.\"
.\" Copyright (c) 2006,2013 Reyk Floeter <reyk@openbsd.org>
.\"
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.\" copyright notice and this permission notice appear in all copies.
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.\" $OpenBSD: src/share/man/man4/vmx.4,v 1.1 2013/05/31 20:18:44 reyk Exp $
.\"
.Dd December 26, 2020
.Dt VMX 4
.Os
.Sh NAME
.Nm vmx
.Nd VMware VMXNET3 Virtual Interface Controller device
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device iflib"
.Cd "device vmx"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_vmx_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for the VMXNET3 virtual NIC available in virtual
machines by VMware.
It appears as a simple Ethernet device but is actually a virtual network
interface to the underlying host operating system.
.Pp
This driver supports the
.Ic VMXNET3
driver protocol, as an alternative to the emulated
.Xr le 4 ,
.Xr em 4
interfaces also available in the VMware environment.
The
.Nm
driver is optimized for the virtual machine, it can provide advanced
capabilities depending on the underlying host operating system and
the physical network interface controller of the host.
The
.Nm
driver supports features like multiqueue support, IPv6
checksum offloading, MSI/MSI-X support and hardware VLAN tagging in
VMware's VLAN Guest Tagging (VGT) mode.
.Pp
The
.Nm
driver supports VMXNET3 VMware virtual NICs provided by the virtual
machine hardware version 7 or newer, as provided by the following
products:
.Pp
.Bl -bullet -compact -offset indent
.It
VMware ESX/ESXi 4.0 and newer
.It
VMware Server 2.0 and newer
.It
VMware Workstation 6.5 and newer
.It
VMware Fusion 2.0 and newer
.El
.Pp
For more information on configuring this device, see
.Xr ifconfig 8 .
.Sh MULTIPLE QUEUES
The
.Nm
driver supports multiple transmit and receive queues.
Multiple queues are only supported by certain VMware products, such as ESXi.
The number of queues allocated depends on the presence of MSI-X,
the number of configured CPUs,
and the tunables listed below.
.Fx
does not enable MSI-X support on VMware by default.
The
.Va hw.pci.honor_msi_blacklist
tunable must be disabled to enable MSI-X support.
.Sh LOADER TUNABLES
Tunables can be set at the
.Xr loader 8
prompt before booting the kernel or stored in
.Xr loader.conf 5 .
.Bl -tag -width indent
.It Va hw.vmx.txnqueue
.It Va hw.vmx. Ns Ar X Ns Va .txnqueue
Maximum number of transmit queues allocated by default by the driver.
The default value is 8.
The maximum supported by the VMXNET3 virtual NIC is 8.
.It Va hw.vmx.rxnqueue
.It Va hw.vmx. Ns Ar X Ns Va .rxnqueue
Maximum number of receive queues allocated by default by the driver.
The default value is 8.
The maximum supported by the VMXNET3 virtual NIC is 16.
.It Va hw.vmx.txndesc
.It Va hw.vmx. Ns Ar X Ns Va .txndesc
.Pp
Number of transmit descriptors allocated by the driver.
The default value is 512.
The value must be a multiple of 32, and the maximum is 4096.
.It Va hw.vmx.rxndesc
.It Va hw.vmx. Ns Ar X Ns Va .rxndesc
.Pp
Number of receive descriptors per ring allocated by the driver.
The default value is 256.
The value must be a multiple of 32, and the maximum is 2048.
There are two rings so the actual usage is doubled.
.El
.Sh EXAMPLES
The following entry must be added to the VMware configuration file
to provide the
.Nm
device:
.Bd -literal -offset indent
ethernet0.virtualDev = "vmxnet3"
.Ed
.Sh SEE ALSO
.Xr altq 4 ,
.Xr arp 4 ,
.Xr em 4 ,
.Xr iflib 4 ,
.Xr le 4 ,
.Xr netintro 4 ,
.Xr ng_ether 4 ,
.Xr vlan 4 ,
.Xr ifconfig 8
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was ported from
.Ox
and significantly rewritten by
.An Bryan Venteicher Aq Mt bryanv@freebsd.org .
The
.Ox
driver was written by
.An Tsubai Masanari .