Experimental features

Experimental features are not suitable for use in production environments. Citrix offers no guarantee that the experimental features will be available in a GA release of Citrix Hypervisor.

Guest UEFI boot

Citrix Hypervisor now allows recent versions of Windows guest operating systems to boot in UEFI mode. UEFI boot provides a richer interface for the guest operating systems to interact with the hardware, which can significantly reduce Windows VM boot times.

Note:

Guest UEFI boot is an experimental feature. You can create UEFI-enabled VMs on hosts that are in a production environment. However, UEFI-enabled VMs must not be used for production purposes. You may have to re-create the VMs when you upgrade the host to a newer version of Citrix Hypervisor.

Citrix Hypervisor supports UEFI boot on newly created Windows 10 (64-bit), Windows Server 2016 (64-bit), and Windows Server 2019 (64-bit) VMs. You must specify the boot mode when creating a VM. It is not possible to change the boot mode of a VM after booting the VM for the first time.

Consider the following when enabling UEFI boot on VMs:

  • Ensure that the UEFI-enabled VM has at least two vCPUs.
  • You can import or export a UEFI-enabled VM created on Citrix Hypervisor as an OVA, OVF, or an XVA file. Importing a UEFI-enabled VM from OVA or OVF packages created on other hypervisors is not supported.
  • UEFI-enabled VMs are not supported with Citrix Machine Creation Services.
  • GPU pass-through is not supported.
  • PVS is not supported.
  • UEFI secure boot is not supported.
  • Use the UEFI settings menu to change the screen resolution of the XenCenter console. For detailed instructions, see Changing the screen resolution.

Enabling UEFI boot

You can use XenCenter or the xe CLI to enable Guest UEFI boot.

Using XenCenter

When you create a VM using the New VM wizard, on the Installation Media page, select UEFI Boot.

Note:

The UEFI Boot option appears grayed out if the VM template you have chosen does not support UEFI boot.

Using the xe CLI

When you create a VM, run the following command before booting the VM for the first time:

    xe vm-param-set uuid=<UUID> HVM-boot-params:firmware=<MODE>

Where, UUID is the VM’s UUID and MODE is either ‘BIOS’ or ‘UEFI’. If you do not specify the mode, it defaults to ‘BIOS’.

To create a UEFI-enabled VM from a template, run the following command:

    UUID=$(xe vm-clone name-label='Windows 10 (64-bit)'
    new-name-label='Windows 10 (64-bit)(UEFI)') xe template-param-set uuid=<UUID> HVM-boot-params:firmware=<MODE>

Changing the screen resolution

To change the screen resolution of the XenCenter console on a UEFI-enabled VM:

  1. Open the Windows Settings
  2. Click the Update & Security button
  3. Under the recovery tab, press the Restart now button.
  4. Navigate to Troubleshoot > Advanced Options > UEFI firmware settings.
  5. Press Restart. During restart, the UEFI settings menu loads.
  6. Navigate to Device Manager > OVMF Platform Configuration. This displays the current screen resolution.
  7. Press Enter to see the screen resolution options.
  8. Use the arrow keys to select the desired screen resolution and press Enter.
  9. Press F10 to save the changes and confirm your choice.
  10. Reboot the VM to see the XenCenter console in an updated screen resolution.

Experimental features