[Qemu-devel] [PATCH 0/6] vhost-user: Specify and implement device IOTLB support

[Maxime Coquelin <maxime.coquelin@redhat.com>]

This series aims at specifying ans implementing the protocol update
required to support device IOTLB with user backends.

In this first non-RFC version, IOTLB messages forging and parsing have been
extracted from the backend implementation; so that both user and kernel
backends share as most code as possible, only the transport remains backend
specifics. Also various smaller fixes have been implementated, taking into
account Peter's review comments. I tagged this third version as non-RFC,
since there is now a DPDK vhost-user backend prototype supporting IOMMU[0],
making possible testing of this series.

The slave requests channel part is re-used from Marc-André's series submitted
last year[1], with main changes from original version being request/feature
names renaming and addition of the REPLY_ACK feature support.

Regarding IOTLB protocol, one noticeable change is the IOTLB miss request
reply made optionnal (i.e. only if slave requests it by setting the
VHOST_USER_NEED_REPLY flag in the message header). This change provides
more flexibility in the backend implementation of the feature.

The protocol is very close to kernel backends, except that a new
communication channel is introduced to enable the slave to send
requests to the master.

[0]: https://gitlab.com/mcoquelin/dpdk-next-virtio/commits/vhost_iotlb_proto
[1]: https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg00095.html

Marc-André Lureau (2):
  vhost-user: add vhost_user to hold the chr
  vhost-user: add slave-req-fd support

Maxime Coquelin (4):
  vhost: propagate errors in vhost_device_iotlb_miss()
  vhost: rework IOTLB messaging
  vhost: Update rings information for IOTLB earlier
  spec/vhost-user spec: Add IOMMU support

 docs/specs/vhost-user.txt         | 107 ++++++++++++++++++++++-
 hw/virtio/vhost-backend.c         | 135 ++++++++++++++++-------------
 hw/virtio/vhost-user.c            | 177 +++++++++++++++++++++++++++++++++++++-
 hw/virtio/vhost.c                 |  38 ++++----
 include/hw/virtio/vhost-backend.h |  23 +++--
 include/hw/virtio/vhost.h         |   2 +-
 6 files changed, 393 insertions(+), 89 deletions(-)

-- 
2.9.3