Re: [dpdk-dev] [PATCH v5] net/virtio-user: add support for server mode

["Yang, Zhiyong" <zhiyong.yang@intel.com>]

Tiwei,

Thanks  a lot for your review and comments.

Reply inline.

> -----Original Message-----
> From: Bie, Tiwei
> Sent: Thursday, April 5, 2018 4:29 PM
> To: Yang, Zhiyong <zhiyong.yang@intel.com>
> Cc: dev@dpdk.org; maxime.coquelin@redhat.com; thomas@monjalon.net;
> Tan, Jianfeng <jianfeng.tan@intel.com>; Wang, Zhihong
> <zhihong.wang@intel.com>; Wang, Dong1 <dong1.wang@intel.com>
> Subject: Re: [PATCH v5] net/virtio-user: add support for server mode
> 
> On Thu, Apr 05, 2018 at 01:17:53AM +0800, zhiyong.yang@intel.com wrote:
> [...]
> > +static int
> > +virtio_user_start_server(struct virtio_user_dev *dev, struct
> > +sockaddr_un *un) {
> > +	int ret;
> > +	int flag;
> > +	int fd = dev->listenfd;
> > +
> > +	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;
> > +
> > +	flag = fcntl(fd, F_GETFL);
> > +	fcntl(fd, F_SETFL, flag | O_NONBLOCK);
> > +	dev->vhostfd = -1;
> > +
> > +	return 0;
> > +err:
> > +	close(dev->listenfd);
> 
> The dev->listenfd isn't created in this function, maybe it's better to avoid
> closing this file in this function.
> 

Ok.

> > +	return -1;
> > +}
> > +
> >  /**
> >   * Set up environment to talk with a vhost user backend.
> >   *
> > @@ -390,6 +418,7 @@ 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 +434,20 @@
> > 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 {
> 
> Maybe it's better to keep the style consistent. How about something like this:
> 
> 	if (dev->is_server) {
> 		if (virtio_user_start_server(fd, &un) < 0) {
> 			PMD_DRV_LOG(ERR, some messages...);
> 			close(fd);
> 			return -1;
> 		}
> 		dev->listenfd = fd;
> 		dev->vhostfd = -1;
> 	} else {
> 

Ok. it looks better.

So, the following code changes also.

> > +		if (connect(fd, (struct sockaddr *)&un, sizeof(un)) < 0) {
> > +			PMD_DRV_LOG(ERR, "connect error, %s",
> strerror(errno));
> > +			close(fd);
> > +			return -1;
> > +		}
> > +		dev->vhostfd = fd;

Keep consistency.

> >  	}
> >
> > -	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..45e324679 100644
> > --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > @@ -254,7 +254,8 @@ virtio_user_fill_intr_handle(struct virtio_user_dev
> *dev)
> >  	eth_dev->intr_handle->fd = -1;
> >  	if (dev->vhostfd >= 0)
> >  		eth_dev->intr_handle->fd = dev->vhostfd;
> > -
> 
> Maybe it's better to keep this empty line (keep it before the return 0).
>

Ok.
 
> > +	else if (dev->is_server)
> > +		eth_dev->intr_handle->fd = dev->listenfd;
> >  	return 0;
> >  }
> >
> > @@ -267,24 +268,29 @@ virtio_user_dev_setup(struct virtio_user_dev
> *dev)
> >  	dev->vhostfds = NULL;
> >  	dev->tapfds = NULL;
> >
> > -	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;
> > +			}
> >  		}
> >  	}
> > -
> 
> There is no need to remove this empty line.
> 
Ok
> >  	if (dev->ops->setup(dev) < 0)
> >  		return -1;
> >
> > @@ -337,16 +343,21 @@ virtio_user_dev_init(struct virtio_user_dev *dev,
> char *path, int queues,
> >  		return -1;
> >  	}
> >
> > -	if (dev->ops->send_request(dev, VHOST_USER_SET_OWNER, NULL)
> < 0) {
> > -		PMD_INIT_LOG(ERR, "set_owner fails: %s", strerror(errno));
> > -		return -1;
> > -	}
> > +	if (dev->vhostfd >= 0) {
> > +		if (dev->ops->send_request(dev,
> VHOST_USER_SET_OWNER, NULL) < 0) {
> > +			PMD_INIT_LOG(ERR, "set_owner fails: %s",
> strerror(errno));
> > +			return -1;
> > +		}
> >
> > -	if (dev->ops->send_request(dev, VHOST_USER_GET_FEATURES,
> > -			    &dev->device_features) < 0) {
> > -		PMD_INIT_LOG(ERR, "get_features failed: %s",
> strerror(errno));
> > -		return -1;
> > +		if (dev->ops->send_request(dev,
> VHOST_USER_GET_FEATURES,
> > +				&dev->device_features) < 0) {
> > +			PMD_INIT_LOG(ERR, "get_features failed: %s",
> strerror(errno));
> > +			return -1;
> > +		}
> > +	} else {
> > +		dev->device_features =
> VIRTIO_USER_SUPPORTED_FEATURES;
> 
> If the backend doesn't support e.g. VIRTIO_RING_F_INDIRECT_DESC.
> Will it cause any problem?
> 
Let me try it  and see what will be happening.

> >  	}
> > +
> >  	if (dev->mac_specified)
> >  		dev->device_features |= (1ull << VIRTIO_NET_F_MAC);
> >
> > @@ -388,6 +399,11 @@ 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;
> > +	}
> > +
> >  	if (dev->vhostfds) {
> >  		for (i = 0; i < dev->max_queue_pairs; ++i)
> >  			close(dev->vhostfds[i]);
> > @@ -396,6 +412,9 @@ virtio_user_dev_uninit(struct virtio_user_dev *dev)
> >  	}
> >
> >  	free(dev->ifname);
> > +
> > +	if (dev->is_server)
> > +		unlink(dev->path);
> >  }
> [...]
> >
> >  static int
> >  get_string_arg(const char *key __rte_unused, @@ -378,10 +438,12 @@
> > 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;
> 
> Maybe it's better to move the definition of vu_dev after eth_dev. And there
> isn't no need to initialize it.
> 

Ok.

thanks
Zhiyong