Hi Maxime, On Fri, Mar 31, 2023 at 11:43 PM Maxime Coquelin <maxime.coque...@redhat.com> wrote: > > This series introduces a new type of backend, VDUSE, > to the Vhost library. > > VDUSE stands for vDPA device in Userspace, it enables > implementing a Virtio device in userspace and have it > attached to the Kernel vDPA bus. > > Once attached to the vDPA bus, it can be used either by > Kernel Virtio drivers, like virtio-net in our case, via > the virtio-vdpa driver. Doing that, the device is visible > to the Kernel networking stack and is exposed to userspace > as a regular netdev. > > It can also be exposed to userspace thanks to the > vhost-vdpa driver, via a vhost-vdpa chardev that can be > passed to QEMU or Virtio-user PMD. > > While VDUSE support is already available in upstream > Kernel, a couple of patches are required to support > network device type: > > https://gitlab.com/mcoquelin/linux/-/tree/vduse_networking_poc > > In order to attach the created VDUSE device to the vDPA > bus, a recent iproute2 version containing the vdpa tool is > required. > > Usage: > ====== > > 1. Probe required Kernel modules > # modprobe vdpa > # modprobe vduse > # modprobe virtio-vdpa > > 2. Build (require vduse kernel headers to be available) > # meson build > # ninja -C build > > 3. Create a VDUSE device (vduse0) using Vhost PMD with > testpmd (with 4 queue pairs in this example) > # ./build/app/dpdk-testpmd --no-pci > --vdev=net_vhost0,iface=/dev/vduse/vduse0,queues=4 --log-level=*:9 -- -i > --txq=4 --rxq=4 > > 4. Attach the VDUSE device to the vDPA bus > # vdpa dev add name vduse0 mgmtdev vduse > => The virtio-net netdev shows up (eth0 here) > # ip l show eth0 > 21: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode > DEFAULT group default qlen 1000 > link/ether c2:73:ea:a7:68:6d brd ff:ff:ff:ff:ff:ff > > 5. Start/stop traffic in testpmd > testpmd> start > testpmd> show port stats 0 > ######################## NIC statistics for port 0 ######################## > RX-packets: 11 RX-missed: 0 RX-bytes: 1482 > RX-errors: 0 > RX-nombuf: 0 > TX-packets: 1 TX-errors: 0 TX-bytes: 62 > > Throughput (since last show) > Rx-pps: 0 Rx-bps: 0 > Tx-pps: 0 Tx-bps: 0 > ############################################################################ > testpmd> stop > > 6. Detach the VDUSE device from the vDPA bus > # vdpa dev del vduse0 > > 7. Quit testpmd > testpmd> quit > > Known issues & remaining work: > ============================== > - Fix issue in FD manager (still polling while FD has been removed) > - Add Netlink support in Vhost library > - Support device reconnection > - Support packed ring > - Enable & test more Virtio features > - Provide performance benchmark results >
Nice work! Thanks for bringing VDUSE to the network area. I wonder if you have some plan to support userspace memory registration [1]? I think this feature can benefit the performance since an extra data copy could be eliminated in our case. [1] https://lwn.net/Articles/902809/ Thanks, Yongji
