[RFC v2 0/5] virtio/vsock: introduce SOCK_DGRAM support

Jiang Wang
2021-09-14T05:55:22Z

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.mail-archive.com/virtualization@lists.linux-foundation.org/msg47457.html

For those who prefer git repo, here is the link for the linux kernel：
https://github.com/Jiang1155/linux/tree/vsock-dgram-v2

qemu patch link:
https://lists.gnu.org/archive/html/qemu-devel/2021-09/msg03462.html

To do:
1. use skb when receiving packets
2. support multiple transport
3. support mergeable rx buffer
4. support disabling F_STREAM feature bit

v1 -> v2 :
- fix migration bug in vhost-vsock
- rename some variables
- clean up some code in virtio-vsock
- use le_to_cpu16 in virtio-vsock

Jiang Wang (5):
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
virtio/vsock: add sysfs for rx buf len for dgram

drivers/vhost/vsock.c | 220 +++++++--
include/linux/virtio_vsock.h | 9 +
include/net/af_vsock.h | 1 +
.../events/vsock_virtio_transport_common.h | 2 +
include/uapi/linux/virtio_vsock.h | 3 +
net/vmw_vsock/af_vsock.c | 12 +
net/vmw_vsock/virtio_transport.c | 463 +++++++++++++++---
net/vmw_vsock/virtio_transport_common.c | 181 ++++++-
tools/testing/vsock/util.c | 105 ++++
tools/testing/vsock/util.h | 4 +
tools/testing/vsock/vsock_test.c | 195 ++++++++
11 files changed, 1083 insertions(+), 112 deletions(-)

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2.20.1