Understanding VirtIO drivers

VirtIO drivers are paravirtualized device drivers required for Microsoft Windows virtual machines to run in Container-native Virtualization. The supported drivers are available in the cnv-tech-preview/virtio-win container disk of the Red Hat Container Catalog.

The cnv-tech-preview/virtio-win container disk must be attached to the virtual machine as a SATA CD drive to enable driver installation. You can install VirtIO drivers during Windows installation on the virtual machine or added to an existing Windows installation.

After the drivers are installed, the cnv-tech-preview/virtio-win container disk can be removed from the virtual machine.

Supported VirtIO drivers for Microsoft Windows virtual machines in Container-native Virtualization

Table 1. Supported drivers
Driver name Hardware ID Description

viostor

VEN_1AF4&DEV_1001
VEN_1AF4&DEV_1042

The block driver. Sometimes displays as an SCSI Controller in the Other devices group.

viorng

VEN_1AF4&DEV_1005
VEN_1AF4&DEV_1044

The entropy source driver. Sometimes displays as a PCI Device in the Other devices group.

NetKVM

VEN_1AF4&DEV_1000
VEN_1AF4&DEV_1041

The network driver. Sometimes displays as an Ethernet Controller in the Other devices group. Available only if a VirtIO NIC is configured.

Adding VirtIO drivers container disk to a virtual machine

Container-native Virtualization distributes VirtIO drivers for Microsoft Windows as a container disk, which is available from the Red Hat Container Catalog. To install these drivers to a Windows virtual machine, attach the cnv-tech-preview/virtio-win container disk to the virtual machine as a SATA CD drive in the virtual machine configuration file.

Prerequisites
  • Download the cnv-tech-preview/virtio-win container disk from the Red Hat Container Catalog. This is not mandatory, because the container disk will be downloaded from the Red Hat registry if it not already present in the cluster, but it can reduce installation time.

Procedure
  1. Add the cnv-tech-preview/virtio-win container disk as a cdrom disk in the Windows virtual machine configuration file. The container disk will be downloaded from the registry if it is not already present in the cluster.

    spec:
      domain:
        devices:
          disks:
            - name: virtiocontainerdisk
              bootOrder: 2 (1)
              cdrom:
                bus: sata
    volumes:
      - containerDisk:
          image: cnv-tech-preview/virtio-win
        name: virtiocontainerdisk
    1 Container-native Virtualization boots virtual machine disks in the order defined in the VirtualMachine configuration file. You can either define other disks for the virtual machine before the cnv-tech-preview/virtio-win container disk or use the optional bootOrder parameter to ensure the virtual machine boots from the correct disk. If you specify the bootOrder for a disk, it must be specified for all disks in the configuration.
  2. The disk is available once the virtual machine has started:

    • If you add the container disk to a running virtual machine, use oc apply -f <vm.yaml> in the CLI or reboot the virtual machine for the changes to take effect.

    • If the virtual machine is not running, use virtctl start <vm>.

After the virtual machine has started, the VirtIO drivers can be installed from the attached SATA CD drive.

Installing VirtIO drivers on an existing Windows virtual machine

Install the VirtIO drivers from the attached SATA CD drive to an existing Windows virtual machine.

This procedure uses a generic approach to adding drivers to Windows. The process might differ slightly between versions of Windows. Refer to the documentation for the version of Windows that you are installing.

Procedure
  1. Start the virtual machine and connect to a graphical console.

  2. Log in to a Windows user session.

  3. Open Device Manager and expand Other devices to list any Unknown device.

    1. You might need to open the Device Properties to identify the unknown device. Right-click the device and select Properties.

    2. Click the Details tab and select Hardware Ids in the Property list.

    3. Compare the Value for the Hardware Ids with the supported VirtIO drivers.

  4. Right-click the device and select Update Driver Software.

  5. Click Browse my computer for driver software and browse to the attached SATA CD drive, where the VirtIO drivers are located. The drivers are arranged hierarchically according to their driver type, operating system, and CPU architecture.

  6. Click Next to install the driver.

  7. Repeat this process for all the necessary VirtIO drivers.

  8. After the driver installs, click Close to close the window.

  9. Reboot the virtual machine to complete the driver installation.

Removing the VirtIO container disk from a virtual machine

After installing all required VirtIO drivers to the virtual machine, the cnv-tech-preview/virtio-win container disk no longer needs to be attached to the virtual machine. Remove the cnv-tech-preview/virtio-win container disk from the virtual machine configuration file.

Procedure
  1. Edit the configuration file and remove the disk and the volume.

    $ oc edit vm <vm-name>
    spec:
      domain:
        devices:
          disks:
            - name: virtiocontainerdisk
              bootOrder: 2
              cdrom:
                bus: sata
    volumes:
      - containerDisk:
          image: cnv-tech-preview/virtio-win
        name: virtiocontainerdisk
  2. Reboot the virtual machine for the changes to take effect.