6.0

Single Root I/O Virtualization (SR-IOV)
vSphere 5.1 and later releases support Single Root I/O Virtualization (SR-IOV). You can use SR-IOV for
networking of virtual machines that are latency sensitive or require more CPU resources.
Overview of SR-IOV
SR-IOV is a specification that allows a single Peripheral Component Interconnect Express (PCIe) physical
device under a single root port to appear as multiple separate physical devices to the hypervisor or the guest
operating system.
SR-IOV uses physical functions (PFs) and virtual functions (VFs) to manage global functions for the SR-IOV
devices. PFs are full PCIe functions that are capable of configuring and managing the SR-IOV functionality.
It is possible to configure or control PCIe devices using PFs, and the PF has full ability to move data in and
out of the device. VFs are lightweight PCIe functions that support data flowing but have a restricted set of
configuration resources.
The number of virtual functions provided to the hypervisor or the guest operating system depends on the
device. SR-IOV enabled PCIe devices require appropriate BIOS and hardware support, as well as SR-IOV
support in the guest operating system driver or hypervisor instance. See the vSphere Networking publication
for more information.
Using SR-IOV in vSphere
In vSphere, a virtual machine can use an SR-IOV virtual function for networking. The virtual machine and
the physical adapter exchange data directly without using the VMkernel as an intermediary. Bypassing the
VMkernel for networking reduces latency and improves CPU efficiency.
In vSphere 5.5 and later, though a virtual switch (standard switch or distributed switch) does not handle the
network traffic of an SR-IOV enabled virtual machine connected to the switch, you can control the assigned
virtual functions by using switch configuration policies at port group or port level.
Configure SR-IOV in a Host Profile
Before you can connect a virtual machine to a virtual function, you must configure the virtual functions of
the physical NIC on your host by using a host profile.
You can also enable SR-IOV virtual functions on the host by using the esxcli system module parameters
set vCLI command on the NIC driver parameter for virtual functions in accordance with the driver
documentation. For more information about using vCLI commands, see vSphere Command-Line Interface
Documentation.
Prerequisites
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Verify that the configuration of your environment supports SR-IOV. See SR-IOV Support.
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Create a host profile using the SR-IOV capable host as a reference. For more information about host
profiles, see the vSphere Host Profiles documentation.
Launch the vSphere Client and log in to a vCenter Server system.
Procedure
1 In the vSphere Client, click Home and select the Host Profiles main view.
2 Select the host profile from the list and click Edit Profile.
3 Expand Kernel Module Configuration > Kernel Module and select the kernel module for the physical
function driver.
vSphere Administration with the vSphere Client
254 VMware, Inc.