[dpdk-dev] [PATCH v6] net/virtio-user: add support for server mode
Yang, Zhiyong
zhiyong.yang at intel.com
Fri Apr 6 09:14:13 CEST 2018
Hi Jianfeng,
> -----Original Message-----
> From: Tan, Jianfeng
> Sent: Friday, April 6, 2018 2:13 AM
> To: Yang, Zhiyong <zhiyong.yang at intel.com>; dev at dpdk.org
> Cc: maxime.coquelin at redhat.com; Bie, Tiwei <tiwei.bie at intel.com>; Wang,
> Dong1 <dong1.wang at intel.com>; Wang, Zhihong <zhihong.wang at intel.com>
> Subject: Re: [PATCH v6] net/virtio-user: add support for server mode
>
>
>
> On 4/6/2018 8:18 AM, zhiyong.yang at intel.com wrote:
> > 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 then connects to. This means that if
> > the backend restarts, it can reconnect to virtio-user and continue
> communications.
> >
> > With current implementation, LSC is enabled at virtio-user side to
> > support to accept the coming connection.
> >
> > Release note is updated in this patch.
> >
> > Signed-off-by: Zhiyong Yang <zhiyong.yang at intel.com>
> > ---
> >
> > Changes in V6:
> > 1. fix report wrong link stauts in server mode.
> > 2. fix some code style issues.
> >
> > Changes in V5:
> > 1. Support server mode virtio-user startup in non-blocking mode.
> > 2. rebase on top of dpdk-next-virtio.
> >
> > Changes in V4:
> > 1. Don't create new pthread any more and use librte_eal interrupt thread.
> > 2. virtio-user doesn't work in blocking mode any more for the first
> connection.
> > Client mode vhost-user startups firstly, then server mode virtio-user
> > creates socket file and startups. Keep consistency with usage of
> > client mode virtio-user.
> >
> > Changes in V3:
> > 1. use EAL epoll mechanism instead of vhost events. Cancel to export
> > vhost event APIs.
> > 2. rebase the code on top of dpdk-next-virtio
> >
> > Changes in V2:
> > 1. split two patches 1/5 and 2/5 from v1 patchset to fix some existing
> > issues which is not strongly related to support for server mode 2.
> > move fdset related functions to librte_eal from librte_vhost exposed
> > as new APIs.
> > 3. release note is added in the patch 5/5.
> > 4. squash data structure change patch into 4/5 according to Maxime's
> suggestion.
> >
> > doc/guides/rel_notes/release_18_05.rst | 6 ++
> > drivers/net/virtio/virtio_user/vhost_user.c | 45 ++++++++--
> > drivers/net/virtio/virtio_user/virtio_user_dev.c | 40 +++++++--
> > drivers/net/virtio/virtio_user/virtio_user_dev.h | 3 +
> > drivers/net/virtio/virtio_user_ethdev.c | 101
> ++++++++++++++++++++---
> > 5 files changed, 171 insertions(+), 24 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..a6df97a00 100644
> > --- a/drivers/net/virtio/virtio_user/vhost_user.c
> > +++ b/drivers/net/virtio/virtio_user/vhost_user.c
> > @@ -378,6 +378,30 @@ vhost_user_sock(struct virtio_user_dev *dev,
> > return 0;
> > }
> >
> > +#define MAX_VIRTIO_USER_BACKLOG 1
> > +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));
> > + return -1;
> > + }
> > + ret = listen(fd, MAX_VIRTIO_USER_BACKLOG);
> > + if (ret < 0)
> > + return -1;
> > +
> > + flag = fcntl(fd, F_GETFL);
> > + fcntl(fd, F_SETFL, flag | O_NONBLOCK);
> > +
> > + return 0;
> > +}
> > +
> > /**
> > * Set up environment to talk with a vhost user backend.
> > *
> > @@ -405,13 +429,24 @@ 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;
> > + if (virtio_user_start_server(dev, &un) < 0) {
> > + PMD_DRV_LOG(ERR, "virtio-user startup fails in
> server mode");
> > + close(fd);
> > + return -1;
> > + }
> > + dev->vhostfd = -1;
> > + } else {
> > + 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;
> > }
> >
> > - dev->vhostfd = fd;
> > return 0;
> > }
> >
> > diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > index f90fee9e5..3b776282c 100644
> > --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> > @@ -99,6 +99,9 @@ virtio_user_start_device(struct virtio_user_dev *dev)
> > uint64_t features;
> > int ret;
> >
> > + if (dev->vhostfd < 0)
> > + return -1;
>
> This breaks virtio-user with vhost-kernel which does not need vhostfd, and
> will be always -1.
>
Ok, I will modify the code as followings
if (is_vhost_user_by_type(dev->path) && dev->vhostfd < 0)
return -1;
(is_vhost_user_by_type(dev->path))
> > +
> > /* Do not check return as already done in init, or reset in stop */
> > dev->ops->send_request(dev, VHOST_USER_SET_OWNER, NULL);
> >
> > @@ -254,6 +257,8 @@ 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;
> > + else if (dev->is_server)
> > + eth_dev->intr_handle->fd = dev->listenfd;
> >
> > return 0;
> > }
> > @@ -267,7 +272,7 @@ virtio_user_dev_setup(struct virtio_user_dev *dev)
> > dev->vhostfds = NULL;
> > dev->tapfds = NULL;
> >
> > - if (is_vhost_user_by_type(dev->path)) {
> > + if (dev->is_server || is_vhost_user_by_type(dev->path)) {
>
> I think we still fail to pick out an invalidated case: specify "server"
> parameter for a vhost-kernel path.
I will add the checking at the starting of the function.
If (dev->is_server && access(dev->path) == 0)
Return -1;
How about the change ?
>
> > dev->ops = &ops_user;
> > } else {
> > dev->ops = &ops_kernel;
> > @@ -337,16 +342,25 @@ 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 {
> > + /* Just pretend vhost-user can support all these features */
>
> Although I don't think we need to fix this, please also note that this could be
> problematic that if some feature is negotiated but not supported by the
> vhost-user which comes later.
>
Good description. I will add it in next version.
Thanks for your those comments
Zhiyong
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