[RFC v1 0/6] virtio/vsock: introduce SOCK_DGRAM support

[Jiang Wang <jiang.wang@bytedance.com>]

This patchset implements support of SOCK_DGRAM for virtio
transport.

Datagram sockets are connectionless and unreliable. To avoid unfair contention
with stream and other sockets, add two more virtqueues and
a new feature bit to indicate if those two new queues exist or not.

Dgram does not use the existing credit update mechanism for
stream sockets. When sending from the guest/driver, sending packets 
synchronously, so the sender will get an error when the virtqueue is full.
When sending from the host/device, send packets asynchronously
because the descriptor memory belongs to the corresponding QEMU
process.

The virtio spec patch is here: 
https://www.spinics.net/lists/linux-virtualization/msg50027.html

For those who prefer git repo, here is the link for the linux kernel：
https://github.com/Jiang1155/linux/tree/vsock-dgram-v1

qemu patch link:
https://github.com/Jiang1155/qemu/tree/vsock-dgram-v1


To do:
1. use skb when receiving packets
2. support multiple transport
3. support mergeable rx buffer


Jiang Wang (6):
  virtio/vsock: add VIRTIO_VSOCK_F_DGRAM feature bit
  virtio/vsock: add support for virtio datagram
  vhost/vsock: add support for vhost dgram.
  vsock_test: add tests for vsock dgram
  vhost/vsock: add kconfig for vhost dgram support
  virtio/vsock: add sysfs for rx buf len for dgram

 drivers/vhost/Kconfig                              |   8 +
 drivers/vhost/vsock.c                              | 207 ++++++++--
 include/linux/virtio_vsock.h                       |   9 +
 include/net/af_vsock.h                             |   1 +
 .../trace/events/vsock_virtio_transport_common.h   |   5 +-
 include/uapi/linux/virtio_vsock.h                  |   4 +
 net/vmw_vsock/af_vsock.c                           |  12 +
 net/vmw_vsock/virtio_transport.c                   | 433 ++++++++++++++++++---
 net/vmw_vsock/virtio_transport_common.c            | 184 ++++++++-
 tools/testing/vsock/util.c                         | 105 +++++
 tools/testing/vsock/util.h                         |   4 +
 tools/testing/vsock/vsock_test.c                   | 195 ++++++++++
 12 files changed, 1070 insertions(+), 97 deletions(-)

-- 
2.11.0