examples/vhost/main.c

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2017 Intel Corporation
 */

#include <arpa/inet.h>
#include <getopt.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/virtio_net.h>
#include <linux/virtio_ring.h>
#include <signal.h>
#include <stdint.h>
#include <sys/eventfd.h>
#include <sys/param.h>
#include <unistd.h>

#include <rte_atomic.h>
#include <rte_cycles.h>
#include <rte_ethdev.h>
#include <rte_log.h>
#include <rte_string_fns.h>
#include <rte_malloc.h>
#include <rte_vhost.h>
#include <rte_ip.h>
#include <rte_tcp.h>
#include <rte_pause.h>

#include "main.h"

#ifndef MAX_QUEUES
#define MAX_QUEUES 128
#endif

/* the maximum number of external ports supported */
#define MAX_SUP_PORTS 1

#define MBUF_CACHE_SIZE 128
#define MBUF_DATA_SIZE  RTE_MBUF_DEFAULT_BUF_SIZE

#define BURST_TX_DRAIN_US 100   /* TX drain every ~100us */

#define BURST_RX_WAIT_US 15 /* Defines how long we wait between retries on RX */
#define BURST_RX_RETRIES 4      /* Number of retries on RX. */

#define JUMBO_FRAME_MAX_SIZE    0x2600

/* State of virtio device. */
#define DEVICE_MAC_LEARNING 0
#define DEVICE_RX           1
#define DEVICE_SAFE_REMOVE  2

/* Configurable number of RX/TX ring descriptors */
#define RTE_TEST_RX_DESC_DEFAULT 1024
#define RTE_TEST_TX_DESC_DEFAULT 512

#define INVALID_PORT_ID 0xFF

/* Max number of devices. Limited by vmdq. */
#define MAX_DEVICES 64

/* Maximum long option length for option parsing. */
#define MAX_LONG_OPT_SZ 64

/* mask of enabled ports */
static uint32_t enabled_port_mask = 0;

/* Promiscuous mode */
static uint32_t promiscuous;

/* number of devices/queues to support*/
static uint32_t num_queues = 0;
static uint32_t num_devices;

static struct rte_mempool *mbuf_pool;
static int mergeable;

/* Enable VM2VM communications. If this is disabled then the MAC address compare is skipped. */
typedef enum {
    VM2VM_DISABLED = 0,
    VM2VM_SOFTWARE = 1,
    VM2VM_HARDWARE = 2,
    VM2VM_LAST
} vm2vm_type;
static vm2vm_type vm2vm_mode = VM2VM_SOFTWARE;

/* Enable stats. */
static uint32_t enable_stats = 0;
/* Enable retries on RX. */
static uint32_t enable_retry = 1;

/* Disable TX checksum offload */
static uint32_t enable_tx_csum;

/* Disable TSO offload */
static uint32_t enable_tso;

static int client_mode;
static int dequeue_zero_copy;

static int builtin_net_driver;

/* Specify timeout (in useconds) between retries on RX. */
static uint32_t burst_rx_delay_time = BURST_RX_WAIT_US;
/* Specify the number of retries on RX. */
static uint32_t burst_rx_retry_num = BURST_RX_RETRIES;

/* Socket file paths. Can be set by user */
static char *socket_files;
static int nb_sockets;

/* empty vmdq configuration structure. Filled in programatically */
static struct rte_eth_conf vmdq_conf_default = {
    .rxmode = {
        .mq_mode        = ETH_MQ_RX_VMDQ_ONLY,
        .split_hdr_size = 0,
        /*
         * VLAN strip is necessary for 1G NIC such as I350,
         * this fixes bug of ipv4 forwarding in guest can't
         * forward pakets from one virtio dev to another virtio dev.
         */
        .offloads = DEV_RX_OFFLOAD_VLAN_STRIP,
    },

    .txmode = {
        .mq_mode = ETH_MQ_TX_NONE,
        .offloads = (DEV_TX_OFFLOAD_IPV4_CKSUM |
                 DEV_TX_OFFLOAD_TCP_CKSUM |
                 DEV_TX_OFFLOAD_VLAN_INSERT |
                 DEV_TX_OFFLOAD_MULTI_SEGS |
                 DEV_TX_OFFLOAD_TCP_TSO),
    },
    .rx_adv_conf = {
        /*
         * should be overridden separately in code with
         * appropriate values
         */
        .vmdq_rx_conf = {
            .nb_queue_pools = ETH_8_POOLS,
            .enable_default_pool = 0,
            .default_pool = 0,
            .nb_pool_maps = 0,
            .pool_map = {{0, 0},},
        },
    },
};


static unsigned lcore_ids[RTE_MAX_LCORE];
static uint16_t ports[RTE_MAX_ETHPORTS];
static unsigned num_ports = 0; 
static uint16_t num_pf_queues, num_vmdq_queues;
static uint16_t vmdq_pool_base, vmdq_queue_base;
static uint16_t queues_per_pool;

const uint16_t vlan_tags[] = {
    1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007,
    1008, 1009, 1010, 1011, 1012, 1013, 1014, 1015,
    1016, 1017, 1018, 1019, 1020, 1021, 1022, 1023,
    1024, 1025, 1026, 1027, 1028, 1029, 1030, 1031,
    1032, 1033, 1034, 1035, 1036, 1037, 1038, 1039,
    1040, 1041, 1042, 1043, 1044, 1045, 1046, 1047,
    1048, 1049, 1050, 1051, 1052, 1053, 1054, 1055,
    1056, 1057, 1058, 1059, 1060, 1061, 1062, 1063,
};

/* ethernet addresses of ports */
static struct ether_addr vmdq_ports_eth_addr[RTE_MAX_ETHPORTS];

static struct vhost_dev_tailq_list vhost_dev_list =
    TAILQ_HEAD_INITIALIZER(vhost_dev_list);

static struct lcore_info lcore_info[RTE_MAX_LCORE];

/* Used for queueing bursts of TX packets. */
struct mbuf_table {
    unsigned len;
    unsigned txq_id;
    struct rte_mbuf *m_table[MAX_PKT_BURST];
};

/* TX queue for each data core. */
struct mbuf_table lcore_tx_queue[RTE_MAX_LCORE];

#define MBUF_TABLE_DRAIN_TSC    ((rte_get_tsc_hz() + US_PER_S - 1) \
                 / US_PER_S * BURST_TX_DRAIN_US)
#define VLAN_HLEN       4

/*
 * Builds up the correct configuration for VMDQ VLAN pool map
 * according to the pool & queue limits.
 */
static inline int
get_eth_conf(struct rte_eth_conf *eth_conf, uint32_t num_devices)
{
    struct rte_eth_vmdq_rx_conf conf;
    struct rte_eth_vmdq_rx_conf *def_conf =
        &vmdq_conf_default.rx_adv_conf.vmdq_rx_conf;
    unsigned i;

    memset(&conf, 0, sizeof(conf));
    conf.nb_queue_pools = (enum rte_eth_nb_pools)num_devices;
    conf.nb_pool_maps = num_devices;
    conf.enable_loop_back = def_conf->enable_loop_back;
    conf.rx_mode = def_conf->rx_mode;

    for (i = 0; i < conf.nb_pool_maps; i++) {
        conf.pool_map[i].vlan_id = vlan_tags[ i ];
        conf.pool_map[i].pools = (1UL << i);
    }

    (void)(rte_memcpy(eth_conf, &vmdq_conf_default, sizeof(*eth_conf)));
    (void)(rte_memcpy(&eth_conf->rx_adv_conf.vmdq_rx_conf, &conf,
           sizeof(eth_conf->rx_adv_conf.vmdq_rx_conf)));
    return 0;
}

/*
 * Validate the device number according to the max pool number gotten form
 * dev_info. If the device number is invalid, give the error message and
 * return -1. Each device must have its own pool.
 */
static inline int
validate_num_devices(uint32_t max_nb_devices)
{
    if (num_devices > max_nb_devices) {
        RTE_LOG(ERR, VHOST_PORT, "invalid number of devices\n");
        return -1;
    }
    return 0;
}

/*
 * Initialises a given port using global settings and with the rx buffers
 * coming from the mbuf_pool passed as parameter
 */
static inline int
port_init(uint16_t port)
{
    struct rte_eth_dev_info dev_info;
    struct rte_eth_conf port_conf;
    struct rte_eth_rxconf *rxconf;
    struct rte_eth_txconf *txconf;
    int16_t rx_rings, tx_rings;
    uint16_t rx_ring_size, tx_ring_size;
    int retval;
    uint16_t q;

    /* The max pool number from dev_info will be used to validate the pool number specified in cmd line */
    rte_eth_dev_info_get (port, &dev_info);

    rxconf = &dev_info.default_rxconf;
    txconf = &dev_info.default_txconf;
    rxconf->rx_drop_en = 1;

    /*configure the number of supported virtio devices based on VMDQ limits */
    num_devices = dev_info.max_vmdq_pools;

    rx_ring_size = RTE_TEST_RX_DESC_DEFAULT;
    tx_ring_size = RTE_TEST_TX_DESC_DEFAULT;

    /*
     * When dequeue zero copy is enabled, guest Tx used vring will be
     * updated only when corresponding mbuf is freed. Thus, the nb_tx_desc
     * (tx_ring_size here) must be small enough so that the driver will
     * hit the free threshold easily and free mbufs timely. Otherwise,
     * guest Tx vring would be starved.
     */
    if (dequeue_zero_copy)
        tx_ring_size = 64;

    tx_rings = (uint16_t)rte_lcore_count();

    retval = validate_num_devices(MAX_DEVICES);
    if (retval < 0)
        return retval;

    /* Get port configuration. */
    retval = get_eth_conf(&port_conf, num_devices);
    if (retval < 0)
        return retval;
    /* NIC queues are divided into pf queues and vmdq queues.  */
    num_pf_queues = dev_info.max_rx_queues - dev_info.vmdq_queue_num;
    queues_per_pool = dev_info.vmdq_queue_num / dev_info.max_vmdq_pools;
    num_vmdq_queues = num_devices * queues_per_pool;
    num_queues = num_pf_queues + num_vmdq_queues;
    vmdq_queue_base = dev_info.vmdq_queue_base;
    vmdq_pool_base  = dev_info.vmdq_pool_base;
    printf("pf queue num: %u, configured vmdq pool num: %u, each vmdq pool has %u queues\n",
        num_pf_queues, num_devices, queues_per_pool);

    if (!rte_eth_dev_is_valid_port(port))
        return -1;

    rx_rings = (uint16_t)dev_info.max_rx_queues;
    if (dev_info.tx_offload_capa & DEV_TX_OFFLOAD_MBUF_FAST_FREE)
        port_conf.txmode.offloads |=
            DEV_TX_OFFLOAD_MBUF_FAST_FREE;
    /* Configure ethernet device. */
    retval = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf);
    if (retval != 0) {
        RTE_LOG(ERR, VHOST_PORT, "Failed to configure port %u: %s.\n",
            port, strerror(-retval));
        return retval;
    }

    retval = rte_eth_dev_adjust_nb_rx_tx_desc(port, &rx_ring_size,
        &tx_ring_size);
    if (retval != 0) {
        RTE_LOG(ERR, VHOST_PORT, "Failed to adjust number of descriptors "
            "for port %u: %s.\n", port, strerror(-retval));
        return retval;
    }
    if (rx_ring_size > RTE_TEST_RX_DESC_DEFAULT) {
        RTE_LOG(ERR, VHOST_PORT, "Mbuf pool has an insufficient size "
            "for Rx queues on port %u.\n", port);
        return -1;
    }

    /* Setup the queues. */
    rxconf->offloads = port_conf.rxmode.offloads;
    for (q = 0; q < rx_rings; q ++) {
        retval = rte_eth_rx_queue_setup(port, q, rx_ring_size,
                        rte_eth_dev_socket_id(port),
                        rxconf,
                        mbuf_pool);
        if (retval < 0) {
            RTE_LOG(ERR, VHOST_PORT,
                "Failed to setup rx queue %u of port %u: %s.\n",
                q, port, strerror(-retval));
            return retval;
        }
    }
    txconf->offloads = port_conf.txmode.offloads;
    for (q = 0; q < tx_rings; q ++) {
        retval = rte_eth_tx_queue_setup(port, q, tx_ring_size,
                        rte_eth_dev_socket_id(port),
                        txconf);
        if (retval < 0) {
            RTE_LOG(ERR, VHOST_PORT,
                "Failed to setup tx queue %u of port %u: %s.\n",
                q, port, strerror(-retval));
            return retval;
        }
    }

    /* Start the device. */
    retval  = rte_eth_dev_start(port);
    if (retval < 0) {
        RTE_LOG(ERR, VHOST_PORT, "Failed to start port %u: %s\n",
            port, strerror(-retval));
        return retval;
    }

    if (promiscuous)
        rte_eth_promiscuous_enable(port);

    rte_eth_macaddr_get(port, &vmdq_ports_eth_addr[port]);
    RTE_LOG(INFO, VHOST_PORT, "Max virtio devices supported: %u\n", num_devices);
    RTE_LOG(INFO, VHOST_PORT, "Port %u MAC: %02"PRIx8" %02"PRIx8" %02"PRIx8
            " %02"PRIx8" %02"PRIx8" %02"PRIx8"\n",
            port,
            vmdq_ports_eth_addr[port].addr_bytes[0],
            vmdq_ports_eth_addr[port].addr_bytes[1],
            vmdq_ports_eth_addr[port].addr_bytes[2],
            vmdq_ports_eth_addr[port].addr_bytes[3],
            vmdq_ports_eth_addr[port].addr_bytes[4],
            vmdq_ports_eth_addr[port].addr_bytes[5]);

    return 0;
}

/*
 * Set socket file path.
 */
static int
us_vhost_parse_socket_path(const char *q_arg)
{
    char *old;

    /* parse number string */
    if (strnlen(q_arg, PATH_MAX) == PATH_MAX)
        return -1;

    old = socket_files;
    socket_files = realloc(socket_files, PATH_MAX * (nb_sockets + 1));
    if (socket_files == NULL) {
        free(old);
        return -1;
    }

    snprintf(socket_files + nb_sockets * PATH_MAX, PATH_MAX, "%s", q_arg);
    nb_sockets++;

    return 0;
}

/*
 * Parse the portmask provided at run time.
 */
static int
parse_portmask(const char *portmask)
{
    char *end = NULL;
    unsigned long pm;

    errno = 0;

    /* parse hexadecimal string */
    pm = strtoul(portmask, &end, 16);
    if ((portmask[0] == '\0') || (end == NULL) || (*end != '\0') || (errno != 0))
        return -1;

    if (pm == 0)
        return -1;

    return pm;

}

/*
 * Parse num options at run time.
 */
static int
parse_num_opt(const char *q_arg, uint32_t max_valid_value)
{
    char *end = NULL;
    unsigned long num;

    errno = 0;

    /* parse unsigned int string */
    num = strtoul(q_arg, &end, 10);
    if ((q_arg[0] == '\0') || (end == NULL) || (*end != '\0') || (errno != 0))
        return -1;

    if (num > max_valid_value)
        return -1;

    return num;

}

/*
 * Display usage
 */
static void
us_vhost_usage(const char *prgname)
{
    RTE_LOG(INFO, VHOST_CONFIG, "%s [EAL options] -- -p PORTMASK\n"
    "       --vm2vm [0|1|2]\n"
    "       --rx_retry [0|1] --mergeable [0|1] --stats [0-N]\n"
    "       --socket-file <path>\n"
    "       --nb-devices ND\n"
    "       -p PORTMASK: Set mask for ports to be used by application\n"
    "       --vm2vm [0|1|2]: disable/software(default)/hardware vm2vm comms\n"
    "       --rx-retry [0|1]: disable/enable(default) retries on rx. Enable retry if destintation queue is full\n"
    "       --rx-retry-delay [0-N]: timeout(in usecond) between retries on RX. This makes effect only if retries on rx enabled\n"
    "       --rx-retry-num [0-N]: the number of retries on rx. This makes effect only if retries on rx enabled\n"
    "       --mergeable [0|1]: disable(default)/enable RX mergeable buffers\n"
    "       --stats [0-N]: 0: Disable stats, N: Time in seconds to print stats\n"
    "       --socket-file: The path of the socket file.\n"
    "       --tx-csum [0|1] disable/enable TX checksum offload.\n"
    "       --tso [0|1] disable/enable TCP segment offload.\n"
    "       --client register a vhost-user socket as client mode.\n"
    "       --dequeue-zero-copy enables dequeue zero copy\n",
           prgname);
}

/*
 * Parse the arguments given in the command line of the application.
 */
static int
us_vhost_parse_args(int argc, char **argv)
{
    int opt, ret;
    int option_index;
    unsigned i;
    const char *prgname = argv[0];
    static struct option long_option[] = {
        {"vm2vm", required_argument, NULL, 0},
        {"rx-retry", required_argument, NULL, 0},
        {"rx-retry-delay", required_argument, NULL, 0},
        {"rx-retry-num", required_argument, NULL, 0},
        {"mergeable", required_argument, NULL, 0},
        {"stats", required_argument, NULL, 0},
        {"socket-file", required_argument, NULL, 0},
        {"tx-csum", required_argument, NULL, 0},
        {"tso", required_argument, NULL, 0},
        {"client", no_argument, &client_mode, 1},
        {"dequeue-zero-copy", no_argument, &dequeue_zero_copy, 1},
        {"builtin-net-driver", no_argument, &builtin_net_driver, 1},
        {NULL, 0, 0, 0},
    };

    /* Parse command line */
    while ((opt = getopt_long(argc, argv, "p:P",
            long_option, &option_index)) != EOF) {
        switch (opt) {
        /* Portmask */
        case 'p':
            enabled_port_mask = parse_portmask(optarg);
            if (enabled_port_mask == 0) {
                RTE_LOG(INFO, VHOST_CONFIG, "Invalid portmask\n");
                us_vhost_usage(prgname);
                return -1;
            }
            break;

        case 'P':
            promiscuous = 1;
            vmdq_conf_default.rx_adv_conf.vmdq_rx_conf.rx_mode =
                ETH_VMDQ_ACCEPT_BROADCAST |
                ETH_VMDQ_ACCEPT_MULTICAST;

            break;

        case 0:
            /* Enable/disable vm2vm comms. */
            if (!strncmp(long_option[option_index].name, "vm2vm",
                MAX_LONG_OPT_SZ)) {
                ret = parse_num_opt(optarg, (VM2VM_LAST - 1));
                if (ret == -1) {
                    RTE_LOG(INFO, VHOST_CONFIG,
                        "Invalid argument for "
                        "vm2vm [0|1|2]\n");
                    us_vhost_usage(prgname);
                    return -1;
                } else {
                    vm2vm_mode = (vm2vm_type)ret;
                }
            }

            /* Enable/disable retries on RX. */
            if (!strncmp(long_option[option_index].name, "rx-retry", MAX_LONG_OPT_SZ)) {
                ret = parse_num_opt(optarg, 1);
                if (ret == -1) {
                    RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for rx-retry [0|1]\n");
                    us_vhost_usage(prgname);
                    return -1;
                } else {
                    enable_retry = ret;
                }
            }

            /* Enable/disable TX checksum offload. */
            if (!strncmp(long_option[option_index].name, "tx-csum", MAX_LONG_OPT_SZ)) {
                ret = parse_num_opt(optarg, 1);
                if (ret == -1) {
                    RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for tx-csum [0|1]\n");
                    us_vhost_usage(prgname);
                    return -1;
                } else
                    enable_tx_csum = ret;
            }

            /* Enable/disable TSO offload. */
            if (!strncmp(long_option[option_index].name, "tso", MAX_LONG_OPT_SZ)) {
                ret = parse_num_opt(optarg, 1);
                if (ret == -1) {
                    RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for tso [0|1]\n");
                    us_vhost_usage(prgname);
                    return -1;
                } else
                    enable_tso = ret;
            }

            /* Specify the retries delay time (in useconds) on RX. */
            if (!strncmp(long_option[option_index].name, "rx-retry-delay", MAX_LONG_OPT_SZ)) {
                ret = parse_num_opt(optarg, INT32_MAX);
                if (ret == -1) {
                    RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for rx-retry-delay [0-N]\n");
                    us_vhost_usage(prgname);
                    return -1;
                } else {
                    burst_rx_delay_time = ret;
                }
            }

            /* Specify the retries number on RX. */
            if (!strncmp(long_option[option_index].name, "rx-retry-num", MAX_LONG_OPT_SZ)) {
                ret = parse_num_opt(optarg, INT32_MAX);
                if (ret == -1) {
                    RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for rx-retry-num [0-N]\n");
                    us_vhost_usage(prgname);
                    return -1;
                } else {
                    burst_rx_retry_num = ret;
                }
            }

            /* Enable/disable RX mergeable buffers. */
            if (!strncmp(long_option[option_index].name, "mergeable", MAX_LONG_OPT_SZ)) {
                ret = parse_num_opt(optarg, 1);
                if (ret == -1) {
                    RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for mergeable [0|1]\n");
                    us_vhost_usage(prgname);
                    return -1;
                } else {
                    mergeable = !!ret;
                    if (ret) {
                        vmdq_conf_default.rxmode.offloads |=
                            DEV_RX_OFFLOAD_JUMBO_FRAME;
                        vmdq_conf_default.rxmode.max_rx_pkt_len
                            = JUMBO_FRAME_MAX_SIZE;
                    }
                }
            }

            /* Enable/disable stats. */
            if (!strncmp(long_option[option_index].name, "stats", MAX_LONG_OPT_SZ)) {
                ret = parse_num_opt(optarg, INT32_MAX);
                if (ret == -1) {
                    RTE_LOG(INFO, VHOST_CONFIG,
                        "Invalid argument for stats [0..N]\n");
                    us_vhost_usage(prgname);
                    return -1;
                } else {
                    enable_stats = ret;
                }
            }

            /* Set socket file path. */
            if (!strncmp(long_option[option_index].name,
                        "socket-file", MAX_LONG_OPT_SZ)) {
                if (us_vhost_parse_socket_path(optarg) == -1) {
                    RTE_LOG(INFO, VHOST_CONFIG,
                    "Invalid argument for socket name (Max %d characters)\n",
                    PATH_MAX);
                    us_vhost_usage(prgname);
                    return -1;
                }
            }

            break;

            /* Invalid option - print options. */
        default:
            us_vhost_usage(prgname);
            return -1;
        }
    }

    for (i = 0; i < RTE_MAX_ETHPORTS; i++) {
        if (enabled_port_mask & (1 << i))
            ports[num_ports++] = i;
    }

    if ((num_ports ==  0) || (num_ports > MAX_SUP_PORTS)) {
        RTE_LOG(INFO, VHOST_PORT, "Current enabled port number is %u,"
            "but only %u port can be enabled\n",num_ports, MAX_SUP_PORTS);
        return -1;
    }

    return 0;
}

/*
 * Update the global var NUM_PORTS and array PORTS according to system ports number
 * and return valid ports number
 */
static unsigned check_ports_num(unsigned nb_ports)
{
    unsigned valid_num_ports = num_ports;
    unsigned portid;

    if (num_ports > nb_ports) {
        RTE_LOG(INFO, VHOST_PORT, "\nSpecified port number(%u) exceeds total system port number(%u)\n",
            num_ports, nb_ports);
        num_ports = nb_ports;
    }

    for (portid = 0; portid < num_ports; portid ++) {
        if (!rte_eth_dev_is_valid_port(ports[portid])) {
            RTE_LOG(INFO, VHOST_PORT,
                "\nSpecified port ID(%u) is not valid\n",
                ports[portid]);
            ports[portid] = INVALID_PORT_ID;
            valid_num_ports--;
        }
    }
    return valid_num_ports;
}

static __rte_always_inline struct vhost_dev *
find_vhost_dev(struct ether_addr *mac)
{
    struct vhost_dev *vdev;

    TAILQ_FOREACH(vdev, &vhost_dev_list, global_vdev_entry) {
        if (vdev->ready == DEVICE_RX &&
            is_same_ether_addr(mac, &vdev->mac_address))
            return vdev;
    }

    return NULL;
}

/*
 * This function learns the MAC address of the device and registers this along with a
 * vlan tag to a VMDQ.
 */
static int
link_vmdq(struct vhost_dev *vdev, struct rte_mbuf *m)
{
    struct ether_hdr *pkt_hdr;
    int i, ret;

    /* Learn MAC address of guest device from packet */
    pkt_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);

    if (find_vhost_dev(&pkt_hdr->s_addr)) {
        RTE_LOG(ERR, VHOST_DATA,
            "(%d) device is using a registered MAC!\n",
            vdev->vid);
        return -1;
    }

    for (i = 0; i < ETHER_ADDR_LEN; i++)
        vdev->mac_address.addr_bytes[i] = pkt_hdr->s_addr.addr_bytes[i];

    /* vlan_tag currently uses the device_id. */
    vdev->vlan_tag = vlan_tags[vdev->vid];

    /* Print out VMDQ registration info. */
    RTE_LOG(INFO, VHOST_DATA,
        "(%d) mac %02x:%02x:%02x:%02x:%02x:%02x and vlan %d registered\n",
        vdev->vid,
        vdev->mac_address.addr_bytes[0], vdev->mac_address.addr_bytes[1],
        vdev->mac_address.addr_bytes[2], vdev->mac_address.addr_bytes[3],
        vdev->mac_address.addr_bytes[4], vdev->mac_address.addr_bytes[5],
        vdev->vlan_tag);

    /* Register the MAC address. */
    ret = rte_eth_dev_mac_addr_add(ports[0], &vdev->mac_address,
                (uint32_t)vdev->vid + vmdq_pool_base);
    if (ret)
        RTE_LOG(ERR, VHOST_DATA,
            "(%d) failed to add device MAC address to VMDQ\n",
            vdev->vid);

    rte_eth_dev_set_vlan_strip_on_queue(ports[0], vdev->vmdq_rx_q, 1);

    /* Set device as ready for RX. */
    vdev->ready = DEVICE_RX;

    return 0;
}

/*
 * Removes MAC address and vlan tag from VMDQ. Ensures that nothing is adding buffers to the RX
 * queue before disabling RX on the device.
 */
static inline void
unlink_vmdq(struct vhost_dev *vdev)
{
    unsigned i = 0;
    unsigned rx_count;
    struct rte_mbuf *pkts_burst[MAX_PKT_BURST];

    if (vdev->ready == DEVICE_RX) {
        /*clear MAC and VLAN settings*/
        rte_eth_dev_mac_addr_remove(ports[0], &vdev->mac_address);
        for (i = 0; i < 6; i++)
            vdev->mac_address.addr_bytes[i] = 0;

        vdev->vlan_tag = 0;

        /*Clear out the receive buffers*/
        rx_count = rte_eth_rx_burst(ports[0],
                    (uint16_t)vdev->vmdq_rx_q, pkts_burst, MAX_PKT_BURST);

        while (rx_count) {
            for (i = 0; i < rx_count; i++)
                rte_pktmbuf_free(pkts_burst[i]);

            rx_count = rte_eth_rx_burst(ports[0],
                    (uint16_t)vdev->vmdq_rx_q, pkts_burst, MAX_PKT_BURST);
        }

        vdev->ready = DEVICE_MAC_LEARNING;
    }
}

static __rte_always_inline void
virtio_xmit(struct vhost_dev *dst_vdev, struct vhost_dev *src_vdev,
        struct rte_mbuf *m)
{
    uint16_t ret;

    if (builtin_net_driver) {
        ret = vs_enqueue_pkts(dst_vdev, VIRTIO_RXQ, &m, 1);
    } else {
        ret = rte_vhost_enqueue_burst(dst_vdev->vid, VIRTIO_RXQ, &m, 1);
    }

    if (enable_stats) {
        rte_atomic64_inc(&dst_vdev->stats.rx_total_atomic);
        rte_atomic64_add(&dst_vdev->stats.rx_atomic, ret);
        src_vdev->stats.tx_total++;
        src_vdev->stats.tx += ret;
    }
}

/*
 * Check if the packet destination MAC address is for a local device. If so then put
 * the packet on that devices RX queue. If not then return.
 */
static __rte_always_inline int
virtio_tx_local(struct vhost_dev *vdev, struct rte_mbuf *m)
{
    struct ether_hdr *pkt_hdr;
    struct vhost_dev *dst_vdev;

    pkt_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);

    dst_vdev = find_vhost_dev(&pkt_hdr->d_addr);
    if (!dst_vdev)
        return -1;

    if (vdev->vid == dst_vdev->vid) {
        RTE_LOG_DP(DEBUG, VHOST_DATA,
            "(%d) TX: src and dst MAC is same. Dropping packet.\n",
            vdev->vid);
        return 0;
    }

    RTE_LOG_DP(DEBUG, VHOST_DATA,
        "(%d) TX: MAC address is local\n", dst_vdev->vid);

    if (unlikely(dst_vdev->remove)) {
        RTE_LOG_DP(DEBUG, VHOST_DATA,
            "(%d) device is marked for removal\n", dst_vdev->vid);
        return 0;
    }

    virtio_xmit(dst_vdev, vdev, m);
    return 0;
}

/*
 * Check if the destination MAC of a packet is one local VM,
 * and get its vlan tag, and offset if it is.
 */
static __rte_always_inline int
find_local_dest(struct vhost_dev *vdev, struct rte_mbuf *m,
    uint32_t *offset, uint16_t *vlan_tag)
{
    struct vhost_dev *dst_vdev;
    struct ether_hdr *pkt_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);

    dst_vdev = find_vhost_dev(&pkt_hdr->d_addr);
    if (!dst_vdev)
        return 0;

    if (vdev->vid == dst_vdev->vid) {
        RTE_LOG_DP(DEBUG, VHOST_DATA,
            "(%d) TX: src and dst MAC is same. Dropping packet.\n",
            vdev->vid);
        return -1;
    }

    /*
     * HW vlan strip will reduce the packet length
     * by minus length of vlan tag, so need restore
     * the packet length by plus it.
     */
    *offset  = VLAN_HLEN;
    *vlan_tag = vlan_tags[vdev->vid];

    RTE_LOG_DP(DEBUG, VHOST_DATA,
        "(%d) TX: pkt to local VM device id: (%d), vlan tag: %u.\n",
        vdev->vid, dst_vdev->vid, *vlan_tag);

    return 0;
}

static uint16_t
get_psd_sum(void *l3_hdr, uint64_t ol_flags)
{
    if (ol_flags & PKT_TX_IPV4)
        return rte_ipv4_phdr_cksum(l3_hdr, ol_flags);
    else /* assume ethertype == ETHER_TYPE_IPv6 */
        return rte_ipv6_phdr_cksum(l3_hdr, ol_flags);
}

static void virtio_tx_offload(struct rte_mbuf *m)
{
    void *l3_hdr;
    struct ipv4_hdr *ipv4_hdr = NULL;
    struct tcp_hdr *tcp_hdr = NULL;
    struct ether_hdr *eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);

    l3_hdr = (char *)eth_hdr + m->l2_len;

    if (m->ol_flags & PKT_TX_IPV4) {
        ipv4_hdr = l3_hdr;
        ipv4_hdr->hdr_checksum = 0;
        m->ol_flags |= PKT_TX_IP_CKSUM;
    }

    tcp_hdr = (struct tcp_hdr *)((char *)l3_hdr + m->l3_len);
    tcp_hdr->cksum = get_psd_sum(l3_hdr, m->ol_flags);
}

static inline void
free_pkts(struct rte_mbuf **pkts, uint16_t n)
{
    while (n--)
        rte_pktmbuf_free(pkts[n]);
}

static __rte_always_inline void
do_drain_mbuf_table(struct mbuf_table *tx_q)
{
    uint16_t count;

    count = rte_eth_tx_burst(ports[0], tx_q->txq_id,
                 tx_q->m_table, tx_q->len);
    if (unlikely(count < tx_q->len))
        free_pkts(&tx_q->m_table[count], tx_q->len - count);

    tx_q->len = 0;
}

/*
 * This function routes the TX packet to the correct interface. This
 * may be a local device or the physical port.
 */
static __rte_always_inline void
virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
{
    struct mbuf_table *tx_q;
    unsigned offset = 0;
    const uint16_t lcore_id = rte_lcore_id();
    struct ether_hdr *nh;


    nh = rte_pktmbuf_mtod(m, struct ether_hdr *);
    if (unlikely(is_broadcast_ether_addr(&nh->d_addr))) {
        struct vhost_dev *vdev2;

        TAILQ_FOREACH(vdev2, &vhost_dev_list, global_vdev_entry) {
            if (vdev2 != vdev)
                virtio_xmit(vdev2, vdev, m);
        }
        goto queue2nic;
    }

    /*check if destination is local VM*/
    if ((vm2vm_mode == VM2VM_SOFTWARE) && (virtio_tx_local(vdev, m) == 0)) {
        rte_pktmbuf_free(m);
        return;
    }

    if (unlikely(vm2vm_mode == VM2VM_HARDWARE)) {
        if (unlikely(find_local_dest(vdev, m, &offset,
                         &vlan_tag) != 0)) {
            rte_pktmbuf_free(m);
            return;
        }
    }

    RTE_LOG_DP(DEBUG, VHOST_DATA,
        "(%d) TX: MAC address is external\n", vdev->vid);

queue2nic:

    /*Add packet to the port tx queue*/
    tx_q = &lcore_tx_queue[lcore_id];

    nh = rte_pktmbuf_mtod(m, struct ether_hdr *);
    if (unlikely(nh->ether_type == rte_cpu_to_be_16(ETHER_TYPE_VLAN))) {
        /* Guest has inserted the vlan tag. */
        struct vlan_hdr *vh = (struct vlan_hdr *) (nh + 1);
        uint16_t vlan_tag_be = rte_cpu_to_be_16(vlan_tag);
        if ((vm2vm_mode == VM2VM_HARDWARE) &&
            (vh->vlan_tci != vlan_tag_be))
            vh->vlan_tci = vlan_tag_be;
    } else {
        m->ol_flags |= PKT_TX_VLAN_PKT;

        /*
         * Find the right seg to adjust the data len when offset is
         * bigger than tail room size.
         */
        if (unlikely(vm2vm_mode == VM2VM_HARDWARE)) {
            if (likely(offset <= rte_pktmbuf_tailroom(m)))
                m->data_len += offset;
            else {
                struct rte_mbuf *seg = m;

                while ((seg->next != NULL) &&
                    (offset > rte_pktmbuf_tailroom(seg)))
                    seg = seg->next;

                seg->data_len += offset;
            }
            m->pkt_len += offset;
        }

        m->vlan_tci = vlan_tag;
    }

    if (m->ol_flags & PKT_TX_TCP_SEG)
        virtio_tx_offload(m);

    tx_q->m_table[tx_q->len++] = m;
    if (enable_stats) {
        vdev->stats.tx_total++;
        vdev->stats.tx++;
    }

    if (unlikely(tx_q->len == MAX_PKT_BURST))
        do_drain_mbuf_table(tx_q);
}


static __rte_always_inline void
drain_mbuf_table(struct mbuf_table *tx_q)
{
    static uint64_t prev_tsc;
    uint64_t cur_tsc;

    if (tx_q->len == 0)
        return;

    cur_tsc = rte_rdtsc();
    if (unlikely(cur_tsc - prev_tsc > MBUF_TABLE_DRAIN_TSC)) {
        prev_tsc = cur_tsc;

        RTE_LOG_DP(DEBUG, VHOST_DATA,
            "TX queue drained after timeout with burst size %u\n",
            tx_q->len);
        do_drain_mbuf_table(tx_q);
    }
}

static __rte_always_inline void
drain_eth_rx(struct vhost_dev *vdev)
{
    uint16_t rx_count, enqueue_count;
    struct rte_mbuf *pkts[MAX_PKT_BURST];

    rx_count = rte_eth_rx_burst(ports[0], vdev->vmdq_rx_q,
                    pkts, MAX_PKT_BURST);
    if (!rx_count)
        return;

    /*
     * When "enable_retry" is set, here we wait and retry when there
     * is no enough free slots in the queue to hold @rx_count packets,
     * to diminish packet loss.
     */
    if (enable_retry &&
        unlikely(rx_count > rte_vhost_avail_entries(vdev->vid,
            VIRTIO_RXQ))) {
        uint32_t retry;

        for (retry = 0; retry < burst_rx_retry_num; retry++) {
            rte_delay_us(burst_rx_delay_time);
            if (rx_count <= rte_vhost_avail_entries(vdev->vid,
                    VIRTIO_RXQ))
                break;
        }
    }

    if (builtin_net_driver) {
        enqueue_count = vs_enqueue_pkts(vdev, VIRTIO_RXQ,
                        pkts, rx_count);
    } else {
        enqueue_count = rte_vhost_enqueue_burst(vdev->vid, VIRTIO_RXQ,
                        pkts, rx_count);
    }
    if (enable_stats) {
        rte_atomic64_add(&vdev->stats.rx_total_atomic, rx_count);
        rte_atomic64_add(&vdev->stats.rx_atomic, enqueue_count);
    }

    free_pkts(pkts, rx_count);
}

static __rte_always_inline void
drain_virtio_tx(struct vhost_dev *vdev)
{
    struct rte_mbuf *pkts[MAX_PKT_BURST];
    uint16_t count;
    uint16_t i;

    if (builtin_net_driver) {
        count = vs_dequeue_pkts(vdev, VIRTIO_TXQ, mbuf_pool,
                    pkts, MAX_PKT_BURST);
    } else {
        count = rte_vhost_dequeue_burst(vdev->vid, VIRTIO_TXQ,
                    mbuf_pool, pkts, MAX_PKT_BURST);
    }

    /* setup VMDq for the first packet */
    if (unlikely(vdev->ready == DEVICE_MAC_LEARNING) && count) {
        if (vdev->remove || link_vmdq(vdev, pkts[0]) == -1)
            free_pkts(pkts, count);
    }

    for (i = 0; i < count; ++i)
        virtio_tx_route(vdev, pkts[i], vlan_tags[vdev->vid]);
}

/*
 * Main function of vhost-switch. It basically does:
 *
 * for each vhost device {
 *    - drain_eth_rx()
 *
 *      Which drains the host eth Rx queue linked to the vhost device,
 *      and deliver all of them to guest virito Rx ring associated with
 *      this vhost device.
 *
 *    - drain_virtio_tx()
 *
 *      Which drains the guest virtio Tx queue and deliver all of them
 *      to the target, which could be another vhost device, or the
 *      physical eth dev. The route is done in function "virtio_tx_route".
 * }
 */
static int
switch_worker(void *arg __rte_unused)
{
    unsigned i;
    unsigned lcore_id = rte_lcore_id();
    struct vhost_dev *vdev;
    struct mbuf_table *tx_q;

    RTE_LOG(INFO, VHOST_DATA, "Procesing on Core %u started\n", lcore_id);

    tx_q = &lcore_tx_queue[lcore_id];
    for (i = 0; i < rte_lcore_count(); i++) {
        if (lcore_ids[i] == lcore_id) {
            tx_q->txq_id = i;
            break;
        }
    }

    while(1) {
        drain_mbuf_table(tx_q);

        /*
         * Inform the configuration core that we have exited the
         * linked list and that no devices are in use if requested.
         */
        if (lcore_info[lcore_id].dev_removal_flag == REQUEST_DEV_REMOVAL)
            lcore_info[lcore_id].dev_removal_flag = ACK_DEV_REMOVAL;

        /*
         * Process vhost devices
         */
        TAILQ_FOREACH(vdev, &lcore_info[lcore_id].vdev_list,
                  lcore_vdev_entry) {
            if (unlikely(vdev->remove)) {
                unlink_vmdq(vdev);
                vdev->ready = DEVICE_SAFE_REMOVE;
                continue;
            }

            if (likely(vdev->ready == DEVICE_RX))
                drain_eth_rx(vdev);

            if (likely(!vdev->remove))
                drain_virtio_tx(vdev);
        }
    }

    return 0;
}

/*
 * Remove a device from the specific data core linked list and from the
 * main linked list. Synchonization  occurs through the use of the
 * lcore dev_removal_flag. Device is made volatile here to avoid re-ordering
 * of dev->remove=1 which can cause an infinite loop in the rte_pause loop.
 */
static void
destroy_device(int vid)
{
    struct vhost_dev *vdev = NULL;
    int lcore;

    TAILQ_FOREACH(vdev, &vhost_dev_list, global_vdev_entry) {
        if (vdev->vid == vid)
            break;
    }
    if (!vdev)
        return;
    /*set the remove flag. */
    vdev->remove = 1;
    while(vdev->ready != DEVICE_SAFE_REMOVE) {
        rte_pause();
    }

    if (builtin_net_driver)
        vs_vhost_net_remove(vdev);

    TAILQ_REMOVE(&lcore_info[vdev->coreid].vdev_list, vdev,
             lcore_vdev_entry);
    TAILQ_REMOVE(&vhost_dev_list, vdev, global_vdev_entry);


    /* Set the dev_removal_flag on each lcore. */
    RTE_LCORE_FOREACH_SLAVE(lcore)
        lcore_info[lcore].dev_removal_flag = REQUEST_DEV_REMOVAL;

    /*
     * Once each core has set the dev_removal_flag to ACK_DEV_REMOVAL
     * we can be sure that they can no longer access the device removed
     * from the linked lists and that the devices are no longer in use.
     */
    RTE_LCORE_FOREACH_SLAVE(lcore) {
        while (lcore_info[lcore].dev_removal_flag != ACK_DEV_REMOVAL)
            rte_pause();
    }

    lcore_info[vdev->coreid].device_num--;

    RTE_LOG(INFO, VHOST_DATA,
        "(%d) device has been removed from data core\n",
        vdev->vid);

    rte_free(vdev);
}

/*
 * A new device is added to a data core. First the device is added to the main linked list
 * and then allocated to a specific data core.
 */
static int
new_device(int vid)
{
    int lcore, core_add = 0;
    uint32_t device_num_min = num_devices;
    struct vhost_dev *vdev;

    vdev = rte_zmalloc("vhost device", sizeof(*vdev), RTE_CACHE_LINE_SIZE);
    if (vdev == NULL) {
        RTE_LOG(INFO, VHOST_DATA,
            "(%d) couldn't allocate memory for vhost dev\n",
            vid);
        return -1;
    }
    vdev->vid = vid;

    if (builtin_net_driver)
        vs_vhost_net_setup(vdev);

    TAILQ_INSERT_TAIL(&vhost_dev_list, vdev, global_vdev_entry);
    vdev->vmdq_rx_q = vid * queues_per_pool + vmdq_queue_base;

    /*reset ready flag*/
    vdev->ready = DEVICE_MAC_LEARNING;
    vdev->remove = 0;

    /* Find a suitable lcore to add the device. */
    RTE_LCORE_FOREACH_SLAVE(lcore) {
        if (lcore_info[lcore].device_num < device_num_min) {
            device_num_min = lcore_info[lcore].device_num;
            core_add = lcore;
        }
    }
    vdev->coreid = core_add;

    TAILQ_INSERT_TAIL(&lcore_info[vdev->coreid].vdev_list, vdev,
              lcore_vdev_entry);
    lcore_info[vdev->coreid].device_num++;

    /* Disable notifications. */
    rte_vhost_enable_guest_notification(vid, VIRTIO_RXQ, 0);
    rte_vhost_enable_guest_notification(vid, VIRTIO_TXQ, 0);

    RTE_LOG(INFO, VHOST_DATA,
        "(%d) device has been added to data core %d\n",
        vid, vdev->coreid);

    return 0;
}

/*
 * These callback allow devices to be added to the data core when configuration
 * has been fully complete.
 */
static const struct vhost_device_ops virtio_net_device_ops =
{
    .new_device =  new_device,
    .destroy_device = destroy_device,
};

/*
 * This is a thread will wake up after a period to print stats if the user has
 * enabled them.
 */
static void *
print_stats(__rte_unused void *arg)
{
    struct vhost_dev *vdev;
    uint64_t tx_dropped, rx_dropped;
    uint64_t tx, tx_total, rx, rx_total;
    const char clr[] = { 27, '[', '2', 'J', '\0' };
    const char top_left[] = { 27, '[', '1', ';', '1', 'H','\0' };

    while(1) {
        sleep(enable_stats);

        /* Clear screen and move to top left */
        printf("%s%s\n", clr, top_left);
        printf("Device statistics =================================\n");

        TAILQ_FOREACH(vdev, &vhost_dev_list, global_vdev_entry) {
            tx_total   = vdev->stats.tx_total;
            tx         = vdev->stats.tx;
            tx_dropped = tx_total - tx;

            rx_total   = rte_atomic64_read(&vdev->stats.rx_total_atomic);
            rx         = rte_atomic64_read(&vdev->stats.rx_atomic);
            rx_dropped = rx_total - rx;

            printf("Statistics for device %d\n"
                "-----------------------\n"
                "TX total:              %" PRIu64 "\n"
                "TX dropped:            %" PRIu64 "\n"
                "TX successful:         %" PRIu64 "\n"
                "RX total:              %" PRIu64 "\n"
                "RX dropped:            %" PRIu64 "\n"
                "RX successful:         %" PRIu64 "\n",
                vdev->vid,
                tx_total, tx_dropped, tx,
                rx_total, rx_dropped, rx);
        }

        printf("===================================================\n");

        fflush(stdout);
    }

    return NULL;
}

static void
unregister_drivers(int socket_num)
{
    int i, ret;

    for (i = 0; i < socket_num; i++) {
        ret = rte_vhost_driver_unregister(socket_files + i * PATH_MAX);
        if (ret != 0)
            RTE_LOG(ERR, VHOST_CONFIG,
                "Fail to unregister vhost driver for %s.\n",
                socket_files + i * PATH_MAX);
    }
}

/* When we receive a INT signal, unregister vhost driver */
static void
sigint_handler(__rte_unused int signum)
{
    /* Unregister vhost driver. */
    unregister_drivers(nb_sockets);

    exit(0);
}

/*
 * While creating an mbuf pool, one key thing is to figure out how
 * many mbuf entries is enough for our use. FYI, here are some
 * guidelines:
 *
 * - Each rx queue would reserve @nr_rx_desc mbufs at queue setup stage
 *
 * - For each switch core (A CPU core does the packet switch), we need
 *   also make some reservation for receiving the packets from virtio
 *   Tx queue. How many is enough depends on the usage. It's normally
 *   a simple calculation like following:
 *
 *       MAX_PKT_BURST * max packet size / mbuf size
 *
 *   So, we definitely need allocate more mbufs when TSO is enabled.
 *
 * - Similarly, for each switching core, we should serve @nr_rx_desc
 *   mbufs for receiving the packets from physical NIC device.
 *
 * - We also need make sure, for each switch core, we have allocated
 *   enough mbufs to fill up the mbuf cache.
 */
static void
create_mbuf_pool(uint16_t nr_port, uint32_t nr_switch_core, uint32_t mbuf_size,
    uint32_t nr_queues, uint32_t nr_rx_desc, uint32_t nr_mbuf_cache)
{
    uint32_t nr_mbufs;
    uint32_t nr_mbufs_per_core;
    uint32_t mtu = 1500;

    if (mergeable)
        mtu = 9000;
    if (enable_tso)
        mtu = 64 * 1024;

    nr_mbufs_per_core  = (mtu + mbuf_size) * MAX_PKT_BURST /
            (mbuf_size - RTE_PKTMBUF_HEADROOM);
    nr_mbufs_per_core += nr_rx_desc;
    nr_mbufs_per_core  = RTE_MAX(nr_mbufs_per_core, nr_mbuf_cache);

    nr_mbufs  = nr_queues * nr_rx_desc;
    nr_mbufs += nr_mbufs_per_core * nr_switch_core;
    nr_mbufs *= nr_port;

    mbuf_pool = rte_pktmbuf_pool_create("MBUF_POOL", nr_mbufs,
                        nr_mbuf_cache, 0, mbuf_size,
                        rte_socket_id());
    if (mbuf_pool == NULL)
        rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");
}

/*
 * Main function, does initialisation and calls the per-lcore functions.
 */
int
main(int argc, char *argv[])
{
    unsigned lcore_id, core_id = 0;
    unsigned nb_ports, valid_num_ports;
    int ret, i;
    uint16_t portid;
    static pthread_t tid;
    uint64_t flags = 0;

    signal(SIGINT, sigint_handler);

    /* init EAL */
    ret = rte_eal_init(argc, argv);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
    argc -= ret;
    argv += ret;

    /* parse app arguments */
    ret = us_vhost_parse_args(argc, argv);
    if (ret < 0)
        rte_exit(EXIT_FAILURE, "Invalid argument\n");

    for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
        TAILQ_INIT(&lcore_info[lcore_id].vdev_list);

        if (rte_lcore_is_enabled(lcore_id))
            lcore_ids[core_id++] = lcore_id;
    }

    if (rte_lcore_count() > RTE_MAX_LCORE)
        rte_exit(EXIT_FAILURE,"Not enough cores\n");

    /* Get the number of physical ports. */
    nb_ports = rte_eth_dev_count_avail();

    /*
     * Update the global var NUM_PORTS and global array PORTS
     * and get value of var VALID_NUM_PORTS according to system ports number
     */
    valid_num_ports = check_ports_num(nb_ports);

    if ((valid_num_ports ==  0) || (valid_num_ports > MAX_SUP_PORTS)) {
        RTE_LOG(INFO, VHOST_PORT, "Current enabled port number is %u,"
            "but only %u port can be enabled\n",num_ports, MAX_SUP_PORTS);
        return -1;
    }

    /*
     * FIXME: here we are trying to allocate mbufs big enough for
     * @MAX_QUEUES, but the truth is we're never going to use that
     * many queues here. We probably should only do allocation for
     * those queues we are going to use.
     */
    create_mbuf_pool(valid_num_ports, rte_lcore_count() - 1, MBUF_DATA_SIZE,
             MAX_QUEUES, RTE_TEST_RX_DESC_DEFAULT, MBUF_CACHE_SIZE);

    if (vm2vm_mode == VM2VM_HARDWARE) {
        /* Enable VT loop back to let L2 switch to do it. */
        vmdq_conf_default.rx_adv_conf.vmdq_rx_conf.enable_loop_back = 1;
        RTE_LOG(DEBUG, VHOST_CONFIG,
            "Enable loop back for L2 switch in vmdq.\n");
    }

    /* initialize all ports */
    RTE_ETH_FOREACH_DEV(portid) {
        /* skip ports that are not enabled */
        if ((enabled_port_mask & (1 << portid)) == 0) {
            RTE_LOG(INFO, VHOST_PORT,
                "Skipping disabled port %d\n", portid);
            continue;
        }
        if (port_init(portid) != 0)
            rte_exit(EXIT_FAILURE,
                "Cannot initialize network ports\n");
    }

    /* Enable stats if the user option is set. */
    if (enable_stats) {
        ret = rte_ctrl_thread_create(&tid, "print-stats", NULL,
                    print_stats, NULL);
        if (ret < 0)
            rte_exit(EXIT_FAILURE,
                "Cannot create print-stats thread\n");
    }

    /* Launch all data cores. */
    RTE_LCORE_FOREACH_SLAVE(lcore_id)
        rte_eal_remote_launch(switch_worker, NULL, lcore_id);

    if (client_mode)
        flags |= RTE_VHOST_USER_CLIENT;

    if (dequeue_zero_copy)
        flags |= RTE_VHOST_USER_DEQUEUE_ZERO_COPY;

    /* Register vhost user driver to handle vhost messages. */
    for (i = 0; i < nb_sockets; i++) {
        char *file = socket_files + i * PATH_MAX;
        ret = rte_vhost_driver_register(file, flags);
        if (ret != 0) {
            unregister_drivers(i);
            rte_exit(EXIT_FAILURE,
                "vhost driver register failure.\n");
        }

        if (builtin_net_driver)
            rte_vhost_driver_set_features(file, VIRTIO_NET_FEATURES);

        if (mergeable == 0) {
            rte_vhost_driver_disable_features(file,
                1ULL << VIRTIO_NET_F_MRG_RXBUF);
        }

        if (enable_tx_csum == 0) {
            rte_vhost_driver_disable_features(file,
                1ULL << VIRTIO_NET_F_CSUM);
        }

        if (enable_tso == 0) {
            rte_vhost_driver_disable_features(file,
                1ULL << VIRTIO_NET_F_HOST_TSO4);
            rte_vhost_driver_disable_features(file,
                1ULL << VIRTIO_NET_F_HOST_TSO6);
            rte_vhost_driver_disable_features(file,
                1ULL << VIRTIO_NET_F_GUEST_TSO4);
            rte_vhost_driver_disable_features(file,
                1ULL << VIRTIO_NET_F_GUEST_TSO6);
        }

        if (promiscuous) {
            rte_vhost_driver_enable_features(file,
                1ULL << VIRTIO_NET_F_CTRL_RX);
        }

        ret = rte_vhost_driver_callback_register(file,
            &virtio_net_device_ops);
        if (ret != 0) {
            rte_exit(EXIT_FAILURE,
                "failed to register vhost driver callbacks.\n");
        }

        if (rte_vhost_driver_start(file) < 0) {
            rte_exit(EXIT_FAILURE,
                "failed to start vhost driver.\n");
        }
    }

    RTE_LCORE_FOREACH_SLAVE(lcore_id)
        rte_eal_wait_lcore(lcore_id);

    return 0;

}