#include <stdint.h>
#include <sys/eventfd.h>
#include <rte_memory.h>
#include <rte_mempool.h>
#include <linux/vhost.h>
#include <linux/virtio_ring.h>

Data Structures
struct	rte_vhost_mem_region
struct	rte_vhost_memory
struct	vhost_device_ops

Functions
static uint64_t	rte_vhost_gpa_to_vva (struct rte_vhost_memory *mem, uint64_t gpa)
void	rte_vhost_log_write (int vid, uint64_t addr, uint64_t len)
void	rte_vhost_log_used_vring (int vid, uint16_t vring_idx, uint64_t offset, uint64_t len)
int	rte_vhost_driver_register (const char *path, uint64_t flags)
int	rte_vhost_driver_set_features (const char *path, uint64_t features)
int	rte_vhost_driver_enable_features (const char *path, uint64_t features)
int	rte_vhost_driver_disable_features (const char *path, uint64_t features)
int	rte_vhost_driver_get_features (const char path, uint64_t features)
int	rte_vhost_get_negotiated_features (int vid, uint64_t *features)
int	rte_vhost_driver_start (const char *path)
int	rte_vhost_get_mtu (int vid, uint16_t *mtu)
int	rte_vhost_get_numa_node (int vid)
__rte_deprecated uint32_t	rte_vhost_get_queue_num (int vid)
uint16_t	rte_vhost_get_vring_num (int vid)
int	rte_vhost_get_ifname (int vid, char *buf, size_t len)
uint16_t	rte_vhost_avail_entries (int vid, uint16_t queue_id)
uint16_t	rte_vhost_enqueue_burst (int vid, uint16_t queue_id, struct rte_mbuf **pkts, uint16_t count)
uint16_t	rte_vhost_dequeue_burst (int vid, uint16_t queue_id, struct rte_mempool mbuf_pool, struct rte_mbuf *pkts, uint16_t count)
int	rte_vhost_get_mem_table (int vid, struct rte_vhost_memory **mem)
int	rte_vhost_get_vhost_vring (int vid, uint16_t vring_idx, struct rte_vhost_vring *vring)

Detailed Description

Interface to vhost-user

Definition in file rte_vhost.h.

Function Documentation

static uint64_t rte_vhost_gpa_to_vva	(	struct rte_vhost_memory *	mem,
		uint64_t	gpa
	)

inlinestatic

Convert guest physical address to host virtual address

Parameters

mem	the guest memory regions
gpa	the guest physical address for querying

Returns: the host virtual address on success, 0 on failure

Examples:: examples/vhost/virtio_net.c.

Definition at line 124 of file rte_vhost.h.

void rte_vhost_log_write	(	int	vid,
		uint64_t	addr,
		uint64_t	len
	)

Log the memory write start with given address.

This function only need be invoked when the live migration starts. Therefore, we won't need call it at all in the most of time. For making the performance impact be minimum, it's suggested to do a check before calling it:

   if (unlikely(RTE_VHOST_NEED_LOG(features)))
           rte_vhost_log_write(vid, addr, len);

Parameters

vid	vhost device ID
addr	the starting address for write
len	the length to write

void rte_vhost_log_used_vring	(	int	vid,
		uint16_t	vring_idx,
		uint64_t	offset,
		uint64_t	len
	)

Log the used ring update start at given offset.

Same as rte_vhost_log_write, it's suggested to do a check before calling it:

   if (unlikely(RTE_VHOST_NEED_LOG(features)))
           rte_vhost_log_used_vring(vid, vring_idx, offset, len);

Parameters

vid	vhost device ID
vring_idx	the vring index
offset	the offset inside the used ring
len	the length to write

int rte_vhost_driver_register	(	const char *	path,
		uint64_t	flags
	)

Register vhost driver. path could be different for multiple instance support.

Examples:: examples/tep_termination/main.c, and examples/vhost/main.c.

int rte_vhost_driver_set_features	(	const char *	path,
		uint64_t	features
	)

Set the feature bits the vhost-user driver supports.

Parameters

path	The vhost-user socket file path
features	Supported features

Returns: 0 on success, -1 on failure

Examples:: examples/vhost/main.c.

int rte_vhost_driver_enable_features	(	const char *	path,
		uint64_t	features
	)

Enable vhost-user driver features.

Note that

the param features should be a subset of the feature bits provided by rte_vhost_driver_set_features().
it must be invoked before vhost-user negotiation starts.

Parameters

path	The vhost-user socket file path
features	Features to enable

Returns: 0 on success, -1 on failure

Examples:: examples/vhost/main.c.

int rte_vhost_driver_disable_features	(	const char *	path,
		uint64_t	features
	)

Disable vhost-user driver features.

The two notes at rte_vhost_driver_enable_features() also apply here.

Parameters

path	The vhost-user socket file path
features	Features to disable

Returns: 0 on success, -1 on failure

Examples:: examples/tep_termination/main.c, and examples/vhost/main.c.

int rte_vhost_driver_get_features	(	const char *	path,
		uint64_t *	features
	)

Get the feature bits before feature negotiation.

Parameters

path	The vhost-user socket file path
features	A pointer to store the queried feature bits

Returns: 0 on success, -1 on failure

int rte_vhost_get_negotiated_features	(	int	vid,
		uint64_t *	features
	)

Get the feature bits after negotiation

Parameters

vid	Vhost device ID
features	A pointer to store the queried feature bits

Returns: 0 on success, -1 on failure

Examples:: examples/vhost/virtio_net.c.

int rte_vhost_driver_start ( const char * path )

Start the vhost-user driver.

This function triggers the vhost-user negotiation.

Parameters

path	The vhost-user socket file path

Returns: 0 on success, -1 on failure

Examples:: examples/tep_termination/main.c, and examples/vhost/main.c.

int rte_vhost_get_mtu	(	int	vid,
		uint16_t *	mtu
	)

Get the MTU value of the device if set in QEMU.

Parameters

vid	virtio-net device ID
mtu	The variable to store the MTU value

Returns: 0: success -EAGAIN: device not yet started -ENOTSUP: device does not support MTU feature

int rte_vhost_get_numa_node ( int vid )

Get the numa node from which the virtio net device's memory is allocated.

Parameters

vid	vhost device ID

Returns: The numa node, -1 on failure

__rte_deprecated uint32_t rte_vhost_get_queue_num ( int vid )

Note this function is deprecated, as it returns a queue pair number, which is vhost specific. Instead, rte_vhost_get_vring_num should be used.

Parameters

vid	vhost device ID

Returns: The number of queues, 0 on failure

uint16_t rte_vhost_get_vring_num ( int vid )

Get the number of vrings the device supports.

Parameters

vid	vhost device ID

Returns: The number of vrings, 0 on failure

Examples:: examples/vhost/virtio_net.c.

int rte_vhost_get_ifname	(	int	vid,
		char *	buf,
		size_t	len
	)

Get the virtio net device's ifname, which is the vhost-user socket file path.

Parameters

vid	vhost device ID
buf	The buffer to stored the queried ifname
len	The length of buf

Returns: 0 on success, -1 on failure

uint16_t rte_vhost_avail_entries	(	int	vid,
		uint16_t	queue_id
	)

Get how many avail entries are left in the queue

Parameters

vid	vhost device ID
queue_id	virtio queue index

Returns: num of avail entires left

Examples:: examples/tep_termination/main.c, and examples/vhost/main.c.

uint16_t rte_vhost_enqueue_burst	(	int	vid,
		uint16_t	queue_id,
		struct rte_mbuf **	pkts,
		uint16_t	count
	)

This function adds buffers to the virtio devices RX virtqueue. Buffers can be received from the physical port or from another virtual device. A packet count is returned to indicate the number of packets that were succesfully added to the RX queue.

Parameters

vid	vhost device ID
queue_id	virtio queue index in mq case
pkts	array to contain packets to be enqueued
count	packets num to be enqueued

Returns: num of packets enqueued

Examples:: examples/tep_termination/vxlan_setup.c, and examples/vhost/main.c.

uint16_t rte_vhost_dequeue_burst	(	int	vid,
		uint16_t	queue_id,
		struct rte_mempool *	mbuf_pool,
		struct rte_mbuf **	pkts,
		uint16_t	count
	)

This function gets guest buffers from the virtio device TX virtqueue, construct host mbufs, copies guest buffer content to host mbufs and store them in pkts to be processed.

Parameters

vid	vhost device ID
queue_id	virtio queue index in mq case
mbuf_pool	mbuf_pool where host mbuf is allocated.
pkts	array to contain packets to be dequeued
count	packets num to be dequeued

Returns: num of packets dequeued

Examples:: examples/tep_termination/main.c, and examples/vhost/main.c.

int rte_vhost_get_mem_table	(	int	vid,
		struct rte_vhost_memory **	mem
	)

Get guest mem table: a list of memory regions.

An rte_vhost_vhost_memory object will be allocated internaly, to hold the guest memory regions. Application should free it at destroy_device() callback.

Parameters

vid	vhost device ID
mem	To store the returned mem regions

Returns: 0 on success, -1 on failure

Examples:: examples/vhost/virtio_net.c.

int rte_vhost_get_vhost_vring	(	int	vid,
		uint16_t	vring_idx,
		struct rte_vhost_vring *	vring
	)

Get guest vring info, including the vring address, vring size, etc.

Parameters

vid	vhost device ID
vring_idx	vring index
vring	the structure to hold the requested vring info

Returns: 0 on success, -1 on failure

Examples:: examples/vhost/virtio_net.c.

Data Structures

Functions

Detailed Description

Function Documentation