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Diffstat (limited to 'doc/guides/nics/virtio.rst')
| -rw-r--r-- | doc/guides/nics/virtio.rst | 66 |
1 files changed, 63 insertions, 3 deletions
diff --git a/doc/guides/nics/virtio.rst b/doc/guides/nics/virtio.rst index 54310157..91bedea6 100644 --- a/doc/guides/nics/virtio.rst +++ b/doc/guides/nics/virtio.rst @@ -87,6 +87,8 @@ In this release, the virtio PMD driver provides the basic functionality of packe * Virtio supports Link State interrupt. +* Virtio supports Rx interrupt (so far, only support 1:1 mapping for queue/interrupt). + * Virtio supports software vlan stripping and inserting. * Virtio supports using port IO to get PCI resource when uio/igb_uio module is not available. @@ -128,7 +130,7 @@ Host2VM communication example .. code-block:: console - examples/kni/build/app/kni -c 0xf -n 4 -- -p 0x1 -P --config="(0,1,3)" + examples/kni/build/app/kni -l 0-3 -n 4 -- -p 0x1 -P --config="(0,1,3)" This command generates one network device vEth0 for physical port. If specify more physical ports, the generated network device will be vEth1, vEth2, and so on. @@ -172,7 +174,7 @@ Host2VM communication example modprobe uio echo 512 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages modprobe uio_pci_generic - python tools/dpdk-devbind.py -b uio_pci_generic 00:03.0 + python usertools/dpdk-devbind.py -b uio_pci_generic 00:03.0 We use testpmd as the forwarding application in this example. @@ -273,4 +275,62 @@ The corresponding callbacks are: Example of using the vector version of the virtio poll mode driver in ``testpmd``:: - testpmd -c 0x7 -n 4 -- -i --txqflags=0xF01 --rxq=1 --txq=1 --nb-cores=1 + testpmd -l 0-2 -n 4 -- -i --txqflags=0xF01 --rxq=1 --txq=1 --nb-cores=1 + + +Interrupt mode +-------------- + +.. _virtio_interrupt_mode: + +There are three kinds of interrupts from a virtio device over PCI bus: config +interrupt, Rx interrupts, and Tx interrupts. Config interrupt is used for +notification of device configuration changes, especially link status (lsc). +Interrupt mode is translated into Rx interrupts in the context of DPDK. + +Prerequisites for Rx interrupts +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +To support Rx interrupts, +#. Check if guest kernel supports VFIO-NOIOMMU: + + Linux started to support VFIO-NOIOMMU since 4.8.0. Make sure the guest + kernel is compiled with: + + .. code-block:: console + + CONFIG_VFIO_NOIOMMU=y + +#. Properly set msix vectors when starting VM: + + Enable multi-queue when starting VM, and specify msix vectors in qemu + cmdline. (N+1) is the minimum, and (2N+2) is mostly recommended. + + .. code-block:: console + + $(QEMU) ... -device virtio-net-pci,mq=on,vectors=2N+2 ... + +#. In VM, insert vfio module in NOIOMMU mode: + + .. code-block:: console + + modprobe vfio enable_unsafe_noiommu_mode=1 + modprobe vfio-pci + +#. In VM, bind the virtio device with vfio-pci: + + .. code-block:: console + + python usertools/dpdk-devbind.py -b vfio-pci 00:03.0 + +Example +~~~~~~~ + +Here we use l3fwd-power as an example to show how to get started. + + Example: + + .. code-block:: console + + $ l3fwd-power -l 0-1 -- -p 1 -P --config="(0,0,1)" \ + --no-numa --parse-ptype |