Re: [dpdk-dev] [RFC PATCH v3 2/2] vhost: Add VHOST PMD

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Oct 22, 2015 at 06:45:50PM +0900, Tetsuya Mukawa wrote:
> The patch introduces a new PMD. This PMD is implemented as thin wrapper
> of librte_vhost. It means librte_vhost is also needed to compile the PMD.
> The vhost messages will be handled only when a port is started. So start
> a port first, then invoke QEMU.
> 
> The PMD has 2 parameters.
>  - iface:  The parameter is used to specify a path connect to a
>            virtio-net device.
>  - queues: The parameter is used to specify the number of the queues
>            virtio-net device has.
>            (Default: 1)
> 
> Here is an example.
> $ ./testpmd -c f -n 4 --vdev 'eth_vhost0,iface=/tmp/sock0,queues=3' -- -i
> 
> To connect above testpmd, here is qemu command example.
> 
> $ qemu-system-x86_64 \
>         <snip>
>         -chardev socket,id=chr0,path=/tmp/sock0 \
>         -netdev vhost-user,id=net0,chardev=chr0,vhostforce \
>         -device virtio-net-pci,netdev=net0
> 
> Signed-off-by: Tetsuya Mukawa <mukawa@igel.co.jp>

Hi Tetsuya,

a few comments inline below.

/Bruce

> ---
>  config/common_linuxapp                      |   6 +
<snip>
> index 0000000..66bfc2b
> --- /dev/null
> +++ b/drivers/net/vhost/rte_eth_vhost.c
> @@ -0,0 +1,735 @@
> +/*-
> + *   BSD LICENSE
> + *
> + *   Copyright (c) 2010-2015 Intel Corporation.
This is probably not the copyright line you want on your new files.

> + *   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 <unistd.h>
> +#include <pthread.h>
> +
> +#include <rte_mbuf.h>
> +#include <rte_ethdev.h>
> +#include <rte_malloc.h>
> +#include <rte_memcpy.h>
> +#include <rte_dev.h>
> +#include <rte_kvargs.h>
> +#include <rte_virtio_net.h>
> +
> +#include "rte_eth_vhost.h"
> +
> +#define ETH_VHOST_IFACE_ARG		"iface"
> +#define ETH_VHOST_QUEUES_ARG		"queues"
> +
> +static const char *drivername = "VHOST PMD";
> +
> +static const char *valid_arguments[] = {
> +	ETH_VHOST_IFACE_ARG,
> +	ETH_VHOST_QUEUES_ARG,
> +	NULL
> +};
> +
> +static struct ether_addr base_eth_addr = {
> +	.addr_bytes = {
> +		0x56 /* V */,
> +		0x48 /* H */,
> +		0x4F /* O */,
> +		0x53 /* S */,
> +		0x54 /* T */,
> +		0x00
> +	}
> +};
> +
> +struct vhost_queue {
> +	struct virtio_net *device;
> +	struct pmd_internal *internal;
> +	struct rte_mempool *mb_pool;
> +	rte_atomic32_t allow_queuing;
> +	rte_atomic32_t while_queuing;
> +	rte_atomic64_t rx_pkts;
> +	rte_atomic64_t tx_pkts;
> +	rte_atomic64_t err_pkts;
> +};
> +
> +struct pmd_internal {
> +	TAILQ_ENTRY(pmd_internal) next;
> +	char *dev_name;
> +	char *iface_name;
> +	unsigned nb_rx_queues;
> +	unsigned nb_tx_queues;
> +
> +	struct vhost_queue rx_vhost_queues[RTE_MAX_QUEUES_PER_PORT];
> +	struct vhost_queue tx_vhost_queues[RTE_MAX_QUEUES_PER_PORT];
> +
> +	volatile uint16_t once;
> +	pthread_t session_th;
> +};
> +
> +TAILQ_HEAD(pmd_internal_head, pmd_internal);
> +static struct pmd_internal_head internals_list =
> +	TAILQ_HEAD_INITIALIZER(internals_list);
> +
> +static pthread_mutex_t internal_list_lock = PTHREAD_MUTEX_INITIALIZER;
> +
> +static struct rte_eth_link pmd_link = {
> +		.link_speed = 10000,
> +		.link_duplex = ETH_LINK_FULL_DUPLEX,
> +		.link_status = 0
> +};
> +
> +static uint16_t
> +eth_vhost_rx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
> +{
> +	struct vhost_queue *r = q;
> +	uint16_t nb_rx = 0;
> +
> +	if (unlikely(r->internal == NULL))
> +		return 0;
> +
> +	if (unlikely(rte_atomic32_read(&r->allow_queuing) == 0))
> +		return 0;
> +
> +	rte_atomic32_set(&r->while_queuing, 1);
> +
> +	if (unlikely(rte_atomic32_read(&r->allow_queuing) == 0))
> +		goto out;
> +
> +	/* Dequeue packets from guest TX queue */
> +	nb_rx = (uint16_t)rte_vhost_dequeue_burst(r->device,
> +			VIRTIO_TXQ, r->mb_pool, bufs, nb_bufs);
> +
> +	rte_atomic64_add(&(r->rx_pkts), nb_rx);

Do we really need to use atomics here? It will slow things down a lot. For
other PMDs the assumption is always that only a single thread can access each
queue at a time - it's up to the app to use locks to enforce that restriction
if necessary.

> +
> +out:
> +	rte_atomic32_set(&r->while_queuing, 0);
> +
> +	return nb_rx;
> +}
> +
> +static uint16_t
> +eth_vhost_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
> +{
> +	struct vhost_queue *r = q;
> +	uint16_t i, nb_tx = 0;
> +
> +	if (unlikely(r->internal == NULL))
> +		return 0;
> +
> +	if (unlikely(rte_atomic32_read(&r->allow_queuing) == 0))
> +		return 0;
> +
> +	rte_atomic32_set(&r->while_queuing, 1);
> +
> +	if (unlikely(rte_atomic32_read(&r->allow_queuing) == 0))
> +		goto out;
> +
> +	/* Enqueue packets to guest RX queue */
> +	nb_tx = (uint16_t)rte_vhost_enqueue_burst(r->device,
> +			VIRTIO_RXQ, bufs, nb_bufs);
> +
> +	rte_atomic64_add(&(r->tx_pkts), nb_tx);
> +	rte_atomic64_add(&(r->err_pkts), nb_bufs - nb_tx);
> +
> +	for (i = 0; likely(i < nb_tx); i++)
> +		rte_pktmbuf_free(bufs[i]);
> +
> +out:
> +	rte_atomic32_set(&r->while_queuing, 0);
> +
> +	return nb_tx;
> +}
> +
> +static int
> +eth_dev_configure(struct rte_eth_dev *dev __rte_unused) { return 0; }
> +
> +static inline struct pmd_internal *
> +find_internal_resource(char *ifname)
> +{
> +	int found = 0;
> +	struct pmd_internal *internal;
> +
> +	if (ifname == NULL)
> +		return NULL;
> +
> +	pthread_mutex_lock(&internal_list_lock);
> +
> +	TAILQ_FOREACH(internal, &internals_list, next) {
> +		if (!strcmp(internal->iface_name, ifname)) {
> +			found = 1;
> +			break;
> +		}
> +	}
> +
> +	pthread_mutex_unlock(&internal_list_lock);
> +
> +	if (!found)
> +		return NULL;
> +
> +	return internal;
> +}
> +
> +static int
> +new_device(struct virtio_net *dev)
> +{
> +	struct rte_eth_dev *eth_dev;
> +	struct pmd_internal *internal;
> +	struct vhost_queue *vq;
> +	uint16_t queues;
> +	unsigned i;
> +
> +	if (dev == NULL) {
> +		RTE_LOG(INFO, PMD, "invalid argument\n");
> +		return -1;
> +	}
> +
> +	internal = find_internal_resource(dev->ifname);
> +	if (internal == NULL) {
> +		RTE_LOG(INFO, PMD, "invalid device name\n");
> +		return -1;
> +	}
> +
> +	/*
> +	 * Todo: To support multi queue, get the number of queues here.
> +	 * So far, vhost provides only one queue.
> +	 */
> +	queues = 1;
> +
> +	if ((queues < internal->nb_rx_queues) ||
> +			(queues < internal->nb_tx_queues)) {
> +		RTE_LOG(INFO, PMD, "Not enough queues\n");
> +		return -1;
> +	}
> +
> +	eth_dev = rte_eth_dev_allocated(internal->dev_name);
> +	if (eth_dev == NULL) {
> +		RTE_LOG(INFO, PMD, "failuer to find ethdev\n");

typo "failure". Probably shoudl also be written just as "Failed to find ethdev".

> +		return -1;
> +	}
> +
> +	for (i = 0; i < internal->nb_rx_queues; i++) {
> +		vq = &internal->rx_vhost_queues[i];
> +		vq->device = dev;
> +		vq->internal = internal;
> +	}
> +	for (i = 0; i < internal->nb_tx_queues; i++) {
> +		vq = &internal->tx_vhost_queues[i];
> +		vq->device = dev;
> +		vq->internal = internal;
> +	}
> +
> +	dev->flags |= VIRTIO_DEV_RUNNING;
> +	dev->pmd_priv = eth_dev;
> +	eth_dev->data->dev_link.link_status = 1;
> +
> +	for (i = 0; i < internal->nb_rx_queues; i++) {
> +		vq = &internal->rx_vhost_queues[i];
> +		rte_atomic32_set(&vq->allow_queuing, 1);
> +	}
> +	for (i = 0; i < internal->nb_tx_queues; i++) {
> +		vq = &internal->tx_vhost_queues[i];
> +		rte_atomic32_set(&vq->allow_queuing, 1);
> +	}
> +	RTE_LOG(INFO, PMD, "New connection established\n");
> +
> +	return 0;
> +}
> +
> +static void
> +destroy_device(volatile struct virtio_net *dev)
> +{
> +	struct rte_eth_dev *eth_dev;
> +	struct pmd_internal *internal;
> +	struct vhost_queue *vq;
> +	unsigned i;
> +
> +	if (dev == NULL) {
> +		RTE_LOG(INFO, PMD, "invalid argument\n");
> +		return;
> +	}
> +
> +	eth_dev = (struct rte_eth_dev *)dev->pmd_priv;
> +	if (eth_dev == NULL) {
> +		RTE_LOG(INFO, PMD, "failuer to find a ethdev\n");
> +		return;
> +	}
> +
> +	internal = eth_dev->data->dev_private;
> +
> +	/* Wait until rx/tx_pkt_burst stops accesing vhost device */
> +	for (i = 0; i < internal->nb_rx_queues; i++) {
> +		vq = &internal->rx_vhost_queues[i];
> +		rte_atomic32_set(&vq->allow_queuing, 0);
> +		while (rte_atomic32_read(&vq->while_queuing))
> +			rte_pause();
> +	}
> +	for (i = 0; i < internal->nb_tx_queues; i++) {
> +		vq = &internal->tx_vhost_queues[i];
> +		rte_atomic32_set(&vq->allow_queuing, 0);
> +		while (rte_atomic32_read(&vq->while_queuing))
> +			rte_pause();
> +	}
> +
> +	eth_dev->data->dev_link.link_status = 0;
> +
> +	dev->pmd_priv = NULL;
> +	dev->flags &= ~VIRTIO_DEV_RUNNING;
> +
> +	for (i = 0; i < internal->nb_rx_queues; i++) {
> +		vq = &internal->rx_vhost_queues[i];
> +		vq->device = NULL;
> +	}
> +	for (i = 0; i < internal->nb_tx_queues; i++) {
> +		vq = &internal->tx_vhost_queues[i];
> +		vq->device = NULL;
> +	}
> +
> +	RTE_LOG(INFO, PMD, "Connection closed\n");
> +}
> +
> +static void *vhost_driver_session(void *param __rte_unused)
> +{
> +	static struct virtio_net_device_ops *vhost_ops;
> +
> +	vhost_ops = rte_zmalloc(NULL, sizeof(*vhost_ops), 0);
> +	if (vhost_ops == NULL)
> +		rte_panic("Can't allocate memory\n");
> +
> +	/* set vhost arguments */
> +	vhost_ops->new_device = new_device;
> +	vhost_ops->destroy_device = destroy_device;
> +	if (rte_vhost_driver_pmd_callback_register(vhost_ops) < 0)
> +		rte_panic("Can't register callbacks\n");
> +
> +	/* start event handling */
> +	rte_vhost_driver_session_start();
> +
> +	rte_free(vhost_ops);
> +	pthread_exit(0);
> +}
> +
> +static void vhost_driver_session_start(struct pmd_internal *internal)
> +{
> +	int ret;
> +
> +	ret = pthread_create(&internal->session_th,
> +			NULL, vhost_driver_session, NULL);
> +	if (ret)
> +		rte_panic("Can't create a thread\n");
> +}
> +
> +static void vhost_driver_session_stop(struct pmd_internal *internal)
> +{
> +	int ret;
> +
> +	ret = pthread_cancel(internal->session_th);
> +	if (ret)
> +		rte_panic("Can't cancel the thread\n");
> +
> +	ret = pthread_join(internal->session_th, NULL);
> +	if (ret)
> +		rte_panic("Can't join the thread\n");
> +}
> +
> +static int
> +eth_dev_start(struct rte_eth_dev *dev)
> +{
> +	int ret;
> +	struct pmd_internal *internal = dev->data->dev_private;
> +
> +	if (rte_atomic16_cmpset(&internal->once, 0, 1)) {
> +		ret = rte_vhost_driver_register(internal->iface_name);
> +		if (ret)
> +			return ret;
> +
> +		vhost_driver_session_start(internal);
> +	}
> +	return 0;
> +}
> +
> +static void
> +eth_dev_stop(struct rte_eth_dev *dev)
> +{
> +	struct pmd_internal *internal = dev->data->dev_private;
> +
> +	if (rte_atomic16_cmpset(&internal->once, 1, 0)) {
> +		rte_vhost_driver_unregister(internal->iface_name);
> +		vhost_driver_session_stop(internal);
> +	}
> +}
> +
> +static int
> +eth_rx_queue_setup(struct rte_eth_dev *dev, uint16_t rx_queue_id,
> +		   uint16_t nb_rx_desc __rte_unused,
> +		   unsigned int socket_id __rte_unused,
> +		   const struct rte_eth_rxconf *rx_conf __rte_unused,
> +		   struct rte_mempool *mb_pool)
> +{
> +	struct pmd_internal *internal = dev->data->dev_private;
> +
> +	internal->rx_vhost_queues[rx_queue_id].mb_pool = mb_pool;
> +	dev->data->rx_queues[rx_queue_id] = &internal->rx_vhost_queues[rx_queue_id];
> +	return 0;
> +}
> +
> +static int
> +eth_tx_queue_setup(struct rte_eth_dev *dev, uint16_t tx_queue_id,
> +		   uint16_t nb_tx_desc __rte_unused,
> +		   unsigned int socket_id __rte_unused,
> +		   const struct rte_eth_txconf *tx_conf __rte_unused)
> +{
> +	struct pmd_internal *internal = dev->data->dev_private;
> +
> +	dev->data->tx_queues[tx_queue_id] = &internal->tx_vhost_queues[tx_queue_id];
> +	return 0;
> +}
> +
> +
> +static void
> +eth_dev_info(struct rte_eth_dev *dev,
> +	     struct rte_eth_dev_info *dev_info)
> +{
> +	struct pmd_internal *internal = dev->data->dev_private;
> +
> +	dev_info->driver_name = drivername;
> +	dev_info->max_mac_addrs = 1;
> +	dev_info->max_rx_pktlen = (uint32_t)-1;
> +	dev_info->max_rx_queues = (uint16_t)internal->nb_rx_queues;
> +	dev_info->max_tx_queues = (uint16_t)internal->nb_tx_queues;
> +	dev_info->min_rx_bufsize = 0;
> +	dev_info->pci_dev = dev->pci_dev;
> +}
> +
> +static void
> +eth_stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *igb_stats)
> +{
> +	unsigned i;
> +	unsigned long rx_total = 0, tx_total = 0, tx_err_total = 0;
> +	const struct pmd_internal *internal = dev->data->dev_private;
> +
> +	for (i = 0; i < RTE_ETHDEV_QUEUE_STAT_CNTRS &&
> +	     i < internal->nb_rx_queues; i++) {
> +		igb_stats->q_ipackets[i] = internal->rx_vhost_queues[i].rx_pkts.cnt;
> +		rx_total += igb_stats->q_ipackets[i];
> +	}
> +
> +	for (i = 0; i < RTE_ETHDEV_QUEUE_STAT_CNTRS &&
> +	     i < internal->nb_tx_queues; i++) {
> +		igb_stats->q_opackets[i] = internal->tx_vhost_queues[i].tx_pkts.cnt;
> +		igb_stats->q_errors[i] = internal->tx_vhost_queues[i].err_pkts.cnt;
> +		tx_total += igb_stats->q_opackets[i];
> +		tx_err_total += igb_stats->q_errors[i];
> +	}
> +
> +	igb_stats->ipackets = rx_total;
> +	igb_stats->opackets = tx_total;
> +	igb_stats->oerrors = tx_err_total;
> +}
> +
> +static void
> +eth_stats_reset(struct rte_eth_dev *dev)
> +{
> +	unsigned i;
> +	struct pmd_internal *internal = dev->data->dev_private;
> +
> +	for (i = 0; i < internal->nb_rx_queues; i++)
> +		internal->rx_vhost_queues[i].rx_pkts.cnt = 0;
> +	for (i = 0; i < internal->nb_tx_queues; i++) {
> +		internal->tx_vhost_queues[i].tx_pkts.cnt = 0;
> +		internal->tx_vhost_queues[i].err_pkts.cnt = 0;
> +	}
> +}
> +
> +static void
> +eth_queue_release(void *q __rte_unused) { ; }
> +static int
> +eth_link_update(struct rte_eth_dev *dev __rte_unused,
> +		int wait_to_complete __rte_unused) { return 0; }
> +
> +static const struct eth_dev_ops ops = {
> +	.dev_start = eth_dev_start,
> +	.dev_stop = eth_dev_stop,
> +	.dev_configure = eth_dev_configure,
> +	.dev_infos_get = eth_dev_info,
> +	.rx_queue_setup = eth_rx_queue_setup,
> +	.tx_queue_setup = eth_tx_queue_setup,
> +	.rx_queue_release = eth_queue_release,
> +	.tx_queue_release = eth_queue_release,
> +	.link_update = eth_link_update,
> +	.stats_get = eth_stats_get,
> +	.stats_reset = eth_stats_reset,
> +};
> +
> +static struct eth_driver rte_vhost_pmd = {
> +	.pci_drv = {
> +		.name = "rte_vhost_pmd",
> +		.drv_flags = RTE_PCI_DRV_DETACHABLE,
> +	},
> +};

If you base this patchset on top of Bernard's patchset to remove the PCI devices
then you shouldn't need these pci_dev and id_table structures.

> +
> +static struct rte_pci_id id_table;
> +
> +static int
> +eth_dev_vhost_create(const char *name, int index,
> +		     char *iface_name,
> +		     int16_t queues,
> +		     const unsigned numa_node)
> +{
> +	struct rte_eth_dev_data *data = NULL;
> +	struct rte_pci_device *pci_dev = NULL;
> +	struct pmd_internal *internal = NULL;
> +	struct rte_eth_dev *eth_dev = NULL;
> +	struct ether_addr *eth_addr = NULL;
> +
> +	RTE_LOG(INFO, PMD, "Creating VHOST-USER backend on numa socket %u\n",
> +		numa_node);
> +
> +	/* now do all data allocation - for eth_dev structure, dummy pci driver
> +	 * and internal (private) data
> +	 */
> +	data = rte_zmalloc_socket(name, sizeof(*data), 0, numa_node);
> +	if (data == NULL)
> +		goto error;
> +
> +	pci_dev = rte_zmalloc_socket(name, sizeof(*pci_dev), 0, numa_node);
> +	if (pci_dev == NULL)
> +		goto error;
> +
> +	internal = rte_zmalloc_socket(name, sizeof(*internal), 0, numa_node);
> +	if (internal == NULL)
> +		goto error;
> +
> +	eth_addr = rte_zmalloc_socket(name, sizeof(*eth_addr), 0, numa_node);
> +	if (eth_addr == NULL)
> +		goto error;
> +	*eth_addr = base_eth_addr;
> +	eth_addr->addr_bytes[5] = index;
> +
> +	/* reserve an ethdev entry */
> +	eth_dev = rte_eth_dev_allocate(name, RTE_ETH_DEV_VIRTUAL);
> +	if (eth_dev == NULL)
> +		goto error;
> +
> +	/* now put it all together
> +	 * - store queue data in internal,
> +	 * - store numa_node info in pci_driver
> +	 * - point eth_dev_data to internal and pci_driver
> +	 * - and point eth_dev structure to new eth_dev_data structure
> +	 */
> +	internal->nb_rx_queues = queues;
> +	internal->nb_tx_queues = queues;
> +	internal->dev_name = strdup(name);
> +	if (internal->dev_name == NULL)
> +		goto error;
> +	internal->iface_name = strdup(iface_name);
> +	if (internal->iface_name == NULL)
> +		goto error;
> +
> +	pthread_mutex_lock(&internal_list_lock);
> +	TAILQ_INSERT_TAIL(&internals_list, internal, next);
> +	pthread_mutex_unlock(&internal_list_lock);
> +
> +	rte_vhost_pmd.pci_drv.name = drivername;
> +	rte_vhost_pmd.pci_drv.id_table = &id_table;
> +
> +	pci_dev->numa_node = numa_node;
> +	pci_dev->driver = &rte_vhost_pmd.pci_drv;
> +
> +	data->dev_private = internal;
> +	data->port_id = eth_dev->data->port_id;
> +	memmove(data->name, eth_dev->data->name, sizeof(data->name));
> +	data->nb_rx_queues = queues;
> +	data->nb_tx_queues = queues;
> +	data->dev_link = pmd_link;
> +	data->mac_addrs = eth_addr;
> +
> +	/* We'll replace the 'data' originally allocated by eth_dev. So the
> +	 * vhost PMD resources won't be shared between multi processes.
> +	 */
> +	eth_dev->data = data;
> +	eth_dev->driver = &rte_vhost_pmd;
> +	eth_dev->dev_ops = &ops;
> +	eth_dev->pci_dev = pci_dev;
> +
> +	/* finally assign rx and tx ops */
> +	eth_dev->rx_pkt_burst = eth_vhost_rx;
> +	eth_dev->tx_pkt_burst = eth_vhost_tx;
> +
> +	return data->port_id;
> +
> +error:
> +	rte_free(data);
> +	rte_free(pci_dev);
> +	rte_free(internal);
> +	rte_free(eth_addr);
> +
> +	return -1;
> +}
> +
> +static inline int
> +open_iface(const char *key __rte_unused, const char *value, void *extra_args)
> +{
> +	const char **iface_name = extra_args;
> +
> +	if (value == NULL)
> +		return -1;
> +
> +	*iface_name = value;
> +
> +	return 0;
> +}
> +
> +static inline int
> +open_queues(const char *key __rte_unused, const char *value, void *extra_args)
> +{
> +	uint16_t *q = extra_args;
> +
> +	if ((value == NULL) || (extra_args == NULL))
> +		return -EINVAL;
> +
> +	*q = (uint16_t)strtoul(value, NULL, 0);
> +	if ((*q == USHRT_MAX) && (errno == ERANGE))
> +		return -1;
> +
> +	if (*q > RTE_MAX_QUEUES_PER_PORT)
> +		return -1;
> +
> +	return 0;
> +}
> +
> +static int
> +rte_pmd_vhost_devinit(const char *name, const char *params)
> +{
> +	struct rte_kvargs *kvlist = NULL;
> +	int ret = 0;
> +	int index;
> +	char *iface_name;
> +	uint16_t queues;
> +
> +	RTE_LOG(INFO, PMD, "Initializing pmd_vhost for %s\n", name);
> +
> +	kvlist = rte_kvargs_parse(params, valid_arguments);
> +	if (kvlist == NULL)
> +		return -1;
> +
> +	if (strlen(name) < strlen("eth_vhost"))
> +		return -1;
> +
> +	index = strtol(name + strlen("eth_vhost"), NULL, 0);
> +	if (errno == ERANGE)
> +		return -1;
> +
> +	if (rte_kvargs_count(kvlist, ETH_VHOST_IFACE_ARG) == 1) {
> +		ret = rte_kvargs_process(kvlist, ETH_VHOST_IFACE_ARG,
> +					 &open_iface, &iface_name);
> +		if (ret < 0)
> +			goto out_free;
> +	}
> +
> +	if (rte_kvargs_count(kvlist, ETH_VHOST_QUEUES_ARG) == 1) {
> +		ret = rte_kvargs_process(kvlist, ETH_VHOST_QUEUES_ARG,
> +					 &open_queues, &queues);
> +		if (ret < 0)
> +			goto out_free;
> +
> +	} else
> +		queues = 1;
> +
> +	eth_dev_vhost_create(name, index,
> +			iface_name, queues, rte_socket_id());
> +
> +out_free:
> +	rte_kvargs_free(kvlist);
> +	return ret;
> +}
> +
> +static int
> +rte_pmd_vhost_devuninit(const char *name)
> +{
> +	struct rte_eth_dev *eth_dev = NULL;
> +	struct pmd_internal *internal;
> +
> +	RTE_LOG(INFO, PMD, "Un-Initializing pmd_vhost for %s\n", name);
> +
> +	if (name == NULL)
> +		return -EINVAL;
> +
> +	/* find an ethdev entry */
> +	eth_dev = rte_eth_dev_allocated(name);
> +	if (eth_dev == NULL)
> +		return -ENODEV;
> +
> +	internal = eth_dev->data->dev_private;
> +
> +	pthread_mutex_lock(&internal_list_lock);
> +	TAILQ_REMOVE(&internals_list, internal, next);
> +	pthread_mutex_unlock(&internal_list_lock);
> +
> +	eth_dev_stop(eth_dev);
> +
> +	if ((internal) && (internal->dev_name))
> +		free(internal->dev_name);
> +	if ((internal) && (internal->iface_name))
> +		free(internal->iface_name);
> +	rte_free(eth_dev->data->dev_private);
> +	rte_free(eth_dev->data);
> +	rte_free(eth_dev->pci_dev);
> +
> +	rte_eth_dev_release_port(eth_dev);
> +	return 0;
> +}
> +
> +static struct rte_driver pmd_vhost_drv = {
> +	.name = "eth_vhost",
> +	.type = PMD_VDEV,
> +	.init = rte_pmd_vhost_devinit,
> +	.uninit = rte_pmd_vhost_devuninit,
> +};
> +
> +struct
> +virtio_net *rte_eth_vhost_portid2vdev(uint16_t port_id)
> +{
> +	struct rte_eth_dev *eth_dev;
> +
> +	if (rte_eth_dev_is_valid_port(port_id) == 0)
> +		return NULL;
> +
> +	eth_dev = &rte_eth_devices[port_id];
> +	if (eth_dev->driver == &rte_vhost_pmd) {
> +		struct pmd_internal *internal;
> +		struct vhost_queue *vq;
> +
> +		internal = eth_dev->data->dev_private;
> +		vq = &internal->rx_vhost_queues[0];
> +		if (vq->device)
> +			return vq->device;
> +	}
> +
> +	return NULL;
> +}
> +
> +PMD_REGISTER_DRIVER(pmd_vhost_drv);
> diff --git a/drivers/net/vhost/rte_eth_vhost.h b/drivers/net/vhost/rte_eth_vhost.h
> new file mode 100644
> index 0000000..0c4d4b5
> --- /dev/null
> +++ b/drivers/net/vhost/rte_eth_vhost.h
> @@ -0,0 +1,65 @@
> +/*-
> + *   BSD LICENSE
> + *
> + *   Copyright(c) 2015 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 _RTE_ETH_AF_PACKET_H_
> +#define _RTE_ETH_AF_PACKET_H_
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +#include <rte_virtio_net.h>
> +
> +/**
> + * The function convert specified port_id to virtio device structure.
> + * The retured device can be used for vhost library APIs.
> + * To use vhost library APIs and vhost PMD parallely, below API should
> + * not be called, because the API will be called by vhost PMD.
> + * - rte_vhost_driver_session_start()
> + * Once a device is managed by vhost PMD, below API should not be called.
> + * - rte_vhost_driver_unregister()
> + * To unregister the device, call Port Hotplug APIs.
> + *
> + * @param port_id
> + *  port number
> + * @return
> + *  virtio net device structure corresponding to the specified port
> + *  NULL will be returned in error cases.
> + */
> +struct virtio_net *rte_eth_vhost_portid2vdev(uint16_t port_id);
> +
> +#ifdef __cplusplus
> +}
> +#endif
> +
> +#endif
> diff --git a/drivers/net/vhost/rte_pmd_vhost_version.map b/drivers/net/vhost/rte_pmd_vhost_version.map
> new file mode 100644
> index 0000000..bf0361a
> --- /dev/null
> +++ b/drivers/net/vhost/rte_pmd_vhost_version.map
> @@ -0,0 +1,8 @@
> +DPDK_2.2 {
> +
> +	global:
> +
> +	rte_eth_vhost_portid2vdev;
> +
> +	local: *;
> +};
> diff --git a/mk/rte.app.mk b/mk/rte.app.mk
> index 3871205..1c42fb1 100644
> --- a/mk/rte.app.mk
> +++ b/mk/rte.app.mk
> @@ -144,7 +144,13 @@ _LDLIBS-$(CONFIG_RTE_LIBRTE_PMD_PCAP)       += -lrte_pmd_pcap
>  _LDLIBS-$(CONFIG_RTE_LIBRTE_PMD_AF_PACKET)  += -lrte_pmd_af_packet
>  _LDLIBS-$(CONFIG_RTE_LIBRTE_PMD_NULL)       += -lrte_pmd_null
>  
> -endif # ! $(CONFIG_RTE_BUILD_SHARED_LIB)
> +ifeq ($(CONFIG_RTE_LIBRTE_VHOST),y)
> +
> +_LDLIBS-$(CONFIG_RTE_LIBRTE_PMD_VHOST)      += -lrte_pmd_vhost
> +
> +endif # ! $(CONFIG_RTE_LIBRTE_VHOST)
> +
> +endif # $(CONFIG_RTE_BUILD_SHARED_LIB)
>  
>  endif # ! CONFIG_RTE_BUILD_COMBINE_LIBS
>  
> -- 
> 2.1.4
>