Configuring an SR-IOV Interface on KVM
If you have a physical NIC that supports SR-IOV, you can attach SR-IOV-enabled vNICs or virtual functions (VFs) to the vSRX instance to improve performance. We recommend that if you use SR-IOV, all revenue ports are configured as SR-IOV.
Note the following about SR-IOV support for vSRX on KVM:
- Starting in Junos OS Release 15.1X49-D90, a vSRX instance deployed on KVM supports SR-IOV on an Intel X710/XL710 NIC in addition to Intel 82599 or X520/540 (see the vSRX Performance Scale Up discussion in Understanding vSRX with KVM).
- Starting in Junos OS Release 18.1R1, a vSRX instance deployed on KVM supports SR-IOV on the Mellanox ConnectX-3 and ConnectX-4 Family Adapters (see the vSRX Performance Scale Up discussion in Understanding vSRX with KVM).
Before you can attach an SR-IOV enabled VF to the vSRX instance, you must complete the following tasks:
- Insert an SR-IOV-capable physical network adapter in the host server.
- Enable the Intel VT-d CPU virtualization extensions in BIOS on your host server. The Intel VT-d extensions provides hardware support for directly assigning a physical devices to guest. Verify the process with the vendor because different systems have different methods to enable VT-d.
- Ensure that SR-IOV is enabled at the system/server BIOS level by going into the BIOS settings during the host server boot-up sequence to confirm the SR-IOV setting. Different server manufacturers have different naming conventions for the BIOS parameter used to enable SR-IOV at the BIOS level. For example, for a Dell server ensure that the SR-IOV Global Enable option is set to Enabled.
- Append intel_iommu=on to the kernel line in
the host OS grub configuration file (
/boot/grub/grub.conf). This action enables IOMMU global support for PCI passthrough in BIOS on your host server. See your host documentation for details. See your host documentation for details. For example, see PCI Devices in the Red Hat Virtualization and Deployment Guide, for details on CentOS.
 | Note: We recommend that you use virt-manager to configure SR-IOV interfaces. See the virsh attach-device command documentation if you want to learn how to add a PCI host device to a VM with the virsh CLI commands. |
To add an SR-IOV VF to a vSRX VM using the virt-manager graphical interface:
- In the Junos OS CLI, shut down the vSRX VM if it is running.
vsrx> request system power-off - In virt-manager, double-click the vSRX VM and select View>Details. The vSRX Virtual Machine details dialog box appears.
- 3. Select the Hardware tab, then click Add Hardware. The Add Hardware dialog box appears.
- Select PCI Host Device from the Hardware list on the left.
- Select the SR-IOV VF for this new virtual interface from the host device list.
- Click Finish to add the new device. The setup is complete and the vSRX VM now has direct access to the device.
- From the virt-manager icon bar at the upper-left side
of the window, click the Power On arrow. The vSRX VM starts. Once
the vSRX is powered on the Running status will display in the window.
You can connect to the management console to watch the boot-up sequence.
Note: After the boot starts, you need to select View>Text Consoles>Serial 1 in virt-manager to connect to the vSRX console.
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