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_rfc In order to attach the created VDUSE device to the vDPA bus, a recent iproute2 version containing the vdpa tool is required. Benchmark results: ================== On this v2, PVP reference benchmark has been run & compared with Vhost-user. When doing macswap forwarding in the worload, no difference is seen. When doing io forwarding in the workload, we see 4% performance degradation with VDUSE, comapred to Vhost-user/Virtio-user. It is explained by the use of the IOTLB layer in the Vhost-library when using VDUSE, whereas Vhost-user/Virtio-user does not make use of it. 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 -> a temporary patch to support reconnection via a tmpfs file is available, upstream solution would be in-kernel and is being developed. -> https://gitlab.com/mcoquelin/dpdk-next-virtio/-/commit/5ad06ce14159a9ce36ee168dd13ef389cec91137 - Support packed ring - Provide more performance benchmark results Changes in v5: ============== - Delay starting/stopping the device to after having replied to the VDUSE event in order to avoid a deadlock encountered when testing with OVS. - Mention reconnection support lack in the release note. Changes in v4: ============== - Applied patch 1 and patch 2 from v3 - Rebased on top of Eelco series - Fix coredump clear in IOTLB cache removal (David) - Remove uneeded ret variable in vhost_vring_inject_irq (David) - Fixed release note (David, Chenbo) Changes in v2/v3: ================= - Fixed mem_set_dump() parameter (patch 4) - Fixed accidental comment change (patch 7, Chenbo) - Change from __builtin_ctz to __builtin_ctzll (patch 9, Chenbo) - move change from patch 12 to 13 (Chenbo) - Enable locks annotation for control queue (Patch 17) - Send control queue notification when used descriptors enqueued (Patch 17) - Lock control queue IOTLB lock (Patch 17) - Fix error path in virtio_net_ctrl_pop() (Patch 17, Chenbo) - Set VDUSE dev FD as NONBLOCK (Patch 18) - Enable more Virtio features (Patch 18) - Remove calls to pthread_setcancelstate() (Patch 22) - Add calls to fdset_pipe_notify() when adding and deleting FDs from a set (Patch 22) - Use RTE_DIM() to get requests string array size (Patch 22) - Set reply result for IOTLB update message (Patch 25, Chenbo) - Fix queues enablement with multiqueue (Patch 26) - Move kickfd creation for better logging (Patch 26) - Improve logging (Patch 26) - Uninstall cvq kickfd in case of handler installation failure (Patch 27) - Enable CVQ notifications once handler is installed (Patch 27) - Don't advertise multiqueue and control queue if app only request single queue pair (Patch 27) - Add release notes Maxime Coquelin (26): vhost: fix IOTLB entries overlap check with previous entry vhost: add helper of IOTLB entries coredump vhost: add helper for IOTLB entries shared page check vhost: don't dump unneeded pages with IOTLB vhost: change to single IOTLB cache per device vhost: add offset field to IOTLB entries vhost: add page size info to IOTLB entry vhost: retry translating IOVA after IOTLB miss vhost: introduce backend ops vhost: add IOTLB cache entry removal callback vhost: add helper for IOTLB misses vhost: add helper for interrupt injection vhost: add API to set max queue pairs net/vhost: use API to set max queue pairs vhost: add control virtqueue support vhost: add VDUSE device creation and destruction vhost: add VDUSE callback for IOTLB miss vhost: add VDUSE callback for IOTLB entry removal vhost: add VDUSE callback for IRQ injection vhost: add VDUSE events handler vhost: add support for virtqueue state get event vhost: add support for VDUSE status set event vhost: add support for VDUSE IOTLB update event vhost: add VDUSE device startup vhost: add multiqueue support to VDUSE vhost: add VDUSE device stop doc/guides/prog_guide/vhost_lib.rst | 4 + doc/guides/rel_notes/release_23_07.rst | 12 + drivers/net/vhost/rte_eth_vhost.c | 3 + lib/vhost/iotlb.c | 333 +++++++------ lib/vhost/iotlb.h | 45 +- lib/vhost/meson.build | 5 + lib/vhost/rte_vhost.h | 17 + lib/vhost/socket.c | 72 ++- lib/vhost/vduse.c | 646 +++++++++++++++++++++++++ lib/vhost/vduse.h | 33 ++ lib/vhost/version.map | 1 + lib/vhost/vhost.c | 70 ++- lib/vhost/vhost.h | 57 ++- lib/vhost/vhost_user.c | 51 +- lib/vhost/vhost_user.h | 2 +- lib/vhost/virtio_net_ctrl.c | 286 +++++++++++ lib/vhost/virtio_net_ctrl.h | 10 + 17 files changed, 1409 insertions(+), 238 deletions(-) create mode 100644 lib/vhost/vduse.c create mode 100644 lib/vhost/vduse.h create mode 100644 lib/vhost/virtio_net_ctrl.c create mode 100644 lib/vhost/virtio_net_ctrl.h -- 2.40.1
