1.. SPDX-License-Identifier: BSD-3-Clause 2 Copyright(c) 2010-2014 Intel Corporation. 3 4Poll Mode Driver for Paravirtual VMXNET3 NIC 5============================================ 6 7The VMXNET3 adapter is the next generation of a paravirtualized NIC, introduced by VMware* ESXi. 8It is designed for performance, offers all the features available in VMXNET2, and adds several new features such as, 9multi-queue support (also known as Receive Side Scaling, RSS), 10IPv6 offloads, and MSI/MSI-X interrupt delivery. 11One can use the same device in a DPDK application with VMXNET3 PMD introduced in DPDK API. 12 13In this chapter, two setups with the use of the VMXNET3 PMD are demonstrated: 14 15#. Vmxnet3 with a native NIC connected to a vSwitch 16 17#. Vmxnet3 chaining VMs connected to a vSwitch 18 19VMXNET3 Implementation in the DPDK 20---------------------------------- 21 22For details on the VMXNET3 device, refer to the VMXNET3 driver's vmxnet3 directory and support manual from VMware*. 23 24For performance details, refer to the following link from VMware: 25 26`http://www.vmware.com/pdf/vsp_4_vmxnet3_perf.pdf <http://www.vmware.com/pdf/vsp_4_vmxnet3_perf.pdf>`_ 27 28As a PMD, the VMXNET3 driver provides the packet reception and transmission callbacks, vmxnet3_recv_pkts and vmxnet3_xmit_pkts. 29 30The VMXNET3 PMD handles all the packet buffer memory allocation and resides in guest address space 31and it is solely responsible to free that memory when not needed. 32The packet buffers and features to be supported are made available to hypervisor via VMXNET3 PCI configuration space BARs. 33During RX/TX, the packet buffers are exchanged by their GPAs, 34and the hypervisor loads the buffers with packets in the RX case and sends packets to vSwitch in the TX case. 35 36The VMXNET3 PMD is compiled with vmxnet3 device headers. 37The interface is similar to that of the other PMDs available in the DPDK API. 38The driver pre-allocates the packet buffers and loads the command ring descriptors in advance. 39The hypervisor fills those packet buffers on packet arrival and write completion ring descriptors, 40which are eventually pulled by the PMD. 41After reception, the DPDK application frees the descriptors and loads new packet buffers for the coming packets. 42The interrupts are disabled and there is no notification required. 43This keeps performance up on the RX side, even though the device provides a notification feature. 44 45In the transmit routine, the DPDK application fills packet buffer pointers in the descriptors of the command ring 46and notifies the hypervisor. 47In response the hypervisor takes packets and passes them to the vSwitch, It writes into the completion descriptors ring. 48The rings are read by the PMD in the next transmit routine call and the buffers and descriptors are freed from memory. 49 50Features and Limitations of VMXNET3 PMD 51--------------------------------------- 52 53In release 1.6.0, the VMXNET3 PMD provides the basic functionality of packet reception and transmission. 54There are several options available for filtering packets at VMXNET3 device level including: 55 56#. MAC Address based filtering: 57 58 * Unicast, Broadcast, All Multicast modes - SUPPORTED BY DEFAULT 59 60 * Multicast with Multicast Filter table - NOT SUPPORTED 61 62 * Promiscuous mode - SUPPORTED 63 64 * RSS based load balancing between queues - SUPPORTED 65 66#. VLAN filtering: 67 68 * VLAN tag based filtering without load balancing - SUPPORTED 69 70.. note:: 71 72 73 * Release 1.6.0 does not support separate headers and body receive cmd_ring and hence, 74 multiple segment buffers are not supported. 75 Only cmd_ring_0 is used for packet buffers, one for each descriptor. 76 77 * Receive and transmit of scattered packets is not supported. 78 79 * Multicast with Multicast Filter table is not supported. 80 81Prerequisites 82------------- 83 84The following prerequisites apply: 85 86* Before starting a VM, a VMXNET3 interface to a VM through VMware vSphere Client must be assigned. 87 This is shown in the figure below. 88 89.. _figure_vmxnet3_int: 90 91.. figure:: img/vmxnet3_int.* 92 93 Assigning a VMXNET3 interface to a VM using VMware vSphere Client 94 95.. note:: 96 97 Depending on the Virtual Machine type, the VMware vSphere Client shows Ethernet adaptors while adding an Ethernet device. 98 Ensure that the VM type used offers a VMXNET3 device. Refer to the VMware documentation for a listed of VMs. 99 100.. note:: 101 102 Follow the *DPDK Getting Started Guide* to setup the basic DPDK environment. 103 104.. note:: 105 106 Follow the *DPDK Sample Application's User Guide*, L2 Forwarding/L3 Forwarding and 107 TestPMD for instructions on how to run a DPDK application using an assigned VMXNET3 device. 108 109VMXNET3 with a Native NIC Connected to a vSwitch 110------------------------------------------------ 111 112This section describes an example setup for Phy-vSwitch-VM-Phy communication. 113 114.. _figure_vswitch_vm: 115 116.. figure:: img/vswitch_vm.* 117 118 VMXNET3 with a Native NIC Connected to a vSwitch 119 120.. note:: 121 122 Other instructions on preparing to use DPDK such as, hugepage enabling, uio port binding are not listed here. 123 Please refer to *DPDK Getting Started Guide and DPDK Sample Application's User Guide* for detailed instructions. 124 125The packet reception and transmission flow path is:: 126 127 Packet generator -> 82576 128 -> VMware ESXi vSwitch 129 -> VMXNET3 device 130 -> Guest VM VMXNET3 port 0 rx burst 131 -> Guest VM 82599 VF port 0 tx burst 132 -> 82599 VF 133 -> Packet generator 134 135VMXNET3 Chaining VMs Connected to a vSwitch 136------------------------------------------- 137 138The following figure shows an example VM-to-VM communication over a Phy-VM-vSwitch-VM-Phy communication channel. 139 140.. _figure_vm_vm_comms: 141 142.. figure:: img/vm_vm_comms.* 143 144 VMXNET3 Chaining VMs Connected to a vSwitch 145 146.. note:: 147 148 When using the L2 Forwarding or L3 Forwarding applications, 149 a destination MAC address needs to be written in packets to hit the other VM's VMXNET3 interface. 150 151In this example, the packet flow path is:: 152 153 Packet generator -> 82599 VF 154 -> Guest VM 82599 port 0 rx burst 155 -> Guest VM VMXNET3 port 1 tx burst 156 -> VMXNET3 device 157 -> VMware ESXi vSwitch 158 -> VMXNET3 device 159 -> Guest VM VMXNET3 port 0 rx burst 160 -> Guest VM 82599 VF port 1 tx burst 161 -> 82599 VF 162 -> Packet generator 163