xref: /dpdk/examples/vhost/main.c (revision 62814bc2e923b3d1867a93a1a4cd6073f5065e41)

/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
 *   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 Intel Corporation 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.
 */

#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 "main.h"
#include "virtio-net.h"
#include "vhost-net-cdev.h"

#define MAX_QUEUES 128

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

/*
 * Calculate the number of buffers needed per port
 */
#define NUM_MBUFS_PER_PORT ((MAX_QUEUES*RTE_TEST_RX_DESC_DEFAULT) +  		\
							(num_switching_cores*MAX_PKT_BURST) +  			\
							(num_switching_cores*RTE_TEST_TX_DESC_DEFAULT) +\
							(num_switching_cores*MBUF_CACHE_SIZE))

#define MBUF_CACHE_SIZE 128
#define MBUF_SIZE (2048 + sizeof(struct rte_mbuf) + RTE_PKTMBUF_HEADROOM)

/*
 * No frame data buffer allocated from host are required for zero copy
 * implementation, guest will allocate the frame data buffer, and vhost
 * directly use it.
 */
#define VIRTIO_DESCRIPTOR_LEN_ZCP 1518
#define MBUF_SIZE_ZCP (VIRTIO_DESCRIPTOR_LEN_ZCP + sizeof(struct rte_mbuf) \
	+ RTE_PKTMBUF_HEADROOM)
#define MBUF_CACHE_SIZE_ZCP 0

/*
 * RX and TX Prefetch, Host, and Write-back threshold values should be
 * carefully set for optimal performance. Consult the network
 * controller's datasheet and supporting DPDK documentation for guidance
 * on how these parameters should be set.
 */
#define RX_PTHRESH 8 /* Default values of RX prefetch threshold reg. */
#define RX_HTHRESH 8 /* Default values of RX host threshold reg. */
#define RX_WTHRESH 4 /* Default values of RX write-back threshold reg. */

/*
 * These default values are optimized for use with the Intel(R) 82599 10 GbE
 * Controller and the DPDK ixgbe PMD. Consider using other values for other
 * network controllers and/or network drivers.
 */
#define TX_PTHRESH 36 /* Default values of TX prefetch threshold reg. */
#define TX_HTHRESH 0  /* Default values of TX host threshold reg. */
#define TX_WTHRESH 0  /* Default values of TX write-back threshold reg. */

#define MAX_PKT_BURST 32 		/* Max burst size for RX/TX */
#define MAX_MRG_PKT_BURST 16 	/* Max burst for merge buffers. Set to 1 due to performance issue. */
#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

/* Config_core_flag status definitions. */
#define REQUEST_DEV_REMOVAL 1
#define ACK_DEV_REMOVAL 0

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

/*
 * Need refine these 2 macros for legacy and DPDK based front end:
 * Max vring avail descriptor/entries from guest - MAX_PKT_BURST
 * And then adjust power 2.
 */
/*
 * For legacy front end, 128 descriptors,
 * half for virtio header, another half for mbuf.
 */
#define RTE_TEST_RX_DESC_DEFAULT_ZCP 32   /* legacy: 32, DPDK virt FE: 128. */
#define RTE_TEST_TX_DESC_DEFAULT_ZCP 64   /* legacy: 64, DPDK virt FE: 64.  */

/* Get first 4 bytes in mbuf headroom. */
#define MBUF_HEADROOM_UINT32(mbuf) (*(uint32_t *)((uint8_t *)(mbuf) \
		+ sizeof(struct rte_mbuf)))

/* true if x is a power of 2 */
#define POWEROF2(x) ((((x)-1) & (x)) == 0)

#define INVALID_PORT_ID 0xFF

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

/* Size of buffers used for snprintfs. */
#define MAX_PRINT_BUFF 6072

/* Maximum character device basename size. */
#define MAX_BASENAME_SZ 10

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

/* Used to compare MAC addresses. */
#define MAC_ADDR_CMP 0xFFFFFFFFFFFFULL

/* Number of descriptors per cacheline. */
#define DESC_PER_CACHELINE (CACHE_LINE_SIZE / sizeof(struct vring_desc))

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

/*Number of switching cores enabled*/
static uint32_t num_switching_cores = 0;

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

/*
 * Enable zero copy, pkts buffer will directly dma to hw descriptor,
 * disabled on default.
 */
static uint32_t zero_copy;

/* number of descriptors to apply*/
static uint32_t num_rx_descriptor = RTE_TEST_RX_DESC_DEFAULT_ZCP;
static uint32_t num_tx_descriptor = RTE_TEST_TX_DESC_DEFAULT_ZCP;

/* max ring descriptor, ixgbe, i40e, e1000 all are 4096. */
#define MAX_RING_DESC 4096

struct vpool {
	struct rte_mempool *pool;
	struct rte_ring *ring;
	uint32_t buf_size;
} vpool_array[MAX_QUEUES+MAX_QUEUES];

/* 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;

/* The type of host physical address translated from guest physical address. */
typedef enum {
	PHYS_ADDR_CONTINUOUS = 0,
	PHYS_ADDR_CROSS_SUBREG = 1,
	PHYS_ADDR_INVALID = 2,
	PHYS_ADDR_LAST
} hpa_type;

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

/* Character device basename. Can be set by user. */
static char dev_basename[MAX_BASENAME_SZ] = "vhost-net";

/* Charater device index. Can be set by user. */
static uint32_t dev_index = 0;

/* This can be set by the user so it is made available here. */
extern uint64_t VHOST_FEATURES;

/* Default configuration for rx and tx thresholds etc. */
static struct rte_eth_rxconf rx_conf_default = {
	.rx_thresh = {
		.pthresh = RX_PTHRESH,
		.hthresh = RX_HTHRESH,
		.wthresh = RX_WTHRESH,
	},
	.rx_drop_en = 1,
};

/*
 * These default values are optimized for use with the Intel(R) 82599 10 GbE
 * Controller and the DPDK ixgbe/igb PMD. Consider using other values for other
 * network controllers and/or network drivers.
 */
static struct rte_eth_txconf tx_conf_default = {
	.tx_thresh = {
		.pthresh = TX_PTHRESH,
		.hthresh = TX_HTHRESH,
		.wthresh = TX_WTHRESH,
	},
	.tx_free_thresh = 0, /* Use PMD default values */
	.tx_rs_thresh = 0, /* Use PMD default values */
};

/* 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,
		.header_split   = 0, /**< Header Split disabled */
		.hw_ip_checksum = 0, /**< IP checksum offload disabled */
		.hw_vlan_filter = 0, /**< VLAN filtering disabled */
		/*
		 * It 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.
		 */
		.hw_vlan_strip  = 1, /**< VLAN strip enabled. */
		.jumbo_frame    = 0, /**< Jumbo Frame Support disabled */
		.hw_strip_crc   = 0, /**< CRC stripped by hardware */
	},

	.txmode = {
		.mq_mode = ETH_MQ_TX_NONE,
	},
	.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 uint8_t ports[RTE_MAX_ETHPORTS];
static unsigned num_ports = 0; /**< The number of ports specified in command line */

static const uint16_t external_pkt_default_vlan_tag = 2000;
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];

/* heads for the main used and free linked lists for the data path. */
static struct virtio_net_data_ll *ll_root_used = NULL;
static struct virtio_net_data_ll *ll_root_free = NULL;

/* Array of data core structures containing information on individual core linked lists. */
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];

/* TX queue fori each virtio device for zero copy. */
struct mbuf_table tx_queue_zcp[MAX_QUEUES];

/* Vlan header struct used to insert vlan tags on TX. */
struct vlan_ethhdr {
	unsigned char   h_dest[ETH_ALEN];
	unsigned char   h_source[ETH_ALEN];
	__be16          h_vlan_proto;
	__be16          h_vlan_TCI;
	__be16          h_vlan_encapsulated_proto;
};

/* IPv4 Header */
struct ipv4_hdr {
	uint8_t  version_ihl;		/**< version and header length */
	uint8_t  type_of_service;	/**< type of service */
	uint16_t total_length;		/**< length of packet */
	uint16_t packet_id;		/**< packet ID */
	uint16_t fragment_offset;	/**< fragmentation offset */
	uint8_t  time_to_live;		/**< time to live */
	uint8_t  next_proto_id;		/**< protocol ID */
	uint16_t hdr_checksum;		/**< header checksum */
	uint32_t src_addr;		/**< source address */
	uint32_t dst_addr;		/**< destination address */
} __attribute__((__packed__));

/* Header lengths. */
#define VLAN_HLEN       4
#define VLAN_ETH_HLEN   18

/* Per-device statistics struct */
struct device_statistics {
	uint64_t tx_total;
	rte_atomic64_t rx_total_atomic;
	uint64_t rx_total;
	uint64_t tx;
	rte_atomic64_t rx_atomic;
	uint64_t rx;
} __rte_cache_aligned;
struct device_statistics dev_statistics[MAX_DEVICES];

/*
 * 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;
	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 =
		vmdq_conf_default.rx_adv_conf.vmdq_rx_conf.enable_loop_back;

	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(uint8_t port)
{
	struct rte_eth_dev_info dev_info;
	struct rte_eth_conf port_conf;
	uint16_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);

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

	if (zero_copy) {
		rx_ring_size = num_rx_descriptor;
		tx_ring_size = num_tx_descriptor;
		tx_rings = dev_info.max_tx_queues;
	} else {
		rx_ring_size = RTE_TEST_RX_DESC_DEFAULT;
		tx_ring_size = RTE_TEST_TX_DESC_DEFAULT;
		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;

	if (port >= rte_eth_dev_count()) return -1;

	rx_rings = (uint16_t)num_queues,
	/* Configure ethernet device. */
	retval = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf);
	if (retval != 0)
		return retval;

	/* Setup the queues. */
	for (q = 0; q < rx_rings; q ++) {
		retval = rte_eth_rx_queue_setup(port, q, rx_ring_size,
						rte_eth_dev_socket_id(port), &rx_conf_default,
						vpool_array[q].pool);
		if (retval < 0)
			return retval;
	}
	for (q = 0; q < tx_rings; q ++) {
		retval = rte_eth_tx_queue_setup(port, q, tx_ring_size,
						rte_eth_dev_socket_id(port), &tx_conf_default);
		if (retval < 0)
			return retval;
	}

	/* Start the device. */
	retval  = rte_eth_dev_start(port);
	if (retval < 0) {
		RTE_LOG(ERR, VHOST_DATA, "Failed to start the device.\n");
		return retval;
	}

	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",
			(unsigned)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 character device basename.
 */
static int
us_vhost_parse_basename(const char *q_arg)
{
	/* parse number string */

	if (strnlen(q_arg, MAX_BASENAME_SZ) > MAX_BASENAME_SZ)
		return -1;
	else
		snprintf((char*)&dev_basename, MAX_BASENAME_SZ, "%s", q_arg);

	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"
	"		--dev-basename <name> --dev-index [0-N]\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"
	"		--dev-basename: The basename to be used for the character device.\n"
	"		--dev-index [0-N]: Defaults to zero if not used. Index is appended to basename.\n"
	"		--zero-copy [0|1]: disable(default)/enable rx/tx "
			"zero copy\n"
	"		--rx-desc-num [0-N]: the number of descriptors on rx, "
			"used only when zero copy is enabled.\n"
	"		--tx-desc-num [0-N]: the number of descriptors on tx, "
			"used only when zero copy is enabled.\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},
		{"dev-basename", required_argument, NULL, 0},
		{"dev-index", required_argument, NULL, 0},
		{"zero-copy", required_argument, NULL, 0},
		{"rx-desc-num", required_argument, NULL, 0},
		{"tx-desc-num", required_argument, NULL, 0},
		{NULL, 0, 0, 0},
	};

	/* Parse command line */
	while ((opt = getopt_long(argc, argv, "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 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;
				}
			}

			/* 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 {
					if (ret) {
						vmdq_conf_default.rxmode.jumbo_frame = 1;
						vmdq_conf_default.rxmode.max_rx_pkt_len
							= JUMBO_FRAME_MAX_SIZE;
						VHOST_FEATURES = (1ULL << VIRTIO_NET_F_MRG_RXBUF);
					}
				}
			}

			/* 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 character device basename. */
			if (!strncmp(long_option[option_index].name, "dev-basename", MAX_LONG_OPT_SZ)) {
				if (us_vhost_parse_basename(optarg) == -1) {
					RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for character device basename (Max %d characters)\n", MAX_BASENAME_SZ);
					us_vhost_usage(prgname);
					return -1;
				}
			}

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

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

				if (zero_copy) {
#ifdef RTE_MBUF_REFCNT
					RTE_LOG(ERR, VHOST_CONFIG, "Before running "
					"zero copy vhost APP, please "
					"disable RTE_MBUF_REFCNT\n"
					"in config file and then rebuild DPDK "
					"core lib!\n"
					"Otherwise please disable zero copy "
					"flag in command line!\n");
					return -1;
#endif
				}
			}

			/* Specify the descriptor number on RX. */
			if (!strncmp(long_option[option_index].name,
				"rx-desc-num", MAX_LONG_OPT_SZ)) {
				ret = parse_num_opt(optarg, MAX_RING_DESC);
				if ((ret == -1) || (!POWEROF2(ret))) {
					RTE_LOG(INFO, VHOST_CONFIG,
					"Invalid argument for rx-desc-num[0-N],"
					"power of 2 required.\n");
					us_vhost_usage(prgname);
					return -1;
				} else {
					num_rx_descriptor = ret;
				}
			}

			/* Specify the descriptor number on TX. */
			if (!strncmp(long_option[option_index].name,
				"tx-desc-num", MAX_LONG_OPT_SZ)) {
				ret = parse_num_opt(optarg, MAX_RING_DESC);
				if ((ret == -1) || (!POWEROF2(ret))) {
					RTE_LOG(INFO, VHOST_CONFIG,
					"Invalid argument for tx-desc-num [0-N],"
					"power of 2 required.\n");
					us_vhost_usage(prgname);
					return -1;
				} else {
					num_tx_descriptor = ret;
				}
			}

			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++] = (uint8_t)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;
	}

	if ((zero_copy == 1) && (vm2vm_mode == VM2VM_SOFTWARE)) {
		RTE_LOG(INFO, VHOST_PORT,
			"Vhost zero copy doesn't support software vm2vm,"
			"please specify 'vm2vm 2' to use hardware vm2vm.\n");
		return -1;
	}

	if ((zero_copy == 1) && (vmdq_conf_default.rxmode.jumbo_frame == 1)) {
		RTE_LOG(INFO, VHOST_PORT,
			"Vhost zero copy doesn't support jumbo frame,"
			"please specify '--mergeable 0' to disable the "
			"mergeable feature.\n");
		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 (ports[portid] >= nb_ports) {
			RTE_LOG(INFO, VHOST_PORT, "\nSpecified port ID(%u) exceeds max system port ID(%u)\n",
				ports[portid], (nb_ports - 1));
			ports[portid] = INVALID_PORT_ID;
			valid_num_ports--;
		}
	}
	return valid_num_ports;
}

/*
 * Macro to print out packet contents. Wrapped in debug define so that the
 * data path is not effected when debug is disabled.
 */
#ifdef DEBUG
#define PRINT_PACKET(device, addr, size, header) do {																\
	char *pkt_addr = (char*)(addr);																					\
	unsigned int index;																								\
	char packet[MAX_PRINT_BUFF];																					\
																													\
	if ((header))																									\
		snprintf(packet, MAX_PRINT_BUFF, "(%"PRIu64") Header size %d: ", (device->device_fh), (size));				\
	else																											\
		snprintf(packet, MAX_PRINT_BUFF, "(%"PRIu64") Packet size %d: ", (device->device_fh), (size));				\
	for (index = 0; index < (size); index++) {																		\
		snprintf(packet + strnlen(packet, MAX_PRINT_BUFF), MAX_PRINT_BUFF - strnlen(packet, MAX_PRINT_BUFF),	\
			"%02hhx ", pkt_addr[index]);																			\
	}																												\
	snprintf(packet + strnlen(packet, MAX_PRINT_BUFF), MAX_PRINT_BUFF - strnlen(packet, MAX_PRINT_BUFF), "\n");	\
																													\
	LOG_DEBUG(VHOST_DATA, "%s", packet);																					\
} while(0)
#else
#define PRINT_PACKET(device, addr, size, header) do{} while(0)
#endif

/*
 * Function to convert guest physical addresses to vhost virtual addresses. This
 * is used to convert virtio buffer addresses.
 */
static inline uint64_t __attribute__((always_inline))
gpa_to_vva(struct virtio_net *dev, uint64_t guest_pa)
{
	struct virtio_memory_regions *region;
	uint32_t regionidx;
	uint64_t vhost_va = 0;

	for (regionidx = 0; regionidx < dev->mem->nregions; regionidx++) {
		region = &dev->mem->regions[regionidx];
		if ((guest_pa >= region->guest_phys_address) &&
			(guest_pa <= region->guest_phys_address_end)) {
			vhost_va = region->address_offset + guest_pa;
			break;
		}
	}
	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") GPA %p| VVA %p\n",
		dev->device_fh, (void*)(uintptr_t)guest_pa, (void*)(uintptr_t)vhost_va);

	return vhost_va;
}

/*
 * Function to convert guest physical addresses to vhost physical addresses.
 * This is used to convert virtio buffer addresses.
 */
static inline uint64_t __attribute__((always_inline))
gpa_to_hpa(struct virtio_net *dev, uint64_t guest_pa,
	uint32_t buf_len, hpa_type *addr_type)
{
	struct virtio_memory_regions_hpa *region;
	uint32_t regionidx;
	uint64_t vhost_pa = 0;

	*addr_type = PHYS_ADDR_INVALID;

	for (regionidx = 0; regionidx < dev->mem->nregions_hpa; regionidx++) {
		region = &dev->mem->regions_hpa[regionidx];
		if ((guest_pa >= region->guest_phys_address) &&
			(guest_pa <= region->guest_phys_address_end)) {
			vhost_pa = region->host_phys_addr_offset + guest_pa;
			if (likely((guest_pa + buf_len - 1)
				<= region->guest_phys_address_end))
				*addr_type = PHYS_ADDR_CONTINUOUS;
			else
				*addr_type = PHYS_ADDR_CROSS_SUBREG;
			break;
		}
	}

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") GPA %p| HPA %p\n",
		dev->device_fh, (void *)(uintptr_t)guest_pa,
		(void *)(uintptr_t)vhost_pa);

	return vhost_pa;
}

/*
 * This function adds buffers to the virtio devices RX virtqueue. Buffers can
 * be received from the physical port or from another virtio device. A packet
 * count is returned to indicate the number of packets that were succesfully
 * added to the RX queue. This function works when mergeable is disabled.
 */
static inline uint32_t __attribute__((always_inline))
virtio_dev_rx(struct virtio_net *dev, struct rte_mbuf **pkts, uint32_t count)
{
	struct vhost_virtqueue *vq;
	struct vring_desc *desc;
	struct rte_mbuf *buff;
	/* The virtio_hdr is initialised to 0. */
	struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0,0,0,0,0,0},0};
	uint64_t buff_addr = 0;
	uint64_t buff_hdr_addr = 0;
	uint32_t head[MAX_PKT_BURST], packet_len = 0;
	uint32_t head_idx, packet_success = 0;
	uint32_t retry = 0;
	uint16_t avail_idx, res_cur_idx;
	uint16_t res_base_idx, res_end_idx;
	uint16_t free_entries;
	uint8_t success = 0;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_rx()\n", dev->device_fh);
	vq = dev->virtqueue[VIRTIO_RXQ];
	count = (count > MAX_PKT_BURST) ? MAX_PKT_BURST : count;

	/* As many data cores may want access to available buffers, they need to be reserved. */
	do {
		res_base_idx = vq->last_used_idx_res;
		avail_idx = *((volatile uint16_t *)&vq->avail->idx);

		free_entries = (avail_idx - res_base_idx);
		/* If retry is enabled and the queue is full then we wait and retry to avoid packet loss. */
		if (enable_retry && unlikely(count > free_entries)) {
			for (retry = 0; retry < burst_rx_retry_num; retry++) {
				rte_delay_us(burst_rx_delay_time);
				avail_idx =
					*((volatile uint16_t *)&vq->avail->idx);
				free_entries = (avail_idx - res_base_idx);
				if (count <= free_entries)
					break;
			}
		}

		/*check that we have enough buffers*/
		if (unlikely(count > free_entries))
			count = free_entries;

		if (count == 0)
			return 0;

		res_end_idx = res_base_idx + count;
		/* vq->last_used_idx_res is atomically updated. */
		success = rte_atomic16_cmpset(&vq->last_used_idx_res, res_base_idx,
									res_end_idx);
	} while (unlikely(success == 0));
	res_cur_idx = res_base_idx;
	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Current Index %d| End Index %d\n", dev->device_fh, res_cur_idx, res_end_idx);

	/* Prefetch available ring to retrieve indexes. */
	rte_prefetch0(&vq->avail->ring[res_cur_idx & (vq->size - 1)]);

	/* Retrieve all of the head indexes first to avoid caching issues. */
	for (head_idx = 0; head_idx < count; head_idx++)
		head[head_idx] = vq->avail->ring[(res_cur_idx + head_idx) & (vq->size - 1)];

	/*Prefetch descriptor index. */
	rte_prefetch0(&vq->desc[head[packet_success]]);

	while (res_cur_idx != res_end_idx) {
		/* Get descriptor from available ring */
		desc = &vq->desc[head[packet_success]];

		buff = pkts[packet_success];

		/* Convert from gpa to vva (guest physical addr -> vhost virtual addr) */
		buff_addr = gpa_to_vva(dev, desc->addr);
		/* Prefetch buffer address. */
		rte_prefetch0((void*)(uintptr_t)buff_addr);

		/* Copy virtio_hdr to packet and increment buffer address */
		buff_hdr_addr = buff_addr;
		packet_len = rte_pktmbuf_data_len(buff) + vq->vhost_hlen;

		/*
		 * If the descriptors are chained the header and data are
		 * placed in separate buffers.
		 */
		if (desc->flags & VRING_DESC_F_NEXT) {
			desc->len = vq->vhost_hlen;
			desc = &vq->desc[desc->next];
			/* Buffer address translation. */
			buff_addr = gpa_to_vva(dev, desc->addr);
			desc->len = rte_pktmbuf_data_len(buff);
		} else {
			buff_addr += vq->vhost_hlen;
			desc->len = packet_len;
		}

		/* Update used ring with desc information */
		vq->used->ring[res_cur_idx & (vq->size - 1)].id = head[packet_success];
		vq->used->ring[res_cur_idx & (vq->size - 1)].len = packet_len;

		/* Copy mbuf data to buffer */
		rte_memcpy((void *)(uintptr_t)buff_addr,
			(const void *)buff->pkt.data,
			rte_pktmbuf_data_len(buff));
		PRINT_PACKET(dev, (uintptr_t)buff_addr,
			rte_pktmbuf_data_len(buff), 0);

		res_cur_idx++;
		packet_success++;

		rte_memcpy((void *)(uintptr_t)buff_hdr_addr,
			(const void *)&virtio_hdr, vq->vhost_hlen);

		PRINT_PACKET(dev, (uintptr_t)buff_hdr_addr, vq->vhost_hlen, 1);

		if (res_cur_idx < res_end_idx) {
			/* Prefetch descriptor index. */
			rte_prefetch0(&vq->desc[head[packet_success]]);
		}
	}

	rte_compiler_barrier();

	/* Wait until it's our turn to add our buffer to the used ring. */
	while (unlikely(vq->last_used_idx != res_base_idx))
		rte_pause();

	*(volatile uint16_t *)&vq->used->idx += count;
	vq->last_used_idx = res_end_idx;

	/* Kick the guest if necessary. */
	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
		eventfd_write((int)vq->kickfd, 1);
	return count;
}

static inline uint32_t __attribute__((always_inline))
copy_from_mbuf_to_vring(struct virtio_net *dev,
	uint16_t res_base_idx, uint16_t res_end_idx,
	struct rte_mbuf *pkt)
{
	uint32_t vec_idx = 0;
	uint32_t entry_success = 0;
	struct vhost_virtqueue *vq;
	/* The virtio_hdr is initialised to 0. */
	struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {
		{0, 0, 0, 0, 0, 0}, 0};
	uint16_t cur_idx = res_base_idx;
	uint64_t vb_addr = 0;
	uint64_t vb_hdr_addr = 0;
	uint32_t seg_offset = 0;
	uint32_t vb_offset = 0;
	uint32_t seg_avail;
	uint32_t vb_avail;
	uint32_t cpy_len, entry_len;

	if (pkt == NULL)
		return 0;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Current Index %d| "
		"End Index %d\n",
		dev->device_fh, cur_idx, res_end_idx);

	/*
	 * Convert from gpa to vva
	 * (guest physical addr -> vhost virtual addr)
	 */
	vq = dev->virtqueue[VIRTIO_RXQ];
	vb_addr =
		gpa_to_vva(dev, vq->buf_vec[vec_idx].buf_addr);
	vb_hdr_addr = vb_addr;

	/* Prefetch buffer address. */
	rte_prefetch0((void *)(uintptr_t)vb_addr);

	virtio_hdr.num_buffers = res_end_idx - res_base_idx;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") RX: Num merge buffers %d\n",
		dev->device_fh, virtio_hdr.num_buffers);

	rte_memcpy((void *)(uintptr_t)vb_hdr_addr,
		(const void *)&virtio_hdr, vq->vhost_hlen);

	PRINT_PACKET(dev, (uintptr_t)vb_hdr_addr, vq->vhost_hlen, 1);

	seg_avail = rte_pktmbuf_data_len(pkt);
	vb_offset = vq->vhost_hlen;
	vb_avail =
		vq->buf_vec[vec_idx].buf_len - vq->vhost_hlen;

	entry_len = vq->vhost_hlen;

	if (vb_avail == 0) {
		uint32_t desc_idx =
			vq->buf_vec[vec_idx].desc_idx;
		vq->desc[desc_idx].len = vq->vhost_hlen;

		if ((vq->desc[desc_idx].flags
			& VRING_DESC_F_NEXT) == 0) {
			/* Update used ring with desc information */
			vq->used->ring[cur_idx & (vq->size - 1)].id
				= vq->buf_vec[vec_idx].desc_idx;
			vq->used->ring[cur_idx & (vq->size - 1)].len
				= entry_len;

			entry_len = 0;
			cur_idx++;
			entry_success++;
		}

		vec_idx++;
		vb_addr =
			gpa_to_vva(dev, vq->buf_vec[vec_idx].buf_addr);

		/* Prefetch buffer address. */
		rte_prefetch0((void *)(uintptr_t)vb_addr);
		vb_offset = 0;
		vb_avail = vq->buf_vec[vec_idx].buf_len;
	}

	cpy_len = RTE_MIN(vb_avail, seg_avail);

	while (cpy_len > 0) {
		/* Copy mbuf data to vring buffer */
		rte_memcpy((void *)(uintptr_t)(vb_addr + vb_offset),
			(const void *)(rte_pktmbuf_mtod(pkt, char*) + seg_offset),
			cpy_len);

		PRINT_PACKET(dev,
			(uintptr_t)(vb_addr + vb_offset),
			cpy_len, 0);

		seg_offset += cpy_len;
		vb_offset += cpy_len;
		seg_avail -= cpy_len;
		vb_avail -= cpy_len;
		entry_len += cpy_len;

		if (seg_avail != 0) {
			/*
			 * The virtio buffer in this vring
			 * entry reach to its end.
			 * But the segment doesn't complete.
			 */
			if ((vq->desc[vq->buf_vec[vec_idx].desc_idx].flags &
				VRING_DESC_F_NEXT) == 0) {
				/* Update used ring with desc information */
				vq->used->ring[cur_idx & (vq->size - 1)].id
					= vq->buf_vec[vec_idx].desc_idx;
				vq->used->ring[cur_idx & (vq->size - 1)].len
					= entry_len;
				entry_len = 0;
				cur_idx++;
				entry_success++;
			}

			vec_idx++;
			vb_addr = gpa_to_vva(dev,
				vq->buf_vec[vec_idx].buf_addr);
			vb_offset = 0;
			vb_avail = vq->buf_vec[vec_idx].buf_len;
			cpy_len = RTE_MIN(vb_avail, seg_avail);
		} else {
			/*
			 * This current segment complete, need continue to
			 * check if the whole packet complete or not.
			 */
			pkt = pkt->pkt.next;
			if (pkt != NULL) {
				/*
				 * There are more segments.
				 */
				if (vb_avail == 0) {
					/*
					 * This current buffer from vring is
					 * used up, need fetch next buffer
					 * from buf_vec.
					 */
					uint32_t desc_idx =
						vq->buf_vec[vec_idx].desc_idx;
					vq->desc[desc_idx].len = vb_offset;

					if ((vq->desc[desc_idx].flags &
						VRING_DESC_F_NEXT) == 0) {
						uint16_t wrapped_idx =
							cur_idx & (vq->size - 1);
						/*
						 * Update used ring with the
						 * descriptor information
						 */
						vq->used->ring[wrapped_idx].id
							= desc_idx;
						vq->used->ring[wrapped_idx].len
							= entry_len;
						entry_success++;
						entry_len = 0;
						cur_idx++;
					}

					/* Get next buffer from buf_vec. */
					vec_idx++;
					vb_addr = gpa_to_vva(dev,
						vq->buf_vec[vec_idx].buf_addr);
					vb_avail =
						vq->buf_vec[vec_idx].buf_len;
					vb_offset = 0;
				}

				seg_offset = 0;
				seg_avail = rte_pktmbuf_data_len(pkt);
				cpy_len = RTE_MIN(vb_avail, seg_avail);
			} else {
				/*
				 * This whole packet completes.
				 */
				uint32_t desc_idx =
					vq->buf_vec[vec_idx].desc_idx;
				vq->desc[desc_idx].len = vb_offset;

				while (vq->desc[desc_idx].flags &
					VRING_DESC_F_NEXT) {
					desc_idx = vq->desc[desc_idx].next;
					 vq->desc[desc_idx].len = 0;
				}

				/* Update used ring with desc information */
				vq->used->ring[cur_idx & (vq->size - 1)].id
					= vq->buf_vec[vec_idx].desc_idx;
				vq->used->ring[cur_idx & (vq->size - 1)].len
					= entry_len;
				entry_len = 0;
				cur_idx++;
				entry_success++;
				seg_avail = 0;
				cpy_len = RTE_MIN(vb_avail, seg_avail);
			}
		}
	}

	return entry_success;
}

/*
 * This function adds buffers to the virtio devices RX virtqueue. Buffers can
 * be received from the physical port or from another virtio device. A packet
 * count is returned to indicate the number of packets that were succesfully
 * added to the RX queue. This function works for mergeable RX.
 */
static inline uint32_t __attribute__((always_inline))
virtio_dev_merge_rx(struct virtio_net *dev, struct rte_mbuf **pkts,
	uint32_t count)
{
	struct vhost_virtqueue *vq;
	uint32_t pkt_idx = 0, entry_success = 0;
	uint32_t retry = 0;
	uint16_t avail_idx, res_cur_idx;
	uint16_t res_base_idx, res_end_idx;
	uint8_t success = 0;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_merge_rx()\n",
		dev->device_fh);
	vq = dev->virtqueue[VIRTIO_RXQ];
	count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);

	if (count == 0)
		return 0;

	for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
		uint32_t secure_len = 0;
		uint16_t need_cnt;
		uint32_t vec_idx = 0;
		uint32_t pkt_len = pkts[pkt_idx]->pkt.pkt_len + vq->vhost_hlen;
		uint16_t i, id;

		do {
			/*
			 * As many data cores may want access to available
			 * buffers, they need to be reserved.
			 */
			res_base_idx = vq->last_used_idx_res;
			res_cur_idx = res_base_idx;

			do {
				avail_idx = *((volatile uint16_t *)&vq->avail->idx);
				if (unlikely(res_cur_idx == avail_idx)) {
					/*
					 * If retry is enabled and the queue is
					 * full then we wait and retry to avoid
					 * packet loss.
					 */
					if (enable_retry) {
						uint8_t cont = 0;
						for (retry = 0; retry < burst_rx_retry_num; retry++) {
							rte_delay_us(burst_rx_delay_time);
							avail_idx =
								*((volatile uint16_t *)&vq->avail->idx);
							if (likely(res_cur_idx != avail_idx)) {
								cont = 1;
								break;
							}
						}
						if (cont == 1)
							continue;
					}

					LOG_DEBUG(VHOST_DATA,
						"(%"PRIu64") Failed "
						"to get enough desc from "
						"vring\n",
						dev->device_fh);
					return pkt_idx;
				} else {
					uint16_t wrapped_idx =
						(res_cur_idx) & (vq->size - 1);
					uint32_t idx =
						vq->avail->ring[wrapped_idx];
					uint8_t next_desc;

					do {
						next_desc = 0;
						secure_len += vq->desc[idx].len;
						if (vq->desc[idx].flags &
							VRING_DESC_F_NEXT) {
							idx = vq->desc[idx].next;
							next_desc = 1;
						}
					} while (next_desc);

					res_cur_idx++;
				}
			} while (pkt_len > secure_len);

			/* vq->last_used_idx_res is atomically updated. */
			success = rte_atomic16_cmpset(&vq->last_used_idx_res,
							res_base_idx,
							res_cur_idx);
		} while (success == 0);

		id = res_base_idx;
		need_cnt = res_cur_idx - res_base_idx;

		for (i = 0; i < need_cnt; i++, id++) {
			uint16_t wrapped_idx = id & (vq->size - 1);
			uint32_t idx = vq->avail->ring[wrapped_idx];
			uint8_t next_desc;
			do {
				next_desc = 0;
				vq->buf_vec[vec_idx].buf_addr =
					vq->desc[idx].addr;
				vq->buf_vec[vec_idx].buf_len =
					vq->desc[idx].len;
				vq->buf_vec[vec_idx].desc_idx = idx;
				vec_idx++;

				if (vq->desc[idx].flags & VRING_DESC_F_NEXT) {
					idx = vq->desc[idx].next;
					next_desc = 1;
				}
			} while (next_desc);
		}

		res_end_idx = res_cur_idx;

		entry_success = copy_from_mbuf_to_vring(dev, res_base_idx,
			res_end_idx, pkts[pkt_idx]);

		rte_compiler_barrier();

		/*
		 * Wait until it's our turn to add our buffer
		 * to the used ring.
		 */
		while (unlikely(vq->last_used_idx != res_base_idx))
			rte_pause();

		*(volatile uint16_t *)&vq->used->idx += entry_success;
		vq->last_used_idx = res_end_idx;

		/* Kick the guest if necessary. */
		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
			eventfd_write((int)vq->kickfd, 1);
	}

	return count;
}

/*
 * Compares a packet destination MAC address to a device MAC address.
 */
static inline int __attribute__((always_inline))
ether_addr_cmp(struct ether_addr *ea, struct ether_addr *eb)
{
	return (((*(uint64_t *)ea ^ *(uint64_t *)eb) & MAC_ADDR_CMP) == 0);
}

/*
 * 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 virtio_net *dev, struct rte_mbuf *m)
{
	struct ether_hdr *pkt_hdr;
	struct virtio_net_data_ll *dev_ll;
	int i, ret;

	/* Learn MAC address of guest device from packet */
	pkt_hdr = (struct ether_hdr *)m->pkt.data;

	dev_ll = ll_root_used;

	while (dev_ll != NULL) {
		if (ether_addr_cmp(&(pkt_hdr->s_addr), &dev_ll->dev->mac_address)) {
			RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") WARNING: This device is using an existing MAC address and has not been registered.\n", dev->device_fh);
			return -1;
		}
		dev_ll = dev_ll->next;
	}

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

	/* vlan_tag currently uses the device_id. */
	dev->vlan_tag = vlan_tags[dev->device_fh];

	/* Print out VMDQ registration info. */
	RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") MAC_ADDRESS %02x:%02x:%02x:%02x:%02x:%02x and VLAN_TAG %d registered\n",
		dev->device_fh,
		dev->mac_address.addr_bytes[0], dev->mac_address.addr_bytes[1],
		dev->mac_address.addr_bytes[2], dev->mac_address.addr_bytes[3],
		dev->mac_address.addr_bytes[4], dev->mac_address.addr_bytes[5],
		dev->vlan_tag);

	/* Register the MAC address. */
	ret = rte_eth_dev_mac_addr_add(ports[0], &dev->mac_address, (uint32_t)dev->device_fh);
	if (ret)
		RTE_LOG(ERR, VHOST_DATA, "(%"PRIu64") Failed to add device MAC address to VMDQ\n",
					dev->device_fh);

	/* Enable stripping of the vlan tag as we handle routing. */
	rte_eth_dev_set_vlan_strip_on_queue(ports[0], (uint16_t)dev->vmdq_rx_q, 1);

	/* Set device as ready for RX. */
	dev->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 virtio_net *dev)
{
	unsigned i = 0;
	unsigned rx_count;
	struct rte_mbuf *pkts_burst[MAX_PKT_BURST];

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

		dev->vlan_tag = 0;

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

		dev->ready = DEVICE_MAC_LEARNING;
	}
}

/*
 * 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 inline unsigned __attribute__((always_inline))
virtio_tx_local(struct virtio_net *dev, struct rte_mbuf *m)
{
	struct virtio_net_data_ll *dev_ll;
	struct ether_hdr *pkt_hdr;
	uint64_t ret = 0;

	pkt_hdr = (struct ether_hdr *)m->pkt.data;

	/*get the used devices list*/
	dev_ll = ll_root_used;

	while (dev_ll != NULL) {
		if ((dev_ll->dev->ready == DEVICE_RX) && ether_addr_cmp(&(pkt_hdr->d_addr),
				          &dev_ll->dev->mac_address)) {

			/* Drop the packet if the TX packet is destined for the TX device. */
			if (dev_ll->dev->device_fh == dev->device_fh) {
				LOG_DEBUG(VHOST_DATA, "(%"PRIu64") TX: Source and destination MAC addresses are the same. Dropping packet.\n",
							dev_ll->dev->device_fh);
				return 0;
			}


			LOG_DEBUG(VHOST_DATA, "(%"PRIu64") TX: MAC address is local\n", dev_ll->dev->device_fh);

			if (dev_ll->dev->remove) {
				/*drop the packet if the device is marked for removal*/
				LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Device is marked for removal\n", dev_ll->dev->device_fh);
			} else {
				uint32_t mergeable =
					dev_ll->dev->features &
					(1 << VIRTIO_NET_F_MRG_RXBUF);

				/*send the packet to the local virtio device*/
				if (likely(mergeable == 0))
					ret = virtio_dev_rx(dev_ll->dev, &m, 1);
				else
					ret = virtio_dev_merge_rx(dev_ll->dev,
						&m, 1);

				if (enable_stats) {
					rte_atomic64_add(
					&dev_statistics[dev_ll->dev->device_fh].rx_total_atomic,
					1);
					rte_atomic64_add(
					&dev_statistics[dev_ll->dev->device_fh].rx_atomic,
					ret);
					dev_statistics[dev->device_fh].tx_total++;
					dev_statistics[dev->device_fh].tx += ret;
				}
			}

			return 0;
		}
		dev_ll = dev_ll->next;
	}

	return -1;
}

/*
 * This function routes the TX packet to the correct interface. This may be a local device
 * or the physical port.
 */
static inline void __attribute__((always_inline))
virtio_tx_route(struct virtio_net* dev, struct rte_mbuf *m, struct rte_mempool *mbuf_pool, uint16_t vlan_tag)
{
	struct mbuf_table *tx_q;
	struct vlan_ethhdr *vlan_hdr;
	struct rte_mbuf **m_table;
	struct rte_mbuf *mbuf, *prev;
	unsigned len, ret, offset = 0;
	const uint16_t lcore_id = rte_lcore_id();
	struct virtio_net_data_ll *dev_ll = ll_root_used;
	struct ether_hdr *pkt_hdr = (struct ether_hdr *)m->pkt.data;

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

	if (vm2vm_mode == VM2VM_HARDWARE) {
		while (dev_ll != NULL) {
			if ((dev_ll->dev->ready == DEVICE_RX)
				&& ether_addr_cmp(&(pkt_hdr->d_addr),
				&dev_ll->dev->mac_address)) {
				/*
				 * Drop the packet if the TX packet is
				 * destined for the TX device.
				 */
				if (dev_ll->dev->device_fh == dev->device_fh) {
					LOG_DEBUG(VHOST_DATA,
					"(%"PRIu64") TX: Source and destination"
					" MAC addresses are the same. Dropping "
					"packet.\n",
					dev_ll->dev->device_fh);
					return;
				}
				offset = 4;
				vlan_tag =
				(uint16_t)
				vlan_tags[(uint16_t)dev_ll->dev->device_fh];

				LOG_DEBUG(VHOST_DATA,
				"(%"PRIu64") TX: pkt to local VM device id:"
				"(%"PRIu64") vlan tag: %d.\n",
				dev->device_fh, dev_ll->dev->device_fh,
				vlan_tag);

				break;
			}
			dev_ll = dev_ll->next;
		}
	}

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") TX: MAC address is external\n", dev->device_fh);

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

	/* Allocate an mbuf and populate the structure. */
	mbuf = rte_pktmbuf_alloc(mbuf_pool);
	if (unlikely(mbuf == NULL)) {
		RTE_LOG(ERR, VHOST_DATA,
			"Failed to allocate memory for mbuf.\n");
		return;
	}

	mbuf->pkt.data_len = m->pkt.data_len + VLAN_HLEN + offset;
	mbuf->pkt.pkt_len = m->pkt.pkt_len + VLAN_HLEN + offset;
	mbuf->pkt.nb_segs = m->pkt.nb_segs;

	/* Copy ethernet header to mbuf. */
	rte_memcpy((void*)mbuf->pkt.data, (const void*)m->pkt.data, ETH_HLEN);


	/* Setup vlan header. Bytes need to be re-ordered for network with htons()*/
	vlan_hdr = (struct vlan_ethhdr *) mbuf->pkt.data;
	vlan_hdr->h_vlan_encapsulated_proto = vlan_hdr->h_vlan_proto;
	vlan_hdr->h_vlan_proto = htons(ETH_P_8021Q);
	vlan_hdr->h_vlan_TCI = htons(vlan_tag);

	/* Copy the remaining packet contents to the mbuf. */
	rte_memcpy((void*) ((uint8_t*)mbuf->pkt.data + VLAN_ETH_HLEN),
		(const void*) ((uint8_t*)m->pkt.data + ETH_HLEN), (m->pkt.data_len - ETH_HLEN));

	/* Copy the remaining segments for the whole packet. */
	prev = mbuf;
	while (m->pkt.next) {
		/* Allocate an mbuf and populate the structure. */
		struct rte_mbuf *next_mbuf = rte_pktmbuf_alloc(mbuf_pool);
		if (unlikely(next_mbuf == NULL)) {
			rte_pktmbuf_free(mbuf);
			RTE_LOG(ERR, VHOST_DATA,
				"Failed to allocate memory for mbuf.\n");
			return;
		}

		m = m->pkt.next;
		prev->pkt.next = next_mbuf;
		prev = next_mbuf;
		next_mbuf->pkt.data_len = m->pkt.data_len;

		/* Copy data to next mbuf. */
		rte_memcpy(rte_pktmbuf_mtod(next_mbuf, void *),
			rte_pktmbuf_mtod(m, const void *), m->pkt.data_len);
	}

	tx_q->m_table[len] = mbuf;
	len++;
	if (enable_stats) {
		dev_statistics[dev->device_fh].tx_total++;
		dev_statistics[dev->device_fh].tx++;
	}

	if (unlikely(len == MAX_PKT_BURST)) {
		m_table = (struct rte_mbuf **)tx_q->m_table;
		ret = rte_eth_tx_burst(ports[0], (uint16_t)tx_q->txq_id, m_table, (uint16_t) len);
		/* Free any buffers not handled by TX and update the port stats. */
		if (unlikely(ret < len)) {
			do {
				rte_pktmbuf_free(m_table[ret]);
			} while (++ret < len);
		}

		len = 0;
	}

	tx_q->len = len;
	return;
}

static inline void __attribute__((always_inline))
virtio_dev_tx(struct virtio_net* dev, struct rte_mempool *mbuf_pool)
{
	struct rte_mbuf m;
	struct vhost_virtqueue *vq;
	struct vring_desc *desc;
	uint64_t buff_addr = 0;
	uint32_t head[MAX_PKT_BURST];
	uint32_t used_idx;
	uint32_t i;
	uint16_t free_entries, packet_success = 0;
	uint16_t avail_idx;

	vq = dev->virtqueue[VIRTIO_TXQ];
	avail_idx =  *((volatile uint16_t *)&vq->avail->idx);

	/* If there are no available buffers then return. */
	if (vq->last_used_idx == avail_idx)
		return;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_tx()\n", dev->device_fh);

	/* Prefetch available ring to retrieve head indexes. */
	rte_prefetch0(&vq->avail->ring[vq->last_used_idx & (vq->size - 1)]);

	/*get the number of free entries in the ring*/
	free_entries = (avail_idx - vq->last_used_idx);

	/* Limit to MAX_PKT_BURST. */
	if (free_entries > MAX_PKT_BURST)
		free_entries = MAX_PKT_BURST;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Buffers available %d\n", dev->device_fh, free_entries);
	/* Retrieve all of the head indexes first to avoid caching issues. */
	for (i = 0; i < free_entries; i++)
		head[i] = vq->avail->ring[(vq->last_used_idx + i) & (vq->size - 1)];

	/* Prefetch descriptor index. */
	rte_prefetch0(&vq->desc[head[packet_success]]);
	rte_prefetch0(&vq->used->ring[vq->last_used_idx & (vq->size - 1)]);

	while (packet_success < free_entries) {
		desc = &vq->desc[head[packet_success]];

		/* Discard first buffer as it is the virtio header */
		desc = &vq->desc[desc->next];

		/* Buffer address translation. */
		buff_addr = gpa_to_vva(dev, desc->addr);
		/* Prefetch buffer address. */
		rte_prefetch0((void*)(uintptr_t)buff_addr);

		used_idx = vq->last_used_idx & (vq->size - 1);

		if (packet_success < (free_entries - 1)) {
			/* Prefetch descriptor index. */
			rte_prefetch0(&vq->desc[head[packet_success+1]]);
			rte_prefetch0(&vq->used->ring[(used_idx + 1) & (vq->size - 1)]);
		}

		/* Update used index buffer information. */
		vq->used->ring[used_idx].id = head[packet_success];
		vq->used->ring[used_idx].len = 0;

		/* Setup dummy mbuf. This is copied to a real mbuf if transmitted out the physical port. */
		m.pkt.data_len = desc->len;
		m.pkt.pkt_len = desc->len;
		m.pkt.data = (void*)(uintptr_t)buff_addr;

		PRINT_PACKET(dev, (uintptr_t)buff_addr, desc->len, 0);

		/* If this is the first received packet we need to learn the MAC and setup VMDQ */
		if (dev->ready == DEVICE_MAC_LEARNING) {
			if (dev->remove || (link_vmdq(dev, &m) == -1)) {
				/*discard frame if device is scheduled for removal or a duplicate MAC address is found. */
				packet_success += free_entries;
				vq->last_used_idx += packet_success;
				break;
			}
		}
		virtio_tx_route(dev, &m, mbuf_pool, (uint16_t)dev->device_fh);

		vq->last_used_idx++;
		packet_success++;
	}

	rte_compiler_barrier();
	vq->used->idx += packet_success;
	/* Kick guest if required. */
	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
		eventfd_write((int)vq->kickfd, 1);
}

/* This function works for TX packets with mergeable feature enabled. */
static inline void __attribute__((always_inline))
virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool)
{
	struct rte_mbuf *m, *prev;
	struct vhost_virtqueue *vq;
	struct vring_desc *desc;
	uint64_t vb_addr = 0;
	uint32_t head[MAX_PKT_BURST];
	uint32_t used_idx;
	uint32_t i;
	uint16_t free_entries, entry_success = 0;
	uint16_t avail_idx;
	uint32_t buf_size = MBUF_SIZE - (sizeof(struct rte_mbuf)
			+ RTE_PKTMBUF_HEADROOM);

	vq = dev->virtqueue[VIRTIO_TXQ];
	avail_idx =  *((volatile uint16_t *)&vq->avail->idx);

	/* If there are no available buffers then return. */
	if (vq->last_used_idx == avail_idx)
		return;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_merge_tx()\n",
		dev->device_fh);

	/* Prefetch available ring to retrieve head indexes. */
	rte_prefetch0(&vq->avail->ring[vq->last_used_idx & (vq->size - 1)]);

	/*get the number of free entries in the ring*/
	free_entries = (avail_idx - vq->last_used_idx);

	/* Limit to MAX_PKT_BURST. */
	free_entries = RTE_MIN(free_entries, MAX_PKT_BURST);

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Buffers available %d\n",
		dev->device_fh, free_entries);
	/* Retrieve all of the head indexes first to avoid caching issues. */
	for (i = 0; i < free_entries; i++)
		head[i] = vq->avail->ring[(vq->last_used_idx + i) & (vq->size - 1)];

	/* Prefetch descriptor index. */
	rte_prefetch0(&vq->desc[head[entry_success]]);
	rte_prefetch0(&vq->used->ring[vq->last_used_idx & (vq->size - 1)]);

	while (entry_success < free_entries) {
		uint32_t vb_avail, vb_offset;
		uint32_t seg_avail, seg_offset;
		uint32_t cpy_len;
		uint32_t seg_num = 0;
		struct rte_mbuf *cur;
		uint8_t alloc_err = 0;

		desc = &vq->desc[head[entry_success]];

		/* Discard first buffer as it is the virtio header */
		desc = &vq->desc[desc->next];

		/* Buffer address translation. */
		vb_addr = gpa_to_vva(dev, desc->addr);
		/* Prefetch buffer address. */
		rte_prefetch0((void *)(uintptr_t)vb_addr);

		used_idx = vq->last_used_idx & (vq->size - 1);

		if (entry_success < (free_entries - 1)) {
			/* Prefetch descriptor index. */
			rte_prefetch0(&vq->desc[head[entry_success+1]]);
			rte_prefetch0(&vq->used->ring[(used_idx + 1) & (vq->size - 1)]);
		}

		/* Update used index buffer information. */
		vq->used->ring[used_idx].id = head[entry_success];
		vq->used->ring[used_idx].len = 0;

		vb_offset = 0;
		vb_avail = desc->len;
		seg_offset = 0;
		seg_avail = buf_size;
		cpy_len = RTE_MIN(vb_avail, seg_avail);

		PRINT_PACKET(dev, (uintptr_t)vb_addr, desc->len, 0);

		/* Allocate an mbuf and populate the structure. */
		m = rte_pktmbuf_alloc(mbuf_pool);
		if (unlikely(m == NULL)) {
			RTE_LOG(ERR, VHOST_DATA,
				"Failed to allocate memory for mbuf.\n");
			return;
		}

		seg_num++;
		cur = m;
		prev = m;
		while (cpy_len != 0) {
			rte_memcpy((void *)(rte_pktmbuf_mtod(cur, char *) + seg_offset),
				(void *)((uintptr_t)(vb_addr + vb_offset)),
				cpy_len);

			seg_offset += cpy_len;
			vb_offset += cpy_len;
			vb_avail -= cpy_len;
			seg_avail -= cpy_len;

			if (vb_avail != 0) {
				/*
				 * The segment reachs to its end,
				 * while the virtio buffer in TX vring has
				 * more data to be copied.
				 */
				cur->pkt.data_len = seg_offset;
				m->pkt.pkt_len += seg_offset;
				/* Allocate mbuf and populate the structure. */
				cur = rte_pktmbuf_alloc(mbuf_pool);
				if (unlikely(cur == NULL)) {
					RTE_LOG(ERR, VHOST_DATA, "Failed to "
						"allocate memory for mbuf.\n");
					rte_pktmbuf_free(m);
					alloc_err = 1;
					break;
				}

				seg_num++;
				prev->pkt.next = cur;
				prev = cur;
				seg_offset = 0;
				seg_avail = buf_size;
			} else {
				if (desc->flags & VRING_DESC_F_NEXT) {
					/*
					 * There are more virtio buffers in
					 * same vring entry need to be copied.
					 */
					if (seg_avail == 0) {
						/*
						 * The current segment hasn't
						 * room to accomodate more
						 * data.
						 */
						cur->pkt.data_len = seg_offset;
						m->pkt.pkt_len += seg_offset;
						/*
						 * Allocate an mbuf and
						 * populate the structure.
						 */
						cur = rte_pktmbuf_alloc(mbuf_pool);
						if (unlikely(cur == NULL)) {
							RTE_LOG(ERR,
								VHOST_DATA,
								"Failed to "
								"allocate memory "
								"for mbuf\n");
							rte_pktmbuf_free(m);
							alloc_err = 1;
							break;
						}
						seg_num++;
						prev->pkt.next = cur;
						prev = cur;
						seg_offset = 0;
						seg_avail = buf_size;
					}

					desc = &vq->desc[desc->next];

					/* Buffer address translation. */
					vb_addr = gpa_to_vva(dev, desc->addr);
					/* Prefetch buffer address. */
					rte_prefetch0((void *)(uintptr_t)vb_addr);
					vb_offset = 0;
					vb_avail = desc->len;

					PRINT_PACKET(dev, (uintptr_t)vb_addr,
						desc->len, 0);
				} else {
					/* The whole packet completes. */
					cur->pkt.data_len = seg_offset;
					m->pkt.pkt_len += seg_offset;
					vb_avail = 0;
				}
			}

			cpy_len = RTE_MIN(vb_avail, seg_avail);
		}

		if (unlikely(alloc_err == 1))
			break;

		m->pkt.nb_segs = seg_num;

		/*
		 * If this is the first received packet we need to learn
		 * the MAC and setup VMDQ
		 */
		if (dev->ready == DEVICE_MAC_LEARNING) {
			if (dev->remove || (link_vmdq(dev, m) == -1)) {
				/*
				 * Discard frame if device is scheduled for
				 * removal or a duplicate MAC address is found.
				 */
				entry_success = free_entries;
				vq->last_used_idx += entry_success;
				rte_pktmbuf_free(m);
				break;
			}
		}

		virtio_tx_route(dev, m, mbuf_pool, (uint16_t)dev->device_fh);
		vq->last_used_idx++;
		entry_success++;
		rte_pktmbuf_free(m);
	}

	rte_compiler_barrier();
	vq->used->idx += entry_success;
	/* Kick guest if required. */
	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
		eventfd_write((int)vq->kickfd, 1);

}

/*
 * This function is called by each data core. It handles all RX/TX registered with the
 * core. For TX the specific lcore linked list is used. For RX, MAC addresses are compared
 * with all devices in the main linked list.
 */
static int
switch_worker(__attribute__((unused)) void *arg)
{
	struct rte_mempool *mbuf_pool = arg;
	struct virtio_net *dev = NULL;
	struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
	struct virtio_net_data_ll *dev_ll;
	struct mbuf_table *tx_q;
	volatile struct lcore_ll_info *lcore_ll;
	const uint64_t drain_tsc = (rte_get_tsc_hz() + US_PER_S - 1) / US_PER_S * BURST_TX_DRAIN_US;
	uint64_t prev_tsc, diff_tsc, cur_tsc, ret_count = 0;
	unsigned ret, i;
	const uint16_t lcore_id = rte_lcore_id();
	const uint16_t num_cores = (uint16_t)rte_lcore_count();
	uint16_t rx_count = 0;
	uint32_t mergeable = 0;

	RTE_LOG(INFO, VHOST_DATA, "Procesing on Core %u started\n", lcore_id);
	lcore_ll = lcore_info[lcore_id].lcore_ll;
	prev_tsc = 0;

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

	while(1) {
		cur_tsc = rte_rdtsc();
		/*
		 * TX burst queue drain
		 */
		diff_tsc = cur_tsc - prev_tsc;
		if (unlikely(diff_tsc > drain_tsc)) {

			if (tx_q->len) {
				LOG_DEBUG(VHOST_DATA, "TX queue drained after timeout with burst size %u \n", tx_q->len);

				/*Tx any packets in the queue*/
				ret = rte_eth_tx_burst(ports[0], (uint16_t)tx_q->txq_id,
									   (struct rte_mbuf **)tx_q->m_table,
									   (uint16_t)tx_q->len);
				if (unlikely(ret < tx_q->len)) {
					do {
						rte_pktmbuf_free(tx_q->m_table[ret]);
					} while (++ret < tx_q->len);
				}

				tx_q->len = 0;
			}

			prev_tsc = cur_tsc;

		}

		rte_prefetch0(lcore_ll->ll_root_used);
		/*
		 * Inform the configuration core that we have exited the linked list and that no devices are
		 * in use if requested.
		 */
		if (lcore_ll->dev_removal_flag == REQUEST_DEV_REMOVAL)
			lcore_ll->dev_removal_flag = ACK_DEV_REMOVAL;

		/*
		 * Process devices
		 */
		dev_ll = lcore_ll->ll_root_used;

		while (dev_ll != NULL) {
			/*get virtio device ID*/
			dev = dev_ll->dev;
			mergeable =
				dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF);

			if (dev->remove) {
				dev_ll = dev_ll->next;
				unlink_vmdq(dev);
				dev->ready = DEVICE_SAFE_REMOVE;
				continue;
			}
			if (likely(dev->ready == DEVICE_RX)) {
				/*Handle guest RX*/
				rx_count = rte_eth_rx_burst(ports[0],
					(uint16_t)dev->vmdq_rx_q, pkts_burst, MAX_PKT_BURST);

				if (rx_count) {
					if (likely(mergeable == 0))
						ret_count =
							virtio_dev_rx(dev,
							pkts_burst, rx_count);
					else
						ret_count =
							virtio_dev_merge_rx(dev,
							pkts_burst, rx_count);

					if (enable_stats) {
						rte_atomic64_add(
						&dev_statistics[dev_ll->dev->device_fh].rx_total_atomic,
						rx_count);
						rte_atomic64_add(
						&dev_statistics[dev_ll->dev->device_fh].rx_atomic, ret_count);
					}
					while (likely(rx_count)) {
						rx_count--;
						rte_pktmbuf_free(pkts_burst[rx_count]);
					}

				}
			}

			if (!dev->remove) {
				/*Handle guest TX*/
				if (likely(mergeable == 0))
					virtio_dev_tx(dev, mbuf_pool);
				else
					virtio_dev_merge_tx(dev, mbuf_pool);
			}

			/*move to the next device in the list*/
			dev_ll = dev_ll->next;
		}
	}

	return 0;
}

/*
 * This function gets available ring number for zero copy rx.
 * Only one thread will call this funciton for a paticular virtio device,
 * so, it is designed as non-thread-safe function.
 */
static inline uint32_t __attribute__((always_inline))
get_available_ring_num_zcp(struct virtio_net *dev)
{
	struct vhost_virtqueue *vq = dev->virtqueue[VIRTIO_RXQ];
	uint16_t avail_idx;

	avail_idx = *((volatile uint16_t *)&vq->avail->idx);
	return (uint32_t)(avail_idx - vq->last_used_idx_res);
}

/*
 * This function gets available ring index for zero copy rx,
 * it will retry 'burst_rx_retry_num' times till it get enough ring index.
 * Only one thread will call this funciton for a paticular virtio device,
 * so, it is designed as non-thread-safe function.
 */
static inline uint32_t __attribute__((always_inline))
get_available_ring_index_zcp(struct virtio_net *dev,
	uint16_t *res_base_idx, uint32_t count)
{
	struct vhost_virtqueue *vq = dev->virtqueue[VIRTIO_RXQ];
	uint16_t avail_idx;
	uint32_t retry = 0;
	uint16_t free_entries;

	*res_base_idx = vq->last_used_idx_res;
	avail_idx = *((volatile uint16_t *)&vq->avail->idx);
	free_entries = (avail_idx - *res_base_idx);

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") in get_available_ring_index_zcp: "
			"avail idx: %d, "
			"res base idx:%d, free entries:%d\n",
			dev->device_fh, avail_idx, *res_base_idx,
			free_entries);

	/*
	 * If retry is enabled and the queue is full then we wait
	 * and retry to avoid packet loss.
	 */
	if (enable_retry && unlikely(count > free_entries)) {
		for (retry = 0; retry < burst_rx_retry_num; retry++) {
			rte_delay_us(burst_rx_delay_time);
			avail_idx = *((volatile uint16_t *)&vq->avail->idx);
			free_entries = (avail_idx - *res_base_idx);
			if (count <= free_entries)
				break;
		}
	}

	/*check that we have enough buffers*/
	if (unlikely(count > free_entries))
		count = free_entries;

	if (unlikely(count == 0)) {
		LOG_DEBUG(VHOST_DATA,
			"(%"PRIu64") Fail in get_available_ring_index_zcp: "
			"avail idx: %d, res base idx:%d, free entries:%d\n",
			dev->device_fh, avail_idx,
			*res_base_idx, free_entries);
		return 0;
	}

	vq->last_used_idx_res = *res_base_idx + count;

	return count;
}

/*
 * This function put descriptor back to used list.
 */
static inline void __attribute__((always_inline))
put_desc_to_used_list_zcp(struct vhost_virtqueue *vq, uint16_t desc_idx)
{
	uint16_t res_cur_idx = vq->last_used_idx;
	vq->used->ring[res_cur_idx & (vq->size - 1)].id = (uint32_t)desc_idx;
	vq->used->ring[res_cur_idx & (vq->size - 1)].len = 0;
	rte_compiler_barrier();
	*(volatile uint16_t *)&vq->used->idx += 1;
	vq->last_used_idx += 1;

	/* Kick the guest if necessary. */
	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
		eventfd_write((int)vq->kickfd, 1);
}

/*
 * This function get available descriptor from vitio vring and un-attached mbuf
 * from vpool->ring, and then attach them together. It needs adjust the offset
 * for buff_addr and phys_addr accroding to PMD implementation, otherwise the
 * frame data may be put to wrong location in mbuf.
 */
static inline void __attribute__((always_inline))
attach_rxmbuf_zcp(struct virtio_net *dev)
{
	uint16_t res_base_idx, desc_idx;
	uint64_t buff_addr, phys_addr;
	struct vhost_virtqueue *vq;
	struct vring_desc *desc;
	struct rte_mbuf *mbuf = NULL;
	struct vpool *vpool;
	hpa_type addr_type;

	vpool = &vpool_array[dev->vmdq_rx_q];
	vq = dev->virtqueue[VIRTIO_RXQ];

	do {
		if (unlikely(get_available_ring_index_zcp(dev, &res_base_idx,
				1) != 1))
			return;
		desc_idx = vq->avail->ring[(res_base_idx) & (vq->size - 1)];

		desc = &vq->desc[desc_idx];
		if (desc->flags & VRING_DESC_F_NEXT) {
			desc = &vq->desc[desc->next];
			buff_addr = gpa_to_vva(dev, desc->addr);
			phys_addr = gpa_to_hpa(dev, desc->addr, desc->len,
					&addr_type);
		} else {
			buff_addr = gpa_to_vva(dev,
					desc->addr + vq->vhost_hlen);
			phys_addr = gpa_to_hpa(dev,
					desc->addr + vq->vhost_hlen,
					desc->len, &addr_type);
		}

		if (unlikely(addr_type == PHYS_ADDR_INVALID)) {
			RTE_LOG(ERR, VHOST_DATA, "(%"PRIu64") Invalid frame buffer"
				" address found when attaching RX frame buffer"
				" address!\n", dev->device_fh);
			put_desc_to_used_list_zcp(vq, desc_idx);
			continue;
		}

		/*
		 * Check if the frame buffer address from guest crosses
		 * sub-region or not.
		 */
		if (unlikely(addr_type == PHYS_ADDR_CROSS_SUBREG)) {
			RTE_LOG(ERR, VHOST_DATA,
				"(%"PRIu64") Frame buffer address cross "
				"sub-regioin found when attaching RX frame "
				"buffer address!\n",
				dev->device_fh);
			put_desc_to_used_list_zcp(vq, desc_idx);
			continue;
		}
	} while (unlikely(phys_addr == 0));

	rte_ring_sc_dequeue(vpool->ring, (void **)&mbuf);
	if (unlikely(mbuf == NULL)) {
		LOG_DEBUG(VHOST_DATA,
			"(%"PRIu64") in attach_rxmbuf_zcp: "
			"ring_sc_dequeue fail.\n",
			dev->device_fh);
		put_desc_to_used_list_zcp(vq, desc_idx);
		return;
	}

	if (unlikely(vpool->buf_size > desc->len)) {
		LOG_DEBUG(VHOST_DATA,
			"(%"PRIu64") in attach_rxmbuf_zcp: frame buffer "
			"length(%d) of descriptor idx: %d less than room "
			"size required: %d\n",
			dev->device_fh, desc->len, desc_idx, vpool->buf_size);
		put_desc_to_used_list_zcp(vq, desc_idx);
		rte_ring_sp_enqueue(vpool->ring, (void *)mbuf);
		return;
	}

	mbuf->buf_addr = (void *)(uintptr_t)(buff_addr - RTE_PKTMBUF_HEADROOM);
	mbuf->pkt.data = (void *)(uintptr_t)(buff_addr);
	mbuf->buf_physaddr = phys_addr - RTE_PKTMBUF_HEADROOM;
	mbuf->pkt.data_len = desc->len;
	MBUF_HEADROOM_UINT32(mbuf) = (uint32_t)desc_idx;

	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in attach_rxmbuf_zcp: res base idx:%d, "
		"descriptor idx:%d\n",
		dev->device_fh, res_base_idx, desc_idx);

	__rte_mbuf_raw_free(mbuf);

	return;
}

/*
 * Detach an attched packet mbuf -
 *  - restore original mbuf address and length values.
 *  - reset pktmbuf data and data_len to their default values.
 *  All other fields of the given packet mbuf will be left intact.
 *
 * @param m
 *   The attached packet mbuf.
 */
static inline void pktmbuf_detach_zcp(struct rte_mbuf *m)
{
	const struct rte_mempool *mp = m->pool;
	void *buf = RTE_MBUF_TO_BADDR(m);
	uint32_t buf_ofs;
	uint32_t buf_len = mp->elt_size - sizeof(*m);
	m->buf_physaddr = rte_mempool_virt2phy(mp, m) + sizeof(*m);

	m->buf_addr = buf;
	m->buf_len = (uint16_t)buf_len;

	buf_ofs = (RTE_PKTMBUF_HEADROOM <= m->buf_len) ?
			RTE_PKTMBUF_HEADROOM : m->buf_len;
	m->pkt.data = (char *) m->buf_addr + buf_ofs;

	m->pkt.data_len = 0;
}

/*
 * This function is called after packets have been transimited. It fetchs mbuf
 * from vpool->pool, detached it and put into vpool->ring. It also update the
 * used index and kick the guest if necessary.
 */
static inline uint32_t __attribute__((always_inline))
txmbuf_clean_zcp(struct virtio_net *dev, struct vpool *vpool)
{
	struct rte_mbuf *mbuf;
	struct vhost_virtqueue *vq = dev->virtqueue[VIRTIO_TXQ];
	uint32_t used_idx = vq->last_used_idx & (vq->size - 1);
	uint32_t index = 0;
	uint32_t mbuf_count = rte_mempool_count(vpool->pool);

	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in txmbuf_clean_zcp: mbuf count in mempool before "
		"clean is: %d\n",
		dev->device_fh, mbuf_count);
	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in txmbuf_clean_zcp: mbuf count in  ring before "
		"clean  is : %d\n",
		dev->device_fh, rte_ring_count(vpool->ring));

	for (index = 0; index < mbuf_count; index++) {
		mbuf = __rte_mbuf_raw_alloc(vpool->pool);
		if (likely(RTE_MBUF_INDIRECT(mbuf)))
			pktmbuf_detach_zcp(mbuf);
		rte_ring_sp_enqueue(vpool->ring, mbuf);

		/* Update used index buffer information. */
		vq->used->ring[used_idx].id = MBUF_HEADROOM_UINT32(mbuf);
		vq->used->ring[used_idx].len = 0;

		used_idx = (used_idx + 1) & (vq->size - 1);
	}

	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in txmbuf_clean_zcp: mbuf count in mempool after "
		"clean is: %d\n",
		dev->device_fh, rte_mempool_count(vpool->pool));
	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in txmbuf_clean_zcp: mbuf count in  ring after "
		"clean  is : %d\n",
		dev->device_fh, rte_ring_count(vpool->ring));
	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in txmbuf_clean_zcp: before updated "
		"vq->last_used_idx:%d\n",
		dev->device_fh, vq->last_used_idx);

	vq->last_used_idx += mbuf_count;

	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in txmbuf_clean_zcp: after updated "
		"vq->last_used_idx:%d\n",
		dev->device_fh, vq->last_used_idx);

	rte_compiler_barrier();

	*(volatile uint16_t *)&vq->used->idx += mbuf_count;

	/* Kick guest if required. */
	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
		eventfd_write((int)vq->kickfd, 1);

	return 0;
}

/*
 * This function is called when a virtio device is destroy.
 * It fetchs mbuf from vpool->pool, and detached it, and put into vpool->ring.
 */
static void mbuf_destroy_zcp(struct vpool *vpool)
{
	struct rte_mbuf *mbuf = NULL;
	uint32_t index, mbuf_count = rte_mempool_count(vpool->pool);

	LOG_DEBUG(VHOST_CONFIG,
		"in mbuf_destroy_zcp: mbuf count in mempool before "
		"mbuf_destroy_zcp is: %d\n",
		mbuf_count);
	LOG_DEBUG(VHOST_CONFIG,
		"in mbuf_destroy_zcp: mbuf count in  ring before "
		"mbuf_destroy_zcp  is : %d\n",
		rte_ring_count(vpool->ring));

	for (index = 0; index < mbuf_count; index++) {
		mbuf = __rte_mbuf_raw_alloc(vpool->pool);
		if (likely(mbuf != NULL)) {
			if (likely(RTE_MBUF_INDIRECT(mbuf)))
				pktmbuf_detach_zcp(mbuf);
			rte_ring_sp_enqueue(vpool->ring, (void *)mbuf);
		}
	}

	LOG_DEBUG(VHOST_CONFIG,
		"in mbuf_destroy_zcp: mbuf count in mempool after "
		"mbuf_destroy_zcp is: %d\n",
		rte_mempool_count(vpool->pool));
	LOG_DEBUG(VHOST_CONFIG,
		"in mbuf_destroy_zcp: mbuf count in ring after "
		"mbuf_destroy_zcp is : %d\n",
		rte_ring_count(vpool->ring));
}

/*
 * This function update the use flag and counter.
 */
static inline uint32_t __attribute__((always_inline))
virtio_dev_rx_zcp(struct virtio_net *dev, struct rte_mbuf **pkts,
	uint32_t count)
{
	struct vhost_virtqueue *vq;
	struct vring_desc *desc;
	struct rte_mbuf *buff;
	/* The virtio_hdr is initialised to 0. */
	struct virtio_net_hdr_mrg_rxbuf virtio_hdr
		= {{0, 0, 0, 0, 0, 0}, 0};
	uint64_t buff_hdr_addr = 0;
	uint32_t head[MAX_PKT_BURST], packet_len = 0;
	uint32_t head_idx, packet_success = 0;
	uint16_t res_cur_idx;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_rx()\n", dev->device_fh);

	if (count == 0)
		return 0;

	vq = dev->virtqueue[VIRTIO_RXQ];
	count = (count > MAX_PKT_BURST) ? MAX_PKT_BURST : count;

	res_cur_idx = vq->last_used_idx;
	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Current Index %d| End Index %d\n",
		dev->device_fh, res_cur_idx, res_cur_idx + count);

	/* Retrieve all of the head indexes first to avoid caching issues. */
	for (head_idx = 0; head_idx < count; head_idx++)
		head[head_idx] = MBUF_HEADROOM_UINT32(pkts[head_idx]);

	/*Prefetch descriptor index. */
	rte_prefetch0(&vq->desc[head[packet_success]]);

	while (packet_success != count) {
		/* Get descriptor from available ring */
		desc = &vq->desc[head[packet_success]];

		buff = pkts[packet_success];
		LOG_DEBUG(VHOST_DATA,
			"(%"PRIu64") in dev_rx_zcp: update the used idx for "
			"pkt[%d] descriptor idx: %d\n",
			dev->device_fh, packet_success,
			MBUF_HEADROOM_UINT32(buff));

		PRINT_PACKET(dev,
			(uintptr_t)(((uint64_t)(uintptr_t)buff->buf_addr)
			+ RTE_PKTMBUF_HEADROOM),
			rte_pktmbuf_data_len(buff), 0);

		/* Buffer address translation for virtio header. */
		buff_hdr_addr = gpa_to_vva(dev, desc->addr);
		packet_len = rte_pktmbuf_data_len(buff) + vq->vhost_hlen;

		/*
		 * If the descriptors are chained the header and data are
		 * placed in separate buffers.
		 */
		if (desc->flags & VRING_DESC_F_NEXT) {
			desc->len = vq->vhost_hlen;
			desc = &vq->desc[desc->next];
			desc->len = rte_pktmbuf_data_len(buff);
		} else {
			desc->len = packet_len;
		}

		/* Update used ring with desc information */
		vq->used->ring[res_cur_idx & (vq->size - 1)].id
			= head[packet_success];
		vq->used->ring[res_cur_idx & (vq->size - 1)].len
			= packet_len;
		res_cur_idx++;
		packet_success++;

		/* A header is required per buffer. */
		rte_memcpy((void *)(uintptr_t)buff_hdr_addr,
			(const void *)&virtio_hdr, vq->vhost_hlen);

		PRINT_PACKET(dev, (uintptr_t)buff_hdr_addr, vq->vhost_hlen, 1);

		if (likely(packet_success < count)) {
			/* Prefetch descriptor index. */
			rte_prefetch0(&vq->desc[head[packet_success]]);
		}
	}

	rte_compiler_barrier();

	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in dev_rx_zcp: before update used idx: "
		"vq.last_used_idx: %d, vq->used->idx: %d\n",
		dev->device_fh, vq->last_used_idx, vq->used->idx);

	*(volatile uint16_t *)&vq->used->idx += count;
	vq->last_used_idx += count;

	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in dev_rx_zcp: after  update used idx: "
		"vq.last_used_idx: %d, vq->used->idx: %d\n",
		dev->device_fh, vq->last_used_idx, vq->used->idx);

	/* Kick the guest if necessary. */
	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
		eventfd_write((int)vq->kickfd, 1);

	return count;
}

/*
 * This function routes the TX packet to the correct interface.
 * This may be a local device or the physical port.
 */
static inline void __attribute__((always_inline))
virtio_tx_route_zcp(struct virtio_net *dev, struct rte_mbuf *m,
	uint32_t desc_idx, uint8_t need_copy)
{
	struct mbuf_table *tx_q;
	struct rte_mbuf **m_table;
	struct rte_mbuf *mbuf = NULL;
	unsigned len, ret, offset = 0;
	struct vpool *vpool;
	struct virtio_net_data_ll *dev_ll = ll_root_used;
	struct ether_hdr *pkt_hdr = (struct ether_hdr *)m->pkt.data;
	uint16_t vlan_tag = (uint16_t)vlan_tags[(uint16_t)dev->device_fh];

	/*Add packet to the port tx queue*/
	tx_q = &tx_queue_zcp[(uint16_t)dev->vmdq_rx_q];
	len = tx_q->len;

	/* Allocate an mbuf and populate the structure. */
	vpool = &vpool_array[MAX_QUEUES + (uint16_t)dev->vmdq_rx_q];
	rte_ring_sc_dequeue(vpool->ring, (void **)&mbuf);
	if (unlikely(mbuf == NULL)) {
		struct vhost_virtqueue *vq = dev->virtqueue[VIRTIO_TXQ];
		RTE_LOG(ERR, VHOST_DATA,
			"(%"PRIu64") Failed to allocate memory for mbuf.\n",
			dev->device_fh);
		put_desc_to_used_list_zcp(vq, desc_idx);
		return;
	}

	if (vm2vm_mode == VM2VM_HARDWARE) {
		/* Avoid using a vlan tag from any vm for external pkt, such as
		 * vlan_tags[dev->device_fh], oterwise, it conflicts when pool
		 * selection, MAC address determines it as an external pkt
		 * which should go to network, while vlan tag determine it as
		 * a vm2vm pkt should forward to another vm. Hardware confuse
		 * such a ambiguous situation, so pkt will lost.
		 */
		vlan_tag = external_pkt_default_vlan_tag;
		while (dev_ll != NULL) {
			if (likely(dev_ll->dev->ready == DEVICE_RX) &&
				ether_addr_cmp(&(pkt_hdr->d_addr),
				&dev_ll->dev->mac_address)) {

				/*
				 * Drop the packet if the TX packet is destined
				 * for the TX device.
				 */
				if (unlikely(dev_ll->dev->device_fh
					== dev->device_fh)) {
					LOG_DEBUG(VHOST_DATA,
					"(%"PRIu64") TX: Source and destination"
					"MAC addresses are the same. Dropping "
					"packet.\n",
					dev_ll->dev->device_fh);
					MBUF_HEADROOM_UINT32(mbuf)
						= (uint32_t)desc_idx;
					__rte_mbuf_raw_free(mbuf);
					return;
				}

				/*
				 * Packet length offset 4 bytes for HW vlan
				 * strip when L2 switch back.
				 */
				offset = 4;
				vlan_tag =
				(uint16_t)
				vlan_tags[(uint16_t)dev_ll->dev->device_fh];

				LOG_DEBUG(VHOST_DATA,
				"(%"PRIu64") TX: pkt to local VM device id:"
				"(%"PRIu64") vlan tag: %d.\n",
				dev->device_fh, dev_ll->dev->device_fh,
				vlan_tag);

				break;
			}
			dev_ll = dev_ll->next;
		}
	}

	mbuf->pkt.nb_segs = m->pkt.nb_segs;
	mbuf->pkt.next = m->pkt.next;
	mbuf->pkt.data_len = m->pkt.data_len + offset;
	mbuf->pkt.pkt_len = mbuf->pkt.data_len;
	if (unlikely(need_copy)) {
		/* Copy the packet contents to the mbuf. */
		rte_memcpy((void *)((uint8_t *)mbuf->pkt.data),
			(const void *) ((uint8_t *)m->pkt.data),
			m->pkt.data_len);
	} else {
		mbuf->pkt.data = m->pkt.data;
		mbuf->buf_physaddr = m->buf_physaddr;
		mbuf->buf_addr = m->buf_addr;
	}
	mbuf->ol_flags = PKT_TX_VLAN_PKT;
	mbuf->pkt.vlan_macip.f.vlan_tci = vlan_tag;
	mbuf->pkt.vlan_macip.f.l2_len = sizeof(struct ether_hdr);
	mbuf->pkt.vlan_macip.f.l3_len = sizeof(struct ipv4_hdr);
	MBUF_HEADROOM_UINT32(mbuf) = (uint32_t)desc_idx;

	tx_q->m_table[len] = mbuf;
	len++;

	LOG_DEBUG(VHOST_DATA,
		"(%"PRIu64") in tx_route_zcp: pkt: nb_seg: %d, next:%s\n",
		dev->device_fh,
		mbuf->pkt.nb_segs,
		(mbuf->pkt.next == NULL) ? "null" : "non-null");

	if (enable_stats) {
		dev_statistics[dev->device_fh].tx_total++;
		dev_statistics[dev->device_fh].tx++;
	}

	if (unlikely(len == MAX_PKT_BURST)) {
		m_table = (struct rte_mbuf **)tx_q->m_table;
		ret = rte_eth_tx_burst(ports[0],
			(uint16_t)tx_q->txq_id, m_table, (uint16_t) len);

		/*
		 * Free any buffers not handled by TX and update
		 * the port stats.
		 */
		if (unlikely(ret < len)) {
			do {
				rte_pktmbuf_free(m_table[ret]);
			} while (++ret < len);
		}

		len = 0;
		txmbuf_clean_zcp(dev, vpool);
	}

	tx_q->len = len;

	return;
}

/*
 * This function TX all available packets in virtio TX queue for one
 * virtio-net device. If it is first packet, it learns MAC address and
 * setup VMDQ.
 */
static inline void __attribute__((always_inline))
virtio_dev_tx_zcp(struct virtio_net *dev)
{
	struct rte_mbuf m;
	struct vhost_virtqueue *vq;
	struct vring_desc *desc;
	uint64_t buff_addr = 0, phys_addr;
	uint32_t head[MAX_PKT_BURST];
	uint32_t i;
	uint16_t free_entries, packet_success = 0;
	uint16_t avail_idx;
	uint8_t need_copy = 0;
	hpa_type addr_type;

	vq = dev->virtqueue[VIRTIO_TXQ];
	avail_idx =  *((volatile uint16_t *)&vq->avail->idx);

	/* If there are no available buffers then return. */
	if (vq->last_used_idx_res == avail_idx)
		return;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_tx()\n", dev->device_fh);

	/* Prefetch available ring to retrieve head indexes. */
	rte_prefetch0(&vq->avail->ring[vq->last_used_idx_res & (vq->size - 1)]);

	/* Get the number of free entries in the ring */
	free_entries = (avail_idx - vq->last_used_idx_res);

	/* Limit to MAX_PKT_BURST. */
	free_entries
		= (free_entries > MAX_PKT_BURST) ? MAX_PKT_BURST : free_entries;

	LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Buffers available %d\n",
		dev->device_fh, free_entries);

	/* Retrieve all of the head indexes first to avoid caching issues. */
	for (i = 0; i < free_entries; i++)
		head[i]
			= vq->avail->ring[(vq->last_used_idx_res + i)
			& (vq->size - 1)];

	vq->last_used_idx_res += free_entries;

	/* Prefetch descriptor index. */
	rte_prefetch0(&vq->desc[head[packet_success]]);
	rte_prefetch0(&vq->used->ring[vq->last_used_idx & (vq->size - 1)]);

	while (packet_success < free_entries) {
		desc = &vq->desc[head[packet_success]];

		/* Discard first buffer as it is the virtio header */
		desc = &vq->desc[desc->next];

		/* Buffer address translation. */
		buff_addr = gpa_to_vva(dev, desc->addr);
		phys_addr = gpa_to_hpa(dev, desc->addr, desc->len, &addr_type);

		if (likely(packet_success < (free_entries - 1)))
			/* Prefetch descriptor index. */
			rte_prefetch0(&vq->desc[head[packet_success + 1]]);

		if (unlikely(addr_type == PHYS_ADDR_INVALID)) {
			RTE_LOG(ERR, VHOST_DATA,
				"(%"PRIu64") Invalid frame buffer address found"
				"when TX packets!\n",
				dev->device_fh);
			packet_success++;
			continue;
		}

		/* Prefetch buffer address. */
		rte_prefetch0((void *)(uintptr_t)buff_addr);

		/*
		 * Setup dummy mbuf. This is copied to a real mbuf if
		 * transmitted out the physical port.
		 */
		m.pkt.data_len = desc->len;
		m.pkt.nb_segs = 1;
		m.pkt.next = NULL;
		m.pkt.data = (void *)(uintptr_t)buff_addr;
		m.buf_addr = m.pkt.data;
		m.buf_physaddr = phys_addr;

		/*
		 * Check if the frame buffer address from guest crosses
		 * sub-region or not.
		 */
		if (unlikely(addr_type == PHYS_ADDR_CROSS_SUBREG)) {
			RTE_LOG(ERR, VHOST_DATA,
				"(%"PRIu64") Frame buffer address cross "
				"sub-regioin found when attaching TX frame "
				"buffer address!\n",
				dev->device_fh);
			need_copy = 1;
		} else
			need_copy = 0;

		PRINT_PACKET(dev, (uintptr_t)buff_addr, desc->len, 0);

		/*
		 * If this is the first received packet we need to learn
		 * the MAC and setup VMDQ
		 */
		if (unlikely(dev->ready == DEVICE_MAC_LEARNING)) {
			if (dev->remove || (link_vmdq(dev, &m) == -1)) {
				/*
				 * Discard frame if device is scheduled for
				 * removal or a duplicate MAC address is found.
				 */
				packet_success += free_entries;
				vq->last_used_idx += packet_success;
				break;
			}
		}

		virtio_tx_route_zcp(dev, &m, head[packet_success], need_copy);
		packet_success++;
	}
}

/*
 * This function is called by each data core. It handles all RX/TX registered
 * with the core. For TX the specific lcore linked list is used. For RX, MAC
 * addresses are compared with all devices in the main linked list.
 */
static int
switch_worker_zcp(__attribute__((unused)) void *arg)
{
	struct virtio_net *dev = NULL;
	struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
	struct virtio_net_data_ll *dev_ll;
	struct mbuf_table *tx_q;
	volatile struct lcore_ll_info *lcore_ll;
	const uint64_t drain_tsc
		= (rte_get_tsc_hz() + US_PER_S - 1) / US_PER_S
		* BURST_TX_DRAIN_US;
	uint64_t prev_tsc, diff_tsc, cur_tsc, ret_count = 0;
	unsigned ret;
	const uint16_t lcore_id = rte_lcore_id();
	uint16_t count_in_ring, rx_count = 0;

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

	lcore_ll = lcore_info[lcore_id].lcore_ll;
	prev_tsc = 0;

	while (1) {
		cur_tsc = rte_rdtsc();

		/* TX burst queue drain */
		diff_tsc = cur_tsc - prev_tsc;
		if (unlikely(diff_tsc > drain_tsc)) {
			/*
			 * Get mbuf from vpool.pool and detach mbuf and
			 * put back into vpool.ring.
			 */
			dev_ll = lcore_ll->ll_root_used;
			while ((dev_ll != NULL) && (dev_ll->dev != NULL)) {
				/* Get virtio device ID */
				dev = dev_ll->dev;

				if (likely(!dev->remove)) {
					tx_q = &tx_queue_zcp[(uint16_t)dev->vmdq_rx_q];
					if (tx_q->len) {
						LOG_DEBUG(VHOST_DATA,
						"TX queue drained after timeout"
						" with burst size %u\n",
						tx_q->len);

						/*
						 * Tx any packets in the queue
						 */
						ret = rte_eth_tx_burst(
							ports[0],
							(uint16_t)tx_q->txq_id,
							(struct rte_mbuf **)
							tx_q->m_table,
							(uint16_t)tx_q->len);
						if (unlikely(ret < tx_q->len)) {
							do {
								rte_pktmbuf_free(
									tx_q->m_table[ret]);
							} while (++ret < tx_q->len);
						}
						tx_q->len = 0;

						txmbuf_clean_zcp(dev,
							&vpool_array[MAX_QUEUES+dev->vmdq_rx_q]);
					}
				}
				dev_ll = dev_ll->next;
			}
			prev_tsc = cur_tsc;
		}

		rte_prefetch0(lcore_ll->ll_root_used);

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

		/* Process devices */
		dev_ll = lcore_ll->ll_root_used;

		while ((dev_ll != NULL) && (dev_ll->dev != NULL)) {
			dev = dev_ll->dev;
			if (unlikely(dev->remove)) {
				dev_ll = dev_ll->next;
				unlink_vmdq(dev);
				dev->ready = DEVICE_SAFE_REMOVE;
				continue;
			}

			if (likely(dev->ready == DEVICE_RX)) {
				uint32_t index = dev->vmdq_rx_q;
				uint16_t i;
				count_in_ring
				= rte_ring_count(vpool_array[index].ring);
				uint16_t free_entries
				= (uint16_t)get_available_ring_num_zcp(dev);

				/*
				 * Attach all mbufs in vpool.ring and put back
				 * into vpool.pool.
				 */
				for (i = 0;
				i < RTE_MIN(free_entries,
				RTE_MIN(count_in_ring, MAX_PKT_BURST));
				i++)
					attach_rxmbuf_zcp(dev);

				/* Handle guest RX */
				rx_count = rte_eth_rx_burst(ports[0],
					(uint16_t)dev->vmdq_rx_q, pkts_burst,
					MAX_PKT_BURST);

				if (rx_count) {
					ret_count = virtio_dev_rx_zcp(dev,
							pkts_burst, rx_count);
					if (enable_stats) {
						dev_statistics[dev->device_fh].rx_total
							+= rx_count;
						dev_statistics[dev->device_fh].rx
							+= ret_count;
					}
					while (likely(rx_count)) {
						rx_count--;
						pktmbuf_detach_zcp(
							pkts_burst[rx_count]);
						rte_ring_sp_enqueue(
							vpool_array[index].ring,
							(void *)pkts_burst[rx_count]);
					}
				}
			}

			if (likely(!dev->remove))
				/* Handle guest TX */
				virtio_dev_tx_zcp(dev);

			/* Move to the next device in the list */
			dev_ll = dev_ll->next;
		}
	}

	return 0;
}


/*
 * Add an entry to a used linked list. A free entry must first be found
 * in the free linked list using get_data_ll_free_entry();
 */
static void
add_data_ll_entry(struct virtio_net_data_ll **ll_root_addr,
	struct virtio_net_data_ll *ll_dev)
{
	struct virtio_net_data_ll *ll = *ll_root_addr;

	/* Set next as NULL and use a compiler barrier to avoid reordering. */
	ll_dev->next = NULL;
	rte_compiler_barrier();

	/* If ll == NULL then this is the first device. */
	if (ll) {
		/* Increment to the tail of the linked list. */
		while ((ll->next != NULL) )
			ll = ll->next;

		ll->next = ll_dev;
	} else {
		*ll_root_addr = ll_dev;
	}
}

/*
 * Remove an entry from a used linked list. The entry must then be added to
 * the free linked list using put_data_ll_free_entry().
 */
static void
rm_data_ll_entry(struct virtio_net_data_ll **ll_root_addr,
	struct virtio_net_data_ll *ll_dev,
	struct virtio_net_data_ll *ll_dev_last)
{
	struct virtio_net_data_ll *ll = *ll_root_addr;

	if (unlikely((ll == NULL) || (ll_dev == NULL)))
		return;

	if (ll_dev == ll)
		*ll_root_addr = ll_dev->next;
	else
		if (likely(ll_dev_last != NULL))
			ll_dev_last->next = ll_dev->next;
		else
			RTE_LOG(ERR, VHOST_CONFIG, "Remove entry form ll failed.\n");
}

/*
 * Find and return an entry from the free linked list.
 */
static struct virtio_net_data_ll *
get_data_ll_free_entry(struct virtio_net_data_ll **ll_root_addr)
{
	struct virtio_net_data_ll *ll_free = *ll_root_addr;
	struct virtio_net_data_ll *ll_dev;

	if (ll_free == NULL)
		return NULL;

	ll_dev = ll_free;
	*ll_root_addr = ll_free->next;

	return ll_dev;
}

/*
 * Place an entry back on to the free linked list.
 */
static void
put_data_ll_free_entry(struct virtio_net_data_ll **ll_root_addr,
	struct virtio_net_data_ll *ll_dev)
{
	struct virtio_net_data_ll *ll_free = *ll_root_addr;

	if (ll_dev == NULL)
		return;

	ll_dev->next = ll_free;
	*ll_root_addr = ll_dev;
}

/*
 * Creates a linked list of a given size.
 */
static struct virtio_net_data_ll *
alloc_data_ll(uint32_t size)
{
	struct virtio_net_data_ll *ll_new;
	uint32_t i;

	/* Malloc and then chain the linked list. */
	ll_new = malloc(size * sizeof(struct virtio_net_data_ll));
	if (ll_new == NULL) {
		RTE_LOG(ERR, VHOST_CONFIG, "Failed to allocate memory for ll_new.\n");
		return NULL;
	}

	for (i = 0; i < size - 1; i++) {
		ll_new[i].dev = NULL;
		ll_new[i].next = &ll_new[i+1];
	}
	ll_new[i].next = NULL;

	return (ll_new);
}

/*
 * Create the main linked list along with each individual cores linked list. A used and a free list
 * are created to manage entries.
 */
static int
init_data_ll (void)
{
	int lcore;

	RTE_LCORE_FOREACH_SLAVE(lcore) {
		lcore_info[lcore].lcore_ll = malloc(sizeof(struct lcore_ll_info));
		if (lcore_info[lcore].lcore_ll == NULL) {
			RTE_LOG(ERR, VHOST_CONFIG, "Failed to allocate memory for lcore_ll.\n");
			return -1;
		}

		lcore_info[lcore].lcore_ll->device_num = 0;
		lcore_info[lcore].lcore_ll->dev_removal_flag = ACK_DEV_REMOVAL;
		lcore_info[lcore].lcore_ll->ll_root_used = NULL;
		if (num_devices % num_switching_cores)
			lcore_info[lcore].lcore_ll->ll_root_free = alloc_data_ll((num_devices / num_switching_cores) + 1);
		else
			lcore_info[lcore].lcore_ll->ll_root_free = alloc_data_ll(num_devices / num_switching_cores);
	}

	/* Allocate devices up to a maximum of MAX_DEVICES. */
	ll_root_free = alloc_data_ll(MIN((num_devices), MAX_DEVICES));

	return 0;
}

/*
 * Set virtqueue flags so that we do not receive interrupts.
 */
static void
set_irq_status (struct virtio_net *dev)
{
	dev->virtqueue[VIRTIO_RXQ]->used->flags = VRING_USED_F_NO_NOTIFY;
	dev->virtqueue[VIRTIO_TXQ]->used->flags = VRING_USED_F_NO_NOTIFY;
}

/*
 * 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 (volatile struct virtio_net *dev)
{
	struct virtio_net_data_ll *ll_lcore_dev_cur;
	struct virtio_net_data_ll *ll_main_dev_cur;
	struct virtio_net_data_ll *ll_lcore_dev_last = NULL;
	struct virtio_net_data_ll *ll_main_dev_last = NULL;
	int lcore;

	dev->flags &= ~VIRTIO_DEV_RUNNING;

	/*set the remove flag. */
	dev->remove = 1;

	while(dev->ready != DEVICE_SAFE_REMOVE) {
		rte_pause();
	}

	/* Search for entry to be removed from lcore ll */
	ll_lcore_dev_cur = lcore_info[dev->coreid].lcore_ll->ll_root_used;
	while (ll_lcore_dev_cur != NULL) {
		if (ll_lcore_dev_cur->dev == dev) {
			break;
		} else {
			ll_lcore_dev_last = ll_lcore_dev_cur;
			ll_lcore_dev_cur = ll_lcore_dev_cur->next;
		}
	}

	if (ll_lcore_dev_cur == NULL) {
		RTE_LOG(ERR, VHOST_CONFIG,
			"(%"PRIu64") Failed to find the dev to be destroy.\n",
			dev->device_fh);
		return;
	}

	/* Search for entry to be removed from main ll */
	ll_main_dev_cur = ll_root_used;
	ll_main_dev_last = NULL;
	while (ll_main_dev_cur != NULL) {
		if (ll_main_dev_cur->dev == dev) {
			break;
		} else {
			ll_main_dev_last = ll_main_dev_cur;
			ll_main_dev_cur = ll_main_dev_cur->next;
		}
	}

	/* Remove entries from the lcore and main ll. */
	rm_data_ll_entry(&lcore_info[ll_lcore_dev_cur->dev->coreid].lcore_ll->ll_root_used, ll_lcore_dev_cur, ll_lcore_dev_last);
	rm_data_ll_entry(&ll_root_used, ll_main_dev_cur, ll_main_dev_last);

	/* Set the dev_removal_flag on each lcore. */
	RTE_LCORE_FOREACH_SLAVE(lcore) {
		lcore_info[lcore].lcore_ll->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].lcore_ll->dev_removal_flag != ACK_DEV_REMOVAL) {
			rte_pause();
		}
	}

	/* Add the entries back to the lcore and main free ll.*/
	put_data_ll_free_entry(&lcore_info[ll_lcore_dev_cur->dev->coreid].lcore_ll->ll_root_free, ll_lcore_dev_cur);
	put_data_ll_free_entry(&ll_root_free, ll_main_dev_cur);

	/* Decrement number of device on the lcore. */
	lcore_info[ll_lcore_dev_cur->dev->coreid].lcore_ll->device_num--;

	RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") Device has been removed from data core\n", dev->device_fh);

	if (zero_copy) {
		struct vpool *vpool = &vpool_array[dev->vmdq_rx_q];

		/* Stop the RX queue. */
		if (rte_eth_dev_rx_queue_stop(ports[0], dev->vmdq_rx_q) != 0) {
			LOG_DEBUG(VHOST_CONFIG,
				"(%"PRIu64") In destroy_device: Failed to stop "
				"rx queue:%d\n",
				dev->device_fh,
				dev->vmdq_rx_q);
		}

		LOG_DEBUG(VHOST_CONFIG,
			"(%"PRIu64") in destroy_device: Start put mbuf in "
			"mempool back to ring for RX queue: %d\n",
			dev->device_fh, dev->vmdq_rx_q);

		mbuf_destroy_zcp(vpool);

		/* Stop the TX queue. */
		if (rte_eth_dev_tx_queue_stop(ports[0], dev->vmdq_rx_q) != 0) {
			LOG_DEBUG(VHOST_CONFIG,
				"(%"PRIu64") In destroy_device: Failed to "
				"stop tx queue:%d\n",
				dev->device_fh, dev->vmdq_rx_q);
		}

		vpool = &vpool_array[dev->vmdq_rx_q + MAX_QUEUES];

		LOG_DEBUG(VHOST_CONFIG,
			"(%"PRIu64") destroy_device: Start put mbuf in mempool "
			"back to ring for TX queue: %d, dev:(%"PRIu64")\n",
			dev->device_fh, (dev->vmdq_rx_q + MAX_QUEUES),
			dev->device_fh);

		mbuf_destroy_zcp(vpool);
	}

}

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

	/* Add device to main ll */
	ll_dev = get_data_ll_free_entry(&ll_root_free);
	if (ll_dev == NULL) {
		RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") No free entry found in linked list. Device limit "
			"of %d devices per core has been reached\n",
			dev->device_fh, num_devices);
		return -1;
	}
	ll_dev->dev = dev;
	add_data_ll_entry(&ll_root_used, ll_dev);
	ll_dev->dev->vmdq_rx_q
		= ll_dev->dev->device_fh * (num_queues / num_devices);

	if (zero_copy) {
		uint32_t index = ll_dev->dev->vmdq_rx_q;
		uint32_t count_in_ring, i;
		struct mbuf_table *tx_q;

		count_in_ring = rte_ring_count(vpool_array[index].ring);

		LOG_DEBUG(VHOST_CONFIG,
			"(%"PRIu64") in new_device: mbuf count in mempool "
			"before attach is: %d\n",
			dev->device_fh,
			rte_mempool_count(vpool_array[index].pool));
		LOG_DEBUG(VHOST_CONFIG,
			"(%"PRIu64") in new_device: mbuf count in  ring "
			"before attach  is : %d\n",
			dev->device_fh, count_in_ring);

		/*
		 * Attach all mbufs in vpool.ring and put back intovpool.pool.
		 */
		for (i = 0; i < count_in_ring; i++)
			attach_rxmbuf_zcp(dev);

		LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") in new_device: mbuf count in "
			"mempool after attach is: %d\n",
			dev->device_fh,
			rte_mempool_count(vpool_array[index].pool));
		LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") in new_device: mbuf count in "
			"ring after attach  is : %d\n",
			dev->device_fh,
			rte_ring_count(vpool_array[index].ring));

		tx_q = &tx_queue_zcp[(uint16_t)dev->vmdq_rx_q];
		tx_q->txq_id = dev->vmdq_rx_q;

		if (rte_eth_dev_tx_queue_start(ports[0], dev->vmdq_rx_q) != 0) {
			struct vpool *vpool = &vpool_array[dev->vmdq_rx_q];

			LOG_DEBUG(VHOST_CONFIG,
				"(%"PRIu64") In new_device: Failed to start "
				"tx queue:%d\n",
				dev->device_fh, dev->vmdq_rx_q);

			mbuf_destroy_zcp(vpool);
			return -1;
		}

		if (rte_eth_dev_rx_queue_start(ports[0], dev->vmdq_rx_q) != 0) {
			struct vpool *vpool = &vpool_array[dev->vmdq_rx_q];

			LOG_DEBUG(VHOST_CONFIG,
				"(%"PRIu64") In new_device: Failed to start "
				"rx queue:%d\n",
				dev->device_fh, dev->vmdq_rx_q);

			/* Stop the TX queue. */
			if (rte_eth_dev_tx_queue_stop(ports[0],
				dev->vmdq_rx_q) != 0) {
				LOG_DEBUG(VHOST_CONFIG,
					"(%"PRIu64") In new_device: Failed to "
					"stop tx queue:%d\n",
					dev->device_fh, dev->vmdq_rx_q);
			}

			mbuf_destroy_zcp(vpool);
			return -1;
		}

	}

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

	/* Find a suitable lcore to add the device. */
	RTE_LCORE_FOREACH_SLAVE(lcore) {
		if (lcore_info[lcore].lcore_ll->device_num < device_num_min) {
			device_num_min = lcore_info[lcore].lcore_ll->device_num;
			core_add = lcore;
		}
	}
	/* Add device to lcore ll */
	ll_dev->dev->coreid = core_add;
	ll_dev = get_data_ll_free_entry(&lcore_info[ll_dev->dev->coreid].lcore_ll->ll_root_free);
	if (ll_dev == NULL) {
		RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") Failed to add device to data core\n", dev->device_fh);
		dev->ready = DEVICE_SAFE_REMOVE;
		destroy_device(dev);
		return -1;
	}
	ll_dev->dev = dev;
	add_data_ll_entry(&lcore_info[ll_dev->dev->coreid].lcore_ll->ll_root_used, ll_dev);

	/* Initialize device stats */
	memset(&dev_statistics[dev->device_fh], 0, sizeof(struct device_statistics));

	/* Disable notifications. */
	set_irq_status(dev);
	lcore_info[ll_dev->dev->coreid].lcore_ll->device_num++;
	dev->flags |= VIRTIO_DEV_RUNNING;

	RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") Device has been added to data core %d\n", dev->device_fh, dev->coreid);

	return 0;
}

/*
 * These callback allow devices to be added to the data core when configuration
 * has been fully complete.
 */
static const struct virtio_net_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(void)
{
	struct virtio_net_data_ll *dev_ll;
	uint64_t tx_dropped, rx_dropped;
	uint64_t tx, tx_total, rx, rx_total;
	uint32_t device_fh;
	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", clr, top_left);

		printf("\nDevice statistics ====================================");

		dev_ll = ll_root_used;
		while (dev_ll != NULL) {
			device_fh = (uint32_t)dev_ll->dev->device_fh;
			tx_total = dev_statistics[device_fh].tx_total;
			tx = dev_statistics[device_fh].tx;
			tx_dropped = tx_total - tx;
			if (zero_copy == 0) {
				rx_total = rte_atomic64_read(
					&dev_statistics[device_fh].rx_total_atomic);
				rx = rte_atomic64_read(
					&dev_statistics[device_fh].rx_atomic);
			} else {
				rx_total = dev_statistics[device_fh].rx_total;
				rx = dev_statistics[device_fh].rx;
			}
			rx_dropped = rx_total - rx;

			printf("\nStatistics for device %"PRIu32" ------------------------------"
					"\nTX total: 		%"PRIu64""
					"\nTX dropped: 		%"PRIu64""
					"\nTX successful: 		%"PRIu64""
					"\nRX total: 		%"PRIu64""
					"\nRX dropped: 		%"PRIu64""
					"\nRX successful: 		%"PRIu64"",
					device_fh,
					tx_total,
					tx_dropped,
					tx,
					rx_total,
					rx_dropped,
					rx);

			dev_ll = dev_ll->next;
		}
		printf("\n======================================================\n");
	}
}

static void
setup_mempool_tbl(int socket, uint32_t index, char *pool_name,
	char *ring_name, uint32_t nb_mbuf)
{
	uint16_t roomsize = VIRTIO_DESCRIPTOR_LEN_ZCP + RTE_PKTMBUF_HEADROOM;
	vpool_array[index].pool
		= rte_mempool_create(pool_name, nb_mbuf, MBUF_SIZE_ZCP,
		MBUF_CACHE_SIZE_ZCP, sizeof(struct rte_pktmbuf_pool_private),
		rte_pktmbuf_pool_init, (void *)(uintptr_t)roomsize,
		rte_pktmbuf_init, NULL, socket, 0);
	if (vpool_array[index].pool != NULL) {
		vpool_array[index].ring
			= rte_ring_create(ring_name,
				rte_align32pow2(nb_mbuf + 1),
				socket, RING_F_SP_ENQ | RING_F_SC_DEQ);
		if (likely(vpool_array[index].ring != NULL)) {
			LOG_DEBUG(VHOST_CONFIG,
				"in setup_mempool_tbl: mbuf count in "
				"mempool is: %d\n",
				rte_mempool_count(vpool_array[index].pool));
			LOG_DEBUG(VHOST_CONFIG,
				"in setup_mempool_tbl: mbuf count in "
				"ring   is: %d\n",
				rte_ring_count(vpool_array[index].ring));
		} else {
			rte_exit(EXIT_FAILURE, "ring_create(%s) failed",
				ring_name);
		}

		/* Need consider head room. */
		vpool_array[index].buf_size = roomsize - RTE_PKTMBUF_HEADROOM;
	} else {
		rte_exit(EXIT_FAILURE, "mempool_create(%s) failed", pool_name);
	}
}


/*
 * Main function, does initialisation and calls the per-lcore functions. The CUSE
 * device is also registered here to handle the IOCTLs.
 */
int
MAIN(int argc, char *argv[])
{
	struct rte_mempool *mbuf_pool = NULL;
	unsigned lcore_id, core_id = 0;
	unsigned nb_ports, valid_num_ports;
	int ret;
	uint8_t portid, queue_id = 0;
	static pthread_t tid;

	/* 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");

	if (rte_eal_pci_probe() != 0)
		rte_exit(EXIT_FAILURE, "Error with NIC driver initialization\n");

	for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id ++)
		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");

	/*set the number of swithcing cores available*/
	num_switching_cores = rte_lcore_count()-1;

	/* Get the number of physical ports. */
	nb_ports = rte_eth_dev_count();
	if (nb_ports > RTE_MAX_ETHPORTS)
		nb_ports = RTE_MAX_ETHPORTS;

	/*
	 * 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;
	}

	if (zero_copy == 0) {
		/* Create the mbuf pool. */
		mbuf_pool = rte_mempool_create(
				"MBUF_POOL",
				NUM_MBUFS_PER_PORT
				* valid_num_ports,
				MBUF_SIZE, MBUF_CACHE_SIZE,
				sizeof(struct rte_pktmbuf_pool_private),
				rte_pktmbuf_pool_init, NULL,
				rte_pktmbuf_init, NULL,
				rte_socket_id(), 0);
		if (mbuf_pool == NULL)
			rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");

		for (queue_id = 0; queue_id < MAX_QUEUES + 1; queue_id++)
			vpool_array[queue_id].pool = mbuf_pool;

		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;
			LOG_DEBUG(VHOST_CONFIG,
				"Enable loop back for L2 switch in vmdq.\n");
		}
	} else {
		uint32_t nb_mbuf;
		char pool_name[RTE_MEMPOOL_NAMESIZE];
		char ring_name[RTE_MEMPOOL_NAMESIZE];

		rx_conf_default.start_rx_per_q = (uint8_t)zero_copy;
		rx_conf_default.rx_drop_en = 0;
		tx_conf_default.start_tx_per_q = (uint8_t)zero_copy;
		nb_mbuf = num_rx_descriptor
			+ num_switching_cores * MBUF_CACHE_SIZE_ZCP
			+ num_switching_cores * MAX_PKT_BURST;

		for (queue_id = 0; queue_id < MAX_QUEUES; queue_id++) {
			snprintf(pool_name, sizeof(pool_name),
				"rxmbuf_pool_%u", queue_id);
			snprintf(ring_name, sizeof(ring_name),
				"rxmbuf_ring_%u", queue_id);
			setup_mempool_tbl(rte_socket_id(), queue_id,
				pool_name, ring_name, nb_mbuf);
		}

		nb_mbuf = num_tx_descriptor
				+ num_switching_cores * MBUF_CACHE_SIZE_ZCP
				+ num_switching_cores * MAX_PKT_BURST;

		for (queue_id = 0; queue_id < MAX_QUEUES; queue_id++) {
			snprintf(pool_name, sizeof(pool_name),
				"txmbuf_pool_%u", queue_id);
			snprintf(ring_name, sizeof(ring_name),
				"txmbuf_ring_%u", queue_id);
			setup_mempool_tbl(rte_socket_id(),
				(queue_id + MAX_QUEUES),
				pool_name, ring_name, nb_mbuf);
		}

		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;
			LOG_DEBUG(VHOST_CONFIG,
				"Enable loop back for L2 switch in vmdq.\n");
		}
	}
	/* Set log level. */
	rte_set_log_level(LOG_LEVEL);

	/* initialize all ports */
	for (portid = 0; portid < nb_ports; 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");
	}

	/* Initialise all linked lists. */
	if (init_data_ll() == -1)
		rte_exit(EXIT_FAILURE, "Failed to initialize linked list\n");

	/* Initialize device stats */
	memset(&dev_statistics, 0, sizeof(dev_statistics));

	/* Enable stats if the user option is set. */
	if (enable_stats)
		pthread_create(&tid, NULL, (void*)print_stats, NULL );

	/* Launch all data cores. */
	if (zero_copy == 0) {
		RTE_LCORE_FOREACH_SLAVE(lcore_id) {
			rte_eal_remote_launch(switch_worker,
				mbuf_pool, lcore_id);
		}
	} else {
		uint32_t count_in_mempool, index, i;
		for (index = 0; index < 2*MAX_QUEUES; index++) {
			/* For all RX and TX queues. */
			count_in_mempool
				= rte_mempool_count(vpool_array[index].pool);

			/*
			 * Transfer all un-attached mbufs from vpool.pool
			 * to vpoo.ring.
			 */
			for (i = 0; i < count_in_mempool; i++) {
				struct rte_mbuf *mbuf
					= __rte_mbuf_raw_alloc(
						vpool_array[index].pool);
				rte_ring_sp_enqueue(vpool_array[index].ring,
						(void *)mbuf);
			}

			LOG_DEBUG(VHOST_CONFIG,
				"in MAIN: mbuf count in mempool at initial "
				"is: %d\n", count_in_mempool);
			LOG_DEBUG(VHOST_CONFIG,
				"in MAIN: mbuf count in  ring at initial  is :"
				" %d\n",
				rte_ring_count(vpool_array[index].ring));
		}

		RTE_LCORE_FOREACH_SLAVE(lcore_id)
			rte_eal_remote_launch(switch_worker_zcp, NULL,
				lcore_id);
	}

	/* Register CUSE device to handle IOCTLs. */
	ret = register_cuse_device((char*)&dev_basename, dev_index, get_virtio_net_callbacks());
	if (ret != 0)
		rte_exit(EXIT_FAILURE,"CUSE device setup failure.\n");

	init_virtio_net(&virtio_net_device_ops);

	/* Start CUSE session. */
	start_cuse_session_loop();
	return 0;

}