[v7,00/11] vhost: support inflight share memory protocol feature

  This patches introduces two new messages VHOST_USER_GET_INFLIGHT_FD
and VHOST_USER_SET_INFLIGHT_FD to support transferring a shared
buffer between qemu and backend.
Now It can both support split and packed ring. The example code show
how these APIs work. The test has passed.

How to test the example:
1, Qemu need two patches.
https://patchwork.kernel.org/patch/10766813/
https://patchwork.kernel.org/patch/10861411/(QEMU merged)
it also needs some manual modifications:
we should confirm that before we send get inflight we have already
sent the set features but it seems Qemu didn't do like this. So we
manually revise this, we can add below code in vhost_dev_get_inflight
    int r;

    r = vhost_dev_set_features(dev, dev->log_enabled);
    if (r < 0) {
        return -errno;
    }
before get_inflight_fd.
2, Guest OS version >= 5.0
3, run the example
4, run the qemu with vhost-user-blk-pci.
 eg:
        -chardev socket,id=spdk_vhost_blk0,reconnect=1,path=xxxx\
        -device vhost-user-blk-pci,ring_packed=on,chardev=spdk_vhost_blk0,num-queues=1\
5, run fio in the guest
6, kill the example and run again.
7, the fio in the guest should continue run without errors.

JinYu (11):
  vhost: add the inflight description
  vhost: add packed ring
  vhost: add the inflight structure
  vhost: add two new messages to support a shared buffer
  vhost: checkout and cleanup the resubmit inflight information
  vhost: add the APIs to operate inflight ring
  vhost: add APIs for user getting inflight ring
  vhost: fix vring functions to support packed ring
  vhost: add an API for judging vq format
  vhost: add APIs to rte_vhost version map
  vhost: add vhost-user-blk example which support inflight

 examples/vhost_blk/Makefile            |   67 ++
 examples/vhost_blk/blk.c               |  125 +++
 examples/vhost_blk/blk_spec.h          |   95 ++
 examples/vhost_blk/meson.build         |   20 +
 examples/vhost_blk/vhost_blk.c         | 1313 ++++++++++++++++++++++++
 examples/vhost_blk/vhost_blk.h         |  116 +++
 examples/vhost_blk/vhost_blk_compat.c  |  195 ++++
 lib/librte_vhost/rte_vhost.h           |  250 ++++-
 lib/librte_vhost/rte_vhost_version.map |    9 +
 lib/librte_vhost/vhost.c               |  416 +++++++-
 lib/librte_vhost/vhost.h               |   16 +
 lib/librte_vhost/vhost_user.c          |  467 ++++++++-
 lib/librte_vhost/vhost_user.h          |   12 +-
 13 files changed, 3088 insertions(+), 13 deletions(-)
 create mode 100644 examples/vhost_blk/Makefile
 create mode 100644 examples/vhost_blk/blk.c
 create mode 100644 examples/vhost_blk/blk_spec.h
 create mode 100644 examples/vhost_blk/meson.build
 create mode 100644 examples/vhost_blk/vhost_blk.c
 create mode 100644 examples/vhost_blk/vhost_blk.h
 create mode 100644 examples/vhost_blk/vhost_blk_compat.c