Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 2170 insertions, 0 deletions

diff --git a/src/seastar/dpdk/examples/vhost/Makefile b/src/seastar/dpdk/examples/vhost/Makefile
new file mode 100644
index 00000000..af7be99a
--- /dev/null
+++ b/src/seastar/dpdk/examples/vhost/Makefile
@@ -0,0 +1,59 @@
+#   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.
+
+ifeq ($(RTE_SDK),)
+$(error "Please define RTE_SDK environment variable")
+endif
+
+# Default target, can be overriden by command line or environment
+RTE_TARGET ?= x86_64-native-linuxapp-gcc
+
+include $(RTE_SDK)/mk/rte.vars.mk
+
+ifneq ($(CONFIG_RTE_EXEC_ENV),"linuxapp")
+$(info This application can only operate in a linuxapp environment, \
+please change the definition of the RTE_TARGET environment variable)
+all:
+else
+
+# binary name
+APP = vhost-switch
+
+# all source are stored in SRCS-y
+SRCS-y := main.c virtio_net.c
+
+CFLAGS += -O2 -D_FILE_OFFSET_BITS=64
+CFLAGS += $(WERROR_FLAGS)
+CFLAGS += -D_GNU_SOURCE
+
+include $(RTE_SDK)/mk/rte.extapp.mk
+
+endif
diff --git a/src/seastar/dpdk/examples/vhost/main.c b/src/seastar/dpdk/examples/vhost/main.c
new file mode 100644
index 00000000..e07f8669
--- /dev/null
+++ b/src/seastar/dpdk/examples/vhost/main.c
@@ -0,0 +1,1587 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2017 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 <rte_vhost.h>
+#include <rte_ip.h>
+#include <rte_tcp.h>
+
+#include "main.h"
+
+#ifndef MAX_QUEUES
+#define MAX_QUEUES 128
+#endif
+
+/* the maximum number of external ports supported */
+#define MAX_SUP_PORTS 1
+
+#define MBUF_CACHE_SIZE	128
+#define MBUF_DATA_SIZE	RTE_MBUF_DEFAULT_BUF_SIZE
+
+#define BURST_TX_DRAIN_US 100	/* TX drain every ~100us */
+
+#define BURST_RX_WAIT_US 15	/* Defines how long we wait between retries on RX */
+#define BURST_RX_RETRIES 4		/* Number of retries on RX. */
+
+#define JUMBO_FRAME_MAX_SIZE    0x2600
+
+/* State of virtio device. */
+#define DEVICE_MAC_LEARNING 0
+#define DEVICE_RX			1
+#define DEVICE_SAFE_REMOVE	2
+
+/* Configurable number of RX/TX ring descriptors */
+#define RTE_TEST_RX_DESC_DEFAULT 1024
+#define RTE_TEST_TX_DESC_DEFAULT 512
+
+#define INVALID_PORT_ID 0xFF
+
+/* Max number of devices. Limited by vmdq. */
+#define MAX_DEVICES 64
+
+/* Size of buffers used for snprintfs. */
+#define MAX_PRINT_BUFF 6072
+
+/* Maximum long option length for option parsing. */
+#define MAX_LONG_OPT_SZ 64
+
+/* mask of enabled ports */
+static uint32_t enabled_port_mask = 0;
+
+/* Promiscuous mode */
+static uint32_t promiscuous;
+
+/* number of devices/queues to support*/
+static uint32_t num_queues = 0;
+static uint32_t num_devices;
+
+static struct rte_mempool *mbuf_pool;
+static int mergeable;
+
+/* Enable VM2VM communications. If this is disabled then the MAC address compare is skipped. */
+typedef enum {
+	VM2VM_DISABLED = 0,
+	VM2VM_SOFTWARE = 1,
+	VM2VM_HARDWARE = 2,
+	VM2VM_LAST
+} vm2vm_type;
+static vm2vm_type vm2vm_mode = VM2VM_SOFTWARE;
+
+/* Enable stats. */
+static uint32_t enable_stats = 0;
+/* Enable retries on RX. */
+static uint32_t enable_retry = 1;
+
+/* Disable TX checksum offload */
+static uint32_t enable_tx_csum;
+
+/* Disable TSO offload */
+static uint32_t enable_tso;
+
+static int client_mode;
+static int dequeue_zero_copy;
+
+static int builtin_net_driver;
+
+/* Specify timeout (in useconds) between retries on RX. */
+static uint32_t burst_rx_delay_time = BURST_RX_WAIT_US;
+/* Specify the number of retries on RX. */
+static uint32_t burst_rx_retry_num = BURST_RX_RETRIES;
+
+/* Socket file paths. Can be set by user */
+static char *socket_files;
+static int nb_sockets;
+
+/* empty vmdq configuration structure. Filled in programatically */
+static struct rte_eth_conf vmdq_conf_default = {
+	.rxmode = {
+		.mq_mode        = ETH_MQ_RX_VMDQ_ONLY,
+		.split_hdr_size = 0,
+		.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   = 1, /**< 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 uint16_t num_pf_queues, num_vmdq_queues;
+static uint16_t vmdq_pool_base, vmdq_queue_base;
+static uint16_t queues_per_pool;
+
+const uint16_t vlan_tags[] = {
+	1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007,
+	1008, 1009, 1010, 1011,	1012, 1013, 1014, 1015,
+	1016, 1017, 1018, 1019, 1020, 1021, 1022, 1023,
+	1024, 1025, 1026, 1027, 1028, 1029, 1030, 1031,
+	1032, 1033, 1034, 1035, 1036, 1037, 1038, 1039,
+	1040, 1041, 1042, 1043, 1044, 1045, 1046, 1047,
+	1048, 1049, 1050, 1051, 1052, 1053, 1054, 1055,
+	1056, 1057, 1058, 1059, 1060, 1061, 1062, 1063,
+};
+
+/* ethernet addresses of ports */
+static struct ether_addr vmdq_ports_eth_addr[RTE_MAX_ETHPORTS];
+
+static struct vhost_dev_tailq_list vhost_dev_list =
+	TAILQ_HEAD_INITIALIZER(vhost_dev_list);
+
+static struct lcore_info lcore_info[RTE_MAX_LCORE];
+
+/* Used for queueing bursts of TX packets. */
+struct mbuf_table {
+	unsigned len;
+	unsigned txq_id;
+	struct rte_mbuf *m_table[MAX_PKT_BURST];
+};
+
+/* TX queue for each data core. */
+struct mbuf_table lcore_tx_queue[RTE_MAX_LCORE];
+
+#define MBUF_TABLE_DRAIN_TSC	((rte_get_tsc_hz() + US_PER_S - 1) \
+				 / US_PER_S * BURST_TX_DRAIN_US)
+#define VLAN_HLEN       4
+
+/*
+ * Builds up the correct configuration for VMDQ VLAN pool map
+ * according to the pool & queue limits.
+ */
+static inline int
+get_eth_conf(struct rte_eth_conf *eth_conf, uint32_t num_devices)
+{
+	struct rte_eth_vmdq_rx_conf conf;
+	struct rte_eth_vmdq_rx_conf *def_conf =
+		&vmdq_conf_default.rx_adv_conf.vmdq_rx_conf;
+	unsigned i;
+
+	memset(&conf, 0, sizeof(conf));
+	conf.nb_queue_pools = (enum rte_eth_nb_pools)num_devices;
+	conf.nb_pool_maps = num_devices;
+	conf.enable_loop_back = def_conf->enable_loop_back;
+	conf.rx_mode = def_conf->rx_mode;
+
+	for (i = 0; i < conf.nb_pool_maps; i++) {
+		conf.pool_map[i].vlan_id = vlan_tags[ i ];
+		conf.pool_map[i].pools = (1UL << i);
+	}
+
+	(void)(rte_memcpy(eth_conf, &vmdq_conf_default, sizeof(*eth_conf)));
+	(void)(rte_memcpy(&eth_conf->rx_adv_conf.vmdq_rx_conf, &conf,
+		   sizeof(eth_conf->rx_adv_conf.vmdq_rx_conf)));
+	return 0;
+}
+
+/*
+ * Validate the device number according to the max pool number gotten form
+ * dev_info. If the device number is invalid, give the error message and
+ * return -1. Each device must have its own pool.
+ */
+static inline int
+validate_num_devices(uint32_t max_nb_devices)
+{
+	if (num_devices > max_nb_devices) {
+		RTE_LOG(ERR, VHOST_PORT, "invalid number of devices\n");
+		return -1;
+	}
+	return 0;
+}
+
+/*
+ * Initialises a given port using global settings and with the rx buffers
+ * coming from the mbuf_pool passed as parameter
+ */
+static inline int
+port_init(uint8_t port)
+{
+	struct rte_eth_dev_info dev_info;
+	struct rte_eth_conf port_conf;
+	struct rte_eth_rxconf *rxconf;
+	struct rte_eth_txconf *txconf;
+	int16_t rx_rings, tx_rings;
+	uint16_t rx_ring_size, tx_ring_size;
+	int retval;
+	uint16_t q;
+
+	/* The max pool number from dev_info will be used to validate the pool number specified in cmd line */
+	rte_eth_dev_info_get (port, &dev_info);
+
+	if (dev_info.max_rx_queues > MAX_QUEUES) {
+		rte_exit(EXIT_FAILURE,
+			"please define MAX_QUEUES no less than %u in %s\n",
+			dev_info.max_rx_queues, __FILE__);
+	}
+
+	rxconf = &dev_info.default_rxconf;
+	txconf = &dev_info.default_txconf;
+	rxconf->rx_drop_en = 1;
+
+	/* Enable vlan offload */
+	txconf->txq_flags &= ~ETH_TXQ_FLAGS_NOVLANOFFL;
+
+	/*configure the number of supported virtio devices based on VMDQ limits */
+	num_devices = dev_info.max_vmdq_pools;
+
+	rx_ring_size = RTE_TEST_RX_DESC_DEFAULT;
+	tx_ring_size = RTE_TEST_TX_DESC_DEFAULT;
+
+	/*
+	 * When dequeue zero copy is enabled, guest Tx used vring will be
+	 * updated only when corresponding mbuf is freed. Thus, the nb_tx_desc
+	 * (tx_ring_size here) must be small enough so that the driver will
+	 * hit the free threshold easily and free mbufs timely. Otherwise,
+	 * guest Tx vring would be starved.
+	 */
+	if (dequeue_zero_copy)
+		tx_ring_size = 64;
+
+	tx_rings = (uint16_t)rte_lcore_count();
+
+	retval = validate_num_devices(MAX_DEVICES);
+	if (retval < 0)
+		return retval;
+
+	/* Get port configuration. */
+	retval = get_eth_conf(&port_conf, num_devices);
+	if (retval < 0)
+		return retval;
+	/* NIC queues are divided into pf queues and vmdq queues.  */
+	num_pf_queues = dev_info.max_rx_queues - dev_info.vmdq_queue_num;
+	queues_per_pool = dev_info.vmdq_queue_num / dev_info.max_vmdq_pools;
+	num_vmdq_queues = num_devices * queues_per_pool;
+	num_queues = num_pf_queues + num_vmdq_queues;
+	vmdq_queue_base = dev_info.vmdq_queue_base;
+	vmdq_pool_base  = dev_info.vmdq_pool_base;
+	printf("pf queue num: %u, configured vmdq pool num: %u, each vmdq pool has %u queues\n",
+		num_pf_queues, num_devices, queues_per_pool);
+
+	if (port >= rte_eth_dev_count()) return -1;
+
+	rx_rings = (uint16_t)dev_info.max_rx_queues;
+	/* Configure ethernet device. */
+	retval = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf);
+	if (retval != 0) {
+		RTE_LOG(ERR, VHOST_PORT, "Failed to configure port %u: %s.\n",
+			port, strerror(-retval));
+		return retval;
+	}
+
+	/* 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),
+						rxconf,
+						mbuf_pool);
+		if (retval < 0) {
+			RTE_LOG(ERR, VHOST_PORT,
+				"Failed to setup rx queue %u of port %u: %s.\n",
+				q, port, strerror(-retval));
+			return retval;
+		}
+	}
+	for (q = 0; q < tx_rings; q ++) {
+		retval = rte_eth_tx_queue_setup(port, q, tx_ring_size,
+						rte_eth_dev_socket_id(port),
+						txconf);
+		if (retval < 0) {
+			RTE_LOG(ERR, VHOST_PORT,
+				"Failed to setup tx queue %u of port %u: %s.\n",
+				q, port, strerror(-retval));
+			return retval;
+		}
+	}
+
+	/* Start the device. */
+	retval  = rte_eth_dev_start(port);
+	if (retval < 0) {
+		RTE_LOG(ERR, VHOST_PORT, "Failed to start port %u: %s\n",
+			port, strerror(-retval));
+		return retval;
+	}
+
+	if (promiscuous)
+		rte_eth_promiscuous_enable(port);
+
+	rte_eth_macaddr_get(port, &vmdq_ports_eth_addr[port]);
+	RTE_LOG(INFO, VHOST_PORT, "Max virtio devices supported: %u\n", num_devices);
+	RTE_LOG(INFO, VHOST_PORT, "Port %u MAC: %02"PRIx8" %02"PRIx8" %02"PRIx8
+			" %02"PRIx8" %02"PRIx8" %02"PRIx8"\n",
+			(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 socket file path.
+ */
+static int
+us_vhost_parse_socket_path(const char *q_arg)
+{
+	/* parse number string */
+	if (strnlen(q_arg, PATH_MAX) == PATH_MAX)
+		return -1;
+
+	socket_files = realloc(socket_files, PATH_MAX * (nb_sockets + 1));
+	snprintf(socket_files + nb_sockets * PATH_MAX, PATH_MAX, "%s", q_arg);
+	nb_sockets++;
+
+	return 0;
+}
+
+/*
+ * Parse the portmask provided at run time.
+ */
+static int
+parse_portmask(const char *portmask)
+{
+	char *end = NULL;
+	unsigned long pm;
+
+	errno = 0;
+
+	/* parse hexadecimal string */
+	pm = strtoul(portmask, &end, 16);
+	if ((portmask[0] == '\0') || (end == NULL) || (*end != '\0') || (errno != 0))
+		return -1;
+
+	if (pm == 0)
+		return -1;
+
+	return pm;
+
+}
+
+/*
+ * Parse num options at run time.
+ */
+static int
+parse_num_opt(const char *q_arg, uint32_t max_valid_value)
+{
+	char *end = NULL;
+	unsigned long num;
+
+	errno = 0;
+
+	/* parse unsigned int string */
+	num = strtoul(q_arg, &end, 10);
+	if ((q_arg[0] == '\0') || (end == NULL) || (*end != '\0') || (errno != 0))
+		return -1;
+
+	if (num > max_valid_value)
+		return -1;
+
+	return num;
+
+}
+
+/*
+ * Display usage
+ */
+static void
+us_vhost_usage(const char *prgname)
+{
+	RTE_LOG(INFO, VHOST_CONFIG, "%s [EAL options] -- -p PORTMASK\n"
+	"		--vm2vm [0|1|2]\n"
+	"		--rx_retry [0|1] --mergeable [0|1] --stats [0-N]\n"
+	"		--socket-file <path>\n"
+	"		--nb-devices ND\n"
+	"		-p PORTMASK: Set mask for ports to be used by application\n"
+	"		--vm2vm [0|1|2]: disable/software(default)/hardware vm2vm comms\n"
+	"		--rx-retry [0|1]: disable/enable(default) retries on rx. Enable retry if destintation queue is full\n"
+	"		--rx-retry-delay [0-N]: timeout(in usecond) between retries on RX. This makes effect only if retries on rx enabled\n"
+	"		--rx-retry-num [0-N]: the number of retries on rx. This makes effect only if retries on rx enabled\n"
+	"		--mergeable [0|1]: disable(default)/enable RX mergeable buffers\n"
+	"		--stats [0-N]: 0: Disable stats, N: Time in seconds to print stats\n"
+	"		--socket-file: The path of the socket file.\n"
+	"		--tx-csum [0|1] disable/enable TX checksum offload.\n"
+	"		--tso [0|1] disable/enable TCP segment offload.\n"
+	"		--client register a vhost-user socket as client mode.\n"
+	"		--dequeue-zero-copy enables dequeue zero copy\n",
+	       prgname);
+}
+
+/*
+ * Parse the arguments given in the command line of the application.
+ */
+static int
+us_vhost_parse_args(int argc, char **argv)
+{
+	int opt, ret;
+	int option_index;
+	unsigned i;
+	const char *prgname = argv[0];
+	static struct option long_option[] = {
+		{"vm2vm", required_argument, NULL, 0},
+		{"rx-retry", required_argument, NULL, 0},
+		{"rx-retry-delay", required_argument, NULL, 0},
+		{"rx-retry-num", required_argument, NULL, 0},
+		{"mergeable", required_argument, NULL, 0},
+		{"stats", required_argument, NULL, 0},
+		{"socket-file", required_argument, NULL, 0},
+		{"tx-csum", required_argument, NULL, 0},
+		{"tso", required_argument, NULL, 0},
+		{"client", no_argument, &client_mode, 1},
+		{"dequeue-zero-copy", no_argument, &dequeue_zero_copy, 1},
+		{"builtin-net-driver", no_argument, &builtin_net_driver, 1},
+		{NULL, 0, 0, 0},
+	};
+
+	/* Parse command line */
+	while ((opt = getopt_long(argc, argv, "p:P",
+			long_option, &option_index)) != EOF) {
+		switch (opt) {
+		/* Portmask */
+		case 'p':
+			enabled_port_mask = parse_portmask(optarg);
+			if (enabled_port_mask == 0) {
+				RTE_LOG(INFO, VHOST_CONFIG, "Invalid portmask\n");
+				us_vhost_usage(prgname);
+				return -1;
+			}
+			break;
+
+		case 'P':
+			promiscuous = 1;
+			vmdq_conf_default.rx_adv_conf.vmdq_rx_conf.rx_mode =
+				ETH_VMDQ_ACCEPT_BROADCAST |
+				ETH_VMDQ_ACCEPT_MULTICAST;
+
+			break;
+
+		case 0:
+			/* Enable/disable vm2vm comms. */
+			if (!strncmp(long_option[option_index].name, "vm2vm",
+				MAX_LONG_OPT_SZ)) {
+				ret = parse_num_opt(optarg, (VM2VM_LAST - 1));
+				if (ret == -1) {
+					RTE_LOG(INFO, VHOST_CONFIG,
+						"Invalid argument for "
+						"vm2vm [0|1|2]\n");
+					us_vhost_usage(prgname);
+					return -1;
+				} else {
+					vm2vm_mode = (vm2vm_type)ret;
+				}
+			}
+
+			/* Enable/disable retries on RX. */
+			if (!strncmp(long_option[option_index].name, "rx-retry", MAX_LONG_OPT_SZ)) {
+				ret = parse_num_opt(optarg, 1);
+				if (ret == -1) {
+					RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for rx-retry [0|1]\n");
+					us_vhost_usage(prgname);
+					return -1;
+				} else {
+					enable_retry = ret;
+				}
+			}
+
+			/* Enable/disable TX checksum offload. */
+			if (!strncmp(long_option[option_index].name, "tx-csum", MAX_LONG_OPT_SZ)) {
+				ret = parse_num_opt(optarg, 1);
+				if (ret == -1) {
+					RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for tx-csum [0|1]\n");
+					us_vhost_usage(prgname);
+					return -1;
+				} else
+					enable_tx_csum = ret;
+			}
+
+			/* Enable/disable TSO offload. */
+			if (!strncmp(long_option[option_index].name, "tso", MAX_LONG_OPT_SZ)) {
+				ret = parse_num_opt(optarg, 1);
+				if (ret == -1) {
+					RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for tso [0|1]\n");
+					us_vhost_usage(prgname);
+					return -1;
+				} else
+					enable_tso = ret;
+			}
+
+			/* Specify the retries delay time (in useconds) on RX. */
+			if (!strncmp(long_option[option_index].name, "rx-retry-delay", MAX_LONG_OPT_SZ)) {
+				ret = parse_num_opt(optarg, INT32_MAX);
+				if (ret == -1) {
+					RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for rx-retry-delay [0-N]\n");
+					us_vhost_usage(prgname);
+					return -1;
+				} else {
+					burst_rx_delay_time = ret;
+				}
+			}
+
+			/* Specify the retries number on RX. */
+			if (!strncmp(long_option[option_index].name, "rx-retry-num", MAX_LONG_OPT_SZ)) {
+				ret = parse_num_opt(optarg, INT32_MAX);
+				if (ret == -1) {
+					RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for rx-retry-num [0-N]\n");
+					us_vhost_usage(prgname);
+					return -1;
+				} else {
+					burst_rx_retry_num = ret;
+				}
+			}
+
+			/* Enable/disable RX mergeable buffers. */
+			if (!strncmp(long_option[option_index].name, "mergeable", MAX_LONG_OPT_SZ)) {
+				ret = parse_num_opt(optarg, 1);
+				if (ret == -1) {
+					RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for mergeable [0|1]\n");
+					us_vhost_usage(prgname);
+					return -1;
+				} else {
+					mergeable = !!ret;
+					if (ret) {
+						vmdq_conf_default.rxmode.jumbo_frame = 1;
+						vmdq_conf_default.rxmode.max_rx_pkt_len
+							= JUMBO_FRAME_MAX_SIZE;
+					}
+				}
+			}
+
+			/* Enable/disable stats. */
+			if (!strncmp(long_option[option_index].name, "stats", MAX_LONG_OPT_SZ)) {
+				ret = parse_num_opt(optarg, INT32_MAX);
+				if (ret == -1) {
+					RTE_LOG(INFO, VHOST_CONFIG,
+						"Invalid argument for stats [0..N]\n");
+					us_vhost_usage(prgname);
+					return -1;
+				} else {
+					enable_stats = ret;
+				}
+			}
+
+			/* Set socket file path. */
+			if (!strncmp(long_option[option_index].name,
+						"socket-file", MAX_LONG_OPT_SZ)) {
+				if (us_vhost_parse_socket_path(optarg) == -1) {
+					RTE_LOG(INFO, VHOST_CONFIG,
+					"Invalid argument for socket name (Max %d characters)\n",
+					PATH_MAX);
+					us_vhost_usage(prgname);
+					return -1;
+				}
+			}
+
+			break;
+
+			/* Invalid option - print options. */
+		default:
+			us_vhost_usage(prgname);
+			return -1;
+		}
+	}
+
+	for (i = 0; i < RTE_MAX_ETHPORTS; i++) {
+		if (enabled_port_mask & (1 << i))
+			ports[num_ports++] = (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;
+	}
+
+	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;
+}
+
+static inline struct vhost_dev *__attribute__((always_inline))
+find_vhost_dev(struct ether_addr *mac)
+{
+	struct vhost_dev *vdev;
+
+	TAILQ_FOREACH(vdev, &vhost_dev_list, global_vdev_entry) {
+		if (vdev->ready == DEVICE_RX &&
+		    is_same_ether_addr(mac, &vdev->mac_address))
+			return vdev;
+	}
+
+	return NULL;
+}
+
+/*
+ * This function learns the MAC address of the device and registers this along with a
+ * vlan tag to a VMDQ.
+ */
+static int
+link_vmdq(struct vhost_dev *vdev, struct rte_mbuf *m)
+{
+	struct ether_hdr *pkt_hdr;
+	int i, ret;
+
+	/* Learn MAC address of guest device from packet */
+	pkt_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
+
+	if (find_vhost_dev(&pkt_hdr->s_addr)) {
+		RTE_LOG(ERR, VHOST_DATA,
+			"(%d) device is using a registered MAC!\n",
+			vdev->vid);
+		return -1;
+	}
+
+	for (i = 0; i < ETHER_ADDR_LEN; i++)
+		vdev->mac_address.addr_bytes[i] = pkt_hdr->s_addr.addr_bytes[i];
+
+	/* vlan_tag currently uses the device_id. */
+	vdev->vlan_tag = vlan_tags[vdev->vid];
+
+	/* Print out VMDQ registration info. */
+	RTE_LOG(INFO, VHOST_DATA,
+		"(%d) mac %02x:%02x:%02x:%02x:%02x:%02x and vlan %d registered\n",
+		vdev->vid,
+		vdev->mac_address.addr_bytes[0], vdev->mac_address.addr_bytes[1],
+		vdev->mac_address.addr_bytes[2], vdev->mac_address.addr_bytes[3],
+		vdev->mac_address.addr_bytes[4], vdev->mac_address.addr_bytes[5],
+		vdev->vlan_tag);
+
+	/* Register the MAC address. */
+	ret = rte_eth_dev_mac_addr_add(ports[0], &vdev->mac_address,
+				(uint32_t)vdev->vid + vmdq_pool_base);
+	if (ret)
+		RTE_LOG(ERR, VHOST_DATA,
+			"(%d) failed to add device MAC address to VMDQ\n",
+			vdev->vid);
+
+	rte_eth_dev_set_vlan_strip_on_queue(ports[0], vdev->vmdq_rx_q, 1);
+
+	/* Set device as ready for RX. */
+	vdev->ready = DEVICE_RX;
+
+	return 0;
+}
+
+/*
+ * Removes MAC address and vlan tag from VMDQ. Ensures that nothing is adding buffers to the RX
+ * queue before disabling RX on the device.
+ */
+static inline void
+unlink_vmdq(struct vhost_dev *vdev)
+{
+	unsigned i = 0;
+	unsigned rx_count;
+	struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
+
+	if (vdev->ready == DEVICE_RX) {
+		/*clear MAC and VLAN settings*/
+		rte_eth_dev_mac_addr_remove(ports[0], &vdev->mac_address);
+		for (i = 0; i < 6; i++)
+			vdev->mac_address.addr_bytes[i] = 0;
+
+		vdev->vlan_tag = 0;
+
+		/*Clear out the receive buffers*/
+		rx_count = rte_eth_rx_burst(ports[0],
+					(uint16_t)vdev->vmdq_rx_q, pkts_burst, MAX_PKT_BURST);
+
+		while (rx_count) {
+			for (i = 0; i < rx_count; i++)
+				rte_pktmbuf_free(pkts_burst[i]);
+
+			rx_count = rte_eth_rx_burst(ports[0],
+					(uint16_t)vdev->vmdq_rx_q, pkts_burst, MAX_PKT_BURST);
+		}
+
+		vdev->ready = DEVICE_MAC_LEARNING;
+	}
+}
+
+static inline void __attribute__((always_inline))
+virtio_xmit(struct vhost_dev *dst_vdev, struct vhost_dev *src_vdev,
+	    struct rte_mbuf *m)
+{
+	uint16_t ret;
+
+	if (builtin_net_driver) {
+		ret = vs_enqueue_pkts(dst_vdev, VIRTIO_RXQ, &m, 1);
+	} else {
+		ret = rte_vhost_enqueue_burst(dst_vdev->vid, VIRTIO_RXQ, &m, 1);
+	}
+
+	if (enable_stats) {
+		rte_atomic64_inc(&dst_vdev->stats.rx_total_atomic);
+		rte_atomic64_add(&dst_vdev->stats.rx_atomic, ret);
+		src_vdev->stats.tx_total++;
+		src_vdev->stats.tx += ret;
+	}
+}
+
+/*
+ * Check if the packet destination MAC address is for a local device. If so then put
+ * the packet on that devices RX queue. If not then return.
+ */
+static inline int __attribute__((always_inline))
+virtio_tx_local(struct vhost_dev *vdev, struct rte_mbuf *m)
+{
+	struct ether_hdr *pkt_hdr;
+	struct vhost_dev *dst_vdev;
+
+	pkt_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
+
+	dst_vdev = find_vhost_dev(&pkt_hdr->d_addr);
+	if (!dst_vdev)
+		return -1;
+
+	if (vdev->vid == dst_vdev->vid) {
+		RTE_LOG_DP(DEBUG, VHOST_DATA,
+			"(%d) TX: src and dst MAC is same. Dropping packet.\n",
+			vdev->vid);
+		return 0;
+	}
+
+	RTE_LOG_DP(DEBUG, VHOST_DATA,
+		"(%d) TX: MAC address is local\n", dst_vdev->vid);
+
+	if (unlikely(dst_vdev->remove)) {
+		RTE_LOG_DP(DEBUG, VHOST_DATA,
+			"(%d) device is marked for removal\n", dst_vdev->vid);
+		return 0;
+	}
+
+	virtio_xmit(dst_vdev, vdev, m);
+	return 0;
+}
+
+/*
+ * Check if the destination MAC of a packet is one local VM,
+ * and get its vlan tag, and offset if it is.
+ */
+static inline int __attribute__((always_inline))
+find_local_dest(struct vhost_dev *vdev, struct rte_mbuf *m,
+	uint32_t *offset, uint16_t *vlan_tag)
+{
+	struct vhost_dev *dst_vdev;
+	struct ether_hdr *pkt_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
+
+	dst_vdev = find_vhost_dev(&pkt_hdr->d_addr);
+	if (!dst_vdev)
+		return 0;
+
+	if (vdev->vid == dst_vdev->vid) {
+		RTE_LOG_DP(DEBUG, VHOST_DATA,
+			"(%d) TX: src and dst MAC is same. Dropping packet.\n",
+			vdev->vid);
+		return -1;
+	}
+
+	/*
+	 * HW vlan strip will reduce the packet length
+	 * by minus length of vlan tag, so need restore
+	 * the packet length by plus it.
+	 */
+	*offset  = VLAN_HLEN;
+	*vlan_tag = vlan_tags[vdev->vid];
+
+	RTE_LOG_DP(DEBUG, VHOST_DATA,
+		"(%d) TX: pkt to local VM device id: (%d), vlan tag: %u.\n",
+		vdev->vid, dst_vdev->vid, *vlan_tag);
+
+	return 0;
+}
+
+static uint16_t
+get_psd_sum(void *l3_hdr, uint64_t ol_flags)
+{
+	if (ol_flags & PKT_TX_IPV4)
+		return rte_ipv4_phdr_cksum(l3_hdr, ol_flags);
+	else /* assume ethertype == ETHER_TYPE_IPv6 */
+		return rte_ipv6_phdr_cksum(l3_hdr, ol_flags);
+}
+
+static void virtio_tx_offload(struct rte_mbuf *m)
+{
+	void *l3_hdr;
+	struct ipv4_hdr *ipv4_hdr = NULL;
+	struct tcp_hdr *tcp_hdr = NULL;
+	struct ether_hdr *eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
+
+	l3_hdr = (char *)eth_hdr + m->l2_len;
+
+	if (m->ol_flags & PKT_TX_IPV4) {
+		ipv4_hdr = l3_hdr;
+		ipv4_hdr->hdr_checksum = 0;
+		m->ol_flags |= PKT_TX_IP_CKSUM;
+	}
+
+	tcp_hdr = (struct tcp_hdr *)((char *)l3_hdr + m->l3_len);
+	tcp_hdr->cksum = get_psd_sum(l3_hdr, m->ol_flags);
+}
+
+static inline void
+free_pkts(struct rte_mbuf **pkts, uint16_t n)
+{
+	while (n--)
+		rte_pktmbuf_free(pkts[n]);
+}
+
+static inline void __attribute__((always_inline))
+do_drain_mbuf_table(struct mbuf_table *tx_q)
+{
+	uint16_t count;
+
+	count = rte_eth_tx_burst(ports[0], tx_q->txq_id,
+				 tx_q->m_table, tx_q->len);
+	if (unlikely(count < tx_q->len))
+		free_pkts(&tx_q->m_table[count], tx_q->len - count);
+
+	tx_q->len = 0;
+}
+
+/*
+ * This function routes the TX packet to the correct interface. This
+ * may be a local device or the physical port.
+ */
+static inline void __attribute__((always_inline))
+virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
+{
+	struct mbuf_table *tx_q;
+	unsigned offset = 0;
+	const uint16_t lcore_id = rte_lcore_id();
+	struct ether_hdr *nh;
+
+
+	nh = rte_pktmbuf_mtod(m, struct ether_hdr *);
+	if (unlikely(is_broadcast_ether_addr(&nh->d_addr))) {
+		struct vhost_dev *vdev2;
+
+		TAILQ_FOREACH(vdev2, &vhost_dev_list, global_vdev_entry) {
+			virtio_xmit(vdev2, vdev, m);
+		}
+		goto queue2nic;
+	}
+
+	/*check if destination is local VM*/
+	if ((vm2vm_mode == VM2VM_SOFTWARE) && (virtio_tx_local(vdev, m) == 0)) {
+		rte_pktmbuf_free(m);
+		return;
+	}
+
+	if (unlikely(vm2vm_mode == VM2VM_HARDWARE)) {
+		if (unlikely(find_local_dest(vdev, m, &offset,
+					     &vlan_tag) != 0)) {
+			rte_pktmbuf_free(m);
+			return;
+		}
+	}
+
+	RTE_LOG_DP(DEBUG, VHOST_DATA,
+		"(%d) TX: MAC address is external\n", vdev->vid);
+
+queue2nic:
+
+	/*Add packet to the port tx queue*/
+	tx_q = &lcore_tx_queue[lcore_id];
+
+	nh = rte_pktmbuf_mtod(m, struct ether_hdr *);
+	if (unlikely(nh->ether_type == rte_cpu_to_be_16(ETHER_TYPE_VLAN))) {
+		/* Guest has inserted the vlan tag. */
+		struct vlan_hdr *vh = (struct vlan_hdr *) (nh + 1);
+		uint16_t vlan_tag_be = rte_cpu_to_be_16(vlan_tag);
+		if ((vm2vm_mode == VM2VM_HARDWARE) &&
+			(vh->vlan_tci != vlan_tag_be))
+			vh->vlan_tci = vlan_tag_be;
+	} else {
+		m->ol_flags |= PKT_TX_VLAN_PKT;
+
+		/*
+		 * Find the right seg to adjust the data len when offset is
+		 * bigger than tail room size.
+		 */
+		if (unlikely(vm2vm_mode == VM2VM_HARDWARE)) {
+			if (likely(offset <= rte_pktmbuf_tailroom(m)))
+				m->data_len += offset;
+			else {
+				struct rte_mbuf *seg = m;
+
+				while ((seg->next != NULL) &&
+					(offset > rte_pktmbuf_tailroom(seg)))
+					seg = seg->next;
+
+				seg->data_len += offset;
+			}
+			m->pkt_len += offset;
+		}
+
+		m->vlan_tci = vlan_tag;
+	}
+
+	if (m->ol_flags & PKT_TX_TCP_SEG)
+		virtio_tx_offload(m);
+
+	tx_q->m_table[tx_q->len++] = m;
+	if (enable_stats) {
+		vdev->stats.tx_total++;
+		vdev->stats.tx++;
+	}
+
+	if (unlikely(tx_q->len == MAX_PKT_BURST))
+		do_drain_mbuf_table(tx_q);
+}
+
+
+static inline void __attribute__((always_inline))
+drain_mbuf_table(struct mbuf_table *tx_q)
+{
+	static uint64_t prev_tsc;
+	uint64_t cur_tsc;
+
+	if (tx_q->len == 0)
+		return;
+
+	cur_tsc = rte_rdtsc();
+	if (unlikely(cur_tsc - prev_tsc > MBUF_TABLE_DRAIN_TSC)) {
+		prev_tsc = cur_tsc;
+
+		RTE_LOG_DP(DEBUG, VHOST_DATA,
+			"TX queue drained after timeout with burst size %u\n",
+			tx_q->len);
+		do_drain_mbuf_table(tx_q);
+	}
+}
+
+static inline void __attribute__((always_inline))
+drain_eth_rx(struct vhost_dev *vdev)
+{
+	uint16_t rx_count, enqueue_count;
+	struct rte_mbuf *pkts[MAX_PKT_BURST];
+
+	rx_count = rte_eth_rx_burst(ports[0], vdev->vmdq_rx_q,
+				    pkts, MAX_PKT_BURST);
+	if (!rx_count)
+		return;
+
+	/*
+	 * When "enable_retry" is set, here we wait and retry when there
+	 * is no enough free slots in the queue to hold @rx_count packets,
+	 * to diminish packet loss.
+	 */
+	if (enable_retry &&
+	    unlikely(rx_count > rte_vhost_avail_entries(vdev->vid,
+			VIRTIO_RXQ))) {
+		uint32_t retry;
+
+		for (retry = 0; retry < burst_rx_retry_num; retry++) {
+			rte_delay_us(burst_rx_delay_time);
+			if (rx_count <= rte_vhost_avail_entries(vdev->vid,
+					VIRTIO_RXQ))
+				break;
+		}
+	}
+
+	if (builtin_net_driver) {
+		enqueue_count = vs_enqueue_pkts(vdev, VIRTIO_RXQ,
+						pkts, rx_count);
+	} else {
+		enqueue_count = rte_vhost_enqueue_burst(vdev->vid, VIRTIO_RXQ,
+						pkts, rx_count);
+	}
+	if (enable_stats) {
+		rte_atomic64_add(&vdev->stats.rx_total_atomic, rx_count);
+		rte_atomic64_add(&vdev->stats.rx_atomic, enqueue_count);
+	}
+
+	free_pkts(pkts, rx_count);
+}
+
+static inline void __attribute__((always_inline))
+drain_virtio_tx(struct vhost_dev *vdev)
+{
+	struct rte_mbuf *pkts[MAX_PKT_BURST];
+	uint16_t count;
+	uint16_t i;
+
+	if (builtin_net_driver) {
+		count = vs_dequeue_pkts(vdev, VIRTIO_TXQ, mbuf_pool,
+					pkts, MAX_PKT_BURST);
+	} else {
+		count = rte_vhost_dequeue_burst(vdev->vid, VIRTIO_TXQ,
+					mbuf_pool, pkts, MAX_PKT_BURST);
+	}
+
+	/* setup VMDq for the first packet */
+	if (unlikely(vdev->ready == DEVICE_MAC_LEARNING) && count) {
+		if (vdev->remove || link_vmdq(vdev, pkts[0]) == -1)
+			free_pkts(pkts, count);
+	}
+
+	for (i = 0; i < count; ++i)
+		virtio_tx_route(vdev, pkts[i], vlan_tags[vdev->vid]);
+}
+
+/*
+ * Main function of vhost-switch. It basically does:
+ *
+ * for each vhost device {
+ *    - drain_eth_rx()
+ *
+ *      Which drains the host eth Rx queue linked to the vhost device,
+ *      and deliver all of them to guest virito Rx ring associated with
+ *      this vhost device.
+ *
+ *    - drain_virtio_tx()
+ *
+ *      Which drains the guest virtio Tx queue and deliver all of them
+ *      to the target, which could be another vhost device, or the
+ *      physical eth dev. The route is done in function "virtio_tx_route".
+ * }
+ */
+static int
+switch_worker(void *arg __rte_unused)
+{
+	unsigned i;
+	unsigned lcore_id = rte_lcore_id();
+	struct vhost_dev *vdev;
+	struct mbuf_table *tx_q;
+
+	RTE_LOG(INFO, VHOST_DATA, "Procesing on Core %u started\n", lcore_id);
+
+	tx_q = &lcore_tx_queue[lcore_id];
+	for (i = 0; i < rte_lcore_count(); i++) {
+		if (lcore_ids[i] == lcore_id) {
+			tx_q->txq_id = i;
+			break;
+		}
+	}
+
+	while(1) {
+		drain_mbuf_table(tx_q);
+
+		/*
+		 * Inform the configuration core that we have exited the
+		 * linked list and that no devices are in use if requested.
+		 */
+		if (lcore_info[lcore_id].dev_removal_flag == REQUEST_DEV_REMOVAL)
+			lcore_info[lcore_id].dev_removal_flag = ACK_DEV_REMOVAL;
+
+		/*
+		 * Process vhost devices
+		 */
+		TAILQ_FOREACH(vdev, &lcore_info[lcore_id].vdev_list,
+			      lcore_vdev_entry) {
+			if (unlikely(vdev->remove)) {
+				unlink_vmdq(vdev);
+				vdev->ready = DEVICE_SAFE_REMOVE;
+				continue;
+			}
+
+			if (likely(vdev->ready == DEVICE_RX))
+				drain_eth_rx(vdev);
+
+			if (likely(!vdev->remove))
+				drain_virtio_tx(vdev);
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Remove a device from the specific data core linked list and from the
+ * main linked list. Synchonization  occurs through the use of the
+ * lcore dev_removal_flag. Device is made volatile here to avoid re-ordering
+ * of dev->remove=1 which can cause an infinite loop in the rte_pause loop.
+ */
+static void
+destroy_device(int vid)
+{
+	struct vhost_dev *vdev = NULL;
+	int lcore;
+
+	TAILQ_FOREACH(vdev, &vhost_dev_list, global_vdev_entry) {
+		if (vdev->vid == vid)
+			break;
+	}
+	if (!vdev)
+		return;
+	/*set the remove flag. */
+	vdev->remove = 1;
+	while(vdev->ready != DEVICE_SAFE_REMOVE) {
+		rte_pause();
+	}
+
+	if (builtin_net_driver)
+		vs_vhost_net_remove(vdev);
+
+	TAILQ_REMOVE(&lcore_info[vdev->coreid].vdev_list, vdev,
+		     lcore_vdev_entry);
+	TAILQ_REMOVE(&vhost_dev_list, vdev, global_vdev_entry);
+
+
+	/* Set the dev_removal_flag on each lcore. */
+	RTE_LCORE_FOREACH_SLAVE(lcore)
+		lcore_info[lcore].dev_removal_flag = REQUEST_DEV_REMOVAL;
+
+	/*
+	 * Once each core has set the dev_removal_flag to ACK_DEV_REMOVAL
+	 * we can be sure that they can no longer access the device removed
+	 * from the linked lists and that the devices are no longer in use.
+	 */
+	RTE_LCORE_FOREACH_SLAVE(lcore) {
+		while (lcore_info[lcore].dev_removal_flag != ACK_DEV_REMOVAL)
+			rte_pause();
+	}
+
+	lcore_info[vdev->coreid].device_num--;
+
+	RTE_LOG(INFO, VHOST_DATA,
+		"(%d) device has been removed from data core\n",
+		vdev->vid);
+
+	rte_free(vdev);
+}
+
+/*
+ * A new device is added to a data core. First the device is added to the main linked list
+ * and the allocated to a specific data core.
+ */
+static int
+new_device(int vid)
+{
+	int lcore, core_add = 0;
+	uint32_t device_num_min = num_devices;
+	struct vhost_dev *vdev;
+
+	vdev = rte_zmalloc("vhost device", sizeof(*vdev), RTE_CACHE_LINE_SIZE);
+	if (vdev == NULL) {
+		RTE_LOG(INFO, VHOST_DATA,
+			"(%d) couldn't allocate memory for vhost dev\n",
+			vid);
+		return -1;
+	}
+	vdev->vid = vid;
+
+	if (builtin_net_driver)
+		vs_vhost_net_setup(vdev);
+
+	TAILQ_INSERT_TAIL(&vhost_dev_list, vdev, global_vdev_entry);
+	vdev->vmdq_rx_q = vid * queues_per_pool + vmdq_queue_base;
+
+	/*reset ready flag*/
+	vdev->ready = DEVICE_MAC_LEARNING;
+	vdev->remove = 0;
+
+	/* Find a suitable lcore to add the device. */
+	RTE_LCORE_FOREACH_SLAVE(lcore) {
+		if (lcore_info[lcore].device_num < device_num_min) {
+			device_num_min = lcore_info[lcore].device_num;
+			core_add = lcore;
+		}
+	}
+	vdev->coreid = core_add;
+
+	TAILQ_INSERT_TAIL(&lcore_info[vdev->coreid].vdev_list, vdev,
+			  lcore_vdev_entry);
+	lcore_info[vdev->coreid].device_num++;
+
+	/* Disable notifications. */
+	rte_vhost_enable_guest_notification(vid, VIRTIO_RXQ, 0);
+	rte_vhost_enable_guest_notification(vid, VIRTIO_TXQ, 0);
+
+	RTE_LOG(INFO, VHOST_DATA,
+		"(%d) device has been added to data core %d\n",
+		vid, vdev->coreid);
+
+	return 0;
+}
+
+/*
+ * These callback allow devices to be added to the data core when configuration
+ * has been fully complete.
+ */
+static const struct vhost_device_ops virtio_net_device_ops =
+{
+	.new_device =  new_device,
+	.destroy_device = destroy_device,
+};
+
+/*
+ * This is a thread will wake up after a period to print stats if the user has
+ * enabled them.
+ */
+static void
+print_stats(void)
+{
+	struct vhost_dev *vdev;
+	uint64_t tx_dropped, rx_dropped;
+	uint64_t tx, tx_total, rx, rx_total;
+	const char clr[] = { 27, '[', '2', 'J', '\0' };
+	const char top_left[] = { 27, '[', '1', ';', '1', 'H','\0' };
+
+	while(1) {
+		sleep(enable_stats);
+
+		/* Clear screen and move to top left */
+		printf("%s%s\n", clr, top_left);
+		printf("Device statistics =================================\n");
+
+		TAILQ_FOREACH(vdev, &vhost_dev_list, global_vdev_entry) {
+			tx_total   = vdev->stats.tx_total;
+			tx         = vdev->stats.tx;
+			tx_dropped = tx_total - tx;
+
+			rx_total   = rte_atomic64_read(&vdev->stats.rx_total_atomic);
+			rx         = rte_atomic64_read(&vdev->stats.rx_atomic);
+			rx_dropped = rx_total - rx;
+
+			printf("Statistics for device %d\n"
+				"-----------------------\n"
+				"TX total:              %" PRIu64 "\n"
+				"TX dropped:            %" PRIu64 "\n"
+				"TX successful:         %" PRIu64 "\n"
+				"RX total:              %" PRIu64 "\n"
+				"RX dropped:            %" PRIu64 "\n"
+				"RX successful:         %" PRIu64 "\n",
+				vdev->vid,
+				tx_total, tx_dropped, tx,
+				rx_total, rx_dropped, rx);
+		}
+
+		printf("===================================================\n");
+	}
+}
+
+static void
+unregister_drivers(int socket_num)
+{
+	int i, ret;
+
+	for (i = 0; i < socket_num; i++) {
+		ret = rte_vhost_driver_unregister(socket_files + i * PATH_MAX);
+		if (ret != 0)
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"Fail to unregister vhost driver for %s.\n",
+				socket_files + i * PATH_MAX);
+	}
+}
+
+/* When we receive a INT signal, unregister vhost driver */
+static void
+sigint_handler(__rte_unused int signum)
+{
+	/* Unregister vhost driver. */
+	unregister_drivers(nb_sockets);
+
+	exit(0);
+}
+
+/*
+ * While creating an mbuf pool, one key thing is to figure out how
+ * many mbuf entries is enough for our use. FYI, here are some
+ * guidelines:
+ *
+ * - Each rx queue would reserve @nr_rx_desc mbufs at queue setup stage
+ *
+ * - For each switch core (A CPU core does the packet switch), we need
+ *   also make some reservation for receiving the packets from virtio
+ *   Tx queue. How many is enough depends on the usage. It's normally
+ *   a simple calculation like following:
+ *
+ *       MAX_PKT_BURST * max packet size / mbuf size
+ *
+ *   So, we definitely need allocate more mbufs when TSO is enabled.
+ *
+ * - Similarly, for each switching core, we should serve @nr_rx_desc
+ *   mbufs for receiving the packets from physical NIC device.
+ *
+ * - We also need make sure, for each switch core, we have allocated
+ *   enough mbufs to fill up the mbuf cache.
+ */
+static void
+create_mbuf_pool(uint16_t nr_port, uint32_t nr_switch_core, uint32_t mbuf_size,
+	uint32_t nr_queues, uint32_t nr_rx_desc, uint32_t nr_mbuf_cache)
+{
+	uint32_t nr_mbufs;
+	uint32_t nr_mbufs_per_core;
+	uint32_t mtu = 1500;
+
+	if (mergeable)
+		mtu = 9000;
+	if (enable_tso)
+		mtu = 64 * 1024;
+
+	nr_mbufs_per_core  = (mtu + mbuf_size) * MAX_PKT_BURST /
+			(mbuf_size - RTE_PKTMBUF_HEADROOM);
+	nr_mbufs_per_core += nr_rx_desc;
+	nr_mbufs_per_core  = RTE_MAX(nr_mbufs_per_core, nr_mbuf_cache);
+
+	nr_mbufs  = nr_queues * nr_rx_desc;
+	nr_mbufs += nr_mbufs_per_core * nr_switch_core;
+	nr_mbufs *= nr_port;
+
+	mbuf_pool = rte_pktmbuf_pool_create("MBUF_POOL", nr_mbufs,
+					    nr_mbuf_cache, 0, mbuf_size,
+					    rte_socket_id());
+	if (mbuf_pool == NULL)
+		rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");
+}
+
+/*
+ * Main function, does initialisation and calls the per-lcore functions.
+ */
+int
+main(int argc, char *argv[])
+{
+	unsigned lcore_id, core_id = 0;
+	unsigned nb_ports, valid_num_ports;
+	int ret, i;
+	uint8_t portid;
+	static pthread_t tid;
+	char thread_name[RTE_MAX_THREAD_NAME_LEN];
+	uint64_t flags = 0;
+
+	signal(SIGINT, sigint_handler);
+
+	/* init EAL */
+	ret = rte_eal_init(argc, argv);
+	if (ret < 0)
+		rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
+	argc -= ret;
+	argv += ret;
+
+	/* parse app arguments */
+	ret = us_vhost_parse_args(argc, argv);
+	if (ret < 0)
+		rte_exit(EXIT_FAILURE, "Invalid argument\n");
+
+	for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
+		TAILQ_INIT(&lcore_info[lcore_id].vdev_list);
+
+		if (rte_lcore_is_enabled(lcore_id))
+			lcore_ids[core_id++] = lcore_id;
+	}
+
+	if (rte_lcore_count() > RTE_MAX_LCORE)
+		rte_exit(EXIT_FAILURE,"Not enough cores\n");
+
+	/* Get the number of physical ports. */
+	nb_ports = rte_eth_dev_count();
+
+	/*
+	 * Update the global var NUM_PORTS and global array PORTS
+	 * and get value of var VALID_NUM_PORTS according to system ports number
+	 */
+	valid_num_ports = check_ports_num(nb_ports);
+
+	if ((valid_num_ports ==  0) || (valid_num_ports > MAX_SUP_PORTS)) {
+		RTE_LOG(INFO, VHOST_PORT, "Current enabled port number is %u,"
+			"but only %u port can be enabled\n",num_ports, MAX_SUP_PORTS);
+		return -1;
+	}
+
+	/*
+	 * FIXME: here we are trying to allocate mbufs big enough for
+	 * @MAX_QUEUES, but the truth is we're never going to use that
+	 * many queues here. We probably should only do allocation for
+	 * those queues we are going to use.
+	 */
+	create_mbuf_pool(valid_num_ports, rte_lcore_count() - 1, MBUF_DATA_SIZE,
+			 MAX_QUEUES, RTE_TEST_RX_DESC_DEFAULT, MBUF_CACHE_SIZE);
+
+	if (vm2vm_mode == VM2VM_HARDWARE) {
+		/* Enable VT loop back to let L2 switch to do it. */
+		vmdq_conf_default.rx_adv_conf.vmdq_rx_conf.enable_loop_back = 1;
+		RTE_LOG(DEBUG, VHOST_CONFIG,
+			"Enable loop back for L2 switch in vmdq.\n");
+	}
+
+	/* initialize all ports */
+	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");
+	}
+
+	/* Enable stats if the user option is set. */
+	if (enable_stats) {
+		ret = pthread_create(&tid, NULL, (void *)print_stats, NULL);
+		if (ret != 0)
+			rte_exit(EXIT_FAILURE,
+				"Cannot create print-stats thread\n");
+
+		/* Set thread_name for aid in debugging.  */
+		snprintf(thread_name, RTE_MAX_THREAD_NAME_LEN, "print-stats");
+		ret = rte_thread_setname(tid, thread_name);
+		if (ret != 0)
+			RTE_LOG(DEBUG, VHOST_CONFIG,
+				"Cannot set print-stats name\n");
+	}
+
+	/* Launch all data cores. */
+	RTE_LCORE_FOREACH_SLAVE(lcore_id)
+		rte_eal_remote_launch(switch_worker, NULL, lcore_id);
+
+	if (client_mode)
+		flags |= RTE_VHOST_USER_CLIENT;
+
+	if (dequeue_zero_copy)
+		flags |= RTE_VHOST_USER_DEQUEUE_ZERO_COPY;
+
+	/* Register vhost user driver to handle vhost messages. */
+	for (i = 0; i < nb_sockets; i++) {
+		char *file = socket_files + i * PATH_MAX;
+		ret = rte_vhost_driver_register(file, flags);
+		if (ret != 0) {
+			unregister_drivers(i);
+			rte_exit(EXIT_FAILURE,
+				"vhost driver register failure.\n");
+		}
+
+		if (builtin_net_driver)
+			rte_vhost_driver_set_features(file, VIRTIO_NET_FEATURES);
+
+		if (mergeable == 0) {
+			rte_vhost_driver_disable_features(file,
+				1ULL << VIRTIO_NET_F_MRG_RXBUF);
+		}
+
+		if (enable_tx_csum == 0) {
+			rte_vhost_driver_disable_features(file,
+				1ULL << VIRTIO_NET_F_CSUM);
+		}
+
+		if (enable_tso == 0) {
+			rte_vhost_driver_disable_features(file,
+				1ULL << VIRTIO_NET_F_HOST_TSO4);
+			rte_vhost_driver_disable_features(file,
+				1ULL << VIRTIO_NET_F_HOST_TSO6);
+			rte_vhost_driver_disable_features(file,
+				1ULL << VIRTIO_NET_F_GUEST_TSO4);
+			rte_vhost_driver_disable_features(file,
+				1ULL << VIRTIO_NET_F_GUEST_TSO6);
+		}
+
+		if (promiscuous) {
+			rte_vhost_driver_enable_features(file,
+				1ULL << VIRTIO_NET_F_CTRL_RX);
+		}
+
+		ret = rte_vhost_driver_callback_register(file,
+			&virtio_net_device_ops);
+		if (ret != 0) {
+			rte_exit(EXIT_FAILURE,
+				"failed to register vhost driver callbacks.\n");
+		}
+
+		if (rte_vhost_driver_start(file) < 0) {
+			rte_exit(EXIT_FAILURE,
+				"failed to start vhost driver.\n");
+		}
+	}
+
+	RTE_LCORE_FOREACH_SLAVE(lcore_id)
+		rte_eal_wait_lcore(lcore_id);
+
+	return 0;
+
+}
diff --git a/src/seastar/dpdk/examples/vhost/main.h b/src/seastar/dpdk/examples/vhost/main.h
new file mode 100644
index 00000000..9a2aca37
--- /dev/null
+++ b/src/seastar/dpdk/examples/vhost/main.h
@@ -0,0 +1,121 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2017 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.
+ */
+
+#ifndef _MAIN_H_
+#define _MAIN_H_
+
+#include <sys/queue.h>
+
+#include <rte_ether.h>
+
+/* Macros for printing using RTE_LOG */
+#define RTE_LOGTYPE_VHOST_CONFIG RTE_LOGTYPE_USER1
+#define RTE_LOGTYPE_VHOST_DATA   RTE_LOGTYPE_USER2
+#define RTE_LOGTYPE_VHOST_PORT   RTE_LOGTYPE_USER3
+
+enum {VIRTIO_RXQ, VIRTIO_TXQ, VIRTIO_QNUM};
+
+#define MAX_PKT_BURST 32		/* Max burst size for RX/TX */
+
+struct device_statistics {
+	uint64_t	tx;
+	uint64_t	tx_total;
+	rte_atomic64_t	rx_atomic;
+	rte_atomic64_t	rx_total_atomic;
+};
+
+struct vhost_queue {
+	struct rte_vhost_vring	vr;
+	uint16_t		last_avail_idx;
+	uint16_t		last_used_idx;
+};
+
+struct vhost_dev {
+	/**< Number of memory regions for gpa to hpa translation. */
+	uint32_t nregions_hpa;
+	/**< Device MAC address (Obtained on first TX packet). */
+	struct ether_addr mac_address;
+	/**< RX VMDQ queue number. */
+	uint16_t vmdq_rx_q;
+	/**< Vlan tag assigned to the pool */
+	uint32_t vlan_tag;
+	/**< Data core that the device is added to. */
+	uint16_t coreid;
+	/**< A device is set as ready if the MAC address has been set. */
+	volatile uint8_t ready;
+	/**< Device is marked for removal from the data core. */
+	volatile uint8_t remove;
+
+	int vid;
+	uint64_t features;
+	size_t hdr_len;
+	uint16_t nr_vrings;
+	struct rte_vhost_memory *mem;
+	struct device_statistics stats;
+	TAILQ_ENTRY(vhost_dev) global_vdev_entry;
+	TAILQ_ENTRY(vhost_dev) lcore_vdev_entry;
+
+#define MAX_QUEUE_PAIRS	4
+	struct vhost_queue queues[MAX_QUEUE_PAIRS * 2];
+} __rte_cache_aligned;
+
+TAILQ_HEAD(vhost_dev_tailq_list, vhost_dev);
+
+
+#define REQUEST_DEV_REMOVAL	1
+#define ACK_DEV_REMOVAL		0
+
+/*
+ * Structure containing data core specific information.
+ */
+struct lcore_info {
+	uint32_t		device_num;
+
+	/* Flag to synchronize device removal. */
+	volatile uint8_t	dev_removal_flag;
+
+	struct vhost_dev_tailq_list vdev_list;
+};
+
+/* we implement non-extra virtio net features */
+#define VIRTIO_NET_FEATURES	0
+
+void vs_vhost_net_setup(struct vhost_dev *dev);
+void vs_vhost_net_remove(struct vhost_dev *dev);
+uint16_t vs_enqueue_pkts(struct vhost_dev *dev, uint16_t queue_id,
+			 struct rte_mbuf **pkts, uint32_t count);
+
+uint16_t vs_dequeue_pkts(struct vhost_dev *dev, uint16_t queue_id,
+			 struct rte_mempool *mbuf_pool,
+			 struct rte_mbuf **pkts, uint16_t count);
+#endif /* _MAIN_H_ */
diff --git a/src/seastar/dpdk/examples/vhost/virtio_net.c b/src/seastar/dpdk/examples/vhost/virtio_net.c
new file mode 100644
index 00000000..cc2c3d88
--- /dev/null
+++ b/src/seastar/dpdk/examples/vhost/virtio_net.c
@@ -0,0 +1,403 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2017 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 <stdint.h>
+#include <stdbool.h>
+#include <linux/virtio_net.h>
+
+#include <rte_mbuf.h>
+#include <rte_memcpy.h>
+#include <rte_vhost.h>
+
+#include "main.h"
+
+/*
+ * A very simple vhost-user net driver implementation, without
+ * any extra features being enabled, such as TSO and mrg-Rx.
+ */
+
+void
+vs_vhost_net_setup(struct vhost_dev *dev)
+{
+	uint16_t i;
+	int vid = dev->vid;
+	struct vhost_queue *queue;
+
+	RTE_LOG(INFO, VHOST_CONFIG,
+		"setting builtin vhost-user net driver\n");
+
+	rte_vhost_get_negotiated_features(vid, &dev->features);
+	if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
+		dev->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	else
+		dev->hdr_len = sizeof(struct virtio_net_hdr);
+
+	rte_vhost_get_mem_table(vid, &dev->mem);
+
+	dev->nr_vrings = rte_vhost_get_vring_num(vid);
+	for (i = 0; i < dev->nr_vrings; i++) {
+		queue = &dev->queues[i];
+
+		queue->last_used_idx  = 0;
+		queue->last_avail_idx = 0;
+		rte_vhost_get_vhost_vring(vid, i, &queue->vr);
+	}
+}
+
+void
+vs_vhost_net_remove(struct vhost_dev *dev)
+{
+	free(dev->mem);
+}
+
+static inline int __attribute__((always_inline))
+enqueue_pkt(struct vhost_dev *dev, struct rte_vhost_vring *vr,
+	    struct rte_mbuf *m, uint16_t desc_idx)
+{
+	uint32_t desc_avail, desc_offset;
+	uint32_t mbuf_avail, mbuf_offset;
+	uint32_t cpy_len;
+	struct vring_desc *desc;
+	uint64_t desc_addr;
+	struct virtio_net_hdr virtio_hdr = {0, 0, 0, 0, 0, 0};
+	/* A counter to avoid desc dead loop chain */
+	uint16_t nr_desc = 1;
+
+	desc = &vr->desc[desc_idx];
+	desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
+	/*
+	 * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
+	 * performance issue with some versions of gcc (4.8.4 and 5.3.0) which
+	 * otherwise stores offset on the stack instead of in a register.
+	 */
+	if (unlikely(desc->len < dev->hdr_len) || !desc_addr)
+		return -1;
+
+	rte_prefetch0((void *)(uintptr_t)desc_addr);
+
+	/* write virtio-net header */
+	*(struct virtio_net_hdr *)(uintptr_t)desc_addr = virtio_hdr;
+
+	desc_offset = dev->hdr_len;
+	desc_avail  = desc->len - dev->hdr_len;
+
+	mbuf_avail  = rte_pktmbuf_data_len(m);
+	mbuf_offset = 0;
+	while (mbuf_avail != 0 || m->next != NULL) {
+		/* done with current mbuf, fetch next */
+		if (mbuf_avail == 0) {
+			m = m->next;
+
+			mbuf_offset = 0;
+			mbuf_avail  = rte_pktmbuf_data_len(m);
+		}
+
+		/* done with current desc buf, fetch next */
+		if (desc_avail == 0) {
+			if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
+				/* Room in vring buffer is not enough */
+				return -1;
+			}
+			if (unlikely(desc->next >= vr->size ||
+				     ++nr_desc > vr->size))
+				return -1;
+
+			desc = &vr->desc[desc->next];
+			desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
+			if (unlikely(!desc_addr))
+				return -1;
+
+			desc_offset = 0;
+			desc_avail  = desc->len;
+		}
+
+		cpy_len = RTE_MIN(desc_avail, mbuf_avail);
+		rte_memcpy((void *)((uintptr_t)(desc_addr + desc_offset)),
+			rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
+			cpy_len);
+
+		mbuf_avail  -= cpy_len;
+		mbuf_offset += cpy_len;
+		desc_avail  -= cpy_len;
+		desc_offset += cpy_len;
+	}
+
+	return 0;
+}
+
+uint16_t
+vs_enqueue_pkts(struct vhost_dev *dev, uint16_t queue_id,
+		struct rte_mbuf **pkts, uint32_t count)
+{
+	struct vhost_queue *queue;
+	struct rte_vhost_vring *vr;
+	uint16_t avail_idx, free_entries, start_idx;
+	uint16_t desc_indexes[MAX_PKT_BURST];
+	uint16_t used_idx;
+	uint32_t i;
+
+	queue = &dev->queues[queue_id];
+	vr    = &queue->vr;
+
+	avail_idx = *((volatile uint16_t *)&vr->avail->idx);
+	start_idx = queue->last_used_idx;
+	free_entries = avail_idx - start_idx;
+	count = RTE_MIN(count, free_entries);
+	count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
+	if (count == 0)
+		return 0;
+
+	/* Retrieve all of the desc indexes first to avoid caching issues. */
+	rte_prefetch0(&vr->avail->ring[start_idx & (vr->size - 1)]);
+	for (i = 0; i < count; i++) {
+		used_idx = (start_idx + i) & (vr->size - 1);
+		desc_indexes[i] = vr->avail->ring[used_idx];
+		vr->used->ring[used_idx].id = desc_indexes[i];
+		vr->used->ring[used_idx].len = pkts[i]->pkt_len +
+					       dev->hdr_len;
+	}
+
+	rte_prefetch0(&vr->desc[desc_indexes[0]]);
+	for (i = 0; i < count; i++) {
+		uint16_t desc_idx = desc_indexes[i];
+		int err;
+
+		err = enqueue_pkt(dev, vr, pkts[i], desc_idx);
+		if (unlikely(err)) {
+			used_idx = (start_idx + i) & (vr->size - 1);
+			vr->used->ring[used_idx].len = dev->hdr_len;
+		}
+
+		if (i + 1 < count)
+			rte_prefetch0(&vr->desc[desc_indexes[i+1]]);
+	}
+
+	rte_smp_wmb();
+
+	*(volatile uint16_t *)&vr->used->idx += count;
+	queue->last_used_idx += count;
+
+	/* flush used->idx update before we read avail->flags. */
+	rte_mb();
+
+	/* Kick the guest if necessary. */
+	if (!(vr->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+			&& (vr->callfd >= 0))
+		eventfd_write(vr->callfd, (eventfd_t)1);
+	return count;
+}
+
+static inline int __attribute__((always_inline))
+dequeue_pkt(struct vhost_dev *dev, struct rte_vhost_vring *vr,
+	    struct rte_mbuf *m, uint16_t desc_idx,
+	    struct rte_mempool *mbuf_pool)
+{
+	struct vring_desc *desc;
+	uint64_t desc_addr;
+	uint32_t desc_avail, desc_offset;
+	uint32_t mbuf_avail, mbuf_offset;
+	uint32_t cpy_len;
+	struct rte_mbuf *cur = m, *prev = m;
+	/* A counter to avoid desc dead loop chain */
+	uint32_t nr_desc = 1;
+
+	desc = &vr->desc[desc_idx];
+	if (unlikely((desc->len < dev->hdr_len)) ||
+			(desc->flags & VRING_DESC_F_INDIRECT))
+		return -1;
+
+	desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
+	if (unlikely(!desc_addr))
+		return -1;
+
+	/*
+	 * We don't support ANY_LAYOUT, neither VERSION_1, meaning
+	 * a Tx packet from guest must have 2 desc buffers at least:
+	 * the first for storing the header and the others for
+	 * storing the data.
+	 *
+	 * And since we don't support TSO, we could simply skip the
+	 * header.
+	 */
+	desc = &vr->desc[desc->next];
+	desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
+	if (unlikely(!desc_addr))
+		return -1;
+	rte_prefetch0((void *)(uintptr_t)desc_addr);
+
+	desc_offset = 0;
+	desc_avail  = desc->len;
+	nr_desc    += 1;
+
+	mbuf_offset = 0;
+	mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
+	while (1) {
+		cpy_len = RTE_MIN(desc_avail, mbuf_avail);
+		rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
+						   mbuf_offset),
+			(void *)((uintptr_t)(desc_addr + desc_offset)),
+			cpy_len);
+
+		mbuf_avail  -= cpy_len;
+		mbuf_offset += cpy_len;
+		desc_avail  -= cpy_len;
+		desc_offset += cpy_len;
+
+		/* This desc reaches to its end, get the next one */
+		if (desc_avail == 0) {
+			if ((desc->flags & VRING_DESC_F_NEXT) == 0)
+				break;
+
+			if (unlikely(desc->next >= vr->size ||
+				     ++nr_desc > vr->size))
+				return -1;
+			desc = &vr->desc[desc->next];
+
+			desc_addr = rte_vhost_gpa_to_vva(dev->mem, desc->addr);
+			if (unlikely(!desc_addr))
+				return -1;
+			rte_prefetch0((void *)(uintptr_t)desc_addr);
+
+			desc_offset = 0;
+			desc_avail  = desc->len;
+		}
+
+		/*
+		 * This mbuf reaches to its end, get a new one
+		 * to hold more data.
+		 */
+		if (mbuf_avail == 0) {
+			cur = rte_pktmbuf_alloc(mbuf_pool);
+			if (unlikely(cur == NULL)) {
+				RTE_LOG(ERR, VHOST_DATA, "Failed to "
+					"allocate memory for mbuf.\n");
+				return -1;
+			}
+
+			prev->next = cur;
+			prev->data_len = mbuf_offset;
+			m->nb_segs += 1;
+			m->pkt_len += mbuf_offset;
+			prev = cur;
+
+			mbuf_offset = 0;
+			mbuf_avail  = cur->buf_len - RTE_PKTMBUF_HEADROOM;
+		}
+	}
+
+	prev->data_len = mbuf_offset;
+	m->pkt_len    += mbuf_offset;
+
+	return 0;
+}
+
+uint16_t
+vs_dequeue_pkts(struct vhost_dev *dev, uint16_t queue_id,
+	struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
+{
+	struct vhost_queue *queue;
+	struct rte_vhost_vring *vr;
+	uint32_t desc_indexes[MAX_PKT_BURST];
+	uint32_t used_idx;
+	uint32_t i = 0;
+	uint16_t free_entries;
+	uint16_t avail_idx;
+
+	queue = &dev->queues[queue_id];
+	vr    = &queue->vr;
+
+	free_entries = *((volatile uint16_t *)&vr->avail->idx) -
+			queue->last_avail_idx;
+	if (free_entries == 0)
+		return 0;
+
+	/* Prefetch available and used ring */
+	avail_idx = queue->last_avail_idx & (vr->size - 1);
+	used_idx  = queue->last_used_idx  & (vr->size - 1);
+	rte_prefetch0(&vr->avail->ring[avail_idx]);
+	rte_prefetch0(&vr->used->ring[used_idx]);
+
+	count = RTE_MIN(count, MAX_PKT_BURST);
+	count = RTE_MIN(count, free_entries);
+
+	/*
+	 * Retrieve all of the head indexes first and pre-update used entries
+	 * to avoid caching issues.
+	 */
+	for (i = 0; i < count; i++) {
+		avail_idx = (queue->last_avail_idx + i) & (vr->size - 1);
+		used_idx  = (queue->last_used_idx  + i) & (vr->size - 1);
+		desc_indexes[i] = vr->avail->ring[avail_idx];
+
+		vr->used->ring[used_idx].id  = desc_indexes[i];
+		vr->used->ring[used_idx].len = 0;
+	}
+
+	/* Prefetch descriptor index. */
+	rte_prefetch0(&vr->desc[desc_indexes[0]]);
+	for (i = 0; i < count; i++) {
+		int err;
+
+		if (likely(i + 1 < count))
+			rte_prefetch0(&vr->desc[desc_indexes[i + 1]]);
+
+		pkts[i] = rte_pktmbuf_alloc(mbuf_pool);
+		if (unlikely(pkts[i] == NULL)) {
+			RTE_LOG(ERR, VHOST_DATA,
+				"Failed to allocate memory for mbuf.\n");
+			break;
+		}
+
+		err = dequeue_pkt(dev, vr, pkts[i], desc_indexes[i], mbuf_pool);
+		if (unlikely(err)) {
+			rte_pktmbuf_free(pkts[i]);
+			break;
+		}
+
+	}
+	if (!i)
+		return 0;
+
+	queue->last_avail_idx += i;
+	queue->last_used_idx += i;
+	rte_smp_wmb();
+	rte_smp_rmb();
+
+	vr->used->idx += i;
+
+	if (!(vr->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+			&& (vr->callfd >= 0))
+		eventfd_write(vr->callfd, (eventfd_t)1);
+
+	return i;
+}