Installation guide
Using SR-IOV
119
4. Activate Virtual Functions
The max_vfs parameter of the igb module allocates the maximum number of Virtual Functions.
The max_vfs parameter causes the driver to spawn, up to the value of the parameter in, Virtual
Functions. For this particular card the valid range is 0 to 7.
Remove the module to change the variable.
# modprobe -r igb
Restart the module with the max_vfs set to 1 or any number of Virtual Functions up to the
maximum supported by your device.
# modprobe igb max_vfs=7
5. Make the Virtual Functions persistent
The modprobe command /etc/modprobe.d/igb.conf options igb max_vfs=7
6. Inspect the new Virtual Functions
Using the lspci command, list the newly added Virtual Functions attached to the Intel 82576
network device.
# lspci | grep 82576
0b:00.0 Ethernet controller: Intel Corporation 82576 Gigabit Network Connection (rev 01)
0b:00.1 Ethernet controller: Intel Corporation 82576 Gigabit Network Connection (rev 01)
0b:10.0 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:10.1 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:10.2 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:10.3 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:10.4 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:10.5 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:10.6 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:10.7 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:11.0 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:11.1 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:11.2 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:11.3 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:11.4 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
0b:11.5 Ethernet controller: Intel Corporation 82576 Virtual Function (rev 01)
The identifier for the PCI device is found with the -n parameter of the lspci command. The
Physical Functions corresponds to 0b:00.0 and 0b:00.1. All the Virtual Functions have
Virtual Function in the description.
7. Verify devices exist with virsh
The libvirt service must recognize the device before adding a device to a guest. libvirt
uses a similar notation to the lspci output. All punctuation characters, ; and ., in lspci output
are changed to underscores (_).
Use the virsh nodedev-list command and the grep command to filter the Intel 82576
network device from the list of available host devices. 0b is the filter for the Intel 82576 network
devices in this example. This may vary for your system and may result in additional devices.
# virsh nodedev-list | grep 0b
pci_0000_0b_00_0
pci_0000_0b_00_1
pci_0000_0b_10_0
pci_0000_0b_10_1