[dpdk-dev] [PATCH v4 0/1] server mode virtio-user

[zhiyong.yang at intel.com]

In a container environment if the vhost-user backend restarts, there's no way
for it to reconnect to virtio-user currently. 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.

The series add support for the feature and target for 18.05 release.

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.
 
Virtio-user supports only one connection at the same time in server/client mode.

How to test?
The following scripts are as reference.

step1:
./x86_64-native-linuxapp-gcc/app/testpmd -c 0x3e000 -n 4 --socket-mem 256,0 \
--vdev 'net_vhost0,iface=/tmp/sock0,client=1,queues=1' -- -i --rxq=1 --txq=1 \
--nb-cores=1 --no-numa

step2:
./x86_64-native-linuxapp-gcc/app/testpmd -c 0x3 -n 4 -m 256,0 --no-pci \
--file-prefix=testpmd0 --vdev=net_virtio_user0,mac=00:11:22:33:44:10, \
path=/tmp/sock0,server=1,queues=1 -- -i --rxq=1 --txq=1 --no-numa

step3: at the virtio-user side, run "start"
step4: at the vhost-user side, run "start tx_first 40000"

Then you can get the numbers by running "show port stats all" at both sides.

Vhost-user restarts (quit and startup again)and can reconnect virtio-user
successfully again and continue communications.

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 creates socket file
and startups. Keep consistency with 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.


Zhiyong Yang (1):
  net/virtio-user: add support for server mode

 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(-)

-- 
2.14.3