---
title: Using UEFI mode for virtual machines
---

# Using UEFI mode for virtual machines {#virt-uefi-mode-for-vms}

You can boot a virtual machine (VM) in Unified Extensible Firmware Interface (UEFI) mode for faster boot times, the ability to boot to larger disks, and added security features.

## About UEFI mode for virtual machines {#virt-about-uefi-mode-for-vms_virt-uefi-mode-for-vms}

Unified Extensible Firmware Interface (UEFI), like legacy BIOS, initializes hardware components and operating system image files when a computer starts. UEFI supports more modern features and customization options than BIOS, enabling faster boot times.

It stores all the information about initialization and startup in a file with a `.efi` extension, which is stored on a special partition called EFI System Partition (ESP). The ESP also contains the boot loader programs for the operating system that is installed on the computer.

## Booting virtual machines in UEFI mode {#virt-booting-vms-uefi-mode_virt-uefi-mode-for-vms}

You can configure a virtual machine to boot in UEFI mode by editing the `VirtualMachine` manifest.

**Prerequisites**

- Install the OpenShift CLI (`oc`).

**Procedure**

1. To boot a virtual machine (VM) in UEFI mode with secure boot active, edit or create a `VirtualMachine` manifest file. Use the `spec.firmware.bootloader` stanza to configure UEFI mode:

   ```yaml
   apiversion: kubevirt.io/v1
   kind: VirtualMachine
   metadata:
     labels:
       special: vm-secureboot
     name: vm-secureboot
   spec:
     template:
       metadata:
         labels:
           special: vm-secureboot
       spec:
         domain:
           devices:
             disks:
             - disk:
                 bus: virtio
               name: containerdisk
           features:
             acpi: {}
             smm:
               enabled: true
           firmware:
             bootloader:
               efi:
                 secureBoot: true
   # ...
   ```

   - You must set `spec.template.spec.domain.features.ssm.enabled` to have a value of `true`.
   - If `spec.template.spec.domain.firmware.bootloader.efi.secureBoot` is set to `true`, then UEFI mode is required. However, you can enable UEFI mode without using Secure Boot.
2. Apply the manifest to your cluster by running the following command:

   ```terminal
   $ oc create -f <file_name>.yaml
   ```

## Configuring VMs with persistent EFI {#configuring-vm-with-persistent-efi_virt-uefi-mode-for-vms}

You can configure a VM to have EFI persistence enabled by editing its manifest file.

**Procedure**

- Edit the VM manifest file and save to apply settings.

  ```yaml
  apiVersion: kubevirt.io/v1
  kind: VirtualMachine
  metadata:
    name: vm
  spec:
    template:
      spec:
        domain:
          firmware:
            bootloader:
              efi:
                persistent: true
  # ...
  ```