Implementing SR-IOV for Red Hat Enterprise Linux on HP ProLiant Servers

Technical white paper | Implementing SR-IOV for Red Hat Enterprise Linux on HP ProLiant Servers

Abstract

Single Root I/O Virtualization is defined by the PCI SIG to address the growing

need for I/O devices. In many instances, virtual machines share I/O devices.

However, the increasing number of virtual machines supported on platforms

demands new ways of improving performance and utilization of limited I/O

resources. This white paper describes the I/O virtualization technology

developed by HP to meet these needs and more.

SR-IOV overview

SR-IOV is an I/O virtualization technology that is defined in the PCI Sig SR-IOV Specification. On platforms that support SR-

IOV, each physical interface can be split into multiple virtual interfaces. Each of these virtual interfaces can then be assigned

to different virtual machines (guest OS instances). A guest OS can directly send and receive data (dma) to and from the

virtual function to which it is assigned. Once the virtual functions are configured on the Host OS, it can run without any

intervention from the Host OS and/or the virtualization layer. With these virtual functions, SR-IOV allows for better

utilization of limited I/O resources and their bandwidth on a platform. Additionally, when using this feature, I/O interfaces

can be isolated and assigned to individual guest OS instances. This allows exclusive and isolated access to the guest OS that

is not shared by other guest instances on the system.

To support SR-IOV, a platform requires several components working together to provide the full benefit of the technology.

These components are:

• SR-IOV capable platform hardware

• System BIOS

• I/O (PCI) devices and I/O device firmware

• Operating System

• OS virtualization module

• I/O device drivers for the Host OS and the Guest OS

The following figure shows an example of SR-IOV configuration with virtual function 1 (vf1) which is directly assigned to

Virtual machine 1, virtual function 2 (vf2) which is directly assigned to Virtual machine 2, and virtual function n (vfn) is

directly assigned to Virtual machine n.

Figure 1. SR-IOV configuration