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diff --git a/doc/guides/sample_app_ug/vdpa.rst b/doc/guides/sample_app_ug/vdpa.rst new file mode 100644 index 00000000..745f196c --- /dev/null +++ b/doc/guides/sample_app_ug/vdpa.rst @@ -0,0 +1,120 @@ +.. SPDX-License-Identifier: BSD-3-Clause + Copyright(c) 2018 Intel Corporation. + +Vdpa Sample Application +======================= + +The vdpa sample application creates vhost-user sockets by using the +vDPA backend. vDPA stands for vhost Data Path Acceleration which utilizes +virtio ring compatible devices to serve virtio driver directly to enable +datapath acceleration. As vDPA driver can help to set up vhost datapath, +this application doesn't need to launch dedicated worker threads for vhost +enqueue/dequeue operations. + +Testing steps +------------- + +This section shows the steps of how to start VMs with vDPA vhost-user +backend and verify network connection & live migration. + +Build +~~~~~ + +To compile the sample application see :doc:`compiling`. + +The application is located in the ``vdpa`` sub-directory. + +Start the vdpa example +~~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: console + + ./vdpa [EAL options] -- [--client] [--interactive|-i] or [--iface SOCKET_PATH] + +where + +* --client means running vdpa app in client mode, in the client mode, QEMU needs + to run as the server mode and take charge of socket file creation. +* --iface specifies the path prefix of the UNIX domain socket file, e.g. + /tmp/vhost-user-, then the socket files will be named as /tmp/vhost-user-<n> + (n starts from 0). +* --interactive means run the vdpa sample in interactive mode, currently 4 + internal cmds are supported: + + 1. help: show help message + 2. list: list all available vdpa devices + 3. create: create a new vdpa port with socket file and vdpa device address + 4. quit: unregister vhost driver and exit the application + +Take IFCVF driver for example: + +.. code-block:: console + + ./vdpa -c 0x2 -n 4 --socket-mem 1024,1024 \ + -w 0000:06:00.3,vdpa=1 -w 0000:06:00.4,vdpa=1 \ + -- --interactive + +.. note:: + Here 0000:06:00.3 and 0000:06:00.4 refer to virtio ring compatible devices, + and we need to bind vfio-pci to them before running vdpa sample. + + * modprobe vfio-pci + * ./usertools/dpdk-devbind.py -b vfio-pci 06:00.3 06:00.4 + +Then we can create 2 vdpa ports in interactive cmdline. + +.. code-block:: console + + vdpa> list + device id device address queue num supported features + 0 0000:06:00.3 1 0x14c238020 + 1 0000:06:00.4 1 0x14c238020 + 2 0000:06:00.5 1 0x14c238020 + + vdpa> create /tmp/vdpa-socket0 0000:06:00.3 + vdpa> create /tmp/vdpa-socket1 0000:06:00.4 + +.. _vdpa_app_run_vm: + +Start the VMs +~~~~~~~~~~~~~ + +.. code-block:: console + + qemu-system-x86_64 -cpu host -enable-kvm \ + <snip> + -mem-prealloc \ + -chardev socket,id=char0,path=<socket_file created in above steps> \ + -netdev type=vhost-user,id=vdpa,chardev=char0 \ + -device virtio-net-pci,netdev=vdpa,mac=00:aa:bb:cc:dd:ee,page-per-vq=on \ + +After the VMs launches, we can login the VMs and configure the ip, verify the +network connection via ping or netperf. + +.. note:: + Suggest to use QEMU 3.0.0 which extends vhost-user for vDPA. + +Live Migration +~~~~~~~~~~~~~~ +vDPA supports cross-backend live migration, user can migrate SW vhost backend +VM to vDPA backend VM and vice versa. Here are the detailed steps. Assume A is +the source host with SW vhost VM and B is the destination host with vDPA. + +1. Start vdpa sample and launch a VM with exact same parameters as the VM on A, + in migration-listen mode: + +.. code-block:: console + + B: <qemu-command-line> -incoming tcp:0:4444 (or other PORT)) + +2. Start the migration (on source host): + +.. code-block:: console + + A: (qemu) migrate -d tcp:<B ip>:4444 (or other PORT) + +3. Check the status (on source host): + +.. code-block:: console + + A: (qemu) info migrate |