[dpdk.git] / lib / librte_pmd_mlx4 / mlx4.c

/*-
 *   BSD LICENSE
 *
 *   Copyright 2012-2015 6WIND S.A.
 *   Copyright 2012 Mellanox.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of 6WIND S.A. nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Known limitations:
 * - Multiple RX VLAN filters can be configured, but only the first one
 *   works properly.
 * - RSS hash key and options cannot be modified.
 * - Hardware counters aren't implemented.
 */

/* System headers. */
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <limits.h>
#include <assert.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <dirent.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <linux/if.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>

/* DPDK headers don't like -pedantic. */
#ifdef PEDANTIC
#pragma GCC diagnostic ignored "-pedantic"
#endif
#include <rte_config.h>
#include <rte_ether.h>
#include <rte_ethdev.h>
#include <rte_dev.h>
#include <rte_mbuf.h>
#include <rte_errno.h>
#include <rte_mempool.h>
#include <rte_prefetch.h>
#include <rte_malloc.h>
#include <rte_spinlock.h>
#include <rte_atomic.h>
#include <rte_version.h>
#include <rte_log.h>
#ifdef PEDANTIC
#pragma GCC diagnostic error "-pedantic"
#endif

/* Verbs header. */
/* ISO C doesn't support unnamed structs/unions, disabling -pedantic. */
#ifdef PEDANTIC
#pragma GCC diagnostic ignored "-pedantic"
#endif

#include <infiniband/verbs.h>

#ifdef PEDANTIC
#pragma GCC diagnostic error "-pedantic"
#endif

/* Generated configuration header. */
#include "mlx4_autoconf.h"

/* PMD header. */
#include "mlx4.h"

/* Runtime logging through RTE_LOG() is enabled when not in debugging mode.
 * Intermediate LOG_*() macros add the required end-of-line characters. */
#ifndef NDEBUG
#define INFO(...) DEBUG(__VA_ARGS__)
#define WARN(...) DEBUG(__VA_ARGS__)
#define ERROR(...) DEBUG(__VA_ARGS__)
#else
#define LOG__(level, m, ...) \
        RTE_LOG(level, PMD, MLX4_DRIVER_NAME ": " m "%c", __VA_ARGS__)
#define LOG_(level, ...) LOG__(level, __VA_ARGS__, '\n')
#define INFO(...) LOG_(INFO, __VA_ARGS__)
#define WARN(...) LOG_(WARNING, __VA_ARGS__)
#define ERROR(...) LOG_(ERR, __VA_ARGS__)
#endif

/* Convenience macros for accessing mbuf fields. */
#define NEXT(m) ((m)->next)
#define DATA_LEN(m) ((m)->data_len)
#define PKT_LEN(m) ((m)->pkt_len)
#define DATA_OFF(m) ((m)->data_off)
#define SET_DATA_OFF(m, o) ((m)->data_off = (o))
#define NB_SEGS(m) ((m)->nb_segs)
#define PORT(m) ((m)->port)

/* Work Request ID data type (64 bit). */
typedef union {
        struct {
                uint32_t id;
                uint16_t offset;
        } data;
        uint64_t raw;
} wr_id_t;

#define WR_ID(o) (((wr_id_t *)&(o))->data)

/* Compile-time check. */
static inline void wr_id_t_check(void)
{
        wr_id_t check[1 + (2 * -!(sizeof(wr_id_t) == sizeof(uint64_t)))];

        (void)check;
        (void)wr_id_t_check;
}

/* If raw send operations are available, use them since they are faster. */
#ifdef SEND_RAW_WR_SUPPORT
typedef struct ibv_send_wr_raw mlx4_send_wr_t;
#define mlx4_post_send ibv_post_send_raw
#else
typedef struct ibv_send_wr mlx4_send_wr_t;
#define mlx4_post_send ibv_post_send
#endif

struct mlx4_rxq_stats {
        unsigned int idx; /**< Mapping index. */
#ifdef MLX4_PMD_SOFT_COUNTERS
        uint64_t ipackets;  /**< Total of successfully received packets. */
        uint64_t ibytes;    /**< Total of successfully received bytes. */
#endif
        uint64_t idropped;  /**< Total of packets dropped when RX ring full. */
        uint64_t rx_nombuf; /**< Total of RX mbuf allocation failures. */
};

struct mlx4_txq_stats {
        unsigned int idx; /**< Mapping index. */
#ifdef MLX4_PMD_SOFT_COUNTERS
        uint64_t opackets; /**< Total of successfully sent packets. */
        uint64_t obytes;   /**< Total of successfully sent bytes. */
#endif
        uint64_t odropped; /**< Total of packets not sent when TX ring full. */
};

/* RX element (scattered packets). */
struct rxq_elt_sp {
        struct ibv_recv_wr wr; /* Work Request. */
        struct ibv_sge sges[MLX4_PMD_SGE_WR_N]; /* Scatter/Gather Elements. */
        struct rte_mbuf *bufs[MLX4_PMD_SGE_WR_N]; /* SGEs buffers. */
};

/* RX element. */
struct rxq_elt {
        struct ibv_recv_wr wr; /* Work Request. */
        struct ibv_sge sge; /* Scatter/Gather Element. */
        /* mbuf pointer is derived from WR_ID(wr.wr_id).offset. */
};

/* RX queue descriptor. */
struct rxq {
        struct priv *priv; /* Back pointer to private data. */
        struct rte_mempool *mp; /* Memory Pool for allocations. */
        struct ibv_mr *mr; /* Memory Region (for mp). */
        struct ibv_cq *cq; /* Completion Queue. */
        struct ibv_qp *qp; /* Queue Pair. */
        /*
         * There is exactly one flow configured per MAC address. Each flow
         * may contain several specifications, one per configured VLAN ID.
         */
        BITFIELD_DECLARE(mac_configured, uint32_t, MLX4_MAX_MAC_ADDRESSES);
        struct ibv_exp_flow *mac_flow[MLX4_MAX_MAC_ADDRESSES];
        struct ibv_exp_flow *promisc_flow; /* Promiscuous flow. */
        struct ibv_exp_flow *allmulti_flow; /* Multicast flow. */
        unsigned int port_id; /* Port ID for incoming packets. */
        unsigned int elts_n; /* (*elts)[] length. */
        union {
                struct rxq_elt_sp (*sp)[]; /* Scattered RX elements. */
                struct rxq_elt (*no_sp)[]; /* RX elements. */
        } elts;
        unsigned int sp:1; /* Use scattered RX elements. */
        uint32_t mb_len; /* Length of a mp-issued mbuf. */
        struct mlx4_rxq_stats stats; /* RX queue counters. */
        unsigned int socket; /* CPU socket ID for allocations. */
};

/* TX element. */
struct txq_elt {
        mlx4_send_wr_t wr; /* Work Request. */
        struct ibv_sge sges[MLX4_PMD_SGE_WR_N]; /* Scatter/Gather Elements. */
        /* mbuf pointer is derived from WR_ID(wr.wr_id).offset. */
};

/* Linear buffer type. It is used when transmitting buffers with too many
 * segments that do not fit the hardware queue (see max_send_sge).
 * Extra segments are copied (linearized) in such buffers, replacing the
 * last SGE during TX.
 * The size is arbitrary but large enough to hold a jumbo frame with
 * 8 segments considering mbuf.buf_len is about 2048 bytes. */
typedef uint8_t linear_t[16384];

/* TX queue descriptor. */
struct txq {
        struct priv *priv; /* Back pointer to private data. */
        struct {
                struct rte_mempool *mp; /* Cached Memory Pool. */
                struct ibv_mr *mr; /* Memory Region (for mp). */
                uint32_t lkey; /* mr->lkey */
        } mp2mr[MLX4_PMD_TX_MP_CACHE]; /* MP to MR translation table. */
        struct ibv_cq *cq; /* Completion Queue. */
        struct ibv_qp *qp; /* Queue Pair. */
#if MLX4_PMD_MAX_INLINE > 0
        uint32_t max_inline; /* Max inline send size <= MLX4_PMD_MAX_INLINE. */
#endif
        unsigned int elts_n; /* (*elts)[] length. */
        struct txq_elt (*elts)[]; /* TX elements. */
        unsigned int elts_head; /* Current index in (*elts)[]. */
        unsigned int elts_tail; /* First element awaiting completion. */
        unsigned int elts_comp; /* Number of completion requests. */
        struct mlx4_txq_stats stats; /* TX queue counters. */
        linear_t (*elts_linear)[]; /* Linearized buffers. */
        struct ibv_mr *mr_linear; /* Memory Region for linearized buffers. */
        unsigned int socket; /* CPU socket ID for allocations. */
};

struct priv {
        struct rte_eth_dev *dev; /* Ethernet device. */
        struct ibv_context *ctx; /* Verbs context. */
        struct ibv_device_attr device_attr; /* Device properties. */
        struct ibv_port_attr port_attr; /* Physical port properties. */
        struct ibv_pd *pd; /* Protection Domain. */
        /*
         * MAC addresses array and configuration bit-field.
         * An extra entry that cannot be modified by the DPDK is reserved
         * for broadcast frames (destination MAC address ff:ff:ff:ff:ff:ff).
         */
        struct ether_addr mac[MLX4_MAX_MAC_ADDRESSES];
        BITFIELD_DECLARE(mac_configured, uint32_t, MLX4_MAX_MAC_ADDRESSES);
        /* VLAN filters. */
        struct {
                unsigned int enabled:1; /* If enabled. */
                unsigned int id:12; /* VLAN ID (0-4095). */
        } vlan_filter[MLX4_MAX_VLAN_IDS]; /* VLAN filters table. */
        /* Device properties. */
        uint16_t mtu; /* Configured MTU. */
        uint8_t port; /* Physical port number. */
        unsigned int started:1; /* Device started, flows enabled. */
        unsigned int promisc:1; /* Device in promiscuous mode. */
        unsigned int promisc_ok:1; /* Promiscuous flow is supported. */
        unsigned int allmulti:1; /* Device receives all multicast packets. */
        unsigned int hw_qpg:1; /* QP groups are supported. */
        unsigned int hw_tss:1; /* TSS is supported. */
        unsigned int hw_rss:1; /* RSS is supported. */
        unsigned int rss:1; /* RSS is enabled. */
#ifdef MLX4_COMPAT_VMWARE
        unsigned int vmware:1; /* Use VMware compatibility. */
#endif
        unsigned int vf:1; /* This is a VF device. */
#ifdef INLINE_RECV
        unsigned int inl_recv_size; /* Inline recv size */
#endif
        unsigned int max_rss_tbl_sz; /* Maximum number of RSS queues. */
        /* RX/TX queues. */
        struct rxq rxq_parent; /* Parent queue when RSS is enabled. */
        unsigned int rxqs_n; /* RX queues array size. */
        unsigned int txqs_n; /* TX queues array size. */
        struct rxq *(*rxqs)[]; /* RX queues. */
        struct txq *(*txqs)[]; /* TX queues. */
        rte_spinlock_t lock; /* Lock for control functions. */
};

/**
 * Lock private structure to protect it from concurrent access in the
 * control path.
 *
 * @param priv
 *   Pointer to private structure.
 */
static void
priv_lock(struct priv *priv)
{
        rte_spinlock_lock(&priv->lock);
}

/**
 * Unlock private structure.
 *
 * @param priv
 *   Pointer to private structure.
 */
static void
priv_unlock(struct priv *priv)
{
        rte_spinlock_unlock(&priv->lock);
}

/* Allocate a buffer on the stack and fill it with a printf format string. */
#define MKSTR(name, ...) \
        char name[snprintf(NULL, 0, __VA_ARGS__) + 1]; \
        \
        snprintf(name, sizeof(name), __VA_ARGS__)

/**
 * Get interface name from private structure.
 *
 * @param[in] priv
 *   Pointer to private structure.
 * @param[out] ifname
 *   Interface name output buffer.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
priv_get_ifname(const struct priv *priv, char (*ifname)[IF_NAMESIZE])
{
        int ret = -1;
        DIR *dir;
        struct dirent *dent;

        {
                MKSTR(path, "%s/device/net", priv->ctx->device->ibdev_path);

                dir = opendir(path);
                if (dir == NULL)
                        return -1;
        }
        while ((dent = readdir(dir)) != NULL) {
                char *name = dent->d_name;
                FILE *file;
                unsigned int dev_id;
                int r;

                if ((name[0] == '.') &&
                    ((name[1] == '\0') ||
                     ((name[1] == '.') && (name[2] == '\0'))))
                        continue;

                MKSTR(path, "%s/device/net/%s/dev_id",
                      priv->ctx->device->ibdev_path, name);

                file = fopen(path, "rb");
                if (file == NULL)
                        continue;
                r = fscanf(file, "%x", &dev_id);
                fclose(file);
                if ((r == 1) && (dev_id == (priv->port - 1u))) {
                        snprintf(*ifname, sizeof(*ifname), "%s", name);
                        ret = 0;
                        break;
                }
        }
        closedir(dir);
        return ret;
}

/**
 * Read from sysfs entry.
 *
 * @param[in] priv
 *   Pointer to private structure.
 * @param[in] entry
 *   Entry name relative to sysfs path.
 * @param[out] buf
 *   Data output buffer.
 * @param size
 *   Buffer size.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
priv_sysfs_read(const struct priv *priv, const char *entry,
                char *buf, size_t size)
{
        char ifname[IF_NAMESIZE];
        FILE *file;
        int ret;
        int err;

        if (priv_get_ifname(priv, &ifname))
                return -1;

        MKSTR(path, "%s/device/net/%s/%s", priv->ctx->device->ibdev_path,
              ifname, entry);

        file = fopen(path, "rb");
        if (file == NULL)
                return -1;
        ret = fread(buf, 1, size, file);
        err = errno;
        if (((size_t)ret < size) && (ferror(file)))
                ret = -1;
        else
                ret = size;
        fclose(file);
        errno = err;
        return ret;
}

/**
 * Write to sysfs entry.
 *
 * @param[in] priv
 *   Pointer to private structure.
 * @param[in] entry
 *   Entry name relative to sysfs path.
 * @param[in] buf
 *   Data buffer.
 * @param size
 *   Buffer size.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
priv_sysfs_write(const struct priv *priv, const char *entry,
                 char *buf, size_t size)
{
        char ifname[IF_NAMESIZE];
        FILE *file;
        int ret;
        int err;

        if (priv_get_ifname(priv, &ifname))
                return -1;

        MKSTR(path, "%s/device/net/%s/%s", priv->ctx->device->ibdev_path,
              ifname, entry);

        file = fopen(path, "wb");
        if (file == NULL)
                return -1;
        ret = fwrite(buf, 1, size, file);
        err = errno;
        if (((size_t)ret < size) || (ferror(file)))
                ret = -1;
        else
                ret = size;
        fclose(file);
        errno = err;
        return ret;
}

/**
 * Get unsigned long sysfs property.
 *
 * @param priv
 *   Pointer to private structure.
 * @param[in] name
 *   Entry name relative to sysfs path.
 * @param[out] value
 *   Value output buffer.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
priv_get_sysfs_ulong(struct priv *priv, const char *name, unsigned long *value)
{
        int ret;
        unsigned long value_ret;
        char value_str[32];

        ret = priv_sysfs_read(priv, name, value_str, (sizeof(value_str) - 1));
        if (ret == -1) {
                DEBUG("cannot read %s value from sysfs: %s",
                      name, strerror(errno));
                return -1;
        }
        value_str[ret] = '\0';
        errno = 0;
        value_ret = strtoul(value_str, NULL, 0);
        if (errno) {
                DEBUG("invalid %s value `%s': %s", name, value_str,
                      strerror(errno));
                return -1;
        }
        *value = value_ret;
        return 0;
}

/**
 * Set unsigned long sysfs property.
 *
 * @param priv
 *   Pointer to private structure.
 * @param[in] name
 *   Entry name relative to sysfs path.
 * @param value
 *   Value to set.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
priv_set_sysfs_ulong(struct priv *priv, const char *name, unsigned long value)
{
        int ret;
        MKSTR(value_str, "%lu", value);

        ret = priv_sysfs_write(priv, name, value_str, (sizeof(value_str) - 1));
        if (ret == -1) {
                DEBUG("cannot write %s `%s' (%lu) to sysfs: %s",
                      name, value_str, value, strerror(errno));
                return -1;
        }
        return 0;
}

/**
 * Perform ifreq ioctl() on associated Ethernet device.
 *
 * @param[in] priv
 *   Pointer to private structure.
 * @param req
 *   Request number to pass to ioctl().
 * @param[out] ifr
 *   Interface request structure output buffer.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
priv_ifreq(const struct priv *priv, int req, struct ifreq *ifr)
{
        int sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
        int ret = -1;

        if (sock == -1)
                return ret;
        if (priv_get_ifname(priv, &ifr->ifr_name) == 0)
                ret = ioctl(sock, req, ifr);
        close(sock);
        return ret;
}

/**
 * Get device MTU.
 *
 * @param priv
 *   Pointer to private structure.
 * @param[out] mtu
 *   MTU value output buffer.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
priv_get_mtu(struct priv *priv, uint16_t *mtu)
{
        unsigned long ulong_mtu;

        if (priv_get_sysfs_ulong(priv, "mtu", &ulong_mtu) == -1)
                return -1;
        *mtu = ulong_mtu;
        return 0;
}

/**
 * Set device MTU.
 *
 * @param priv
 *   Pointer to private structure.
 * @param mtu
 *   MTU value to set.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
priv_set_mtu(struct priv *priv, uint16_t mtu)
{
        return priv_set_sysfs_ulong(priv, "mtu", mtu);
}

/**
 * Set device flags.
 *
 * @param priv
 *   Pointer to private structure.
 * @param keep
 *   Bitmask for flags that must remain untouched.
 * @param flags
 *   Bitmask for flags to modify.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
priv_set_flags(struct priv *priv, unsigned int keep, unsigned int flags)
{
        unsigned long tmp;

        if (priv_get_sysfs_ulong(priv, "flags", &tmp) == -1)
                return -1;
        tmp &= keep;
        tmp |= flags;
        return priv_set_sysfs_ulong(priv, "flags", tmp);
}

/* Device configuration. */

static int
rxq_setup(struct rte_eth_dev *dev, struct rxq *rxq, uint16_t desc,
          unsigned int socket, const struct rte_eth_rxconf *conf,
          struct rte_mempool *mp);

static void
rxq_cleanup(struct rxq *rxq);

/**
 * Ethernet device configuration.
 *
 * Prepare the driver for a given number of TX and RX queues.
 * Allocate parent RSS queue when several RX queues are requested.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
dev_configure(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int rxqs_n = dev->data->nb_rx_queues;
        unsigned int txqs_n = dev->data->nb_tx_queues;
        unsigned int tmp;
        int ret;

        priv->rxqs = (void *)dev->data->rx_queues;
        priv->txqs = (void *)dev->data->tx_queues;
        if (txqs_n != priv->txqs_n) {
                INFO("%p: TX queues number update: %u -> %u",
                     (void *)dev, priv->txqs_n, txqs_n);
                priv->txqs_n = txqs_n;
        }
        if (rxqs_n == priv->rxqs_n)
                return 0;
        INFO("%p: RX queues number update: %u -> %u",
             (void *)dev, priv->rxqs_n, rxqs_n);
        /* If RSS is enabled, disable it first. */
        if (priv->rss) {
                unsigned int i;

                /* Only if there are no remaining child RX queues. */
                for (i = 0; (i != priv->rxqs_n); ++i)
                        if ((*priv->rxqs)[i] != NULL)
                                return EINVAL;
                rxq_cleanup(&priv->rxq_parent);
                priv->rss = 0;
                priv->rxqs_n = 0;
        }
        if (rxqs_n <= 1) {
                /* Nothing else to do. */
                priv->rxqs_n = rxqs_n;
                return 0;
        }
        /* Allocate a new RSS parent queue if supported by hardware. */
        if (!priv->hw_rss) {
                ERROR("%p: only a single RX queue can be configured when"
                      " hardware doesn't support RSS",
                      (void *)dev);
                return EINVAL;
        }
        /* Fail if hardware doesn't support that many RSS queues. */
        if (rxqs_n >= priv->max_rss_tbl_sz) {
                ERROR("%p: only %u RX queues can be configured for RSS",
                      (void *)dev, priv->max_rss_tbl_sz);
                return EINVAL;
        }
        priv->rss = 1;
        tmp = priv->rxqs_n;
        priv->rxqs_n = rxqs_n;
        ret = rxq_setup(dev, &priv->rxq_parent, 0, 0, NULL, NULL);
        if (!ret)
                return 0;
        /* Failure, rollback. */
        priv->rss = 0;
        priv->rxqs_n = tmp;
        assert(ret > 0);
        return ret;
}

/**
 * DPDK callback for Ethernet device configuration.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 *
 * @return
 *   0 on success, negative errno value on failure.
 */
static int
mlx4_dev_configure(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        int ret;

        priv_lock(priv);
        ret = dev_configure(dev);
        assert(ret >= 0);
        priv_unlock(priv);
        return -ret;
}

/* TX queues handling. */

/**
 * Allocate TX queue elements.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param elts_n
 *   Number of elements to allocate.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
txq_alloc_elts(struct txq *txq, unsigned int elts_n)
{
        unsigned int i;
        struct txq_elt (*elts)[elts_n] =
                rte_calloc_socket("TXQ", 1, sizeof(*elts), 0, txq->socket);
        linear_t (*elts_linear)[elts_n] =
                rte_calloc_socket("TXQ", 1, sizeof(*elts_linear), 0,
                                  txq->socket);
        struct ibv_mr *mr_linear = NULL;
        int ret = 0;

        if ((elts == NULL) || (elts_linear == NULL)) {
                ERROR("%p: can't allocate packets array", (void *)txq);
                ret = ENOMEM;
                goto error;
        }
        mr_linear =
                ibv_reg_mr(txq->priv->pd, elts_linear, sizeof(*elts_linear),
                           (IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE));
        if (mr_linear == NULL) {
                ERROR("%p: unable to configure MR, ibv_reg_mr() failed",
                      (void *)txq);
                ret = EINVAL;
                goto error;
        }
        for (i = 0; (i != elts_n); ++i) {
                struct txq_elt *elt = &(*elts)[i];
                mlx4_send_wr_t *wr = &elt->wr;

                /* Configure WR. */
                WR_ID(wr->wr_id).id = i;
                WR_ID(wr->wr_id).offset = 0;
                wr->sg_list = &elt->sges[0];
                wr->opcode = IBV_WR_SEND;
                /* Other fields are updated during TX. */
        }
        DEBUG("%p: allocated and configured %u WRs", (void *)txq, elts_n);
        txq->elts_n = elts_n;
        txq->elts = elts;
        txq->elts_head = 0;
        txq->elts_tail = 0;
        txq->elts_comp = 0;
        txq->elts_linear = elts_linear;
        txq->mr_linear = mr_linear;
        assert(ret == 0);
        return 0;
error:
        if (mr_linear != NULL)
                claim_zero(ibv_dereg_mr(mr_linear));
        if (elts_linear != NULL)
                rte_free(elts_linear);
        if (elts != NULL)
                rte_free(elts);
        DEBUG("%p: failed, freed everything", (void *)txq);
        assert(ret > 0);
        return ret;
}

/**
 * Free TX queue elements.
 *
 * @param txq
 *   Pointer to TX queue structure.
 */
static void
txq_free_elts(struct txq *txq)
{
        unsigned int i;
        unsigned int elts_n = txq->elts_n;
        struct txq_elt (*elts)[elts_n] = txq->elts;
        linear_t (*elts_linear)[elts_n] = txq->elts_linear;
        struct ibv_mr *mr_linear = txq->mr_linear;

        DEBUG("%p: freeing WRs", (void *)txq);
        txq->elts_n = 0;
        txq->elts = NULL;
        txq->elts_linear = NULL;
        txq->mr_linear = NULL;
        if (mr_linear != NULL)
                claim_zero(ibv_dereg_mr(mr_linear));
        if (elts_linear != NULL)
                rte_free(elts_linear);
        if (elts == NULL)
                return;
        for (i = 0; (i != elemof(*elts)); ++i) {
                struct txq_elt *elt = &(*elts)[i];

                if (WR_ID(elt->wr.wr_id).offset == 0)
                        continue;
                rte_pktmbuf_free((void *)(elt->sges[0].addr -
                                          WR_ID(elt->wr.wr_id).offset));
        }
        rte_free(elts);
}


/**
 * Clean up a TX queue.
 *
 * Destroy objects, free allocated memory and reset the structure for reuse.
 *
 * @param txq
 *   Pointer to TX queue structure.
 */
static void
txq_cleanup(struct txq *txq)
{
        size_t i;

        DEBUG("cleaning up %p", (void *)txq);
        txq_free_elts(txq);
        if (txq->qp != NULL)
                claim_zero(ibv_destroy_qp(txq->qp));
        if (txq->cq != NULL)
                claim_zero(ibv_destroy_cq(txq->cq));
        for (i = 0; (i != elemof(txq->mp2mr)); ++i) {
                if (txq->mp2mr[i].mp == NULL)
                        break;
                assert(txq->mp2mr[i].mr != NULL);
                claim_zero(ibv_dereg_mr(txq->mp2mr[i].mr));
        }
        memset(txq, 0, sizeof(*txq));
}

/**
 * Manage TX completions.
 *
 * When sending a burst, mlx4_tx_burst() posts several WRs.
 * To improve performance, a completion event is only required for the last of
 * them. Doing so discards completion information for other WRs, but this
 * information would not be used anyway.
 *
 * @param txq
 *   Pointer to TX queue structure.
 *
 * @return
 *   0 on success, -1 on failure.
 */
static int
txq_complete(struct txq *txq)
{
        unsigned int elts_comp = txq->elts_comp;
        unsigned int elts_tail;
        const unsigned int elts_n = txq->elts_n;
        struct ibv_wc wcs[elts_comp];
        int wcs_n;

        if (unlikely(elts_comp == 0))
                return 0;
#ifdef DEBUG_SEND
        DEBUG("%p: processing %u work requests completions",
              (void *)txq, elts_comp);
#endif
        wcs_n = ibv_poll_cq(txq->cq, elts_comp, wcs);
        if (unlikely(wcs_n == 0))
                return 0;
        if (unlikely(wcs_n < 0)) {
                DEBUG("%p: ibv_poll_cq() failed (wcs_n=%d)",
                      (void *)txq, wcs_n);
                return -1;
        }
        elts_comp -= wcs_n;
        assert(elts_comp <= txq->elts_comp);
        /*
         * Work Completion ID contains the associated element index in
         * (*txq->elts)[]. Since WCs are returned in order, we only need to
         * look at the last WC to clear older Work Requests.
         *
         * Assume WC status is successful as nothing can be done about it
         * anyway.
         */
        elts_tail = WR_ID(wcs[wcs_n - 1].wr_id).id;
        /* Consume the last WC. */
        if (++elts_tail >= elts_n)
                elts_tail = 0;
        txq->elts_tail = elts_tail;
        txq->elts_comp = elts_comp;
        return 0;
}

/**
 * Get Memory Region (MR) <-> Memory Pool (MP) association from txq->mp2mr[].
 * Add MP to txq->mp2mr[] if it's not registered yet. If mp2mr[] is full,
 * remove an entry first.
 *
 * @param txq
 *   Pointer to TX queue structure.
 * @param[in] mp
 *   Memory Pool for which a Memory Region lkey must be returned.
 *
 * @return
 *   mr->lkey on success, (uint32_t)-1 on failure.
 */
static uint32_t
txq_mp2mr(struct txq *txq, struct rte_mempool *mp)
{
        unsigned int i;
        struct ibv_mr *mr;

        for (i = 0; (i != elemof(txq->mp2mr)); ++i) {
                if (unlikely(txq->mp2mr[i].mp == NULL)) {
                        /* Unknown MP, add a new MR for it. */
                        break;
                }
                if (txq->mp2mr[i].mp == mp) {
                        assert(txq->mp2mr[i].lkey != (uint32_t)-1);
                        assert(txq->mp2mr[i].mr->lkey == txq->mp2mr[i].lkey);
                        return txq->mp2mr[i].lkey;
                }
        }
        /* Add a new entry, register MR first. */
        DEBUG("%p: discovered new memory pool %p", (void *)txq, (void *)mp);
        mr = ibv_reg_mr(txq->priv->pd,
                        (void *)mp->elt_va_start,
                        (mp->elt_va_end - mp->elt_va_start),
                        (IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE));
        if (unlikely(mr == NULL)) {
                DEBUG("%p: unable to configure MR, ibv_reg_mr() failed.",
                      (void *)txq);
                return (uint32_t)-1;
        }
        if (unlikely(i == elemof(txq->mp2mr))) {
                /* Table is full, remove oldest entry. */
                DEBUG("%p: MR <-> MP table full, dropping oldest entry.",
                      (void *)txq);
                --i;
                claim_zero(ibv_dereg_mr(txq->mp2mr[i].mr));
                memmove(&txq->mp2mr[0], &txq->mp2mr[1],
                        (sizeof(txq->mp2mr) - sizeof(txq->mp2mr[0])));
        }
        /* Store the new entry. */
        txq->mp2mr[i].mp = mp;
        txq->mp2mr[i].mr = mr;
        txq->mp2mr[i].lkey = mr->lkey;
        DEBUG("%p: new MR lkey for MP %p: 0x%08" PRIu32,
              (void *)txq, (void *)mp, txq->mp2mr[i].lkey);
        return txq->mp2mr[i].lkey;
}

/**
 * Copy scattered mbuf contents to a single linear buffer.
 *
 * @param[out] linear
 *   Linear output buffer.
 * @param[in] buf
 *   Scattered input buffer.
 *
 * @return
 *   Number of bytes copied to the output buffer or 0 if not large enough.
 */
static unsigned int
linearize_mbuf(linear_t *linear, struct rte_mbuf *buf)
{
        unsigned int size = 0;
        unsigned int offset;

        do {
                unsigned int len = DATA_LEN(buf);

                offset = size;
                size += len;
                if (unlikely(size > sizeof(*linear)))
                        return 0;
                memcpy(&(*linear)[offset],
                       rte_pktmbuf_mtod(buf, uint8_t *),
                       len);
                buf = NEXT(buf);
        } while (buf != NULL);
        return size;
}

/**
 * DPDK callback for TX.
 *
 * @param dpdk_txq
 *   Generic pointer to TX queue structure.
 * @param[in] pkts
 *   Packets to transmit.
 * @param pkts_n
 *   Number of packets in array.
 *
 * @return
 *   Number of packets successfully transmitted (<= pkts_n).
 */
static uint16_t
mlx4_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
        struct txq *txq = (struct txq *)dpdk_txq;
        mlx4_send_wr_t head;
        mlx4_send_wr_t **wr_next = &head.next;
        mlx4_send_wr_t *bad_wr;
        unsigned int elts_head = txq->elts_head;
        const unsigned int elts_tail = txq->elts_tail;
        const unsigned int elts_n = txq->elts_n;
        unsigned int i;
        unsigned int max;
        int err;

        txq_complete(txq);
        max = (elts_n - (elts_head - elts_tail));
        if (max > elts_n)
                max -= elts_n;
        assert(max >= 1);
        assert(max <= elts_n);
        /* Always leave one free entry in the ring. */
        --max;
        if (max == 0)
                return 0;
        if (max > pkts_n)
                max = pkts_n;
        for (i = 0; (i != max); ++i) {
                struct rte_mbuf *buf = pkts[i];
                struct txq_elt *elt = &(*txq->elts)[elts_head];
                mlx4_send_wr_t *wr = &elt->wr;
                unsigned int segs = NB_SEGS(buf);
#if (MLX4_PMD_MAX_INLINE > 0) || defined(MLX4_PMD_SOFT_COUNTERS)
                unsigned int sent_size = 0;
#endif
                unsigned int j;
                int linearize = 0;

                /* Clean up old buffer. */
                if (likely(WR_ID(wr->wr_id).offset != 0)) {
                        struct rte_mbuf *tmp = (void *)
                                (elt->sges[0].addr - WR_ID(wr->wr_id).offset);

                        /* Faster than rte_pktmbuf_free(). */
                        do {
                                struct rte_mbuf *next = NEXT(tmp);

                                rte_pktmbuf_free_seg(tmp);
                                tmp = next;
                        } while (tmp != NULL);
                }
#ifndef NDEBUG
                /* For assert(). */
                WR_ID(wr->wr_id).offset = 0;
                for (j = 0; ((int)j < wr->num_sge); ++j) {
                        elt->sges[j].addr = 0;
                        elt->sges[j].length = 0;
                        elt->sges[j].lkey = 0;
                }
                wr->next = NULL;
                wr->num_sge = 0;
#endif
                /* Sanity checks, most of which are only relevant with
                 * debugging enabled. */
                assert(WR_ID(wr->wr_id).id == elts_head);
                assert(WR_ID(wr->wr_id).offset == 0);
                assert(wr->next == NULL);
                assert(wr->sg_list == &elt->sges[0]);
                assert(wr->num_sge == 0);
                assert(wr->opcode == IBV_WR_SEND);
                /* When there are too many segments, extra segments are
                 * linearized in the last SGE. */
                if (unlikely(segs > elemof(elt->sges))) {
                        segs = (elemof(elt->sges) - 1);
                        linearize = 1;
                }
                /* Set WR fields. */
                assert(((uintptr_t)rte_pktmbuf_mtod(buf, char *) -
                        (uintptr_t)buf) <= 0xffff);
                WR_ID(wr->wr_id).offset =
                        ((uintptr_t)rte_pktmbuf_mtod(buf, char *) -
                         (uintptr_t)buf);
                wr->num_sge = segs;
                /* Register segments as SGEs. */
                for (j = 0; (j != segs); ++j) {
                        struct ibv_sge *sge = &elt->sges[j];
                        uint32_t lkey;

                        /* Retrieve Memory Region key for this memory pool. */
                        lkey = txq_mp2mr(txq, buf->pool);
                        if (unlikely(lkey == (uint32_t)-1)) {
                                /* MR does not exist. */
                                DEBUG("%p: unable to get MP <-> MR"
                                      " association", (void *)txq);
                                /* Clean up TX element. */
                                WR_ID(elt->wr.wr_id).offset = 0;
#ifndef NDEBUG
                                /* For assert(). */
                                while (j) {
                                        --j;
                                        --sge;
                                        sge->addr = 0;
                                        sge->length = 0;
                                        sge->lkey = 0;
                                }
                                wr->num_sge = 0;
#endif
                                goto stop;
                        }
                        /* Sanity checks, only relevant with debugging
                         * enabled. */
                        assert(sge->addr == 0);
                        assert(sge->length == 0);
                        assert(sge->lkey == 0);
                        /* Update SGE. */
                        sge->addr = (uintptr_t)rte_pktmbuf_mtod(buf, char *);
                        if (txq->priv->vf)
                                rte_prefetch0((volatile void *)sge->addr);
                        sge->length = DATA_LEN(buf);
                        sge->lkey = lkey;
#if (MLX4_PMD_MAX_INLINE > 0) || defined(MLX4_PMD_SOFT_COUNTERS)
                        sent_size += sge->length;
#endif
                        buf = NEXT(buf);
                }
                /* If buf is not NULL here and is not going to be linearized,
                 * nb_segs is not valid. */
                assert(j == segs);
                assert((buf == NULL) || (linearize));
                /* Linearize extra segments. */
                if (linearize) {
                        struct ibv_sge *sge = &elt->sges[segs];
                        linear_t *linear = &(*txq->elts_linear)[elts_head];
                        unsigned int size = linearize_mbuf(linear, buf);

                        assert(segs == (elemof(elt->sges) - 1));
                        if (size == 0) {
                                /* Invalid packet. */
                                DEBUG("%p: packet too large to be linearized.",
                                      (void *)txq);
                                /* Clean up TX element. */
                                WR_ID(elt->wr.wr_id).offset = 0;
#ifndef NDEBUG
                                /* For assert(). */
                                while (j) {
                                        --j;
                                        --sge;
                                        sge->addr = 0;
                                        sge->length = 0;
                                        sge->lkey = 0;
                                }
                                wr->num_sge = 0;
#endif
                                goto stop;
                        }
                        /* If MLX4_PMD_SGE_WR_N is 1, free mbuf immediately
                         * and clear offset from WR ID. */
                        if (elemof(elt->sges) == 1) {
                                do {
                                        struct rte_mbuf *next = NEXT(buf);

                                        rte_pktmbuf_free_seg(buf);
                                        buf = next;
                                } while (buf != NULL);
                                WR_ID(wr->wr_id).offset = 0;
                        }
                        /* Set WR fields and fill SGE with linear buffer. */
                        ++wr->num_sge;
                        /* Sanity checks, only relevant with debugging
                         * enabled. */
                        assert(sge->addr == 0);
                        assert(sge->length == 0);
                        assert(sge->lkey == 0);
                        /* Update SGE. */
                        sge->addr = (uintptr_t)&(*linear)[0];
                        sge->length = size;
                        sge->lkey = txq->mr_linear->lkey;
#if (MLX4_PMD_MAX_INLINE > 0) || defined(MLX4_PMD_SOFT_COUNTERS)
                        sent_size += size;
#endif
                }
                /* Link WRs together for ibv_post_send(). */
                *wr_next = wr;
                wr_next = &wr->next;
#if MLX4_PMD_MAX_INLINE > 0
                if (sent_size <= txq->max_inline)
                        wr->send_flags = IBV_SEND_INLINE;
                else
#endif
                        wr->send_flags = 0;
                if (++elts_head >= elts_n)
                        elts_head = 0;
#ifdef MLX4_PMD_SOFT_COUNTERS
                /* Increment sent bytes counter. */
                txq->stats.obytes += sent_size;
#endif
        }
stop:
        /* Take a shortcut if nothing must be sent. */
        if (unlikely(i == 0))
                return 0;
#ifdef MLX4_PMD_SOFT_COUNTERS
        /* Increment sent packets counter. */
        txq->stats.opackets += i;
#endif
        *wr_next = NULL;
        /* The last WR is the only one asking for a completion event. */
        containerof(wr_next, mlx4_send_wr_t, next)->
                send_flags |= IBV_SEND_SIGNALED;
        err = mlx4_post_send(txq->qp, head.next, &bad_wr);
        if (unlikely(err)) {
                unsigned int unsent = 0;

                /* An error occurred, completion event is lost. Fix counters. */
                while (bad_wr != NULL) {
                        struct txq_elt *elt =
                                containerof(bad_wr, struct txq_elt, wr);
                        mlx4_send_wr_t *wr = &elt->wr;
                        mlx4_send_wr_t *next = wr->next;
#if defined(MLX4_PMD_SOFT_COUNTERS) || !defined(NDEBUG)
                        unsigned int j;
#endif

                        assert(wr == bad_wr);
                        /* Clean up TX element without freeing it, caller
                         * should take care of this. */
                        WR_ID(elt->wr.wr_id).offset = 0;
#ifdef MLX4_PMD_SOFT_COUNTERS
                        for (j = 0; ((int)j < wr->num_sge); ++j)
                                txq->stats.obytes -= wr->sg_list[j].length;
#endif
                        ++unsent;
#ifndef NDEBUG
                        /* For assert(). */
                        for (j = 0; ((int)j < wr->num_sge); ++j) {
                                elt->sges[j].addr = 0;
                                elt->sges[j].length = 0;
                                elt->sges[j].lkey = 0;
                        }
                        wr->next = NULL;
                        wr->num_sge = 0;
#endif
                        bad_wr = next;
                }
#ifdef MLX4_PMD_SOFT_COUNTERS
                txq->stats.opackets -= unsent;
#endif
                assert(i >= unsent);
                i -= unsent;
                /* "Unsend" remaining packets. */
                elts_head -= unsent;
                if (elts_head >= elts_n)
                        elts_head += elts_n;
                assert(elts_head < elts_n);
                DEBUG("%p: mlx4_post_send() failed, %u unprocessed WRs: %s",
                      (void *)txq, unsent,
                      ((err <= -1) ? "Internal error" : strerror(err)));
        } else
                ++txq->elts_comp;
        txq->elts_head = elts_head;
        return i;
}

/**
 * Configure a TX queue.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param txq
 *   Pointer to TX queue structure.
 * @param desc
 *   Number of descriptors to configure in queue.
 * @param socket
 *   NUMA socket on which memory must be allocated.
 * @param[in] conf
 *   Thresholds parameters.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
txq_setup(struct rte_eth_dev *dev, struct txq *txq, uint16_t desc,
          unsigned int socket, const struct rte_eth_txconf *conf)
{
        struct priv *priv = dev->data->dev_private;
        struct txq tmpl = {
                .priv = priv,
                .socket = socket
        };
        union {
                struct ibv_qp_init_attr init;
                struct ibv_exp_qp_attr mod;
        } attr;
        int ret = 0;

        (void)conf; /* Thresholds configuration (ignored). */
        if ((desc == 0) || (desc % MLX4_PMD_SGE_WR_N)) {
                ERROR("%p: invalid number of TX descriptors (must be a"
                      " multiple of %d)", (void *)dev, desc);
                return EINVAL;
        }
        desc /= MLX4_PMD_SGE_WR_N;
        /* MRs will be registered in mp2mr[] later. */
        tmpl.cq = ibv_create_cq(priv->ctx, desc, NULL, NULL, 0);
        if (tmpl.cq == NULL) {
                ret = ENOMEM;
                ERROR("%p: CQ creation failure: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        DEBUG("priv->device_attr.max_qp_wr is %d",
              priv->device_attr.max_qp_wr);
        DEBUG("priv->device_attr.max_sge is %d",
              priv->device_attr.max_sge);
        attr.init = (struct ibv_qp_init_attr){
                /* CQ to be associated with the send queue. */
                .send_cq = tmpl.cq,
                /* CQ to be associated with the receive queue. */
                .recv_cq = tmpl.cq,
                .cap = {
                        /* Max number of outstanding WRs. */
                        .max_send_wr = ((priv->device_attr.max_qp_wr < desc) ?
                                        priv->device_attr.max_qp_wr :
                                        desc),
                        /* Max number of scatter/gather elements in a WR. */
                        .max_send_sge = ((priv->device_attr.max_sge <
                                          MLX4_PMD_SGE_WR_N) ?
                                         priv->device_attr.max_sge :
                                         MLX4_PMD_SGE_WR_N),
#if MLX4_PMD_MAX_INLINE > 0
                        .max_inline_data = MLX4_PMD_MAX_INLINE,
#endif
                },
                .qp_type = IBV_QPT_RAW_PACKET,
                /* Do *NOT* enable this, completions events are managed per
                 * TX burst. */
                .sq_sig_all = 0
        };
        tmpl.qp = ibv_create_qp(priv->pd, &attr.init);
        if (tmpl.qp == NULL) {
                ret = (errno ? errno : EINVAL);
                ERROR("%p: QP creation failure: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
#if MLX4_PMD_MAX_INLINE > 0
        /* ibv_create_qp() updates this value. */
        tmpl.max_inline = attr.init.cap.max_inline_data;
#endif
        attr.mod = (struct ibv_exp_qp_attr){
                /* Move the QP to this state. */
                .qp_state = IBV_QPS_INIT,
                /* Primary port number. */
                .port_num = priv->port
        };
        ret = ibv_exp_modify_qp(tmpl.qp, &attr.mod,
                                (IBV_EXP_QP_STATE | IBV_EXP_QP_PORT));
        if (ret) {
                ERROR("%p: QP state to IBV_QPS_INIT failed: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        ret = txq_alloc_elts(&tmpl, desc);
        if (ret) {
                ERROR("%p: TXQ allocation failed: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        attr.mod = (struct ibv_exp_qp_attr){
                .qp_state = IBV_QPS_RTR
        };
        ret = ibv_exp_modify_qp(tmpl.qp, &attr.mod, IBV_EXP_QP_STATE);
        if (ret) {
                ERROR("%p: QP state to IBV_QPS_RTR failed: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        attr.mod.qp_state = IBV_QPS_RTS;
        ret = ibv_exp_modify_qp(tmpl.qp, &attr.mod, IBV_EXP_QP_STATE);
        if (ret) {
                ERROR("%p: QP state to IBV_QPS_RTS failed: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        /* Clean up txq in case we're reinitializing it. */
        DEBUG("%p: cleaning-up old txq just in case", (void *)txq);
        txq_cleanup(txq);
        *txq = tmpl;
        DEBUG("%p: txq updated with %p", (void *)txq, (void *)&tmpl);
        assert(ret == 0);
        return 0;
error:
        txq_cleanup(&tmpl);
        assert(ret > 0);
        return ret;
}

/**
 * DPDK callback to configure a TX queue.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param idx
 *   TX queue index.
 * @param desc
 *   Number of descriptors to configure in queue.
 * @param socket
 *   NUMA socket on which memory must be allocated.
 * @param[in] conf
 *   Thresholds parameters.
 *
 * @return
 *   0 on success, negative errno value on failure.
 */
static int
mlx4_tx_queue_setup(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
                    unsigned int socket, const struct rte_eth_txconf *conf)
{
        struct priv *priv = dev->data->dev_private;
        struct txq *txq = (*priv->txqs)[idx];
        int ret;

        priv_lock(priv);
        DEBUG("%p: configuring queue %u for %u descriptors",
              (void *)dev, idx, desc);
        if (idx >= priv->txqs_n) {
                ERROR("%p: queue index out of range (%u >= %u)",
                      (void *)dev, idx, priv->txqs_n);
                priv_unlock(priv);
                return -EOVERFLOW;
        }
        if (txq != NULL) {
                DEBUG("%p: reusing already allocated queue index %u (%p)",
                      (void *)dev, idx, (void *)txq);
                if (priv->started) {
                        priv_unlock(priv);
                        return -EEXIST;
                }
                (*priv->txqs)[idx] = NULL;
                txq_cleanup(txq);
        } else {
                txq = rte_calloc_socket("TXQ", 1, sizeof(*txq), 0, socket);
                if (txq == NULL) {
                        ERROR("%p: unable to allocate queue index %u",
                              (void *)dev, idx);
                        priv_unlock(priv);
                        return -ENOMEM;
                }
        }
        ret = txq_setup(dev, txq, desc, socket, conf);
        if (ret)
                rte_free(txq);
        else {
                txq->stats.idx = idx;
                DEBUG("%p: adding TX queue %p to list",
                      (void *)dev, (void *)txq);
                (*priv->txqs)[idx] = txq;
                /* Update send callback. */
                dev->tx_pkt_burst = mlx4_tx_burst;
        }
        priv_unlock(priv);
        return -ret;
}

/**
 * DPDK callback to release a TX queue.
 *
 * @param dpdk_txq
 *   Generic TX queue pointer.
 */
static void
mlx4_tx_queue_release(void *dpdk_txq)
{
        struct txq *txq = (struct txq *)dpdk_txq;
        struct priv *priv;
        unsigned int i;

        if (txq == NULL)
                return;
        priv = txq->priv;
        priv_lock(priv);
        for (i = 0; (i != priv->txqs_n); ++i)
                if ((*priv->txqs)[i] == txq) {
                        DEBUG("%p: removing TX queue %p from list",
                              (void *)priv->dev, (void *)txq);
                        (*priv->txqs)[i] = NULL;
                        break;
                }
        txq_cleanup(txq);
        rte_free(txq);
        priv_unlock(priv);
}

/* RX queues handling. */

/**
 * Allocate RX queue elements with scattered packets support.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 * @param elts_n
 *   Number of elements to allocate.
 * @param[in] pool
 *   If not NULL, fetch buffers from this array instead of allocating them
 *   with rte_pktmbuf_alloc().
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
rxq_alloc_elts_sp(struct rxq *rxq, unsigned int elts_n,
                  struct rte_mbuf **pool)
{
        unsigned int i;
        struct rxq_elt_sp (*elts)[elts_n] =
                rte_calloc_socket("RXQ elements", 1, sizeof(*elts), 0,
                                  rxq->socket);
        int ret = 0;

        if (elts == NULL) {
                ERROR("%p: can't allocate packets array", (void *)rxq);
                ret = ENOMEM;
                goto error;
        }
        /* For each WR (packet). */
        for (i = 0; (i != elts_n); ++i) {
                unsigned int j;
                struct rxq_elt_sp *elt = &(*elts)[i];
                struct ibv_recv_wr *wr = &elt->wr;
                struct ibv_sge (*sges)[(elemof(elt->sges))] = &elt->sges;

                /* These two arrays must have the same size. */
                assert(elemof(elt->sges) == elemof(elt->bufs));
                /* Configure WR. */
                wr->wr_id = i;
                wr->next = &(*elts)[(i + 1)].wr;
                wr->sg_list = &(*sges)[0];
                wr->num_sge = elemof(*sges);
                /* For each SGE (segment). */
                for (j = 0; (j != elemof(elt->bufs)); ++j) {
                        struct ibv_sge *sge = &(*sges)[j];
                        struct rte_mbuf *buf;

                        if (pool != NULL) {
                                buf = *(pool++);
                                assert(buf != NULL);
                                rte_pktmbuf_reset(buf);
                        } else
                                buf = rte_pktmbuf_alloc(rxq->mp);
                        if (buf == NULL) {
                                assert(pool == NULL);
                                ERROR("%p: empty mbuf pool", (void *)rxq);
                                ret = ENOMEM;
                                goto error;
                        }
                        elt->bufs[j] = buf;
                        /* Headroom is reserved by rte_pktmbuf_alloc(). */
                        assert(DATA_OFF(buf) == RTE_PKTMBUF_HEADROOM);
                        /* Buffer is supposed to be empty. */
                        assert(rte_pktmbuf_data_len(buf) == 0);
                        assert(rte_pktmbuf_pkt_len(buf) == 0);
                        /* sge->addr must be able to store a pointer. */
                        assert(sizeof(sge->addr) >= sizeof(uintptr_t));
                        if (j == 0) {
                                /* The first SGE keeps its headroom. */
                                sge->addr = (uintptr_t)rte_pktmbuf_mtod(buf,
                                                                        char *);
                                sge->length = (buf->buf_len -
                                               RTE_PKTMBUF_HEADROOM);
                        } else {
                                /* Subsequent SGEs lose theirs. */
                                assert(DATA_OFF(buf) == RTE_PKTMBUF_HEADROOM);
                                SET_DATA_OFF(buf, 0);
                                sge->addr = (uintptr_t)buf->buf_addr;
                                sge->length = buf->buf_len;
                        }
                        sge->lkey = rxq->mr->lkey;
                        /* Redundant check for tailroom. */
                        assert(sge->length == rte_pktmbuf_tailroom(buf));
                }
        }
        /* The last WR pointer must be NULL. */
        (*elts)[(i - 1)].wr.next = NULL;
        DEBUG("%p: allocated and configured %u WRs (%zu segments)",
              (void *)rxq, elts_n, (elts_n * elemof((*elts)[0].sges)));
        rxq->elts_n = elts_n;
        rxq->elts.sp = elts;
        assert(ret == 0);
        return 0;
error:
        if (elts != NULL) {
                assert(pool == NULL);
                for (i = 0; (i != elemof(*elts)); ++i) {
                        unsigned int j;
                        struct rxq_elt_sp *elt = &(*elts)[i];

                        for (j = 0; (j != elemof(elt->bufs)); ++j) {
                                struct rte_mbuf *buf = elt->bufs[j];

                                if (buf != NULL)
                                        rte_pktmbuf_free_seg(buf);
                        }
                }
                rte_free(elts);
        }
        DEBUG("%p: failed, freed everything", (void *)rxq);
        assert(ret > 0);
        return ret;
}

/**
 * Free RX queue elements with scattered packets support.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 */
static void
rxq_free_elts_sp(struct rxq *rxq)
{
        unsigned int i;
        unsigned int elts_n = rxq->elts_n;
        struct rxq_elt_sp (*elts)[elts_n] = rxq->elts.sp;

        DEBUG("%p: freeing WRs", (void *)rxq);
        rxq->elts_n = 0;
        rxq->elts.sp = NULL;
        if (elts == NULL)
                return;
        for (i = 0; (i != elemof(*elts)); ++i) {
                unsigned int j;
                struct rxq_elt_sp *elt = &(*elts)[i];

                for (j = 0; (j != elemof(elt->bufs)); ++j) {
                        struct rte_mbuf *buf = elt->bufs[j];

                        if (buf != NULL)
                                rte_pktmbuf_free_seg(buf);
                }
        }
        rte_free(elts);
}

/**
 * Allocate RX queue elements.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 * @param elts_n
 *   Number of elements to allocate.
 * @param[in] pool
 *   If not NULL, fetch buffers from this array instead of allocating them
 *   with rte_pktmbuf_alloc().
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
rxq_alloc_elts(struct rxq *rxq, unsigned int elts_n, struct rte_mbuf **pool)
{
        unsigned int i;
        struct rxq_elt (*elts)[elts_n] =
                rte_calloc_socket("RXQ elements", 1, sizeof(*elts), 0,
                                  rxq->socket);
        int ret = 0;

        if (elts == NULL) {
                ERROR("%p: can't allocate packets array", (void *)rxq);
                ret = ENOMEM;
                goto error;
        }
        /* For each WR (packet). */
        for (i = 0; (i != elts_n); ++i) {
                struct rxq_elt *elt = &(*elts)[i];
                struct ibv_recv_wr *wr = &elt->wr;
                struct ibv_sge *sge = &(*elts)[i].sge;
                struct rte_mbuf *buf;

                if (pool != NULL) {
                        buf = *(pool++);
                        assert(buf != NULL);
                        rte_pktmbuf_reset(buf);
                } else
                        buf = rte_pktmbuf_alloc(rxq->mp);
                if (buf == NULL) {
                        assert(pool == NULL);
                        ERROR("%p: empty mbuf pool", (void *)rxq);
                        ret = ENOMEM;
                        goto error;
                }
                /* Configure WR. Work request ID contains its own index in
                 * the elts array and the offset between SGE buffer header and
                 * its data. */
                WR_ID(wr->wr_id).id = i;
                WR_ID(wr->wr_id).offset =
                        (((uintptr_t)buf->buf_addr + RTE_PKTMBUF_HEADROOM) -
                         (uintptr_t)buf);
                wr->next = &(*elts)[(i + 1)].wr;
                wr->sg_list = sge;
                wr->num_sge = 1;
                /* Headroom is reserved by rte_pktmbuf_alloc(). */
                assert(DATA_OFF(buf) == RTE_PKTMBUF_HEADROOM);
                /* Buffer is supposed to be empty. */
                assert(rte_pktmbuf_data_len(buf) == 0);
                assert(rte_pktmbuf_pkt_len(buf) == 0);
                /* sge->addr must be able to store a pointer. */
                assert(sizeof(sge->addr) >= sizeof(uintptr_t));
                /* SGE keeps its headroom. */
                sge->addr = (uintptr_t)
                        ((uint8_t *)buf->buf_addr + RTE_PKTMBUF_HEADROOM);
                sge->length = (buf->buf_len - RTE_PKTMBUF_HEADROOM);
                sge->lkey = rxq->mr->lkey;
                /* Redundant check for tailroom. */
                assert(sge->length == rte_pktmbuf_tailroom(buf));
                /* Make sure elts index and SGE mbuf pointer can be deduced
                 * from WR ID. */
                if ((WR_ID(wr->wr_id).id != i) ||
                    ((void *)(sge->addr - WR_ID(wr->wr_id).offset) != buf)) {
                        ERROR("%p: cannot store index and offset in WR ID",
                              (void *)rxq);
                        sge->addr = 0;
                        rte_pktmbuf_free(buf);
                        ret = EOVERFLOW;
                        goto error;
                }
        }
        /* The last WR pointer must be NULL. */
        (*elts)[(i - 1)].wr.next = NULL;
        DEBUG("%p: allocated and configured %u single-segment WRs",
              (void *)rxq, elts_n);
        rxq->elts_n = elts_n;
        rxq->elts.no_sp = elts;
        assert(ret == 0);
        return 0;
error:
        if (elts != NULL) {
                assert(pool == NULL);
                for (i = 0; (i != elemof(*elts)); ++i) {
                        struct rxq_elt *elt = &(*elts)[i];
                        struct rte_mbuf *buf;

                        if (elt->sge.addr == 0)
                                continue;
                        assert(WR_ID(elt->wr.wr_id).id == i);
                        buf = (void *)
                                (elt->sge.addr - WR_ID(elt->wr.wr_id).offset);
                        rte_pktmbuf_free_seg(buf);
                }
                rte_free(elts);
        }
        DEBUG("%p: failed, freed everything", (void *)rxq);
        assert(ret > 0);
        return ret;
}

/**
 * Free RX queue elements.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 */
static void
rxq_free_elts(struct rxq *rxq)
{
        unsigned int i;
        unsigned int elts_n = rxq->elts_n;
        struct rxq_elt (*elts)[elts_n] = rxq->elts.no_sp;

        DEBUG("%p: freeing WRs", (void *)rxq);
        rxq->elts_n = 0;
        rxq->elts.no_sp = NULL;
        if (elts == NULL)
                return;
        for (i = 0; (i != elemof(*elts)); ++i) {
                struct rxq_elt *elt = &(*elts)[i];
                struct rte_mbuf *buf;

                if (elt->sge.addr == 0)
                        continue;
                assert(WR_ID(elt->wr.wr_id).id == i);
                buf = (void *)(elt->sge.addr - WR_ID(elt->wr.wr_id).offset);
                rte_pktmbuf_free_seg(buf);
        }
        rte_free(elts);
}

/**
 * Unregister a MAC address from a RX queue.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 * @param mac_index
 *   MAC address index.
 */
static void
rxq_mac_addr_del(struct rxq *rxq, unsigned int mac_index)
{
#if defined(NDEBUG) || defined(MLX4_COMPAT_VMWARE)
        struct priv *priv = rxq->priv;
        const uint8_t (*mac)[ETHER_ADDR_LEN] =
                (const uint8_t (*)[ETHER_ADDR_LEN])
                priv->mac[mac_index].addr_bytes;
#endif

        assert(mac_index < elemof(priv->mac));
        if (!BITFIELD_ISSET(rxq->mac_configured, mac_index)) {
                assert(rxq->mac_flow[mac_index] == NULL);
                return;
        }
        DEBUG("%p: removing MAC address %02x:%02x:%02x:%02x:%02x:%02x"
              " index %u",
              (void *)rxq,
              (*mac)[0], (*mac)[1], (*mac)[2], (*mac)[3], (*mac)[4], (*mac)[5],
              mac_index);
#ifdef MLX4_COMPAT_VMWARE
        if (priv->vmware) {
                union ibv_gid gid = { .raw = { 0 } };

                memcpy(&gid.raw[10], *mac, sizeof(*mac));
                claim_zero(ibv_detach_mcast(rxq->qp, &gid, 0));
                BITFIELD_RESET(rxq->mac_configured, mac_index);
                return;
        }
#endif
        assert(rxq->mac_flow[mac_index] != NULL);
        claim_zero(ibv_exp_destroy_flow(rxq->mac_flow[mac_index]));
        rxq->mac_flow[mac_index] = NULL;
        BITFIELD_RESET(rxq->mac_configured, mac_index);
}

/**
 * Unregister all MAC addresses from a RX queue.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 */
static void
rxq_mac_addrs_del(struct rxq *rxq)
{
        struct priv *priv = rxq->priv;
        unsigned int i;

        for (i = 0; (i != elemof(priv->mac)); ++i)
                rxq_mac_addr_del(rxq, i);
}

static int rxq_promiscuous_enable(struct rxq *);
static void rxq_promiscuous_disable(struct rxq *);

/**
 * Register a MAC address in a RX queue.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 * @param mac_index
 *   MAC address index to register.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
rxq_mac_addr_add(struct rxq *rxq, unsigned int mac_index)
{
        struct priv *priv = rxq->priv;
        const uint8_t (*mac)[ETHER_ADDR_LEN] =
                (const uint8_t (*)[ETHER_ADDR_LEN])
                priv->mac[mac_index].addr_bytes;
        unsigned int vlans = 0;
        unsigned int specs = 0;
        unsigned int i, j;
        struct ibv_exp_flow *flow;

        assert(mac_index < elemof(priv->mac));
        if (BITFIELD_ISSET(rxq->mac_configured, mac_index))
                rxq_mac_addr_del(rxq, mac_index);
        /* Number of configured VLANs. */
        for (i = 0; (i != elemof(priv->vlan_filter)); ++i)
                if (priv->vlan_filter[i].enabled)
                        ++vlans;
        specs = (vlans ? vlans : 1);

        /* Allocate flow specification on the stack. */
        struct ibv_exp_flow_attr data
                [1 +
                 (sizeof(struct ibv_exp_flow_spec_eth[specs]) /
                  sizeof(struct ibv_exp_flow_attr)) +
                 !!(sizeof(struct ibv_exp_flow_spec_eth[specs]) %
                    sizeof(struct ibv_exp_flow_attr))];
        struct ibv_exp_flow_attr *attr = (void *)&data[0];
        struct ibv_exp_flow_spec_eth *spec = (void *)&data[1];

        /*
         * No padding must be inserted by the compiler between attr and spec.
         * This layout is expected by libibverbs.
         */
        assert(((uint8_t *)attr + sizeof(*attr)) == (uint8_t *)spec);
        *attr = (struct ibv_exp_flow_attr){
                .type = IBV_EXP_FLOW_ATTR_NORMAL,
                .num_of_specs = specs,
                .port = priv->port,
                .flags = 0
        };
        *spec = (struct ibv_exp_flow_spec_eth){
                .type = IBV_EXP_FLOW_SPEC_ETH,
                .size = sizeof(*spec),
                .val = {
                        .dst_mac = {
                                (*mac)[0], (*mac)[1], (*mac)[2],
                                (*mac)[3], (*mac)[4], (*mac)[5]
                        }
                },
                .mask = {
                        .dst_mac = "\xff\xff\xff\xff\xff\xff",
                        .vlan_tag = (vlans ? htons(0xfff) : 0)
                }
        };
        /* Fill VLAN specifications. */
        for (i = 0, j = 0; (i != elemof(priv->vlan_filter)); ++i) {
                if (!priv->vlan_filter[i].enabled)
                        continue;
                assert(j != vlans);
                if (j)
                        spec[j] = spec[0];
                spec[j].val.vlan_tag = htons(priv->vlan_filter[i].id);
                ++j;
        }
        DEBUG("%p: adding MAC address %02x:%02x:%02x:%02x:%02x:%02x index %u"
              " (%u VLAN(s) configured)",
              (void *)rxq,
              (*mac)[0], (*mac)[1], (*mac)[2], (*mac)[3], (*mac)[4], (*mac)[5],
              mac_index,
              vlans);
#ifdef MLX4_COMPAT_VMWARE
        if (priv->vmware) {
                union ibv_gid gid = { .raw = { 0 } };

                /* Call multicast attach with unicast mac to get traffic. */
                memcpy(&gid.raw[10], *mac, sizeof(*mac));
                errno = 0;
                if (ibv_attach_mcast(rxq->qp, &gid, 0)) {
                        if (errno)
                                return errno;
                        return EINVAL;
                }
                BITFIELD_SET(rxq->mac_configured, mac_index);
                return 0;
        }
#endif
        /* Create related flow. */
        errno = 0;
        flow = ibv_exp_create_flow(rxq->qp, attr);
        if (flow == NULL) {
                int err = errno;

                /* Flow creation failure is not fatal when in DMFS A0 mode.
                 * Ignore error if promiscuity is already enabled or can be
                 * enabled. */
                if (priv->promisc_ok)
                        return 0;
                if ((rxq->promisc_flow != NULL) ||
                    (rxq_promiscuous_enable(rxq) == 0)) {
                        if (rxq->promisc_flow != NULL)
                                rxq_promiscuous_disable(rxq);
                        WARN("cannot configure normal flow but promiscuous"
                             " mode is fine, assuming promiscuous optimization"
                             " is enabled"
                             " (options mlx4_core log_num_mgm_entry_size=-7)");
                        priv->promisc_ok = 1;
                        return 0;
                }
                errno = err;
                /* It's not clear whether errno is always set in this case. */
                ERROR("%p: flow configuration failed, errno=%d: %s",
                      (void *)rxq, errno,
                      (errno ? strerror(errno) : "Unknown error"));
                if (errno)
                        return errno;
                return EINVAL;
        }
        assert(rxq->mac_flow[mac_index] == NULL);
        rxq->mac_flow[mac_index] = flow;
        BITFIELD_SET(rxq->mac_configured, mac_index);
        return 0;
}

/**
 * Register all MAC addresses in a RX queue.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
rxq_mac_addrs_add(struct rxq *rxq)
{
        struct priv *priv = rxq->priv;
        unsigned int i;
        int ret;

        for (i = 0; (i != elemof(priv->mac)); ++i) {
                if (!BITFIELD_ISSET(priv->mac_configured, i))
                        continue;
                ret = rxq_mac_addr_add(rxq, i);
                if (!ret)
                        continue;
                /* Failure, rollback. */
                while (i != 0)
                        rxq_mac_addr_del(rxq, --i);
                assert(ret > 0);
                return ret;
        }
        return 0;
}

/**
 * Unregister a MAC address.
 *
 * In RSS mode, the MAC address is unregistered from the parent queue,
 * otherwise it is unregistered from each queue directly.
 *
 * @param priv
 *   Pointer to private structure.
 * @param mac_index
 *   MAC address index.
 */
static void
priv_mac_addr_del(struct priv *priv, unsigned int mac_index)
{
        unsigned int i;

        assert(mac_index < elemof(priv->mac));
        if (!BITFIELD_ISSET(priv->mac_configured, mac_index))
                return;
        if (priv->rss) {
                rxq_mac_addr_del(&priv->rxq_parent, mac_index);
                goto end;
        }
        for (i = 0; (i != priv->dev->data->nb_rx_queues); ++i)
                rxq_mac_addr_del((*priv->rxqs)[i], mac_index);
end:
        BITFIELD_RESET(priv->mac_configured, mac_index);
}

/**
 * Register a MAC address.
 *
 * In RSS mode, the MAC address is registered in the parent queue,
 * otherwise it is registered in each queue directly.
 *
 * @param priv
 *   Pointer to private structure.
 * @param mac_index
 *   MAC address index to use.
 * @param mac
 *   MAC address to register.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
priv_mac_addr_add(struct priv *priv, unsigned int mac_index,
                  const uint8_t (*mac)[ETHER_ADDR_LEN])
{
        unsigned int i;
        int ret;

        assert(mac_index < elemof(priv->mac));
        /* First, make sure this address isn't already configured. */
        for (i = 0; (i != elemof(priv->mac)); ++i) {
                /* Skip this index, it's going to be reconfigured. */
                if (i == mac_index)
                        continue;
                if (!BITFIELD_ISSET(priv->mac_configured, i))
                        continue;
                if (memcmp(priv->mac[i].addr_bytes, *mac, sizeof(*mac)))
                        continue;
                /* Address already configured elsewhere, return with error. */
                return EADDRINUSE;
        }
        if (BITFIELD_ISSET(priv->mac_configured, mac_index))
                priv_mac_addr_del(priv, mac_index);
        priv->mac[mac_index] = (struct ether_addr){
                {
                        (*mac)[0], (*mac)[1], (*mac)[2],
                        (*mac)[3], (*mac)[4], (*mac)[5]
                }
        };
        /* If device isn't started, this is all we need to do. */
        if (!priv->started) {
#ifndef NDEBUG
                /* Verify that all queues have this index disabled. */
                for (i = 0; (i != priv->rxqs_n); ++i) {
                        if ((*priv->rxqs)[i] == NULL)
                                continue;
                        assert(!BITFIELD_ISSET
                               ((*priv->rxqs)[i]->mac_configured, mac_index));
                }
#endif
                goto end;
        }
        if (priv->rss) {
                ret = rxq_mac_addr_add(&priv->rxq_parent, mac_index);
                if (ret)
                        return ret;
                goto end;
        }
        for (i = 0; (i != priv->rxqs_n); ++i) {
                if ((*priv->rxqs)[i] == NULL)
                        continue;
                ret = rxq_mac_addr_add((*priv->rxqs)[i], mac_index);
                if (!ret)
                        continue;
                /* Failure, rollback. */
                while (i != 0)
                        if ((*priv->rxqs)[(--i)] != NULL)
                                rxq_mac_addr_del((*priv->rxqs)[i], mac_index);
                return ret;
        }
end:
        BITFIELD_SET(priv->mac_configured, mac_index);
        return 0;
}

/**
 * Enable allmulti mode in a RX queue.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
rxq_allmulticast_enable(struct rxq *rxq)
{
        struct ibv_exp_flow *flow;
        struct ibv_exp_flow_attr attr = {
                .type = IBV_EXP_FLOW_ATTR_MC_DEFAULT,
                .num_of_specs = 0,
                .port = rxq->priv->port,
                .flags = 0
        };

#ifdef MLX4_COMPAT_VMWARE
        if (rxq->priv->vmware) {
                ERROR("%p: allmulticast mode is not supported in VMware",
                      (void *)rxq);
                return EINVAL;
        }
#endif
        DEBUG("%p: enabling allmulticast mode", (void *)rxq);
        if (rxq->allmulti_flow != NULL)
                return EBUSY;
        errno = 0;
        flow = ibv_exp_create_flow(rxq->qp, &attr);
        if (flow == NULL) {
                /* It's not clear whether errno is always set in this case. */
                ERROR("%p: flow configuration failed, errno=%d: %s",
                      (void *)rxq, errno,
                      (errno ? strerror(errno) : "Unknown error"));
                if (errno)
                        return errno;
                return EINVAL;
        }
        rxq->allmulti_flow = flow;
        DEBUG("%p: allmulticast mode enabled", (void *)rxq);
        return 0;
}

/**
 * Disable allmulti mode in a RX queue.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 */
static void
rxq_allmulticast_disable(struct rxq *rxq)
{
#ifdef MLX4_COMPAT_VMWARE
        if (rxq->priv->vmware) {
                ERROR("%p: allmulticast mode is not supported in VMware",
                      (void *)rxq);
                return;
        }
#endif
        DEBUG("%p: disabling allmulticast mode", (void *)rxq);
        if (rxq->allmulti_flow == NULL)
                return;
        claim_zero(ibv_exp_destroy_flow(rxq->allmulti_flow));
        rxq->allmulti_flow = NULL;
        DEBUG("%p: allmulticast mode disabled", (void *)rxq);
}

/**
 * Enable promiscuous mode in a RX queue.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
rxq_promiscuous_enable(struct rxq *rxq)
{
        struct ibv_exp_flow *flow;
        struct ibv_exp_flow_attr attr = {
                .type = IBV_EXP_FLOW_ATTR_ALL_DEFAULT,
                .num_of_specs = 0,
                .port = rxq->priv->port,
                .flags = 0
        };

#ifdef MLX4_COMPAT_VMWARE
        if (rxq->priv->vmware) {
                ERROR("%p: promiscuous mode is not supported in VMware",
                      (void *)rxq);
                return EINVAL;
        }
#endif
        if (rxq->priv->vf)
                return 0;
        DEBUG("%p: enabling promiscuous mode", (void *)rxq);
        if (rxq->promisc_flow != NULL)
                return EBUSY;
        errno = 0;
        flow = ibv_exp_create_flow(rxq->qp, &attr);
        if (flow == NULL) {
                /* It's not clear whether errno is always set in this case. */
                ERROR("%p: flow configuration failed, errno=%d: %s",
                      (void *)rxq, errno,
                      (errno ? strerror(errno) : "Unknown error"));
                if (errno)
                        return errno;
                return EINVAL;
        }
        rxq->promisc_flow = flow;
        DEBUG("%p: promiscuous mode enabled", (void *)rxq);
        return 0;
}

/**
 * Disable promiscuous mode in a RX queue.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 */
static void
rxq_promiscuous_disable(struct rxq *rxq)
{
#ifdef MLX4_COMPAT_VMWARE
        if (rxq->priv->vmware) {
                ERROR("%p: promiscuous mode is not supported in VMware",
                      (void *)rxq);
                return;
        }
#endif
        if (rxq->priv->vf)
                return;
        DEBUG("%p: disabling promiscuous mode", (void *)rxq);
        if (rxq->promisc_flow == NULL)
                return;
        claim_zero(ibv_exp_destroy_flow(rxq->promisc_flow));
        rxq->promisc_flow = NULL;
        DEBUG("%p: promiscuous mode disabled", (void *)rxq);
}

/**
 * Clean up a RX queue.
 *
 * Destroy objects, free allocated memory and reset the structure for reuse.
 *
 * @param rxq
 *   Pointer to RX queue structure.
 */
static void
rxq_cleanup(struct rxq *rxq)
{
        DEBUG("cleaning up %p", (void *)rxq);
        if (rxq->sp)
                rxq_free_elts_sp(rxq);
        else
                rxq_free_elts(rxq);
        if (rxq->qp != NULL) {
                rxq_promiscuous_disable(rxq);
                rxq_allmulticast_disable(rxq);
                rxq_mac_addrs_del(rxq);
                claim_zero(ibv_destroy_qp(rxq->qp));
        }
        if (rxq->cq != NULL)
                claim_zero(ibv_destroy_cq(rxq->cq));
        if (rxq->mr != NULL)
                claim_zero(ibv_dereg_mr(rxq->mr));
        memset(rxq, 0, sizeof(*rxq));
}

static uint16_t
mlx4_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n);

/**
 * DPDK callback for RX with scattered packets support.
 *
 * @param dpdk_rxq
 *   Generic pointer to RX queue structure.
 * @param[out] pkts
 *   Array to store received packets.
 * @param pkts_n
 *   Maximum number of packets in array.
 *
 * @return
 *   Number of packets successfully received (<= pkts_n).
 */
static uint16_t
mlx4_rx_burst_sp(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
        struct rxq *rxq = (struct rxq *)dpdk_rxq;
        struct rxq_elt_sp (*elts)[rxq->elts_n] = rxq->elts.sp;
        struct ibv_wc wcs[pkts_n];
        struct ibv_recv_wr head;
        struct ibv_recv_wr **next = &head.next;
        struct ibv_recv_wr *bad_wr;
        int ret = 0;
        int wcs_n;
        int i;

        if (unlikely(!rxq->sp))
                return mlx4_rx_burst(dpdk_rxq, pkts, pkts_n);
        if (unlikely(elts == NULL)) /* See RTE_DEV_CMD_SET_MTU. */
                return 0;
        wcs_n = ibv_poll_cq(rxq->cq, pkts_n, wcs);
        if (unlikely(wcs_n == 0))
                return 0;
        if (unlikely(wcs_n < 0)) {
                DEBUG("rxq=%p, ibv_poll_cq() failed (wc_n=%d)",
                      (void *)rxq, wcs_n);
                return 0;
        }
        assert(wcs_n <= (int)pkts_n);
        /* For each work completion. */
        for (i = 0; (i != wcs_n); ++i) {
                struct ibv_wc *wc = &wcs[i];
                uint64_t wr_id = wc->wr_id;
                uint32_t len = wc->byte_len;
                struct rxq_elt_sp *elt = &(*elts)[wr_id];
                struct ibv_recv_wr *wr = &elt->wr;
                struct rte_mbuf *pkt_buf = NULL; /* Buffer returned in pkts. */
                struct rte_mbuf **pkt_buf_next = &pkt_buf;
                unsigned int seg_headroom = RTE_PKTMBUF_HEADROOM;
                unsigned int j = 0;

                /* Sanity checks. */
                assert(wr_id < rxq->elts_n);
                assert(wr_id == wr->wr_id);
                assert(wr->sg_list == elt->sges);
                assert(wr->num_sge == elemof(elt->sges));
                /* Link completed WRs together for repost. */
                *next = wr;
                next = &wr->next;
                if (unlikely(wc->status != IBV_WC_SUCCESS)) {
                        /* Whatever, just repost the offending WR. */
                        DEBUG("rxq=%p, wr_id=%" PRIu64 ": bad work completion"
                              " status (%d): %s",
                              (void *)rxq, wc->wr_id, wc->status,
                              ibv_wc_status_str(wc->status));
#ifdef MLX4_PMD_SOFT_COUNTERS
                        /* Increase dropped packets counter. */
                        ++rxq->stats.idropped;
#endif
                        goto repost;
                }
                /*
                 * Replace spent segments with new ones, concatenate and
                 * return them as pkt_buf.
                 */
                while (1) {
                        struct ibv_sge *sge = &elt->sges[j];
                        struct rte_mbuf *seg = elt->bufs[j];
                        struct rte_mbuf *rep;
                        unsigned int seg_tailroom;

                        /*
                         * Fetch initial bytes of packet descriptor into a
                         * cacheline while allocating rep.
                         */
                        rte_prefetch0(seg);
                        rep = __rte_mbuf_raw_alloc(rxq->mp);
                        if (unlikely(rep == NULL)) {
                                /*
                                 * Unable to allocate a replacement mbuf,
                                 * repost WR.
                                 */
                                DEBUG("rxq=%p, wr_id=%" PRIu64 ":"
                                      " can't allocate a new mbuf",
                                      (void *)rxq, wr_id);
                                if (pkt_buf != NULL)
                                        rte_pktmbuf_free(pkt_buf);
                                /* Increase out of memory counters. */
                                ++rxq->stats.rx_nombuf;
                                ++rxq->priv->dev->data->rx_mbuf_alloc_failed;
                                goto repost;
                        }
#ifndef NDEBUG
                        /* Poison user-modifiable fields in rep. */
                        NEXT(rep) = (void *)((uintptr_t)-1);
                        SET_DATA_OFF(rep, 0xdead);
                        DATA_LEN(rep) = 0xd00d;
                        PKT_LEN(rep) = 0xdeadd00d;
                        NB_SEGS(rep) = 0x2a;
                        PORT(rep) = 0x2a;
                        rep->ol_flags = -1;
#endif
                        assert(rep->buf_len == seg->buf_len);
                        assert(rep->buf_len == rxq->mb_len);
                        /* Reconfigure sge to use rep instead of seg. */
                        assert(sge->lkey == rxq->mr->lkey);
                        sge->addr = ((uintptr_t)rep->buf_addr + seg_headroom);
                        elt->bufs[j] = rep;
                        ++j;
                        /* Update pkt_buf if it's the first segment, or link
                         * seg to the previous one and update pkt_buf_next. */
                        *pkt_buf_next = seg;
                        pkt_buf_next = &NEXT(seg);
                        /* Update seg information. */
                        seg_tailroom = (seg->buf_len - seg_headroom);
                        assert(sge->length == seg_tailroom);
                        SET_DATA_OFF(seg, seg_headroom);
                        if (likely(len <= seg_tailroom)) {
                                /* Last segment. */
                                DATA_LEN(seg) = len;
                                PKT_LEN(seg) = len;
                                /* Sanity check. */
                                assert(rte_pktmbuf_headroom(seg) ==
                                       seg_headroom);
                                assert(rte_pktmbuf_tailroom(seg) ==
                                       (seg_tailroom - len));
                                break;
                        }
                        DATA_LEN(seg) = seg_tailroom;
                        PKT_LEN(seg) = seg_tailroom;
                        /* Sanity check. */
                        assert(rte_pktmbuf_headroom(seg) == seg_headroom);
                        assert(rte_pktmbuf_tailroom(seg) == 0);
                        /* Fix len and clear headroom for next segments. */
                        len -= seg_tailroom;
                        seg_headroom = 0;
                }
                /* Update head and tail segments. */
                *pkt_buf_next = NULL;
                assert(pkt_buf != NULL);
                assert(j != 0);
                NB_SEGS(pkt_buf) = j;
                PORT(pkt_buf) = rxq->port_id;
                PKT_LEN(pkt_buf) = wc->byte_len;
                pkt_buf->ol_flags = 0;

                /* Return packet. */
                *(pkts++) = pkt_buf;
                ++ret;
#ifdef MLX4_PMD_SOFT_COUNTERS
                /* Increase bytes counter. */
                rxq->stats.ibytes += wc->byte_len;
#endif
repost:
                continue;
        }
        *next = NULL;
        /* Repost WRs. */
#ifdef DEBUG_RECV
        DEBUG("%p: reposting %d WRs starting from %" PRIu64 " (%p)",
              (void *)rxq, wcs_n, wcs[0].wr_id, (void *)head.next);
#endif
        i = ibv_post_recv(rxq->qp, head.next, &bad_wr);
        if (unlikely(i)) {
                /* Inability to repost WRs is fatal. */
                DEBUG("%p: ibv_post_recv(): failed for WR %p: %s",
                      (void *)rxq->priv,
                      (void *)bad_wr,
                      strerror(i));
                abort();
        }
#ifdef MLX4_PMD_SOFT_COUNTERS
        /* Increase packets counter. */
        rxq->stats.ipackets += ret;
#endif
        return ret;
}

/**
 * DPDK callback for RX.
 *
 * The following function is the same as mlx4_rx_burst_sp(), except it doesn't
 * manage scattered packets. Improves performance when MRU is lower than the
 * size of the first segment.
 *
 * @param dpdk_rxq
 *   Generic pointer to RX queue structure.
 * @param[out] pkts
 *   Array to store received packets.
 * @param pkts_n
 *   Maximum number of packets in array.
 *
 * @return
 *   Number of packets successfully received (<= pkts_n).
 */
static uint16_t
mlx4_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
        struct rxq *rxq = (struct rxq *)dpdk_rxq;
        struct rxq_elt (*elts)[rxq->elts_n] = rxq->elts.no_sp;
        struct ibv_wc wcs[pkts_n];
        struct ibv_recv_wr head;
        struct ibv_recv_wr **next = &head.next;
        struct ibv_recv_wr *bad_wr;
        int ret = 0;
        int wcs_n;
        int i;

        if (unlikely(rxq->sp))
                return mlx4_rx_burst_sp(dpdk_rxq, pkts, pkts_n);
        wcs_n = ibv_poll_cq(rxq->cq, pkts_n, wcs);
        if (unlikely(wcs_n == 0))
                return 0;
        if (unlikely(wcs_n < 0)) {
                DEBUG("rxq=%p, ibv_poll_cq() failed (wc_n=%d)",
                      (void *)rxq, wcs_n);
                return 0;
        }
        assert(wcs_n <= (int)pkts_n);
        /* For each work completion. */
        for (i = 0; (i != wcs_n); ++i) {
                struct ibv_wc *wc = &wcs[i];
                uint64_t wr_id = wc->wr_id;
                uint32_t len = wc->byte_len;
                struct rxq_elt *elt = &(*elts)[WR_ID(wr_id).id];
                struct ibv_recv_wr *wr = &elt->wr;
                struct rte_mbuf *seg =
                        (void *)(elt->sge.addr - WR_ID(wr_id).offset);
                struct rte_mbuf *rep;

                /* Sanity checks. */
                assert(WR_ID(wr_id).id < rxq->elts_n);
                assert(wr_id == wr->wr_id);
                assert(wr->sg_list == &elt->sge);
                assert(wr->num_sge == 1);
                /* Link completed WRs together for repost. */
                *next = wr;
                next = &wr->next;
                if (unlikely(wc->status != IBV_WC_SUCCESS)) {
                        /* Whatever, just repost the offending WR. */
                        DEBUG("rxq=%p, wr_id=%" PRIu32 ": bad work completion"
                              " status (%d): %s",
                              (void *)rxq, WR_ID(wr_id).id, wc->status,
                              ibv_wc_status_str(wc->status));
#ifdef MLX4_PMD_SOFT_COUNTERS
                        /* Increase dropped packets counter. */
                        ++rxq->stats.idropped;
#endif
                        goto repost;
                }
                /*
                 * Fetch initial bytes of packet descriptor into a
                 * cacheline while allocating rep.
                 */
                rte_prefetch0(seg);
                rep = __rte_mbuf_raw_alloc(rxq->mp);
                if (unlikely(rep == NULL)) {
                        /*
                         * Unable to allocate a replacement mbuf,
                         * repost WR.
                         */
                        DEBUG("rxq=%p, wr_id=%" PRIu32 ":"
                              " can't allocate a new mbuf",
                              (void *)rxq, WR_ID(wr_id).id);
                        /* Increase out of memory counters. */
                        ++rxq->stats.rx_nombuf;
                        ++rxq->priv->dev->data->rx_mbuf_alloc_failed;
                        goto repost;
                }

                /* Reconfigure sge to use rep instead of seg. */
                elt->sge.addr = (uintptr_t)rep->buf_addr + RTE_PKTMBUF_HEADROOM;
                assert(elt->sge.lkey == rxq->mr->lkey);
                WR_ID(wr->wr_id).offset =
                        (((uintptr_t)rep->buf_addr + RTE_PKTMBUF_HEADROOM) -
                         (uintptr_t)rep);
                assert(WR_ID(wr->wr_id).id == WR_ID(wr_id).id);

                /* Update seg information. */
                SET_DATA_OFF(seg, RTE_PKTMBUF_HEADROOM);
                NB_SEGS(seg) = 1;
                PORT(seg) = rxq->port_id;
                NEXT(seg) = NULL;
                PKT_LEN(seg) = len;
                DATA_LEN(seg) = len;
                seg->ol_flags = 0;

                /* Return packet. */
                *(pkts++) = seg;
                ++ret;
#ifdef MLX4_PMD_SOFT_COUNTERS
                /* Increase bytes counter. */
                rxq->stats.ibytes += wc->byte_len;
#endif
repost:
                continue;
        }
        *next = NULL;
        /* Repost WRs. */
#ifdef DEBUG_RECV
        DEBUG("%p: reposting %d WRs starting from %" PRIu32 " (%p)",
              (void *)rxq, wcs_n, WR_ID(wcs[0].wr_id).id, (void *)head.next);
#endif
        i = ibv_post_recv(rxq->qp, head.next, &bad_wr);
        if (unlikely(i)) {
                /* Inability to repost WRs is fatal. */
                DEBUG("%p: ibv_post_recv(): failed for WR %p: %s",
                      (void *)rxq->priv,
                      (void *)bad_wr,
                      strerror(i));
                abort();
        }
#ifdef MLX4_PMD_SOFT_COUNTERS
        /* Increase packets counter. */
        rxq->stats.ipackets += ret;
#endif
        return ret;
}

#ifdef INLINE_RECV

/**
 * Allocate a Queue Pair in case inline receive is supported.
 *
 * @param priv
 *   Pointer to private structure.
 * @param cq
 *   Completion queue to associate with QP.
 * @param desc
 *   Number of descriptors in QP (hint only).
 *
 * @return
 *   QP pointer or NULL in case of error.
 */
static struct ibv_qp *
rxq_setup_qp(struct priv *priv, struct ibv_cq *cq, uint16_t desc)
{
        struct ibv_exp_qp_init_attr attr = {
                /* CQ to be associated with the send queue. */
                .send_cq = cq,
                /* CQ to be associated with the receive queue. */
                .recv_cq = cq,
                .max_inl_recv = priv->inl_recv_size,
                .cap = {
                        /* Max number of outstanding WRs. */
                        .max_recv_wr = ((priv->device_attr.max_qp_wr < desc) ?
                                        priv->device_attr.max_qp_wr :
                                        desc),
                        /* Max number of scatter/gather elements in a WR. */
                        .max_recv_sge = ((priv->device_attr.max_sge <
                                          MLX4_PMD_SGE_WR_N) ?
                                         priv->device_attr.max_sge :
                                         MLX4_PMD_SGE_WR_N),
                },
                .qp_type = IBV_QPT_RAW_PACKET,
                .pd = priv->pd
        };

        attr.comp_mask = IBV_EXP_QP_INIT_ATTR_PD;
        attr.comp_mask |= IBV_EXP_QP_INIT_ATTR_INL_RECV;

        return ibv_exp_create_qp(priv->ctx, &attr);
}

#else /* INLINE_RECV */

/**
 * Allocate a Queue Pair.
 *
 * @param priv
 *   Pointer to private structure.
 * @param cq
 *   Completion queue to associate with QP.
 * @param desc
 *   Number of descriptors in QP (hint only).
 *
 * @return
 *   QP pointer or NULL in case of error.
 */
static struct ibv_qp *
rxq_setup_qp(struct priv *priv, struct ibv_cq *cq, uint16_t desc)
{
        struct ibv_qp_init_attr attr = {
                /* CQ to be associated with the send queue. */
                .send_cq = cq,
                /* CQ to be associated with the receive queue. */
                .recv_cq = cq,
                .cap = {
                        /* Max number of outstanding WRs. */
                        .max_recv_wr = ((priv->device_attr.max_qp_wr < desc) ?
                                        priv->device_attr.max_qp_wr :
                                        desc),
                        /* Max number of scatter/gather elements in a WR. */
                        .max_recv_sge = ((priv->device_attr.max_sge <
                                          MLX4_PMD_SGE_WR_N) ?
                                         priv->device_attr.max_sge :
                                         MLX4_PMD_SGE_WR_N),
                },
                .qp_type = IBV_QPT_RAW_PACKET
        };

        return ibv_create_qp(priv->pd, &attr);
}

#endif /* INLINE_RECV */

#ifdef RSS_SUPPORT

/**
 * Allocate a RSS Queue Pair.
 *
 * @param priv
 *   Pointer to private structure.
 * @param cq
 *   Completion queue to associate with QP.
 * @param desc
 *   Number of descriptors in QP (hint only).
 * @param parent
 *   If nonzero, create a parent QP, otherwise a child.
 *
 * @return
 *   QP pointer or NULL in case of error.
 */
static struct ibv_qp *
rxq_setup_qp_rss(struct priv *priv, struct ibv_cq *cq, uint16_t desc,
                 int parent)
{
        struct ibv_exp_qp_init_attr attr = {
                /* CQ to be associated with the send queue. */
                .send_cq = cq,
                /* CQ to be associated with the receive queue. */
                .recv_cq = cq,
#ifdef INLINE_RECV
                .max_inl_recv = priv->inl_recv_size,
#endif
                .cap = {
                        /* Max number of outstanding WRs. */
                        .max_recv_wr = ((priv->device_attr.max_qp_wr < desc) ?
                                        priv->device_attr.max_qp_wr :
                                        desc),
                        /* Max number of scatter/gather elements in a WR. */
                        .max_recv_sge = ((priv->device_attr.max_sge <
                                          MLX4_PMD_SGE_WR_N) ?
                                         priv->device_attr.max_sge :
                                         MLX4_PMD_SGE_WR_N),
                },
                .qp_type = IBV_QPT_RAW_PACKET,
                .comp_mask = (IBV_EXP_QP_INIT_ATTR_PD |
                              IBV_EXP_QP_INIT_ATTR_QPG),
                .pd = priv->pd
        };

#ifdef INLINE_RECV
        attr.comp_mask |= IBV_EXP_QP_INIT_ATTR_INL_RECV;
#endif
        if (parent) {
                attr.qpg.qpg_type = IBV_EXP_QPG_PARENT;
                /* TSS isn't necessary. */
                attr.qpg.parent_attrib.tss_child_count = 0;
                attr.qpg.parent_attrib.rss_child_count = priv->rxqs_n;
                DEBUG("initializing parent RSS queue");
        } else {
                attr.qpg.qpg_type = IBV_EXP_QPG_CHILD_RX;
                attr.qpg.qpg_parent = priv->rxq_parent.qp;
                DEBUG("initializing child RSS queue");
        }
        return ibv_exp_create_qp(priv->ctx, &attr);
}

#endif /* RSS_SUPPORT */

/**
 * Reconfigure a RX queue with new parameters.
 *
 * rxq_rehash() does not allocate mbufs, which, if not done from the right
 * thread (such as a control thread), may corrupt the pool.
 * In case of failure, the queue is left untouched.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param rxq
 *   RX queue pointer.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
rxq_rehash(struct rte_eth_dev *dev, struct rxq *rxq)
{
        struct priv *priv = rxq->priv;
        struct rxq tmpl = *rxq;
        unsigned int mbuf_n;
        unsigned int desc_n;
        struct rte_mbuf **pool;
        unsigned int i, k;
        struct ibv_exp_qp_attr mod;
        struct ibv_recv_wr *bad_wr;
        int err;
        int parent = (rxq == &priv->rxq_parent);

        if (parent) {
                ERROR("%p: cannot rehash parent queue %p",
                      (void *)dev, (void *)rxq);
                return EINVAL;
        }
        DEBUG("%p: rehashing queue %p", (void *)dev, (void *)rxq);
        /* Number of descriptors and mbufs currently allocated. */
        desc_n = (tmpl.elts_n * (tmpl.sp ? MLX4_PMD_SGE_WR_N : 1));
        mbuf_n = desc_n;
        /* Enable scattered packets support for this queue if necessary. */
        if ((dev->data->dev_conf.rxmode.jumbo_frame) &&
            (dev->data->dev_conf.rxmode.max_rx_pkt_len >
             (tmpl.mb_len - RTE_PKTMBUF_HEADROOM))) {
                tmpl.sp = 1;
                desc_n /= MLX4_PMD_SGE_WR_N;
        } else
                tmpl.sp = 0;
        DEBUG("%p: %s scattered packets support (%u WRs)",
              (void *)dev, (tmpl.sp ? "enabling" : "disabling"), desc_n);
        /* If scatter mode is the same as before, nothing to do. */
        if (tmpl.sp == rxq->sp) {
                DEBUG("%p: nothing to do", (void *)dev);
                return 0;
        }
        /* Remove attached flows if RSS is disabled (no parent queue). */
        if (!priv->rss) {
                rxq_allmulticast_disable(&tmpl);
                rxq_promiscuous_disable(&tmpl);
                rxq_mac_addrs_del(&tmpl);
                /* Update original queue in case of failure. */
                rxq->allmulti_flow = tmpl.allmulti_flow;
                rxq->promisc_flow = tmpl.promisc_flow;
                memcpy(rxq->mac_configured, tmpl.mac_configured,
                       sizeof(rxq->mac_configured));
                memcpy(rxq->mac_flow, tmpl.mac_flow, sizeof(rxq->mac_flow));
        }
        /* From now on, any failure will render the queue unusable.
         * Reinitialize QP. */
        mod = (struct ibv_exp_qp_attr){ .qp_state = IBV_QPS_RESET };
        err = ibv_exp_modify_qp(tmpl.qp, &mod, IBV_EXP_QP_STATE);
        if (err) {
                ERROR("%p: cannot reset QP: %s", (void *)dev, strerror(err));
                assert(err > 0);
                return err;
        }
        err = ibv_resize_cq(tmpl.cq, desc_n);
        if (err) {
                ERROR("%p: cannot resize CQ: %s", (void *)dev, strerror(err));
                assert(err > 0);
                return err;
        }
        mod = (struct ibv_exp_qp_attr){
                /* Move the QP to this state. */
                .qp_state = IBV_QPS_INIT,
                /* Primary port number. */
                .port_num = priv->port
        };
        err = ibv_exp_modify_qp(tmpl.qp, &mod,
                                (IBV_EXP_QP_STATE |
#ifdef RSS_SUPPORT
                                 (parent ? IBV_EXP_QP_GROUP_RSS : 0) |
#endif /* RSS_SUPPORT */
                                 IBV_EXP_QP_PORT));
        if (err) {
                ERROR("%p: QP state to IBV_QPS_INIT failed: %s",
                      (void *)dev, strerror(err));
                assert(err > 0);
                return err;
        };
        /* Reconfigure flows. Do not care for errors. */
        if (!priv->rss) {
                rxq_mac_addrs_add(&tmpl);
                if (priv->promisc)
                        rxq_promiscuous_enable(&tmpl);
                if (priv->allmulti)
                        rxq_allmulticast_enable(&tmpl);
                /* Update original queue in case of failure. */
                rxq->allmulti_flow = tmpl.allmulti_flow;
                rxq->promisc_flow = tmpl.promisc_flow;
                memcpy(rxq->mac_configured, tmpl.mac_configured,
                       sizeof(rxq->mac_configured));
                memcpy(rxq->mac_flow, tmpl.mac_flow, sizeof(rxq->mac_flow));
        }
        /* Allocate pool. */
        pool = rte_malloc(__func__, (mbuf_n * sizeof(*pool)), 0);
        if (pool == NULL) {
                ERROR("%p: cannot allocate memory", (void *)dev);
                return ENOBUFS;
        }
        /* Snatch mbufs from original queue. */
        k = 0;
        if (rxq->sp) {
                struct rxq_elt_sp (*elts)[rxq->elts_n] = rxq->elts.sp;

                for (i = 0; (i != elemof(*elts)); ++i) {
                        struct rxq_elt_sp *elt = &(*elts)[i];
                        unsigned int j;

                        for (j = 0; (j != elemof(elt->bufs)); ++j) {
                                assert(elt->bufs[j] != NULL);
                                pool[k++] = elt->bufs[j];
                        }
                }
        } else {
                struct rxq_elt (*elts)[rxq->elts_n] = rxq->elts.no_sp;

                for (i = 0; (i != elemof(*elts)); ++i) {
                        struct rxq_elt *elt = &(*elts)[i];
                        struct rte_mbuf *buf = (void *)
                                (elt->sge.addr - WR_ID(elt->wr.wr_id).offset);

                        assert(WR_ID(elt->wr.wr_id).id == i);
                        pool[k++] = buf;
                }
        }
        assert(k == mbuf_n);
        tmpl.elts_n = 0;
        tmpl.elts.sp = NULL;
        assert((void *)&tmpl.elts.sp == (void *)&tmpl.elts.no_sp);
        err = ((tmpl.sp) ?
               rxq_alloc_elts_sp(&tmpl, desc_n, pool) :
               rxq_alloc_elts(&tmpl, desc_n, pool));
        if (err) {
                ERROR("%p: cannot reallocate WRs, aborting", (void *)dev);
                rte_free(pool);
                assert(err > 0);
                return err;
        }
        assert(tmpl.elts_n == desc_n);
        assert(tmpl.elts.sp != NULL);
        rte_free(pool);
        /* Clean up original data. */
        rxq->elts_n = 0;
        rte_free(rxq->elts.sp);
        rxq->elts.sp = NULL;
        /* Post WRs. */
        err = ibv_post_recv(tmpl.qp,
                            (tmpl.sp ?
                             &(*tmpl.elts.sp)[0].wr :
                             &(*tmpl.elts.no_sp)[0].wr),
                            &bad_wr);
        if (err) {
                ERROR("%p: ibv_post_recv() failed for WR %p: %s",
                      (void *)dev,
                      (void *)bad_wr,
                      strerror(err));
                goto skip_rtr;
        }
        mod = (struct ibv_exp_qp_attr){
                .qp_state = IBV_QPS_RTR
        };
        err = ibv_exp_modify_qp(tmpl.qp, &mod, IBV_EXP_QP_STATE);
        if (err)
                ERROR("%p: QP state to IBV_QPS_RTR failed: %s",
                      (void *)dev, strerror(err));
skip_rtr:
        *rxq = tmpl;
        assert(err >= 0);
        return err;
}

/**
 * Configure a RX queue.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param rxq
 *   Pointer to RX queue structure.
 * @param desc
 *   Number of descriptors to configure in queue.
 * @param socket
 *   NUMA socket on which memory must be allocated.
 * @param[in] conf
 *   Thresholds parameters.
 * @param mp
 *   Memory pool for buffer allocations.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
rxq_setup(struct rte_eth_dev *dev, struct rxq *rxq, uint16_t desc,
          unsigned int socket, const struct rte_eth_rxconf *conf,
          struct rte_mempool *mp)
{
        struct priv *priv = dev->data->dev_private;
        struct rxq tmpl = {
                .priv = priv,
                .mp = mp,
                .socket = socket
        };
        struct ibv_exp_qp_attr mod;
        struct ibv_recv_wr *bad_wr;
        struct rte_mbuf *buf;
        int ret = 0;
        int parent = (rxq == &priv->rxq_parent);

        (void)conf; /* Thresholds configuration (ignored). */
        /*
         * If this is a parent queue, hardware must support RSS and
         * RSS must be enabled.
         */
        assert((!parent) || ((priv->hw_rss) && (priv->rss)));
        if (parent) {
                /* Even if unused, ibv_create_cq() requires at least one
                 * descriptor. */
                desc = 1;
                goto skip_mr;
        }
        if ((desc == 0) || (desc % MLX4_PMD_SGE_WR_N)) {
                ERROR("%p: invalid number of RX descriptors (must be a"
                      " multiple of %d)", (void *)dev, desc);
                return EINVAL;
        }
        /* Get mbuf length. */
        buf = rte_pktmbuf_alloc(mp);
        if (buf == NULL) {
                ERROR("%p: unable to allocate mbuf", (void *)dev);
                return ENOMEM;
        }
        tmpl.mb_len = buf->buf_len;
        assert((rte_pktmbuf_headroom(buf) +
                rte_pktmbuf_tailroom(buf)) == tmpl.mb_len);
        assert(rte_pktmbuf_headroom(buf) == RTE_PKTMBUF_HEADROOM);
        rte_pktmbuf_free(buf);
        /* Enable scattered packets support for this queue if necessary. */
        if ((dev->data->dev_conf.rxmode.jumbo_frame) &&
            (dev->data->dev_conf.rxmode.max_rx_pkt_len >
             (tmpl.mb_len - RTE_PKTMBUF_HEADROOM))) {
                tmpl.sp = 1;
                desc /= MLX4_PMD_SGE_WR_N;
        }
        DEBUG("%p: %s scattered packets support (%u WRs)",
              (void *)dev, (tmpl.sp ? "enabling" : "disabling"), desc);
        /* Use the entire RX mempool as the memory region. */
        tmpl.mr = ibv_reg_mr(priv->pd,
                             (void *)mp->elt_va_start,
                             (mp->elt_va_end - mp->elt_va_start),
                             (IBV_ACCESS_LOCAL_WRITE |
                              IBV_ACCESS_REMOTE_WRITE));
        if (tmpl.mr == NULL) {
                ret = EINVAL;
                ERROR("%p: MR creation failure: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
skip_mr:
        tmpl.cq = ibv_create_cq(priv->ctx, desc, NULL, NULL, 0);
        if (tmpl.cq == NULL) {
                ret = ENOMEM;
                ERROR("%p: CQ creation failure: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        DEBUG("priv->device_attr.max_qp_wr is %d",
              priv->device_attr.max_qp_wr);
        DEBUG("priv->device_attr.max_sge is %d",
              priv->device_attr.max_sge);
#ifdef RSS_SUPPORT
        if (priv->rss)
                tmpl.qp = rxq_setup_qp_rss(priv, tmpl.cq, desc, parent);
        else
#endif /* RSS_SUPPORT */
                tmpl.qp = rxq_setup_qp(priv, tmpl.cq, desc);
        if (tmpl.qp == NULL) {
                ret = (errno ? errno : EINVAL);
                ERROR("%p: QP creation failure: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        mod = (struct ibv_exp_qp_attr){
                /* Move the QP to this state. */
                .qp_state = IBV_QPS_INIT,
                /* Primary port number. */
                .port_num = priv->port
        };
        ret = ibv_exp_modify_qp(tmpl.qp, &mod,
                                (IBV_EXP_QP_STATE |
#ifdef RSS_SUPPORT
                                 (parent ? IBV_EXP_QP_GROUP_RSS : 0) |
#endif /* RSS_SUPPORT */
                                 IBV_EXP_QP_PORT));
        if (ret) {
                ERROR("%p: QP state to IBV_QPS_INIT failed: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        if ((parent) || (!priv->rss))  {
                /* Configure MAC and broadcast addresses. */
                ret = rxq_mac_addrs_add(&tmpl);
                if (ret) {
                        ERROR("%p: QP flow attachment failed: %s",
                              (void *)dev, strerror(ret));
                        goto error;
                }
        }
        /* Allocate descriptors for RX queues, except for the RSS parent. */
        if (parent)
                goto skip_alloc;
        if (tmpl.sp)
                ret = rxq_alloc_elts_sp(&tmpl, desc, NULL);
        else
                ret = rxq_alloc_elts(&tmpl, desc, NULL);
        if (ret) {
                ERROR("%p: RXQ allocation failed: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        ret = ibv_post_recv(tmpl.qp,
                            (tmpl.sp ?
                             &(*tmpl.elts.sp)[0].wr :
                             &(*tmpl.elts.no_sp)[0].wr),
                            &bad_wr);
        if (ret) {
                ERROR("%p: ibv_post_recv() failed for WR %p: %s",
                      (void *)dev,
                      (void *)bad_wr,
                      strerror(ret));
                goto error;
        }
skip_alloc:
        mod = (struct ibv_exp_qp_attr){
                .qp_state = IBV_QPS_RTR
        };
        ret = ibv_exp_modify_qp(tmpl.qp, &mod, IBV_EXP_QP_STATE);
        if (ret) {
                ERROR("%p: QP state to IBV_QPS_RTR failed: %s",
                      (void *)dev, strerror(ret));
                goto error;
        }
        /* Save port ID. */
        tmpl.port_id = dev->data->port_id;
        DEBUG("%p: RTE port ID: %u", (void *)rxq, tmpl.port_id);
        /* Clean up rxq in case we're reinitializing it. */
        DEBUG("%p: cleaning-up old rxq just in case", (void *)rxq);
        rxq_cleanup(rxq);
        *rxq = tmpl;
        DEBUG("%p: rxq updated with %p", (void *)rxq, (void *)&tmpl);
        assert(ret == 0);
        return 0;
error:
        rxq_cleanup(&tmpl);
        assert(ret > 0);
        return ret;
}

/**
 * DPDK callback to configure a RX queue.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param idx
 *   RX queue index.
 * @param desc
 *   Number of descriptors to configure in queue.
 * @param socket
 *   NUMA socket on which memory must be allocated.
 * @param[in] conf
 *   Thresholds parameters.
 * @param mp
 *   Memory pool for buffer allocations.
 *
 * @return
 *   0 on success, negative errno value on failure.
 */
static int
mlx4_rx_queue_setup(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
                    unsigned int socket, const struct rte_eth_rxconf *conf,
                    struct rte_mempool *mp)
{
        struct priv *priv = dev->data->dev_private;
        struct rxq *rxq = (*priv->rxqs)[idx];
        int ret;

        priv_lock(priv);
        DEBUG("%p: configuring queue %u for %u descriptors",
              (void *)dev, idx, desc);
        if (idx >= priv->rxqs_n) {
                ERROR("%p: queue index out of range (%u >= %u)",
                      (void *)dev, idx, priv->rxqs_n);
                priv_unlock(priv);
                return -EOVERFLOW;
        }
        if (rxq != NULL) {
                DEBUG("%p: reusing already allocated queue index %u (%p)",
                      (void *)dev, idx, (void *)rxq);
                if (priv->started) {
                        priv_unlock(priv);
                        return -EEXIST;
                }
                (*priv->rxqs)[idx] = NULL;
                rxq_cleanup(rxq);
        } else {
                rxq = rte_calloc_socket("RXQ", 1, sizeof(*rxq), 0, socket);
                if (rxq == NULL) {
                        ERROR("%p: unable to allocate queue index %u",
                              (void *)dev, idx);
                        priv_unlock(priv);
                        return -ENOMEM;
                }
        }
        ret = rxq_setup(dev, rxq, desc, socket, conf, mp);
        if (ret)
                rte_free(rxq);
        else {
                rxq->stats.idx = idx;
                DEBUG("%p: adding RX queue %p to list",
                      (void *)dev, (void *)rxq);
                (*priv->rxqs)[idx] = rxq;
                /* Update receive callback. */
                if (rxq->sp)
                        dev->rx_pkt_burst = mlx4_rx_burst_sp;
                else
                        dev->rx_pkt_burst = mlx4_rx_burst;
        }
        priv_unlock(priv);
        return -ret;
}

/**
 * DPDK callback to release a RX queue.
 *
 * @param dpdk_rxq
 *   Generic RX queue pointer.
 */
static void
mlx4_rx_queue_release(void *dpdk_rxq)
{
        struct rxq *rxq = (struct rxq *)dpdk_rxq;
        struct priv *priv;
        unsigned int i;

        if (rxq == NULL)
                return;
        priv = rxq->priv;
        priv_lock(priv);
        assert(rxq != &priv->rxq_parent);
        for (i = 0; (i != priv->rxqs_n); ++i)
                if ((*priv->rxqs)[i] == rxq) {
                        DEBUG("%p: removing RX queue %p from list",
                              (void *)priv->dev, (void *)rxq);
                        (*priv->rxqs)[i] = NULL;
                        break;
                }
        rxq_cleanup(rxq);
        rte_free(rxq);
        priv_unlock(priv);
}

/**
 * DPDK callback to start the device.
 *
 * Simulate device start by attaching all configured flows.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 *
 * @return
 *   0 on success, negative errno value on failure.
 */
static int
mlx4_dev_start(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int i = 0;
        unsigned int r;
        struct rxq *rxq;

        priv_lock(priv);
        if (priv->started) {
                priv_unlock(priv);
                return 0;
        }
        DEBUG("%p: attaching configured flows to all RX queues", (void *)dev);
        priv->started = 1;
        if (priv->rss) {
                rxq = &priv->rxq_parent;
                r = 1;
        } else {
                rxq = (*priv->rxqs)[0];
                r = priv->rxqs_n;
        }
        /* Iterate only once when RSS is enabled. */
        do {
                int ret;

                /* Ignore nonexistent RX queues. */
                if (rxq == NULL)
                        continue;
                ret = rxq_mac_addrs_add(rxq);
                if (!ret && priv->promisc)
                        ret = rxq_promiscuous_enable(rxq);
                if (!ret && priv->allmulti)
                        ret = rxq_allmulticast_enable(rxq);
                if (!ret)
                        continue;
                WARN("%p: QP flow attachment failed: %s",
                     (void *)dev, strerror(ret));
                /* Rollback. */
                while (i != 0) {
                        rxq = (*priv->rxqs)[--i];
                        if (rxq != NULL) {
                                rxq_allmulticast_disable(rxq);
                                rxq_promiscuous_disable(rxq);
                                rxq_mac_addrs_del(rxq);
                        }
                }
                priv->started = 0;
                return -ret;
        } while ((--r) && ((rxq = (*priv->rxqs)[++i]), i));
        priv_unlock(priv);
        return 0;
}

/**
 * DPDK callback to stop the device.
 *
 * Simulate device stop by detaching all configured flows.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 */
static void
mlx4_dev_stop(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int i = 0;
        unsigned int r;
        struct rxq *rxq;

        priv_lock(priv);
        if (!priv->started) {
                priv_unlock(priv);
                return;
        }
        DEBUG("%p: detaching flows from all RX queues", (void *)dev);
        priv->started = 0;
        if (priv->rss) {
                rxq = &priv->rxq_parent;
                r = 1;
        } else {
                rxq = (*priv->rxqs)[0];
                r = priv->rxqs_n;
        }
        /* Iterate only once when RSS is enabled. */
        do {
                /* Ignore nonexistent RX queues. */
                if (rxq == NULL)
                        continue;
                rxq_allmulticast_disable(rxq);
                rxq_promiscuous_disable(rxq);
                rxq_mac_addrs_del(rxq);
        } while ((--r) && ((rxq = (*priv->rxqs)[++i]), i));
        priv_unlock(priv);
}

/**
 * Dummy DPDK callback for TX.
 *
 * This function is used to temporarily replace the real callback during
 * unsafe control operations on the queue, or in case of error.
 *
 * @param dpdk_txq
 *   Generic pointer to TX queue structure.
 * @param[in] pkts
 *   Packets to transmit.
 * @param pkts_n
 *   Number of packets in array.
 *
 * @return
 *   Number of packets successfully transmitted (<= pkts_n).
 */
static uint16_t
removed_tx_burst(void *dpdk_txq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
        (void)dpdk_txq;
        (void)pkts;
        (void)pkts_n;
        return 0;
}

/**
 * Dummy DPDK callback for RX.
 *
 * This function is used to temporarily replace the real callback during
 * unsafe control operations on the queue, or in case of error.
 *
 * @param dpdk_rxq
 *   Generic pointer to RX queue structure.
 * @param[out] pkts
 *   Array to store received packets.
 * @param pkts_n
 *   Maximum number of packets in array.
 *
 * @return
 *   Number of packets successfully received (<= pkts_n).
 */
static uint16_t
removed_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
        (void)dpdk_rxq;
        (void)pkts;
        (void)pkts_n;
        return 0;
}

/**
 * DPDK callback to close the device.
 *
 * Destroy all queues and objects, free memory.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 */
static void
mlx4_dev_close(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        void *tmp;
        unsigned int i;

        priv_lock(priv);
        DEBUG("%p: closing device \"%s\"",
              (void *)dev,
              ((priv->ctx != NULL) ? priv->ctx->device->name : ""));
        /* Prevent crashes when queues are still in use. This is unfortunately
         * still required for DPDK 1.3 because some programs (such as testpmd)
         * never release them before closing the device. */
        dev->rx_pkt_burst = removed_rx_burst;
        dev->tx_pkt_burst = removed_tx_burst;
        if (priv->rxqs != NULL) {
                /* XXX race condition if mlx4_rx_burst() is still running. */
                usleep(1000);
                for (i = 0; (i != priv->rxqs_n); ++i) {
                        tmp = (*priv->rxqs)[i];
                        if (tmp == NULL)
                                continue;
                        (*priv->rxqs)[i] = NULL;
                        rxq_cleanup(tmp);
                        rte_free(tmp);
                }
                priv->rxqs_n = 0;
                priv->rxqs = NULL;
        }
        if (priv->txqs != NULL) {
                /* XXX race condition if mlx4_tx_burst() is still running. */
                usleep(1000);
                for (i = 0; (i != priv->txqs_n); ++i) {
                        tmp = (*priv->txqs)[i];
                        if (tmp == NULL)
                                continue;
                        (*priv->txqs)[i] = NULL;
                        txq_cleanup(tmp);
                        rte_free(tmp);
                }
                priv->txqs_n = 0;
                priv->txqs = NULL;
        }
        if (priv->rss)
                rxq_cleanup(&priv->rxq_parent);
        if (priv->pd != NULL) {
                assert(priv->ctx != NULL);
                claim_zero(ibv_dealloc_pd(priv->pd));
                claim_zero(ibv_close_device(priv->ctx));
        } else
                assert(priv->ctx == NULL);
        priv_unlock(priv);
        memset(priv, 0, sizeof(*priv));
}

/**
 * DPDK callback to get information about the device.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param[out] info
 *   Info structure output buffer.
 */
static void
mlx4_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *info)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int max;

        priv_lock(priv);
        /* FIXME: we should ask the device for these values. */
        info->min_rx_bufsize = 32;
        info->max_rx_pktlen = 65536;
        /*
         * Since we need one CQ per QP, the limit is the minimum number
         * between the two values.
         */
        max = ((priv->device_attr.max_cq > priv->device_attr.max_qp) ?
               priv->device_attr.max_qp : priv->device_attr.max_cq);
        /* If max >= 65535 then max = 0, max_rx_queues is uint16_t. */
        if (max >= 65535)
                max = 65535;
        info->max_rx_queues = max;
        info->max_tx_queues = max;
        info->max_mac_addrs = elemof(priv->mac);
        priv_unlock(priv);
}

/**
 * DPDK callback to get device statistics.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param[out] stats
 *   Stats structure output buffer.
 */
static void
mlx4_stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *stats)
{
        struct priv *priv = dev->data->dev_private;
        struct rte_eth_stats tmp = { .ipackets = 0 };
        unsigned int i;
        unsigned int idx;

        priv_lock(priv);
        /* Add software counters. */
        for (i = 0; (i != priv->rxqs_n); ++i) {
                struct rxq *rxq = (*priv->rxqs)[i];

                if (rxq == NULL)
                        continue;
                idx = rxq->stats.idx;
                if (idx < RTE_ETHDEV_QUEUE_STAT_CNTRS) {
#ifdef MLX4_PMD_SOFT_COUNTERS
                        tmp.q_ipackets[idx] += rxq->stats.ipackets;
                        tmp.q_ibytes[idx] += rxq->stats.ibytes;
#endif
                        tmp.q_errors[idx] += (rxq->stats.idropped +
                                              rxq->stats.rx_nombuf);
                }
#ifdef MLX4_PMD_SOFT_COUNTERS
                tmp.ipackets += rxq->stats.ipackets;
                tmp.ibytes += rxq->stats.ibytes;
#endif
                tmp.ierrors += rxq->stats.idropped;
                tmp.rx_nombuf += rxq->stats.rx_nombuf;
        }
        for (i = 0; (i != priv->txqs_n); ++i) {
                struct txq *txq = (*priv->txqs)[i];

                if (txq == NULL)
                        continue;
                idx = txq->stats.idx;
                if (idx < RTE_ETHDEV_QUEUE_STAT_CNTRS) {
#ifdef MLX4_PMD_SOFT_COUNTERS
                        tmp.q_opackets[idx] += txq->stats.opackets;
                        tmp.q_obytes[idx] += txq->stats.obytes;
#endif
                        tmp.q_errors[idx] += txq->stats.odropped;
                }
#ifdef MLX4_PMD_SOFT_COUNTERS
                tmp.opackets += txq->stats.opackets;
                tmp.obytes += txq->stats.obytes;
#endif
                tmp.oerrors += txq->stats.odropped;
        }
#ifndef MLX4_PMD_SOFT_COUNTERS
        /* FIXME: retrieve and add hardware counters. */
#endif
        *stats = tmp;
        priv_unlock(priv);
}

/**
 * DPDK callback to clear device statistics.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 */
static void
mlx4_stats_reset(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int i;
        unsigned int idx;

        priv_lock(priv);
        for (i = 0; (i != priv->rxqs_n); ++i) {
                if ((*priv->rxqs)[i] == NULL)
                        continue;
                idx = (*priv->rxqs)[i]->stats.idx;
                (*priv->rxqs)[i]->stats =
                        (struct mlx4_rxq_stats){ .idx = idx };
        }
        for (i = 0; (i != priv->txqs_n); ++i) {
                if ((*priv->txqs)[i] == NULL)
                        continue;
                idx = (*priv->rxqs)[i]->stats.idx;
                (*priv->txqs)[i]->stats =
                        (struct mlx4_txq_stats){ .idx = idx };
        }
#ifndef MLX4_PMD_SOFT_COUNTERS
        /* FIXME: reset hardware counters. */
#endif
        priv_unlock(priv);
}

/**
 * DPDK callback to remove a MAC address.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param index
 *   MAC address index.
 */
static void
mlx4_mac_addr_remove(struct rte_eth_dev *dev, uint32_t index)
{
        struct priv *priv = dev->data->dev_private;

        priv_lock(priv);
        DEBUG("%p: removing MAC address from index %" PRIu32,
              (void *)dev, index);
        if (index >= MLX4_MAX_MAC_ADDRESSES)
                goto end;
        /* Refuse to remove the broadcast address, this one is special. */
        if (!memcmp(priv->mac[index].addr_bytes, "\xff\xff\xff\xff\xff\xff",
                    ETHER_ADDR_LEN))
                goto end;
        priv_mac_addr_del(priv, index);
end:
        priv_unlock(priv);
}

/**
 * DPDK callback to add a MAC address.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param mac_addr
 *   MAC address to register.
 * @param index
 *   MAC address index.
 * @param vmdq
 *   VMDq pool index to associate address with (ignored).
 */
static void
mlx4_mac_addr_add(struct rte_eth_dev *dev, struct ether_addr *mac_addr,
                  uint32_t index, uint32_t vmdq)
{
        struct priv *priv = dev->data->dev_private;

        (void)vmdq;
        priv_lock(priv);
        DEBUG("%p: adding MAC address at index %" PRIu32,
              (void *)dev, index);
        if (index >= MLX4_MAX_MAC_ADDRESSES)
                goto end;
        /* Refuse to add the broadcast address, this one is special. */
        if (!memcmp(mac_addr->addr_bytes, "\xff\xff\xff\xff\xff\xff",
                    ETHER_ADDR_LEN))
                goto end;
        priv_mac_addr_add(priv, index,
                          (const uint8_t (*)[ETHER_ADDR_LEN])
                          mac_addr->addr_bytes);
end:
        priv_unlock(priv);
}

/**
 * DPDK callback to enable promiscuous mode.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 */
static void
mlx4_promiscuous_enable(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int i;
        int ret;

        priv_lock(priv);
        if (priv->promisc) {
                priv_unlock(priv);
                return;
        }
        /* If device isn't started, this is all we need to do. */
        if (!priv->started)
                goto end;
        if (priv->rss) {
                ret = rxq_promiscuous_enable(&priv->rxq_parent);
                if (ret) {
                        priv_unlock(priv);
                        return;
                }
                goto end;
        }
        for (i = 0; (i != priv->rxqs_n); ++i) {
                if ((*priv->rxqs)[i] == NULL)
                        continue;
                ret = rxq_promiscuous_enable((*priv->rxqs)[i]);
                if (!ret)
                        continue;
                /* Failure, rollback. */
                while (i != 0)
                        if ((*priv->rxqs)[--i] != NULL)
                                rxq_promiscuous_disable((*priv->rxqs)[i]);
                priv_unlock(priv);
                return;
        }
end:
        priv->promisc = 1;
        priv_unlock(priv);
}

/**
 * DPDK callback to disable promiscuous mode.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 */
static void
mlx4_promiscuous_disable(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int i;

        priv_lock(priv);
        if (!priv->promisc) {
                priv_unlock(priv);
                return;
        }
        if (priv->rss) {
                rxq_promiscuous_disable(&priv->rxq_parent);
                goto end;
        }
        for (i = 0; (i != priv->rxqs_n); ++i)
                if ((*priv->rxqs)[i] != NULL)
                        rxq_promiscuous_disable((*priv->rxqs)[i]);
end:
        priv->promisc = 0;
        priv_unlock(priv);
}

/**
 * DPDK callback to enable allmulti mode.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 */
static void
mlx4_allmulticast_enable(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int i;
        int ret;

        priv_lock(priv);
        if (priv->allmulti) {
                priv_unlock(priv);
                return;
        }
        /* If device isn't started, this is all we need to do. */
        if (!priv->started)
                goto end;
        if (priv->rss) {
                ret = rxq_allmulticast_enable(&priv->rxq_parent);
                if (ret) {
                        priv_unlock(priv);
                        return;
                }
                goto end;
        }
        for (i = 0; (i != priv->rxqs_n); ++i) {
                if ((*priv->rxqs)[i] == NULL)
                        continue;
                ret = rxq_allmulticast_enable((*priv->rxqs)[i]);
                if (!ret)
                        continue;
                /* Failure, rollback. */
                while (i != 0)
                        if ((*priv->rxqs)[--i] != NULL)
                                rxq_allmulticast_disable((*priv->rxqs)[i]);
                priv_unlock(priv);
                return;
        }
end:
        priv->allmulti = 1;
        priv_unlock(priv);
}

/**
 * DPDK callback to disable allmulti mode.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 */
static void
mlx4_allmulticast_disable(struct rte_eth_dev *dev)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int i;

        priv_lock(priv);
        if (!priv->allmulti) {
                priv_unlock(priv);
                return;
        }
        if (priv->rss) {
                rxq_allmulticast_disable(&priv->rxq_parent);
                goto end;
        }
        for (i = 0; (i != priv->rxqs_n); ++i)
                if ((*priv->rxqs)[i] != NULL)
                        rxq_allmulticast_disable((*priv->rxqs)[i]);
end:
        priv->allmulti = 0;
        priv_unlock(priv);
}

/**
 * DPDK callback to retrieve physical link information (unlocked version).
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param wait_to_complete
 *   Wait for request completion (ignored).
 */
static int
mlx4_link_update_unlocked(struct rte_eth_dev *dev, int wait_to_complete)
{
        struct priv *priv = dev->data->dev_private;
        struct ibv_port_attr port_attr;
        static const uint8_t width_mult[] = {
                /* Multiplier values taken from devinfo.c in libibverbs. */
                0, 1, 4, 0, 8, 0, 0, 0, 12, 0
        };

        (void)wait_to_complete;
        errno = ibv_query_port(priv->ctx, priv->port, &port_attr);
        if (errno) {
                WARN("port query failed: %s", strerror(errno));
                return -1;
        }
        dev->data->dev_link = (struct rte_eth_link){
                .link_speed = (ibv_rate_to_mbps(mult_to_ibv_rate
                                                (port_attr.active_speed)) *
                               width_mult[(port_attr.active_width %
                                           sizeof(width_mult))]),
                .link_duplex = ETH_LINK_FULL_DUPLEX,
                .link_status = (port_attr.state == IBV_PORT_ACTIVE)
        };
        if (memcmp(&port_attr, &priv->port_attr, sizeof(port_attr))) {
                /* Link status changed. */
                priv->port_attr = port_attr;
                return 0;
        }
        /* Link status is still the same. */
        return -1;
}

/**
 * DPDK callback to retrieve physical link information.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param wait_to_complete
 *   Wait for request completion (ignored).
 */
static int
mlx4_link_update(struct rte_eth_dev *dev, int wait_to_complete)
{
        struct priv *priv = dev->data->dev_private;
        int ret;

        priv_lock(priv);
        ret = mlx4_link_update_unlocked(dev, wait_to_complete);
        priv_unlock(priv);
        return ret;
}

/**
 * DPDK callback to change the MTU.
 *
 * Setting the MTU affects hardware MRU (packets larger than the MTU cannot be
 * received). Use this as a hint to enable/disable scattered packets support
 * and improve performance when not needed.
 * Since failure is not an option, reconfiguring queues on the fly is not
 * recommended.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param in_mtu
 *   New MTU.
 *
 * @return
 *   0 on success, negative errno value on failure.
 */
static int
mlx4_dev_set_mtu(struct rte_eth_dev *dev, uint16_t mtu)
{
        struct priv *priv = dev->data->dev_private;
        int ret = 0;
        unsigned int i;
        uint16_t (*rx_func)(void *, struct rte_mbuf **, uint16_t) =
                mlx4_rx_burst;

        priv_lock(priv);
        /* Set kernel interface MTU first. */
        if (priv_set_mtu(priv, mtu)) {
                ret = errno;
                WARN("cannot set port %u MTU to %u: %s", priv->port, mtu,
                     strerror(ret));
                goto out;
        } else
                DEBUG("adapter port %u MTU set to %u", priv->port, mtu);
        priv->mtu = mtu;
        /* Temporarily replace RX handler with a fake one, assuming it has not
         * been copied elsewhere. */
        dev->rx_pkt_burst = removed_rx_burst;
        /* Make sure everyone has left mlx4_rx_burst() and uses
         * removed_rx_burst() instead. */
        rte_wmb();
        usleep(1000);
        /* Reconfigure each RX queue. */
        for (i = 0; (i != priv->rxqs_n); ++i) {
                struct rxq *rxq = (*priv->rxqs)[i];
                unsigned int max_frame_len;
                int sp;

                if (rxq == NULL)
                        continue;
                /* Calculate new maximum frame length according to MTU and
                 * toggle scattered support (sp) if necessary. */
                max_frame_len = (priv->mtu + ETHER_HDR_LEN +
                                 (ETHER_MAX_VLAN_FRAME_LEN - ETHER_MAX_LEN));
                sp = (max_frame_len > (rxq->mb_len - RTE_PKTMBUF_HEADROOM));
                /* Provide new values to rxq_setup(). */
                dev->data->dev_conf.rxmode.jumbo_frame = sp;
                dev->data->dev_conf.rxmode.max_rx_pkt_len = max_frame_len;
                ret = rxq_rehash(dev, rxq);
                if (ret) {
                        /* Force SP RX if that queue requires it and abort. */
                        if (rxq->sp)
                                rx_func = mlx4_rx_burst_sp;
                        break;
                }
                /* Reenable non-RSS queue attributes. No need to check
                 * for errors at this stage. */
                if (!priv->rss) {
                        rxq_mac_addrs_add(rxq);
                        if (priv->promisc)
                                rxq_promiscuous_enable(rxq);
                        if (priv->allmulti)
                                rxq_allmulticast_enable(rxq);
                }
                /* Scattered burst function takes priority. */
                if (rxq->sp)
                        rx_func = mlx4_rx_burst_sp;
        }
        /* Burst functions can now be called again. */
        rte_wmb();
        dev->rx_pkt_burst = rx_func;
out:
        priv_unlock(priv);
        assert(ret >= 0);
        return -ret;
}

/**
 * DPDK callback to get flow control status.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param[out] fc_conf
 *   Flow control output buffer.
 *
 * @return
 *   0 on success, negative errno value on failure.
 */
static int
mlx4_dev_get_flow_ctrl(struct rte_eth_dev *dev, struct rte_eth_fc_conf *fc_conf)
{
        struct priv *priv = dev->data->dev_private;
        struct ifreq ifr;
        struct ethtool_pauseparam ethpause = {
                .cmd = ETHTOOL_GPAUSEPARAM
        };
        int ret;

        ifr.ifr_data = &ethpause;
        priv_lock(priv);
        if (priv_ifreq(priv, SIOCETHTOOL, &ifr)) {
                ret = errno;
                WARN("ioctl(SIOCETHTOOL, ETHTOOL_GPAUSEPARAM)"
                     " failed: %s",
                     strerror(ret));
                goto out;
        }

        fc_conf->autoneg = ethpause.autoneg;
        if (ethpause.rx_pause && ethpause.tx_pause)
                fc_conf->mode = RTE_FC_FULL;
        else if (ethpause.rx_pause)
                fc_conf->mode = RTE_FC_RX_PAUSE;
        else if (ethpause.tx_pause)
                fc_conf->mode = RTE_FC_TX_PAUSE;
        else
                fc_conf->mode = RTE_FC_NONE;
        ret = 0;

out:
        priv_unlock(priv);
        assert(ret >= 0);
        return -ret;
}

/**
 * DPDK callback to modify flow control parameters.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param[in] fc_conf
 *   Flow control parameters.
 *
 * @return
 *   0 on success, negative errno value on failure.
 */
static int
mlx4_dev_set_flow_ctrl(struct rte_eth_dev *dev, struct rte_eth_fc_conf *fc_conf)
{
        struct priv *priv = dev->data->dev_private;
        struct ifreq ifr;
        struct ethtool_pauseparam ethpause = {
                .cmd = ETHTOOL_SPAUSEPARAM
        };
        int ret;

        ifr.ifr_data = &ethpause;
        ethpause.autoneg = fc_conf->autoneg;
        if (((fc_conf->mode & RTE_FC_FULL) == RTE_FC_FULL) ||
            (fc_conf->mode & RTE_FC_RX_PAUSE))
                ethpause.rx_pause = 1;
        else
                ethpause.rx_pause = 0;

        if (((fc_conf->mode & RTE_FC_FULL) == RTE_FC_FULL) ||
            (fc_conf->mode & RTE_FC_TX_PAUSE))
                ethpause.tx_pause = 1;
        else
                ethpause.tx_pause = 0;

        priv_lock(priv);
        if (priv_ifreq(priv, SIOCETHTOOL, &ifr)) {
                ret = errno;
                WARN("ioctl(SIOCETHTOOL, ETHTOOL_SPAUSEPARAM)"
                     " failed: %s",
                     strerror(ret));
                goto out;
        }
        ret = 0;

out:
        priv_unlock(priv);
        assert(ret >= 0);
        return -ret;
}

/**
 * Configure a VLAN filter.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param vlan_id
 *   VLAN ID to filter.
 * @param on
 *   Toggle filter.
 *
 * @return
 *   0 on success, errno value on failure.
 */
static int
vlan_filter_set(struct rte_eth_dev *dev, uint16_t vlan_id, int on)
{
        struct priv *priv = dev->data->dev_private;
        unsigned int i;
        unsigned int j = -1;

        DEBUG("%p: %s VLAN filter ID %" PRIu16,
              (void *)dev, (on ? "enable" : "disable"), vlan_id);
        for (i = 0; (i != elemof(priv->vlan_filter)); ++i) {
                if (!priv->vlan_filter[i].enabled) {
                        /* Unused index, remember it. */
                        j = i;
                        continue;
                }
                if (priv->vlan_filter[i].id != vlan_id)
                        continue;
                /* This VLAN ID is already known, use its index. */
                j = i;
                break;
        }
        /* Check if there's room for another VLAN filter. */
        if (j == (unsigned int)-1)
                return ENOMEM;
        /*
         * VLAN filters apply to all configured MAC addresses, flow
         * specifications must be reconfigured accordingly.
         */
        priv->vlan_filter[j].id = vlan_id;
        if ((on) && (!priv->vlan_filter[j].enabled)) {
                /*
                 * Filter is disabled, enable it.
                 * Rehashing flows in all RX queues is necessary.
                 */
                if (priv->rss)
                        rxq_mac_addrs_del(&priv->rxq_parent);
                else
                        for (i = 0; (i != priv->rxqs_n); ++i)
                                if ((*priv->rxqs)[i] != NULL)
                                        rxq_mac_addrs_del((*priv->rxqs)[i]);
                priv->vlan_filter[j].enabled = 1;
                if (priv->started) {
                        if (priv->rss)
                                rxq_mac_addrs_add(&priv->rxq_parent);
                        else
                                for (i = 0; (i != priv->rxqs_n); ++i) {
                                        if ((*priv->rxqs)[i] == NULL)
                                                continue;
                                        rxq_mac_addrs_add((*priv->rxqs)[i]);
                                }
                }
        } else if ((!on) && (priv->vlan_filter[j].enabled)) {
                /*
                 * Filter is enabled, disable it.
                 * Rehashing flows in all RX queues is necessary.
                 */
                if (priv->rss)
                        rxq_mac_addrs_del(&priv->rxq_parent);
                else
                        for (i = 0; (i != priv->rxqs_n); ++i)
                                if ((*priv->rxqs)[i] != NULL)
                                        rxq_mac_addrs_del((*priv->rxqs)[i]);
                priv->vlan_filter[j].enabled = 0;
                if (priv->started) {
                        if (priv->rss)
                                rxq_mac_addrs_add(&priv->rxq_parent);
                        else
                                for (i = 0; (i != priv->rxqs_n); ++i) {
                                        if ((*priv->rxqs)[i] == NULL)
                                                continue;
                                        rxq_mac_addrs_add((*priv->rxqs)[i]);
                                }
                }
        }
        return 0;
}

/**
 * DPDK callback to configure a VLAN filter.
 *
 * @param dev
 *   Pointer to Ethernet device structure.
 * @param vlan_id
 *   VLAN ID to filter.
 * @param on
 *   Toggle filter.
 *
 * @return
 *   0 on success, negative errno value on failure.
 */
static int
mlx4_vlan_filter_set(struct rte_eth_dev *dev, uint16_t vlan_id, int on)
{
        struct priv *priv = dev->data->dev_private;
        int ret;

        priv_lock(priv);
        ret = vlan_filter_set(dev, vlan_id, on);
        priv_unlock(priv);
        assert(ret >= 0);
        return -ret;
}

static struct eth_dev_ops mlx4_dev_ops = {
        .dev_configure = mlx4_dev_configure,
        .dev_start = mlx4_dev_start,
        .dev_stop = mlx4_dev_stop,
        .dev_close = mlx4_dev_close,
        .promiscuous_enable = mlx4_promiscuous_enable,
        .promiscuous_disable = mlx4_promiscuous_disable,
        .allmulticast_enable = mlx4_allmulticast_enable,
        .allmulticast_disable = mlx4_allmulticast_disable,
        .link_update = mlx4_link_update,
        .stats_get = mlx4_stats_get,
        .stats_reset = mlx4_stats_reset,
        .queue_stats_mapping_set = NULL,
        .dev_infos_get = mlx4_dev_infos_get,
        .vlan_filter_set = mlx4_vlan_filter_set,
        .vlan_tpid_set = NULL,
        .vlan_strip_queue_set = NULL,
        .vlan_offload_set = NULL,
        .rx_queue_setup = mlx4_rx_queue_setup,
        .tx_queue_setup = mlx4_tx_queue_setup,
        .rx_queue_release = mlx4_rx_queue_release,
        .tx_queue_release = mlx4_tx_queue_release,
        .dev_led_on = NULL,
        .dev_led_off = NULL,
        .flow_ctrl_get = mlx4_dev_get_flow_ctrl,
        .flow_ctrl_set = mlx4_dev_set_flow_ctrl,
        .priority_flow_ctrl_set = NULL,
        .mac_addr_remove = mlx4_mac_addr_remove,
        .mac_addr_add = mlx4_mac_addr_add,
        .mtu_set = mlx4_dev_set_mtu,
        .fdir_add_signature_filter = NULL,
        .fdir_update_signature_filter = NULL,
        .fdir_remove_signature_filter = NULL,
        .fdir_add_perfect_filter = NULL,
        .fdir_update_perfect_filter = NULL,
        .fdir_remove_perfect_filter = NULL,
        .fdir_set_masks = NULL
};

/**
 * Get PCI information from struct ibv_device.
 *
 * @param device
 *   Pointer to Ethernet device structure.
 * @param[out] pci_addr
 *   PCI bus address output buffer.
 *
 * @return
 *   0 on success, -1 on failure and errno is set.
 */
static int
mlx4_ibv_device_to_pci_addr(const struct ibv_device *device,
                            struct rte_pci_addr *pci_addr)
{
        FILE *file;
        char line[32];
        MKSTR(path, "%s/device/uevent", device->ibdev_path);

        file = fopen(path, "rb");
        if (file == NULL)
                return -1;
        while (fgets(line, sizeof(line), file) == line) {
                size_t len = strlen(line);
                int ret;

                /* Truncate long lines. */
                if (len == (sizeof(line) - 1))
                        while (line[(len - 1)] != '\n') {
                                ret = fgetc(file);
                                if (ret == EOF)
                                        break;
                                line[(len - 1)] = ret;
                        }
                /* Extract information. */
                if (sscanf(line,
                           "PCI_SLOT_NAME="
                           "%" SCNx16 ":%" SCNx8 ":%" SCNx8 ".%" SCNx8 "\n",
                           &pci_addr->domain,
                           &pci_addr->bus,
                           &pci_addr->devid,
                           &pci_addr->function) == 4) {
                        ret = 0;
                        break;
                }
        }
        fclose(file);
        return 0;
}

/**
 * Derive MAC address from port GID.
 *
 * @param[out] mac
 *   MAC address output buffer.
 * @param port
 *   Physical port number.
 * @param[in] gid
 *   Port GID.
 */
static void
mac_from_gid(uint8_t (*mac)[ETHER_ADDR_LEN], uint32_t port, uint8_t *gid)
{
        memcpy(&(*mac)[0], gid + 8, 3);
        memcpy(&(*mac)[3], gid + 13, 3);
        if (port == 1)
                (*mac)[0] ^= 2;
}

/* Support up to 32 adapters. */
static struct {
        struct rte_pci_addr pci_addr; /* associated PCI address */
        uint32_t ports; /* physical ports bitfield. */
} mlx4_dev[32];

/**
 * Get device index in mlx4_dev[] from PCI bus address.
 *
 * @param[in] pci_addr
 *   PCI bus address to look for.
 *
 * @return
 *   mlx4_dev[] index on success, -1 on failure.
 */
static int
mlx4_dev_idx(struct rte_pci_addr *pci_addr)
{
        unsigned int i;
        int ret = -1;

        assert(pci_addr != NULL);
        for (i = 0; (i != elemof(mlx4_dev)); ++i) {
                if ((mlx4_dev[i].pci_addr.domain == pci_addr->domain) &&
                    (mlx4_dev[i].pci_addr.bus == pci_addr->bus) &&
                    (mlx4_dev[i].pci_addr.devid == pci_addr->devid) &&
                    (mlx4_dev[i].pci_addr.function == pci_addr->function))
                        return i;
                if ((mlx4_dev[i].ports == 0) && (ret == -1))
                        ret = i;
        }
        return ret;
}

/**
 * Retrieve integer value from environment variable.
 *
 * @param[in] name
 *   Environment variable name.
 *
 * @return
 *   Integer value, 0 if the variable is not set.
 */
static int
mlx4_getenv_int(const char *name)
{
        const char *val = getenv(name);

        if (val == NULL)
                return 0;
        return atoi(val);
}

static struct eth_driver mlx4_driver;

/**
 * DPDK callback to register a PCI device.
 *
 * This function creates an Ethernet device for each port of a given
 * PCI device.
 *
 * @param[in] pci_drv
 *   PCI driver structure (mlx4_driver).
 * @param[in] pci_dev
 *   PCI device information.
 *
 * @return
 *   0 on success, negative errno value on failure.
 */
static int
mlx4_pci_devinit(struct rte_pci_driver *pci_drv, struct rte_pci_device *pci_dev)
{
        struct ibv_device **list;
        struct ibv_device *ibv_dev;
        int err = 0;
        struct ibv_context *attr_ctx = NULL;
        struct ibv_device_attr device_attr;
        unsigned int vf;
        int idx;
        int i;

        (void)pci_drv;
        assert(pci_drv == &mlx4_driver.pci_drv);
        /* Get mlx4_dev[] index. */
        idx = mlx4_dev_idx(&pci_dev->addr);
        if (idx == -1) {
                ERROR("this driver cannot support any more adapters");
                return -ENOMEM;
        }
        DEBUG("using driver device index %d", idx);

        /* Save PCI address. */
        mlx4_dev[idx].pci_addr = pci_dev->addr;
        list = ibv_get_device_list(&i);
        if (list == NULL) {
                assert(errno);
                return -errno;
        }
        assert(i >= 0);
        /*
         * For each listed device, check related sysfs entry against
         * the provided PCI ID.
         */
        while (i != 0) {
                struct rte_pci_addr pci_addr;

                --i;
                DEBUG("checking device \"%s\"", list[i]->name);
                if (mlx4_ibv_device_to_pci_addr(list[i], &pci_addr))
                        continue;
                if ((pci_dev->addr.domain != pci_addr.domain) ||
                    (pci_dev->addr.bus != pci_addr.bus) ||
                    (pci_dev->addr.devid != pci_addr.devid) ||
                    (pci_dev->addr.function != pci_addr.function))
                        continue;
                vf = (pci_dev->id.device_id ==
                      PCI_DEVICE_ID_MELLANOX_CONNECTX3VF);
                INFO("PCI information matches, using device \"%s\" (VF: %s)",
                     list[i]->name, (vf ? "true" : "false"));
                attr_ctx = ibv_open_device(list[i]);
                err = errno;
                break;
        }
        if (attr_ctx == NULL) {
                if (err == 0)
                        err = ENODEV;
                ibv_free_device_list(list);
                assert(err > 0);
                return -err;
        }
        ibv_dev = list[i];

        DEBUG("device opened");
        if (ibv_query_device(attr_ctx, &device_attr))
                goto error;
        INFO("%u port(s) detected", device_attr.phys_port_cnt);

        for (i = 0; i < device_attr.phys_port_cnt; i++) {
                uint32_t port = i + 1; /* ports are indexed from one */
                uint32_t test = (1 << i);
                struct ibv_context *ctx = NULL;
                struct ibv_port_attr port_attr;
                struct ibv_pd *pd = NULL;
                struct priv *priv = NULL;
                struct rte_eth_dev *eth_dev;
#if defined(INLINE_RECV) || defined(RSS_SUPPORT)
                struct ibv_exp_device_attr exp_device_attr;
#endif
                struct ether_addr mac;
                union ibv_gid temp_gid;

#ifdef RSS_SUPPORT
                exp_device_attr.comp_mask =
                        (IBV_EXP_DEVICE_ATTR_EXP_CAP_FLAGS |
                         IBV_EXP_DEVICE_ATTR_RSS_TBL_SZ);
#endif /* RSS_SUPPORT */

                DEBUG("using port %u (%08" PRIx32 ")", port, test);

                ctx = ibv_open_device(ibv_dev);
                if (ctx == NULL)
                        goto port_error;

                /* Check port status. */
                err = ibv_query_port(ctx, port, &port_attr);
                if (err) {
                        ERROR("port query failed: %s", strerror(err));
                        goto port_error;
                }
                if (port_attr.state != IBV_PORT_ACTIVE)
                        WARN("bad state for port %d: \"%s\" (%d)",
                             port, ibv_port_state_str(port_attr.state),
                             port_attr.state);

                /* Allocate protection domain. */
                pd = ibv_alloc_pd(ctx);
                if (pd == NULL) {
                        ERROR("PD allocation failure");
                        err = ENOMEM;
                        goto port_error;
                }

                mlx4_dev[idx].ports |= test;

                /* from rte_ethdev.c */
                priv = rte_zmalloc("ethdev private structure",
                                   sizeof(*priv),
                                   RTE_CACHE_LINE_SIZE);
                if (priv == NULL) {
                        ERROR("priv allocation failure");
                        err = ENOMEM;
                        goto port_error;
                }

                priv->ctx = ctx;
                priv->device_attr = device_attr;
                priv->port_attr = port_attr;
                priv->port = port;
                priv->pd = pd;
                priv->mtu = ETHER_MTU;
#ifdef RSS_SUPPORT
                if (ibv_exp_query_device(ctx, &exp_device_attr)) {
                        INFO("experimental ibv_exp_query_device");
                        goto port_error;
                }
                if ((exp_device_attr.exp_device_cap_flags &
                     IBV_EXP_DEVICE_QPG) &&
                    (exp_device_attr.exp_device_cap_flags &
                     IBV_EXP_DEVICE_UD_RSS) &&
                    (exp_device_attr.comp_mask &
                     IBV_EXP_DEVICE_ATTR_RSS_TBL_SZ) &&
                    (exp_device_attr.max_rss_tbl_sz > 0)) {
                        priv->hw_qpg = 1;
                        priv->hw_rss = 1;
                        priv->max_rss_tbl_sz = exp_device_attr.max_rss_tbl_sz;
                } else {
                        priv->hw_qpg = 0;
                        priv->hw_rss = 0;
                        priv->max_rss_tbl_sz = 0;
                }
                priv->hw_tss = !!(exp_device_attr.exp_device_cap_flags &
                                  IBV_EXP_DEVICE_UD_TSS);
                DEBUG("device flags: %s%s%s",
                      (priv->hw_qpg ? "IBV_DEVICE_QPG " : ""),
                      (priv->hw_tss ? "IBV_DEVICE_TSS " : ""),
                      (priv->hw_rss ? "IBV_DEVICE_RSS " : ""));
                if (priv->hw_rss)
                        DEBUG("maximum RSS indirection table size: %u",
                              exp_device_attr.max_rss_tbl_sz);
#endif /* RSS_SUPPORT */

#ifdef INLINE_RECV
                priv->inl_recv_size = mlx4_getenv_int("MLX4_INLINE_RECV_SIZE");

                if (priv->inl_recv_size) {
                        exp_device_attr.comp_mask =
                                IBV_EXP_DEVICE_ATTR_INLINE_RECV_SZ;
                        if (ibv_exp_query_device(ctx, &exp_device_attr)) {
                                INFO("Couldn't query device for inline-receive"
                                     " capabilities.");
                                priv->inl_recv_size = 0;
                        } else {
                                if ((unsigned)exp_device_attr.inline_recv_sz <
                                    priv->inl_recv_size) {
                                        INFO("Max inline-receive (%d) <"
                                             " requested inline-receive (%u)",
                                             exp_device_attr.inline_recv_sz,
                                             priv->inl_recv_size);
                                        priv->inl_recv_size =
                                                exp_device_attr.inline_recv_sz;
                                }
                        }
                        INFO("Set inline receive size to %u",
                             priv->inl_recv_size);
                }
#endif /* INLINE_RECV */

#ifdef MLX4_COMPAT_VMWARE
                if (mlx4_getenv_int("MLX4_COMPAT_VMWARE"))
                        priv->vmware = 1;
#else /* MLX4_COMPAT_VMWARE */
                (void)mlx4_getenv_int;
#endif /* MLX4_COMPAT_VMWARE */
                priv->vf = vf;
                if (ibv_query_gid(ctx, port, 0, &temp_gid)) {
                        ERROR("ibv_query_gid() failure");
                        goto port_error;
                }
                /* Configure the first MAC address by default. */
                mac_from_gid(&mac.addr_bytes, port, temp_gid.raw);
                INFO("port %u MAC address is %02x:%02x:%02x:%02x:%02x:%02x",
                     priv->port,
                     mac.addr_bytes[0], mac.addr_bytes[1],
                     mac.addr_bytes[2], mac.addr_bytes[3],
                     mac.addr_bytes[4], mac.addr_bytes[5]);
                /* Register MAC and broadcast addresses. */
                claim_zero(priv_mac_addr_add(priv, 0,
                                             (const uint8_t (*)[ETHER_ADDR_LEN])
                                             mac.addr_bytes));
                claim_zero(priv_mac_addr_add(priv, 1,
                                             &(const uint8_t [ETHER_ADDR_LEN])
                                             { "\xff\xff\xff\xff\xff\xff" }));
#ifndef NDEBUG
                {
                        char ifname[IF_NAMESIZE];

                        if (priv_get_ifname(priv, &ifname) == 0)
                                DEBUG("port %u ifname is \"%s\"",
                                      priv->port, ifname);
                        else
                                DEBUG("port %u ifname is unknown", priv->port);
                }
#endif
                /* Get actual MTU if possible. */
                priv_get_mtu(priv, &priv->mtu);
                DEBUG("port %u MTU is %u", priv->port, priv->mtu);

                /* from rte_ethdev.c */
#if RTE_VERSION >= RTE_VERSION_NUM(1, 7, 0, 0)
                {
                        char name[RTE_ETH_NAME_MAX_LEN];

                        snprintf(name, sizeof(name), "%s port %u",
                                 ibv_get_device_name(ibv_dev), port);
                        eth_dev = rte_eth_dev_allocate(name);
                }
#else
                eth_dev = rte_eth_dev_allocate();
#endif
                if (eth_dev == NULL) {
                        ERROR("can not allocate rte ethdev");
                        err = ENOMEM;
                        goto port_error;
                }

                eth_dev->data->dev_private = priv;
                eth_dev->pci_dev = pci_dev;
                eth_dev->driver = &mlx4_driver;
                eth_dev->data->rx_mbuf_alloc_failed = 0;
#if RTE_VERSION >= RTE_VERSION_NUM(1, 7, 0, 0)
                eth_dev->data->mtu = ETHER_MTU;
#else
                eth_dev->data->max_frame_size = ETHER_MAX_LEN;
#endif

                priv->dev = eth_dev;
                eth_dev->dev_ops = &mlx4_dev_ops;
                eth_dev->data->mac_addrs = priv->mac;

                /* Bring Ethernet device up. */
                DEBUG("forcing Ethernet interface up");
                priv_set_flags(priv, ~IFF_UP, IFF_UP);
                continue;

port_error:
                if (priv)
                        rte_free(priv);
                if (pd)
                        claim_zero(ibv_dealloc_pd(pd));
                if (ctx)
                        claim_zero(ibv_close_device(ctx));
                break;
        }

        /*
         * XXX if something went wrong in the loop above, there is a resource
         * leak (ctx, pd, priv, dpdk ethdev) but we can do nothing about it as
         * long as the dpdk does not provide a way to deallocate a ethdev and a
         * way to enumerate the registered ethdevs to free the previous ones.
         */

        /* no port found, complain */
        if (!mlx4_dev[idx].ports) {
                err = ENODEV;
                goto error;
        }

error:
        if (attr_ctx)
                claim_zero(ibv_close_device(attr_ctx));
        if (list)
                ibv_free_device_list(list);
        assert(err >= 0);
        return -err;
}

static struct rte_pci_id mlx4_pci_id_map[] = {
        {
                .vendor_id = PCI_VENDOR_ID_MELLANOX,
                .device_id = PCI_DEVICE_ID_MELLANOX_CONNECTX3,
                .subsystem_vendor_id = PCI_ANY_ID,
                .subsystem_device_id = PCI_ANY_ID
        },
        {
                .vendor_id = PCI_VENDOR_ID_MELLANOX,
                .device_id = PCI_DEVICE_ID_MELLANOX_CONNECTX3PRO,
                .subsystem_vendor_id = PCI_ANY_ID,
                .subsystem_device_id = PCI_ANY_ID
        },
        {
                .vendor_id = PCI_VENDOR_ID_MELLANOX,
                .device_id = PCI_DEVICE_ID_MELLANOX_CONNECTX3VF,
                .subsystem_vendor_id = PCI_ANY_ID,
                .subsystem_device_id = PCI_ANY_ID
        },
        {
                .vendor_id = 0
        }
};

static struct eth_driver mlx4_driver = {
        .pci_drv = {
                .name = MLX4_DRIVER_NAME,
                .id_table = mlx4_pci_id_map,
                .devinit = mlx4_pci_devinit,
        },
        .dev_private_size = sizeof(struct priv)
};

/**
 * Driver initialization routine.
 */
static int
rte_mlx4_pmd_init(const char *name, const char *args)
{
        (void)name;
        (void)args;
        rte_eal_pci_register(&mlx4_driver.pci_drv);
        return 0;
}

static struct rte_driver rte_mlx4_driver = {
        .type = PMD_PDEV,
        .name = MLX4_DRIVER_NAME,
        .init = rte_mlx4_pmd_init,
};

PMD_REGISTER_DRIVER(rte_mlx4_driver)