Arch Linux

joejoe31b

Member

From: New Zealand

Registered: 2017-01-02

Posts: 2

Website

VFIO VGA-passthrough attempt - no /sys/kernel/iommu_groups items

Hi everyone,

I have been using Arch on-and-off for around three years, and love it. This forum has been a trove of information that has consistenly helped me I have never needed to post for help on this forum, but I am stumped with my setup of a VFIO VGA-passthrough and was hoping someone will know where I have gone wrong.

I have been following (1) (2) (3) these guides predominitely.

I am on a desktop running an Intel i5 6600K processor on an MSI Z170A KRAIT GAMING motherboard with a Gigabyte 1070 G1. I am using the propreitary NVIDIA drivers, with the nouveau drivers blacklisted in my /etc/modprobe.d

As the title states, after all I have tried, I get no entries in the /sys/kernel/iommu_groups directory:

>> ls -la /sys/kernel/iommu_groups
total 0
drwxr-xr-x  2 root root 0 Jan  2 20:05 .
drwxr-xr-x 10 root root 0 Jan  2 20:05 ..

I have installed and am running the linux-vfio kernel from the AUR.

I have vt-d enabled by default in my BIOS, with these GRUB boot parameters:

GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on pcie_acs_override=downstream"

I ran this command from the OVMF PCI passthrough wiki page, and only got the following results:

>> dmesg|grep -e DMAR -e IOMMU
[    0.000000] Warning: PCIe ACS overrides enabled; This may allow non-IOMMU protected peer-to-peer DMA
[    0.000000] DMAR: IOMMU enabled

I even added vfio to the modules section of my /etc/mkinitcpio.conf and regenerated it with mkinitcpio -p linux-vfio as per the wiki's guide.

MODULES="vfio vfio_iommu_type1 vfio_pci vfio_virqfd"

I haven't continued with the guides past this point, as they all have results in their /sys/kernel/iommu_groups folder, and I get the impression that it is needed for a sucessful UEFI VGA-passthrough. Some of the guides even said that no results would mean I don't have IOMMU enabled properly.

Any help is much appreciated. Please ask if there is any more information I can give you!