6.7

Table Of Contents
Procedure
1 Locate the virtual machine in the vSphere Web Client.
a Select a data center, folder, cluster, resource pool, or host and click the VMs tab.
b Click Virtual Machines and double-click the virtual machine from the list.
2 Power off the virtual machine.
3 On the Configure tab of the virtual machine, expand Settings and select VM Hardware.
4 Click Edit and select the Virtual Hardware tab in the dialog box displaying the settings.
5 Expand the Memory section, and set the Limit to Unlimited.
6 From the New device drop-down menu select PCI Device and click Add.
7 From the New PCI device drop-down menu select the passthrough device to use, and click OK.
8 Power on the virtual machine.
Adding a DirectPath I/O device to a virtual machine sets memory reservation to the memory size of the
virtual machine.
Single Root I/O Virtualization (SR-IOV)
vSphere supports 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 SR-IOV Support.
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.
vSphere Networking
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