Yes dmesg | grep "EFI v" [ 0.000000] efi: EFI v2.70 by American Megatrends On Fri, 2020-04-03 at 14:29 -0400, Jonathan Billings wrote: > On Fri, Apr 03, 2020 at 07:37:10PM +0300, Georgios wrote: > > Hi. > > Im trying to set intel_iommu=on on kernel parameters at grub but > > for > > some reason it doesnt work. > > > > I edit /etc/default/grub file and i add the parameter. > > > > then i run grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg and then > > i > > reboot. > > > > when i run virt-host-validate i get > > > > QEMU: Checking if IOMMU is enabled by kernel: WARN (IOMMU appears > > to be > > disabled in kernel. Add intel_iommu=on to kernel cmdline arguments) > > > > when i edit the grub menu durring boot and i put intel_iommu=on and > > the > > i run again virt-host-validate i get > > > > QEMU: Checking if IOMMU is enabled by kernel: PASS > > > > > > any ideas? > > This is a libvirtd KVM machine? Are you sure you're using UEFI? >