b7fe612ac1
Fix typos in the names of kernel drivers based on UIO, and make sure the generic term for the interface is UIO in capitals. Fixes:3a78b2f732("doc: add virtio crypto PMD guide") Fixes:3cc4d996fa("doc: update VFIO usage in qat crypto guide") Fixes:39922c470e("doc: add known uio_pci_generic issue for i40e") Fixes:86fa6c57a1("doc: add known igb_uio issue for i40e") Fixes:beff6d8e8e("net/netvsc: add documentation") Cc: stable@dpdk.org Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
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6.4 KiB
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164 lines
6.4 KiB
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.. SPDX-License-Identifier: BSD-3-Clause
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Copyright(c) 2010-2014 Intel Corporation.
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Poll Mode Driver for Paravirtual VMXNET3 NIC
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============================================
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The VMXNET3 adapter is the next generation of a paravirtualized NIC, introduced by VMware* ESXi.
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It is designed for performance, offers all the features available in VMXNET2, and adds several new features such as,
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multi-queue support (also known as Receive Side Scaling, RSS),
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IPv6 offloads, and MSI/MSI-X interrupt delivery.
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One can use the same device in a DPDK application with VMXNET3 PMD introduced in DPDK API.
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In this chapter, two setups with the use of the VMXNET3 PMD are demonstrated:
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#. Vmxnet3 with a native NIC connected to a vSwitch
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#. Vmxnet3 chaining VMs connected to a vSwitch
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VMXNET3 Implementation in the DPDK
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----------------------------------
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For details on the VMXNET3 device, refer to the VMXNET3 driver's vmxnet3 directory and support manual from VMware*.
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For performance details, refer to the following link from VMware:
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`http://www.vmware.com/pdf/vsp_4_vmxnet3_perf.pdf <http://www.vmware.com/pdf/vsp_4_vmxnet3_perf.pdf>`_
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As a PMD, the VMXNET3 driver provides the packet reception and transmission callbacks, vmxnet3_recv_pkts and vmxnet3_xmit_pkts.
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The VMXNET3 PMD handles all the packet buffer memory allocation and resides in guest address space
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and it is solely responsible to free that memory when not needed.
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The packet buffers and features to be supported are made available to hypervisor via VMXNET3 PCI configuration space BARs.
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During RX/TX, the packet buffers are exchanged by their GPAs,
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and the hypervisor loads the buffers with packets in the RX case and sends packets to vSwitch in the TX case.
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The VMXNET3 PMD is compiled with vmxnet3 device headers.
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The interface is similar to that of the other PMDs available in the DPDK API.
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The driver pre-allocates the packet buffers and loads the command ring descriptors in advance.
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The hypervisor fills those packet buffers on packet arrival and write completion ring descriptors,
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which are eventually pulled by the PMD.
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After reception, the DPDK application frees the descriptors and loads new packet buffers for the coming packets.
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The interrupts are disabled and there is no notification required.
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This keeps performance up on the RX side, even though the device provides a notification feature.
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In the transmit routine, the DPDK application fills packet buffer pointers in the descriptors of the command ring
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and notifies the hypervisor.
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In response the hypervisor takes packets and passes them to the vSwitch, It writes into the completion descriptors ring.
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The rings are read by the PMD in the next transmit routine call and the buffers and descriptors are freed from memory.
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Features and Limitations of VMXNET3 PMD
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---------------------------------------
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In release 1.6.0, the VMXNET3 PMD provides the basic functionality of packet reception and transmission.
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There are several options available for filtering packets at VMXNET3 device level including:
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#. MAC Address based filtering:
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* Unicast, Broadcast, All Multicast modes - SUPPORTED BY DEFAULT
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* Multicast with Multicast Filter table - NOT SUPPORTED
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* Promiscuous mode - SUPPORTED
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* RSS based load balancing between queues - SUPPORTED
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#. VLAN filtering:
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* VLAN tag based filtering without load balancing - SUPPORTED
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.. note::
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* Release 1.6.0 does not support separate headers and body receive cmd_ring and hence,
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multiple segment buffers are not supported.
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Only cmd_ring_0 is used for packet buffers, one for each descriptor.
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* Receive and transmit of scattered packets is not supported.
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* Multicast with Multicast Filter table is not supported.
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Prerequisites
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-------------
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The following prerequisites apply:
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* Before starting a VM, a VMXNET3 interface to a VM through VMware vSphere Client must be assigned.
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This is shown in the figure below.
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.. _figure_vmxnet3_int:
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.. figure:: img/vmxnet3_int.*
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Assigning a VMXNET3 interface to a VM using VMware vSphere Client
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.. note::
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Depending on the Virtual Machine type, the VMware vSphere Client shows Ethernet adaptors while adding an Ethernet device.
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Ensure that the VM type used offers a VMXNET3 device. Refer to the VMware documentation for a listed of VMs.
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.. note::
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Follow the *DPDK Getting Started Guide* to setup the basic DPDK environment.
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.. note::
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Follow the *DPDK Sample Application's User Guide*, L2 Forwarding/L3 Forwarding and
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TestPMD for instructions on how to run a DPDK application using an assigned VMXNET3 device.
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VMXNET3 with a Native NIC Connected to a vSwitch
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------------------------------------------------
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This section describes an example setup for Phy-vSwitch-VM-Phy communication.
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.. _figure_vswitch_vm:
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.. figure:: img/vswitch_vm.*
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VMXNET3 with a Native NIC Connected to a vSwitch
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.. note::
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Other instructions on preparing to use DPDK such as,
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hugepage enabling, UIO port binding are not listed here.
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Please refer to *DPDK Getting Started Guide and DPDK Sample Application's User Guide* for detailed instructions.
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The packet reception and transmission flow path is::
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Packet generator -> 82576
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-> VMware ESXi vSwitch
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-> VMXNET3 device
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-> Guest VM VMXNET3 port 0 rx burst
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-> Guest VM 82599 VF port 0 tx burst
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-> 82599 VF
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-> Packet generator
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VMXNET3 Chaining VMs Connected to a vSwitch
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-------------------------------------------
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The following figure shows an example VM-to-VM communication over a Phy-VM-vSwitch-VM-Phy communication channel.
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.. _figure_vm_vm_comms:
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.. figure:: img/vm_vm_comms.*
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VMXNET3 Chaining VMs Connected to a vSwitch
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.. note::
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When using the L2 Forwarding or L3 Forwarding applications,
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a destination MAC address needs to be written in packets to hit the other VM's VMXNET3 interface.
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In this example, the packet flow path is::
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Packet generator -> 82599 VF
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-> Guest VM 82599 port 0 rx burst
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-> Guest VM VMXNET3 port 1 tx burst
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-> VMXNET3 device
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-> VMware ESXi vSwitch
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-> VMXNET3 device
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-> Guest VM VMXNET3 port 0 rx burst
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-> Guest VM 82599 VF port 1 tx burst
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-> 82599 VF
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-> Packet generator
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