[dpdk-dev] [PATCH v8 0/8] vhost-user multiple queues enabling

[Yuanhan Liu]

This patch set enables vhost-user multiple queue feature.


v8:

   - put SET_VRING_ENABLE() patch before the patch actually
     enable mq, since that make more sense.

   - don't change the kickfd reset behavior for patch 3

   - move virt_queue field to the end of virtio_net struct.

   - comment and type fixe


v7:

   - Removed vhost-user mq examples in this patch set
   
     Because the example leverages the hardware VMDq feature to
     demonstrate the mq feature, which introduces too much 
     limitation, yet it's turned out to be not elegant.
   
   - Commit log fixes
   
   - Dropped the patch to fix RESET_OWNER handling, as I found
     Jerome's solution works as well, and it makes more sense to
     me:
   
     http://dpdk.org/dev/patchwork/project/dpdk/list/?submitter=354



Overview
========

It depends on some QEMU patches that has already been merged to upstream.
Those qemu patches introduce some new vhost-user messages, for vhost-user
mq enabling negotiation. Here is the main negotiation steps (Qemu
as master, and DPDK vhost-user as slave):

- Master queries features by VHOST_USER_GET_FEATURES from slave

- Check if VHOST_USER_F_PROTOCOL_FEATURES exist. If not, mq is not
  supported. (check patch 1 for why VHOST_USER_F_PROTOCOL_FEATURES
  is introduced)

- Master then sends another command, VHOST_USER_GET_QUEUE_NUM, for
  querying how many queues the slave supports.

  Master will compare the result with the requested queue number.
  Qemu exits if the former is smaller.

- Master then tries to initiate all queue pairs by sending some vhost
  user commands, including VHOST_USER_SET_VRING_CALL, which will
  trigger the slave to do related vring setup, such as vring allocation.


Till now, all necessary initiation and negotiation are done. And master
could send another message, VHOST_USER_SET_VRING_ENABLE, to enable/disable
a specific queue dynamically later.


Patchset
========

Patch 1-6 are all prepare works for enabling mq; they are all atomic
changes, with "do not breaking anything" beared in mind while making
them.

Patch 7 actually enables mq feature, by setting two key feature flags.


Test with OVS
=============

Marcel created a simple yet quite clear test guide with OVS at:

   http://wiki.qemu.org/Features/vhost-user-ovs-dpdk




---
Changchun Ouyang (3):
  vhost: rxtx: use queue id instead of constant ring index
  virtio: fix deadloop due to reading virtio_net_config incorrectly
  vhost: add VHOST_USER_SET_VRING_ENABLE message

Yuanhan Liu (5):
  vhost-user: add protocol features support
  vhost-user: add VHOST_USER_GET_QUEUE_NUM message
  vhost: vring queue setup for multiple queue support
  vhost-user: enable vhost-user multiple queue
  doc: update release note for vhost-user mq support

 doc/guides/rel_notes/release_2_2.rst          |   4 +
 drivers/net/virtio/virtio_ethdev.c            |  16 ++-
 lib/librte_vhost/rte_virtio_net.h             |  13 +-
 lib/librte_vhost/vhost_rxtx.c                 |  53 +++++---
 lib/librte_vhost/vhost_user/vhost-net-user.c  |  25 +++-
 lib/librte_vhost/vhost_user/vhost-net-user.h  |   4 +
 lib/librte_vhost/vhost_user/virtio-net-user.c |  86 ++++++++++---
 lib/librte_vhost/vhost_user/virtio-net-user.h |  10 ++
 lib/librte_vhost/virtio-net.c                 | 168 ++++++++++++++++----------
 9 files changed, 275 insertions(+), 104 deletions(-)

-- 
1.9.0