Advanced Virtio-net Devices Configuration¶

If you are using virtio-net, it is important that you understand the different types of virtio-net devices.

When you create a virtio-net device, the model type "virtio" will be used by default:

<interface type="network">
 <mac address="52:54:00:00:00:00"/>
 <source network="default"/>
 <model type="virtio"/>
 <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
</interface>

However, the real model is either virtio-transitional or virtio-non-transitional. OpenVMS supports both models, but the default will be chosen by the hypervisor.

A virtio-transitional device can work with virtio 0.9 or virtio 1.0 guest drivers and only works with PCI controllers. Note that only up to 9 devices of this type can be attached to a virtual machine at any given time.
A virtio-non-transitional device can only work with virtio 1.0 guest drivers. The libvirt tool will connect the device to PCIe or PCI controller. It allows for more throughput and is therefore the recommended version.

In certain cases, it may be beneficial to explicitly set the model type to "virtio-non-transitional". You can do so by specifying the model type on the virt-install command or by editing the XML file.

CLIXML

--network type=direct,source=$networkdev,source_mode=passthrough, mac=$mac,model=virtio-non-transitional \

<interface type="network">
 <mac address="52:54:00:00:00:00"/>
 <source network="default"/>
 <model type="virtio-non-transitional"/>
 <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
</interface>

For more information on the virtio device models, refer to the Virtio device models article.