Adding `intel_iommu=on` to kernel command line

Ask Fedora
1

Hi, I am currently going through a guide which tells me this:

Activate Intel VT-d in the kernel by appending the intel_iommu=on parameter to the kernel line of the kernel line in the /boot/grub/grub.conf file.

I don’t know how to access and use the kernel as I have never done it before. Can you please explain me how exactly I execute this step?

I am using Fedora 34, Gnome. Thank you very much!

How to enable "BIOS Firmware Updates" as per the fwupd HSI
2

sudo grubby --update-kernel=ALL --args=“intel_iommu=on”

reboot

To remove

sudo grubby --update-kernel=ALL --remove-args=“intel_iommu”

reboot

But I think this feature should be enabled from bios/UEFI (If supported ).

4 Likes
3

@youssefmsourani, ensure you wrap code in <code>s, else quotations shall be converted into their more stylistic UTF counterparts, alongside code being interpreted as CommonMark.

Indeed, that’s what I see without it in GRUB2, per sudo dmesg | grep -i iommu:

[    0.390548] iommu: Default domain type: Translated
[    0.390548] iommu: DMA domain TLB invalidation policy: lazy mode
[    0.451421] pci 0000:00:00.2: AMD-Vi: IOMMU performance counters supported
[    0.451468] pci 0000:00:01.0: Adding to iommu group 0
[    0.451485] pci 0000:00:01.1: Adding to iommu group 1
[    0.451500] pci 0000:00:01.2: Adding to iommu group 2
[    0.451573] pci 0000:00:02.0: Adding to iommu group 3
[    0.451591] pci 0000:00:02.1: Adding to iommu group 4
[    0.451606] pci 0000:00:02.2: Adding to iommu group 5
[    0.451629] pci 0000:00:03.0: Adding to iommu group 6
[    0.451652] pci 0000:00:04.0: Adding to iommu group 7
[    0.451676] pci 0000:00:08.0: Adding to iommu group 8
[    0.451691] pci 0000:00:08.1: Adding to iommu group 9
[    0.451707] pci 0000:00:08.3: Adding to iommu group 10
[    0.451738] pci 0000:00:14.0: Adding to iommu group 11
[    0.451752] pci 0000:00:14.3: Adding to iommu group 11
[    0.451830] pci 0000:00:18.0: Adding to iommu group 12
[    0.451845] pci 0000:00:18.1: Adding to iommu group 12
[    0.451860] pci 0000:00:18.2: Adding to iommu group 12
[    0.451875] pci 0000:00:18.3: Adding to iommu group 12
[    0.451890] pci 0000:00:18.4: Adding to iommu group 12
[    0.451905] pci 0000:00:18.5: Adding to iommu group 12
[    0.451921] pci 0000:00:18.6: Adding to iommu group 12
[    0.451936] pci 0000:00:18.7: Adding to iommu group 12
[    0.451952] pci 0000:01:00.0: Adding to iommu group 13
[    0.451969] pci 0000:02:00.0: Adding to iommu group 14
[    0.451989] pci 0000:03:00.0: Adding to iommu group 15
[    0.452007] pci 0000:03:00.1: Adding to iommu group 16
[    0.452023] pci 0000:04:00.0: Adding to iommu group 17
[    0.452039] pci 0000:05:00.0: Adding to iommu group 18
[    0.452055] pci 0000:05:01.0: Adding to iommu group 19
[    0.452071] pci 0000:05:02.0: Adding to iommu group 20
[    0.452087] pci 0000:05:03.0: Adding to iommu group 21
[    0.452109] pci 0000:06:00.0: Adding to iommu group 22
[    0.452126] pci 0000:08:00.0: Adding to iommu group 23
[    0.452141] pci 0000:45:00.0: Adding to iommu group 24
[    0.452157] pci 0000:46:00.0: Adding to iommu group 25
[    0.452173] pci 0000:46:04.0: Adding to iommu group 26
[    0.452189] pci 0000:46:05.0: Adding to iommu group 27
[    0.452204] pci 0000:46:06.0: Adding to iommu group 28
[    0.452220] pci 0000:46:07.0: Adding to iommu group 29
[    0.452236] pci 0000:46:08.0: Adding to iommu group 30
[    0.452253] pci 0000:46:0c.0: Adding to iommu group 31
[    0.452269] pci 0000:46:0d.0: Adding to iommu group 32
[    0.452275] pci 0000:47:00.0: Adding to iommu group 25
[    0.452281] pci 0000:48:00.0: Adding to iommu group 26
[    0.452287] pci 0000:49:00.0: Adding to iommu group 27
[    0.452292] pci 0000:4a:00.0: Adding to iommu group 28
[    0.452297] pci 0000:4b:00.0: Adding to iommu group 29
[    0.452303] pci 0000:4c:00.0: Adding to iommu group 30
[    0.452308] pci 0000:4d:00.0: Adding to iommu group 30
[    0.452314] pci 0000:4d:04.0: Adding to iommu group 30
[    0.452320] pci 0000:4d:05.0: Adding to iommu group 30
[    0.452326] pci 0000:4d:06.0: Adding to iommu group 30
[    0.452332] pci 0000:4d:07.0: Adding to iommu group 30
[    0.452338] pci 0000:4d:08.0: Adding to iommu group 30
[    0.452343] pci 0000:4d:0c.0: Adding to iommu group 30
[    0.452348] pci 0000:4d:0d.0: Adding to iommu group 30
[    0.452354] pci 0000:4e:00.0: Adding to iommu group 30
[    0.452360] pci 0000:53:00.0: Adding to iommu group 30
[    0.452366] pci 0000:54:00.0: Adding to iommu group 30
[    0.452371] pci 0000:55:00.0: Adding to iommu group 30
[    0.452377] pci 0000:56:00.0: Adding to iommu group 31
[    0.452382] pci 0000:57:00.0: Adding to iommu group 32
[    0.452399] pci 0000:58:00.0: Adding to iommu group 33
[    0.452430] pci 0000:59:00.0: Adding to iommu group 34
[    0.452447] pci 0000:59:00.1: Adding to iommu group 35
[    0.452463] pci 0000:59:00.2: Adding to iommu group 36
[    0.452479] pci 0000:59:00.3: Adding to iommu group 37
[    0.452496] pci 0000:59:00.4: Adding to iommu group 38
[    0.452512] pci 0000:59:00.6: Adding to iommu group 39
[    0.452529] pci 0000:5a:00.0: Adding to iommu group 40
[    0.519554] perf/amd_iommu: Detected AMD IOMMU #0 (2 banks, 4 counters/bank).

@shacc189, if you’re adhering to siberoloji.com/how-to-run-windows-in-a-vm-with-gpu-acceleration-on-arch-linux/#for-amd, it may solely be applicable to Arch.

How does one create a Windows (11 25H2) VM with GPU passthrough (in Fedora 42)?