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vhost: introduce API to start a specific driver

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We used to use rte_vhost_driver_session_start() to trigger the vhost-user
session. It takes no argument, thus it's a global trigger. And it could
be problematic.

The issue is, currently, rte_vhost_driver_register(path, flags) actually
tries to put it into the session loop (by fdset_add). However, it needs
a set of APIs to set a vhost-user driver properly:
  * rte_vhost_driver_register(path, flags);
  * rte_vhost_driver_set_features(path, features);
  * rte_vhost_driver_callback_register(path, vhost_device_ops);

If a new vhost-user driver is registered after the trigger (think OVS-DPDK
that could add a port dynamically from cmdline), the current code will
effectively starts the session for the new driver just after the first
API rte_vhost_driver_register() is invoked, leaving later calls taking
no effect at all.

To handle the case properly, this patch introduce a new API,
rte_vhost_driver_start(path), to trigger a specific vhost-user driver.
To do that, the rte_vhost_driver_register(path, flags) is simplified
to create the socket only and let rte_vhost_driver_start(path) to
actually put it into the session loop.

Meanwhile, the rte_vhost_driver_session_start is removed: we could hide
the session thread internally (create the thread if it has not been
created). This would also simplify the application.

NOTE: the API order in prog guide is slightly adjusted for showing the
correct invoke order.

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
This commit is contained in:
Yuanhan Liu 2017-04-01 15:22:56 +08:00
parent 52f8091f05
commit af14759181
10 changed files with 104 additions and 103 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
doc/guides/prog_guide/vhost_lib.rst
View File

@ -116,12 +116,6 @@ The following is an overview of some key Vhost API functions:
vhost-user driver could be vhost-user net, yet it could be something else,
say, vhost-user SCSI.
* ``rte_vhost_driver_session_start()``
This function starts the vhost session loop to handle vhost messages. It
starts an infinite loop, therefore it should be called in a dedicated
thread.
* ``rte_vhost_driver_callback_register(path, vhost_device_ops)``
This function registers a set of callbacks, to let DPDK applications take
@ -149,6 +143,17 @@ The following is an overview of some key Vhost API functions:
``VHOST_F_LOG_ALL`` will be set/cleared at the start/end of live
migration, respectively.
* ``rte_vhost_driver_disable/enable_features(path, features))``
This function disables/enables some features. For example, it can be used to
disable mergeable buffers and TSO features, which both are enabled by
default.
* ``rte_vhost_driver_start(path)``
This function triggers the vhost-user negotiation. It should be invoked at
the end of initializing a vhost-user driver.
* ``rte_vhost_enqueue_burst(vid, queue_id, pkts, count)``
Transmits (enqueues) ``count`` packets from host to guest.
@ -157,13 +162,6 @@ The following is an overview of some key Vhost API functions:
Receives (dequeues) ``count`` packets from guest, and stored them at ``pkts``.
* ``rte_vhost_driver_disable/enable_features(path, features))``
This function disables/enables some features. For example, it can be used to
disable mergeable buffers and TSO features, which both are enabled by
default.
Vhost-user Implementations
--------------------------

4
doc/guides/rel_notes/release_17_05.rst
View File

@ -315,6 +315,10 @@ API Changes
* The vhost struct ``virtio_net_device_ops`` is renamed to
``vhost_device_ops``
* The vhost API ``rte_vhost_driver_session_start`` is removed. Instead,
``rte_vhost_driver_start`` should be used, and no need to create a
thread to call it.
ABI Changes
-----------

50
drivers/net/vhost/rte_eth_vhost.c
View File

@ -128,9 +128,6 @@ static struct internal_list_head internal_list =
static pthread_mutex_t internal_list_lock = PTHREAD_MUTEX_INITIALIZER;
static rte_atomic16_t nb_started_ports;
static pthread_t session_th;
static struct rte_eth_link pmd_link = {
.link_speed = 10000,
.link_duplex = ETH_LINK_FULL_DUPLEX,
@ -769,42 +766,6 @@ rte_eth_vhost_get_vid_from_port_id(uint8_t port_id)
return vid;
}
static void *
vhost_driver_session(void *param __rte_unused)
{
/* start event handling */
rte_vhost_driver_session_start();
return NULL;
}
static int
vhost_driver_session_start(void)
{
int ret;
ret = pthread_create(&session_th,
NULL, vhost_driver_session, NULL);
if (ret)
RTE_LOG(ERR, PMD, "Can't create a thread\n");
return ret;
}
static void
vhost_driver_session_stop(void)
{
int ret;
ret = pthread_cancel(session_th);
if (ret)
RTE_LOG(ERR, PMD, "Can't cancel the thread\n");
ret = pthread_join(session_th, NULL);
if (ret)
RTE_LOG(ERR, PMD, "Can't join the thread\n");
}
static int
eth_dev_start(struct rte_eth_dev *dev)
{
@ -1120,10 +1081,10 @@ eth_dev_vhost_create(const char *name, char *iface_name, int16_t queues,
goto error;
}
/* We need only one message handling thread */
if (rte_atomic16_add_return(&nb_started_ports, 1) == 1) {
if (vhost_driver_session_start())
goto error;
if (rte_vhost_driver_start(iface_name) < 0) {
RTE_LOG(ERR, PMD, "Failed to start driver for %s\n",
iface_name);
goto error;
}
return data->port_id;
@ -1250,9 +1211,6 @@ rte_pmd_vhost_remove(const char *name)
eth_dev_close(eth_dev);
if (rte_atomic16_sub_return(&nb_started_ports, 1) == 0)
vhost_driver_session_stop();
rte_free(vring_states[eth_dev->data->port_id]);
vring_states[eth_dev->data->port_id] = NULL;

8
examples/tep_termination/main.c
View File

@ -1263,7 +1263,13 @@ main(int argc, char *argv[])
"failed to register vhost driver callbacks.\n");
}
rte_vhost_driver_session_start();
if (rte_vhost_driver_start(dev_basename) < 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;
}

9
examples/vhost/main.c
View File

@ -1545,9 +1545,16 @@ main(int argc, char *argv[])
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_vhost_driver_session_start();
RTE_LCORE_FOREACH_SLAVE(lcore_id)
rte_eal_wait_lcore(lcore_id);
return 0;
}

9
lib/librte_vhost/fd_man.c
View File

@ -210,8 +210,8 @@ fdset_del(struct fdset *pfdset, int fd)
* will wait until the flag is reset to zero(which indicates the callback is
* finished), then it could free the context after fdset_del.
*/
void
fdset_event_dispatch(struct fdset *pfdset)
void *
fdset_event_dispatch(void *arg)
{
int i;
struct pollfd *pfd;
@ -221,9 +221,10 @@ fdset_event_dispatch(struct fdset *pfdset)
int fd, numfds;
int remove1, remove2;
int need_shrink;
struct fdset *pfdset = arg;
if (pfdset == NULL)
return;
return NULL;
while (1) {
@ -294,4 +295,6 @@ fdset_event_dispatch(struct fdset *pfdset)
if (need_shrink)
fdset_shrink(pfdset);
}
return NULL;
}

2
lib/librte_vhost/fd_man.h
View File

@ -64,6 +64,6 @@ int fdset_add(struct fdset *pfdset, int fd,
void *fdset_del(struct fdset *pfdset, int fd);
void fdset_event_dispatch(struct fdset *pfdset);
void *fdset_event_dispatch(void *arg);
#endif

2
lib/librte_vhost/rte_vhost_version.map
View File

@ -4,7 +4,6 @@ DPDK_2.0 {
rte_vhost_dequeue_burst;
rte_vhost_driver_callback_register;
rte_vhost_driver_register;
rte_vhost_driver_session_start;
rte_vhost_enable_guest_notification;
rte_vhost_enqueue_burst;
@ -35,6 +34,7 @@ DPDK_17.05 {
rte_vhost_driver_enable_features;
rte_vhost_driver_get_features;
rte_vhost_driver_set_features;
rte_vhost_driver_start;
rte_vhost_get_mem_table;
rte_vhost_get_mtu;
rte_vhost_get_negotiated_features;

15
lib/librte_vhost/rte_virtio_net.h
View File

@ -256,8 +256,19 @@ int rte_vhost_get_negotiated_features(int vid, uint64_t *features);
/* Register callbacks. */
int rte_vhost_driver_callback_register(const char *path,
struct vhost_device_ops const * const ops);
/* Start vhost driver session blocking loop. */
int rte_vhost_driver_session_start(void);
/**
*
* Start the vhost-user driver.
*
* This function triggers the vhost-user negotiation.
*
* @param path
* The vhost-user socket file path
* @return
* 0 on success, -1 on failure
*/
int rte_vhost_driver_start(const char *path);
/**
* Get the MTU value of the device if set in QEMU.

84
lib/librte_vhost/socket.c
View File

@ -63,7 +63,8 @@ struct vhost_user_socket {
struct vhost_user_connection_list conn_list;
pthread_mutex_t conn_mutex;
char *path;
int listenfd;
int socket_fd;
struct sockaddr_un un;
bool is_server;
bool reconnect;
bool dequeue_zero_copy;
@ -101,7 +102,8 @@ struct vhost_user {
static void vhost_user_server_new_connection(int fd, void *data, int *remove);
static void vhost_user_read_cb(int fd, void *dat, int *remove);
static int vhost_user_create_client(struct vhost_user_socket *vsocket);
static int create_unix_socket(struct vhost_user_socket *vsocket);
static int vhost_user_start_client(struct vhost_user_socket *vsocket);
static struct vhost_user vhost_user = {
.fdset = {
@ -280,23 +282,26 @@ vhost_user_read_cb(int connfd, void *dat, int *remove)
free(conn);
if (vsocket->reconnect)
vhost_user_create_client(vsocket);
if (vsocket->reconnect) {
create_unix_socket(vsocket);
vhost_user_start_client(vsocket);
}
}
}
static int
create_unix_socket(const char *path, struct sockaddr_un *un, bool is_server)
create_unix_socket(struct vhost_user_socket *vsocket)
{
int fd;
struct sockaddr_un *un = &vsocket->un;
fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd < 0)
return -1;
RTE_LOG(INFO, VHOST_CONFIG, "vhost-user %s: socket created, fd: %d\n",
is_server ? "server" : "client", fd);
vsocket->is_server ? "server" : "client", fd);
if (!is_server && fcntl(fd, F_SETFL, O_NONBLOCK)) {
if (!vsocket->is_server && fcntl(fd, F_SETFL, O_NONBLOCK)) {
RTE_LOG(ERR, VHOST_CONFIG,
"vhost-user: can't set nonblocking mode for socket, fd: "
"%d (%s)\n", fd, strerror(errno));
@ -306,25 +311,21 @@ create_unix_socket(const char *path, struct sockaddr_un *un, bool is_server)
memset(un, 0, sizeof(*un));
un->sun_family = AF_UNIX;
strncpy(un->sun_path, path, sizeof(un->sun_path));
strncpy(un->sun_path, vsocket->path, sizeof(un->sun_path));
un->sun_path[sizeof(un->sun_path) - 1] = '\0';
return fd;
vsocket->socket_fd = fd;
return 0;
}
static int
vhost_user_create_server(struct vhost_user_socket *vsocket)
vhost_user_start_server(struct vhost_user_socket *vsocket)
{
int fd;
int ret;
struct sockaddr_un un;
int fd = vsocket->socket_fd;
const char *path = vsocket->path;
fd = create_unix_socket(path, &un, vsocket->is_server);
if (fd < 0)
return -1;
ret = bind(fd, (struct sockaddr *)&un, sizeof(un));
ret = bind(fd, (struct sockaddr *)&vsocket->un, sizeof(vsocket->un));
if (ret < 0) {
RTE_LOG(ERR, VHOST_CONFIG,
"failed to bind to %s: %s; remove it and try again\n",
@ -337,7 +338,6 @@ vhost_user_create_server(struct vhost_user_socket *vsocket)
if (ret < 0)
goto err;
vsocket->listenfd = fd;
ret = fdset_add(&vhost_user.fdset, fd, vhost_user_server_new_connection,
NULL, vsocket);
if (ret < 0) {
@ -456,20 +456,15 @@ vhost_user_reconnect_init(void)
}
static int
vhost_user_create_client(struct vhost_user_socket *vsocket)
vhost_user_start_client(struct vhost_user_socket *vsocket)
{
int fd;
int ret;
struct sockaddr_un un;
int fd = vsocket->socket_fd;
const char *path = vsocket->path;
struct vhost_user_reconnect *reconn;
fd = create_unix_socket(path, &un, vsocket->is_server);
if (fd < 0)
return -1;
ret = vhost_user_connect_nonblock(fd, (struct sockaddr *)&un,
sizeof(un));
ret = vhost_user_connect_nonblock(fd, (struct sockaddr *)&vsocket->un,
sizeof(vsocket->un));
if (ret == 0) {
vhost_user_add_connection(fd, vsocket);
return 0;
@ -492,7 +487,7 @@ vhost_user_create_client(struct vhost_user_socket *vsocket)
close(fd);
return -1;
}
reconn->un = un;
reconn->un = vsocket->un;
reconn->fd = fd;
reconn->vsocket = vsocket;
pthread_mutex_lock(&reconn_list.mutex);
@ -645,11 +640,10 @@ rte_vhost_driver_register(const char *path, uint64_t flags)
goto out;
}
}
ret = vhost_user_create_client(vsocket);
} else {
vsocket->is_server = true;
ret = vhost_user_create_server(vsocket);
}
ret = create_unix_socket(vsocket);
if (ret < 0) {
free(vsocket->path);
free(vsocket);
@ -705,8 +699,8 @@ rte_vhost_driver_unregister(const char *path)
if (!strcmp(vsocket->path, path)) {
if (vsocket->is_server) {
fdset_del(&vhost_user.fdset, vsocket->listenfd);
close(vsocket->listenfd);
fdset_del(&vhost_user.fdset, vsocket->socket_fd);
close(vsocket->socket_fd);
unlink(path);
} else if (vsocket->reconnect) {
vhost_user_remove_reconnect(vsocket);
@ -776,8 +770,28 @@ vhost_driver_callback_get(const char *path)
}
int
rte_vhost_driver_session_start(void)
rte_vhost_driver_start(const char *path)
{
fdset_event_dispatch(&vhost_user.fdset);
return 0;
struct vhost_user_socket *vsocket;
static pthread_t fdset_tid;
pthread_mutex_lock(&vhost_user.mutex);
vsocket = find_vhost_user_socket(path);
pthread_mutex_unlock(&vhost_user.mutex);
if (!vsocket)
return -1;
if (fdset_tid == 0) {
int ret = pthread_create(&fdset_tid, NULL, fdset_event_dispatch,
&vhost_user.fdset);
if (ret < 0)
RTE_LOG(ERR, VHOST_CONFIG,
"failed to create fdset handling thread");
}
if (vsocket->is_server)
return vhost_user_start_server(vsocket);
else
return vhost_user_start_client(vsocket);
}