[dpdk-dev] [PATCH v4 1/1] net/virtio-user: add support for server mode

Tan, Jianfeng jianfeng.tan at intel.com
Tue Apr 3 17:16:26 CEST 2018



On 4/3/2018 8:20 PM, zhiyong.yang at intel.com wrote:
> virtio-user adds support for server mode in this patch.
>
> Client mode vhost-user startup firstly, server mode virtio-user startups
> and creates the socket file to exchange vhost messages.
>
> If the connection is broken, client mode vhost-user can support to
> reconnect virtio-user.
>
> Server mode virtio-user supports many times' vhost-user reconnections with
> the same parameter configurations.
>
> Release note is updated in the patch.

With current implementation, we have to enable LSC; or no chance to 
accept the coming connection. We shall point this out.

And if possible, split this patch into multiple patches.

>
> Signed-off-by: Zhiyong Yang <zhiyong.yang at intel.com>
> ---
>   doc/guides/rel_notes/release_18_05.rst           |   6 ++
>   drivers/net/virtio/virtio_user/vhost_user.c      |  64 ++++++++++++--
>   drivers/net/virtio/virtio_user/virtio_user_dev.c |  45 +++++++---
>   drivers/net/virtio/virtio_user/virtio_user_dev.h |   4 +
>   drivers/net/virtio/virtio_user_ethdev.c          | 103 +++++++++++++++++++++--
>   5 files changed, 194 insertions(+), 28 deletions(-)
>
> diff --git a/doc/guides/rel_notes/release_18_05.rst b/doc/guides/rel_notes/release_18_05.rst
> index 9cc77f893..f8897b2e9 100644
> --- a/doc/guides/rel_notes/release_18_05.rst
> +++ b/doc/guides/rel_notes/release_18_05.rst
> @@ -58,6 +58,12 @@ New Features
>     * Added support for NVGRE, VXLAN and GENEVE filters in flow API.
>     * Added support for DROP action in flow API.
>   
> +* **Added support for virtio-user server mode.**
> +  In a container environment if the vhost-user backend restarts, there's no way
> +  for it to reconnect to virtio-user. To address this, support for server mode
> +  is added. In this mode the socket file is created by virtio-user, which the
> +  backend connects to. This means that if the backend restarts, it can reconnect
> +  to virtio-user and continue communications.
>   
>   API Changes
>   -----------
> diff --git a/drivers/net/virtio/virtio_user/vhost_user.c b/drivers/net/virtio/virtio_user/vhost_user.c
> index 91c6449bb..1b3401d4f 100644
> --- a/drivers/net/virtio/virtio_user/vhost_user.c
> +++ b/drivers/net/virtio/virtio_user/vhost_user.c
> @@ -378,6 +378,50 @@ vhost_user_sock(struct virtio_user_dev *dev,
>   	return 0;
>   }
>   
> +static void
> +virtio_user_set_block(int fd, bool enabled)

This is only used once, no need to abstract it into a function?

> +{
> +	int f;
> +
> +	f = fcntl(fd, F_GETFL);
> +	if (enabled)
> +		fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
> +	else
> +		fcntl(fd, F_SETFL, f | O_NONBLOCK);
> +}
> +
> +#define MAX_VIRTIO_USER_BACKLOG 128

We only allow one connection from vhost-user, so how about just make the 
backlog queue length as 1?

> +static int
> +virtio_user_start_server(struct virtio_user_dev *dev, struct sockaddr_un *un)
> +{
> +	int ret;
> +	int fd = dev->listenfd;
> +	int connectfd;
> +
> +	ret = bind(fd, (struct sockaddr *)un, sizeof(*un));
> +	if (ret < 0) {
> +		PMD_DRV_LOG(ERR, "failed to bind to %s: %s; remove it and try again\n",
> +			    dev->path, strerror(errno));
> +		goto err;
> +	}
> +	ret = listen(fd, MAX_VIRTIO_USER_BACKLOG);
> +	if (ret < 0)
> +		goto err;
> +
> +	connectfd = accept(fd, NULL, NULL);
> +	if (connectfd >= 0)
> +		dev->connected = true;
> +	else
> +		goto err;

if (connectfd < 0)
         goto err;

dev->connected = true;
dev->vhostfd = connectfd;
...

> +
> +	dev->vhostfd = connectfd;
> +	virtio_user_set_block(connectfd, true);
> +	return 0;
> +err:
> +	close(dev->listenfd);
> +	return -1;
> +}
> +
>   /**
>    * Set up environment to talk with a vhost user backend.
>    *
> @@ -390,6 +434,7 @@ vhost_user_setup(struct virtio_user_dev *dev)
>   {
>   	int fd;
>   	int flag;
> +	int ret = 0;
>   	struct sockaddr_un un;
>   
>   	fd = socket(AF_UNIX, SOCK_STREAM, 0);
> @@ -405,14 +450,21 @@ vhost_user_setup(struct virtio_user_dev *dev)
>   	memset(&un, 0, sizeof(un));
>   	un.sun_family = AF_UNIX;
>   	snprintf(un.sun_path, sizeof(un.sun_path), "%s", dev->path);
> -	if (connect(fd, (struct sockaddr *)&un, sizeof(un)) < 0) {
> -		PMD_DRV_LOG(ERR, "connect error, %s", strerror(errno));
> -		close(fd);
> -		return -1;
> +
> +	if (dev->is_server) {
> +		dev->listenfd = fd;
> +		ret = virtio_user_start_server(dev, &un);
> +	} else {
> +		dev->vhostfd = fd;
> +		if (connect(fd, (struct sockaddr *)&un, sizeof(un)) < 0) {
> +			PMD_DRV_LOG(ERR, "connect error, %s", strerror(errno));
> +			close(fd);
> +			return -1;
> +		}
> +		dev->connected = true;
>   	}
>   
> -	dev->vhostfd = fd;
> -	return 0;
> +	return ret;
>   }
>   
>   static int
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index f90fee9e5..dd9fa9bdf 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -142,6 +142,9 @@ int virtio_user_stop_device(struct virtio_user_dev *dev)
>   {
>   	uint32_t i;
>   
> +	if (!dev->connected)
> +		return -1;
> +
>   	for (i = 0; i < dev->max_queue_pairs; ++i)
>   		dev->ops->enable_qp(dev, i, 0);
>   
> @@ -267,21 +270,27 @@ virtio_user_dev_setup(struct virtio_user_dev *dev)
>   	dev->vhostfds = NULL;
>   	dev->tapfds = NULL;

Add a check here:
if (dev->is_server && !is_vhost_user_by_type(dev->path))
         return error;

>   
> -	if (is_vhost_user_by_type(dev->path)) {
> -		dev->ops = &ops_user;
> +	if (dev->is_server) {
> +		dev->ops = &ops_user;/* server mode only supports vhost user*/
>   	} else {
> -		dev->ops = &ops_kernel;
> -
> -		dev->vhostfds = malloc(dev->max_queue_pairs * sizeof(int));
> -		dev->tapfds = malloc(dev->max_queue_pairs * sizeof(int));
> -		if (!dev->vhostfds || !dev->tapfds) {
> -			PMD_INIT_LOG(ERR, "Failed to malloc");
> -			return -1;
> -		}
> -
> -		for (q = 0; q < dev->max_queue_pairs; ++q) {
> -			dev->vhostfds[q] = -1;
> -			dev->tapfds[q] = -1;
> +		if (is_vhost_user_by_type(dev->path)) {
> +			dev->ops = &ops_user;
> +		} else {
> +			dev->ops = &ops_kernel;
> +
> +			dev->vhostfds = malloc(dev->max_queue_pairs *
> +					       sizeof(int));
> +			dev->tapfds = malloc(dev->max_queue_pairs *
> +					     sizeof(int));
> +			if (!dev->vhostfds || !dev->tapfds) {
> +				PMD_INIT_LOG(ERR, "Failed to malloc");
> +				return -1;
> +			}
> +
> +			for (q = 0; q < dev->max_queue_pairs; ++q) {
> +				dev->vhostfds[q] = -1;
> +				dev->tapfds[q] = -1;
> +			}
>   		}
>   	}
>   
> @@ -388,6 +397,11 @@ virtio_user_dev_uninit(struct virtio_user_dev *dev)
>   
>   	close(dev->vhostfd);
>   
> +	if (dev->is_server && dev->listenfd >= 0) {
> +		close(dev->listenfd);
> +		dev->listenfd = -1;
> +	}
> +	dev->connected = false;
>   	if (dev->vhostfds) {
>   		for (i = 0; i < dev->max_queue_pairs; ++i)
>   			close(dev->vhostfds[i]);
> @@ -396,6 +410,9 @@ virtio_user_dev_uninit(struct virtio_user_dev *dev)
>   	}
>   
>   	free(dev->ifname);
> +
> +	if (dev->is_server)
> +		unlink(dev->path);
>   }
>   
>   static uint8_t
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h b/drivers/net/virtio/virtio_user/virtio_user_dev.h
> index 64467b4f9..68056720d 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
> @@ -6,6 +6,7 @@
>   #define _VIRTIO_USER_DEV_H
>   
>   #include <limits.h>
> +#include <stdbool.h>
>   #include "../virtio_pci.h"
>   #include "../virtio_ring.h"
>   #include "vhost.h"
> @@ -13,6 +14,9 @@
>   struct virtio_user_dev {
>   	/* for vhost_user backend */
>   	int		vhostfd;
> +	int		listenfd;   /* listening fd */
> +	bool		connected;  /* connection status */

Seems not necessary to add this field; as the connection status can be 
deduced from (vhostfd>=0)

> +	bool		is_server;  /* server or client mode */
>   
>   	/* for vhost_kernel backend */
>   	char		*ifname;
> diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
> index 263649006..5b8c8e291 100644
> --- a/drivers/net/virtio/virtio_user_ethdev.c
> +++ b/drivers/net/virtio/virtio_user_ethdev.c
> @@ -24,15 +24,76 @@
>   #define virtio_user_get_dev(hw) \
>   	((struct virtio_user_dev *)(hw)->virtio_user_dev)
>   
> +static void
> +virtio_user_server_reconnection(struct virtio_user_dev *dev)

s/reconnection/reconnect?

> +{
> +	int ret;
> +	int flag;
> +	int connectfd;
> +	struct rte_eth_dev *eth_dev = &rte_eth_devices[dev->port_id];
> +
> +	if (dev->connected)
> +		return;
> +
> +	connectfd = accept(dev->listenfd, NULL, NULL);
> +	if (connectfd < 0)
> +		return;
> +
> +	dev->vhostfd = connectfd;
> +	flag = fcntl(connectfd, F_GETFD);
> +	fcntl(connectfd, F_SETFL, flag & ~O_NONBLOCK);
> +
> +	ret = virtio_user_start_device(dev);
> +	if (ret < 0)
> +		return;
> +
> +	if (eth_dev->data->dev_flags & RTE_ETH_DEV_INTR_LSC) {
> +		if (rte_intr_disable(eth_dev->intr_handle) < 0) {
> +			PMD_DRV_LOG(ERR, "interrupt disable failed");
> +			return;
> +		}
> +		rte_intr_callback_unregister(eth_dev->intr_handle,
> +					     virtio_interrupt_handler,
> +					     eth_dev);
> +		eth_dev->intr_handle->fd = connectfd;
> +		rte_intr_callback_register(eth_dev->intr_handle,
> +					   virtio_interrupt_handler, eth_dev);
> +
> +		if (rte_intr_enable(eth_dev->intr_handle) < 0) {
> +			PMD_DRV_LOG(ERR, "interrupt enable failed");
> +			return;
> +		}
> +	}
> +	dev->connected = true;
> +	PMD_INIT_LOG(NOTICE, "server mode virtio-user reconnection succeeds!");
> +}
> +
>   static void
>   virtio_user_delayed_handler(void *param)
>   {
>   	struct virtio_hw *hw = (struct virtio_hw *)param;
> -	struct rte_eth_dev *dev = &rte_eth_devices[hw->port_id];
> +	struct rte_eth_dev *eth_dev = &rte_eth_devices[hw->port_id];
> +	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
>   
> -	rte_intr_callback_unregister(dev->intr_handle,
> -				     virtio_interrupt_handler,
> -				     dev);
> +	if (rte_intr_disable(eth_dev->intr_handle) < 0) {
> +		PMD_DRV_LOG(ERR, "interrupt disable failed");
> +		return;
> +	}
> +	rte_intr_callback_unregister(eth_dev->intr_handle,
> +				     virtio_interrupt_handler, eth_dev);
> +	if (dev->is_server) {
> +		if (dev->vhostfd >= 0) {
> +			close(dev->vhostfd);
> +			dev->vhostfd = -1;
> +		}
> +		eth_dev->intr_handle->fd = dev->listenfd;
> +		rte_intr_callback_register(eth_dev->intr_handle,
> +					   virtio_interrupt_handler, eth_dev);
> +		if (rte_intr_enable(eth_dev->intr_handle) < 0) {
> +			PMD_DRV_LOG(ERR, "interrupt enable failed");
> +			return;
> +		}
> +	}
>   }
>   
>   static void
> @@ -65,8 +126,7 @@ virtio_user_read_dev_config(struct virtio_hw *hw, size_t offset,
>   			r = recv(dev->vhostfd, buf, 128, MSG_PEEK);

As server mode and the connection is not connected, vhostfd is -1 now, 
then r < 0 and errno is EBADF, how could it go into server handling in 
the "else if" block?

>   			if (r == 0 || (r < 0 && errno != EAGAIN)) {
>   				dev->status &= (~VIRTIO_NET_S_LINK_UP);
> -				PMD_DRV_LOG(ERR, "virtio-user port %u is down",
> -					    hw->port_id);
> +
>   				/* Only client mode is available now. Once the

Can you also correct this note as we support server mode now?

>   				 * connection is broken, it can never be up
>   				 * again. Besides, this function could be called
> @@ -74,9 +134,14 @@ virtio_user_read_dev_config(struct virtio_hw *hw, size_t offset,
>   				 * callback cannot be unregistered here, set an
>   				 * alarm to do it.
>   				 */
> -				rte_eal_alarm_set(1,
> +				if (dev->connected) {
> +					dev->connected = false;
> +					PMD_DRV_LOG(ERR, "virtio-user port %u is down",
> +						    hw->port_id);
> +					rte_eal_alarm_set(1,
>   						  virtio_user_delayed_handler,
>   						  (void *)hw);
> +				}
>   			} else {
>   				dev->status |= VIRTIO_NET_S_LINK_UP;
>   			}
> @@ -85,7 +150,10 @@ virtio_user_read_dev_config(struct virtio_hw *hw, size_t offset,
>   				PMD_DRV_LOG(ERR, "error clearing O_NONBLOCK flag");
>   				return;
>   			}
> -		}
> +
> +		} else if (dev->is_server)
> +			virtio_user_server_reconnection(dev);
> +
>   		*(uint16_t *)dst = dev->status;
>   	}
>   
> @@ -278,12 +346,15 @@ static const char *valid_args[] = {
>   	VIRTIO_USER_ARG_QUEUE_SIZE,
>   #define VIRTIO_USER_ARG_INTERFACE_NAME "iface"
>   	VIRTIO_USER_ARG_INTERFACE_NAME,
> +#define VIRTIO_USER_ARG_SERVER_MODE "server"
> +	VIRTIO_USER_ARG_SERVER_MODE,
>   	NULL
>   };
>   
>   #define VIRTIO_USER_DEF_CQ_EN	0
>   #define VIRTIO_USER_DEF_Q_NUM	1
>   #define VIRTIO_USER_DEF_Q_SZ	256
> +#define VIRTIO_USER_DEF_SERVER_MODE	0
>   
>   static int
>   get_string_arg(const char *key __rte_unused,
> @@ -378,10 +449,12 @@ virtio_user_pmd_probe(struct rte_vdev_device *dev)
>   	uint64_t queues = VIRTIO_USER_DEF_Q_NUM;
>   	uint64_t cq = VIRTIO_USER_DEF_CQ_EN;
>   	uint64_t queue_size = VIRTIO_USER_DEF_Q_SZ;
> +	uint64_t server_mode = VIRTIO_USER_DEF_SERVER_MODE;
>   	char *path = NULL;
>   	char *ifname = NULL;
>   	char *mac_addr = NULL;
>   	int ret = -1;
> +	struct virtio_user_dev *vu_dev = NULL;
>   
>   	kvlist = rte_kvargs_parse(rte_vdev_device_args(dev), valid_args);
>   	if (!kvlist) {
> @@ -445,6 +518,15 @@ virtio_user_pmd_probe(struct rte_vdev_device *dev)
>   		}
>   	}
>   
> +	if (rte_kvargs_count(kvlist, VIRTIO_USER_ARG_SERVER_MODE) == 1) {
> +		if (rte_kvargs_process(kvlist, VIRTIO_USER_ARG_SERVER_MODE,
> +				       &get_integer_arg, &server_mode) < 0) {
> +			PMD_INIT_LOG(ERR, "error to parse %s",
> +				     VIRTIO_USER_ARG_SERVER_MODE);
> +			goto end;
> +		}
> +	}
> +
>   	if (rte_kvargs_count(kvlist, VIRTIO_USER_ARG_CQ_NUM) == 1) {
>   		if (rte_kvargs_process(kvlist, VIRTIO_USER_ARG_CQ_NUM,
>   				       &get_integer_arg, &cq) < 0) {
> @@ -476,6 +558,11 @@ virtio_user_pmd_probe(struct rte_vdev_device *dev)
>   		}
>   
>   		hw = eth_dev->data->dev_private;
> +		vu_dev = virtio_user_get_dev(hw);
> +		if (server_mode == 1)
> +			vu_dev->is_server = true;
> +		else
> +			vu_dev->is_server = false;
>   		if (virtio_user_dev_init(hw->virtio_user_dev, path, queues, cq,
>   				 queue_size, mac_addr, &ifname) < 0) {
>   			PMD_INIT_LOG(ERR, "virtio_user_dev_init fails");



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