[dpdk-dev] [PATCH v2 0/7] virtio_user as an alternative exception path

[Jianfeng Tan]

v2: (Lots of them are from yuanhan's comment)
  - Add offloding feature.
  - Add multiqueue support.
  - Add a new patch to postpone the sending of driver ok notification.
  - Put fix patch ahead of the whole patch series.
  - Split original 0001 patch into 0003 and 0004 patches.
  - Remove the original vhost_internal design, just add those into
    struct virtio_user_dev for simplicity.
  - Reword "control" to "send_request".
  - Reword "host_features" to "device_features". 

In v16.07, we upstreamed a virtual device, virtio_user (with vhost-user
as the backend). The path to go with a vhost-kernel backend has been
dropped for bad performance comparing to vhost-user and code simplicity.

But after a second thought, virtio_user + vhost-kernel is a good 
candidate as an exceptional path, such as KNI, which exchanges packets
with kernel networking stack.
  - maintenance: vhost-net (kernel) is upstreamed and extensively used 
    kernel module. We don't need any out-of-tree module like KNI.
  - performance: as with KNI, this solution would use one or more
    kthreads to send/receive packets from user space DPDK applications,
    which has little impact on user space polling thread (except that
    it might enter into kernel space to wake up those kthreads if
    necessary).
  - features: vhost-net is born to be a networking solution, which has
    lots of networking related featuers, like multi queue, tso, multi-seg
    mbuf, etc.

Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>

Jianfeng Tan (7):
  net/virtio_user: fix wrongly set features
  net/virtio_user: postpone DRIVER OK notification
  net/virtio_user: move vhost user specific code
  net/virtio_user: abstract virtio user backend ops
  net/virtio_user: add vhost kernel support
  net/virtio_user: enable offloading
  net/virtio_user: enable multiqueue with vhost kernel

 drivers/net/virtio/Makefile                      |   1 +
 drivers/net/virtio/virtio_ethdev.c               |   3 +-
 drivers/net/virtio/virtio_user/vhost.h           |  51 +--
 drivers/net/virtio/virtio_user/vhost_kernel.c    | 476 +++++++++++++++++++++++
 drivers/net/virtio/virtio_user/vhost_user.c      |  86 ++--
 drivers/net/virtio/virtio_user/virtio_user_dev.c | 122 +++---
 drivers/net/virtio/virtio_user/virtio_user_dev.h |  16 +-
 drivers/net/virtio/virtio_user_ethdev.c          |   4 +-
 8 files changed, 642 insertions(+), 117 deletions(-)
 create mode 100644 drivers/net/virtio/virtio_user/vhost_kernel.c

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2.7.4