GRUB Configuration
Enabling flags needed for Virtualization/QEMU/KVM/libvirtd
Start by using your favorite terminal text editor. In this example, we’ll be using nano.
sudo nano /etc/default/grub
We’ll need to check our GRUB CMD Line flags and add various ones depending on the users’ hardware.
| Intel CPU | AMD GPU | Needed Regardless |
|---|---|---|
| intel_iommu=on | video=efifb:off | iommu=pt |
Example GRUB configuration for an AMD CPU + AMD GPU host:
GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3 quiet"
GRUB_CMDLINE_LINUX="rootfstype=ext4 iommu=pt video=efifb:off"
When you’re done make sure you use grub-mkconfig to update the GRUB Bootloader. A Restart is required to apply changes.
sudo grub-mkconfig -o /boot/grub/grub.cfg
You can now verify that the following changes were made, by checking the current flags booted with.
cat /proc/cmdline
Example Output:
[royalgraphx@hypervisor ~]$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-linux-zen root=UUID=c95503f3-e0fa-493e-9943-98b03aa1d280 rw rootfstype=ext4 iommu=pt video=efifb:off loglevel=3 quiet