc ) );
			goto err_probe;
		}
	}

	return 0;

 err_probe:
	for_each_table_entry_continue_reverse ( driver, IB_DRIVERS )
		driver->remove ( ibdev );
	list_del ( &ibdev->list );
	ibdev_put ( ibdev );
	return rc;
}

/**
 * Unregister Infiniband device
 *
 * @v ibdev		Infiniband device
 */
void unregister_ibdev ( struct ib_device *ibdev ) {
	struct ib_driver *driver;

	/* Remove device */
	for_each_table_entry_reverse ( driver, IB_DRIVERS )
		driver->remove ( ibdev );

	/* Remove from device list */
	list_del ( &ibdev->list );
	ibdev_put ( ibdev );
	DBGC ( ibdev, "IBDEV %p unregistered\n", ibdev );
}

/**
 * Find Infiniband device by GID
 *
 * @v gid		GID
 * @ret ibdev		Infiniband device, or NULL
 */
struct ib_device * find_ibdev ( union ib_gid *gid ) {
	struct ib_device *ibdev;

	for_each_ibdev ( ibdev ) {
		if ( memcmp ( gid, &ibdev->gid, sizeof ( *gid ) ) == 0 )
			return ibdev;
	}
	return NULL;
}

/**
 * Get most recently opened Infiniband device
 *
 * @ret ibdev		Most recently opened Infiniband device, or NULL
 */
struct ib_device * last_opened_ibdev ( void ) {
	struct ib_device *ibdev;

	ibdev = list_first_entry ( &open_ib_devices, struct ib_device,
				   open_list );
	if ( ! ibdev )
		return NULL;

	assert ( ibdev->open_count != 0 );
	return ibdev;
}

/* Drag in IPoIB */
REQUIRE_OBJECT ( ipoib );