How to enable IOMMU for PCI passthrough?

[ATMTech]

Hi, I am currently attempting to pass some PCI devices to some of my KVM virtual machines. When trying to detach them via virsh nodedev-detach, I get an error: argument unsupported: VFIO device assignment is currently not supported on this system. From my knowledge working with KVM on other Linux distributions, I believe this would be because IOMMU has not been enabled. I have tried to edit the grub configs to add the kernel parameter but it doesn't seem to stick because of the OS reverting changes. How should I approach enabling it?

 

[ornias]

How about enabling those virtualisation features in your bios first and adding some clear system specifications too ;-)

 

[ATMTech]

All virtualization features are enabled in the bios (VT-D, SVM, etc).

System Specs
Motherboard - Gigabyte x570 Taichi
CPU - Ryzen 9 5900x
RAM - 64GB 3200MHz ECC
PCIe NIC - Intel PRO/1000 Pt Dual Port Server Adapter (target for passthrough)
GPU - AMD RX 570 (target for passthrough later)
Drives:
2x 256GB SATA Mirrored (for OS)
2x 1TB NVME Mirrored (for VMs)
5x 2TB HDD RaidZ1

 

[silverback]

Try this link on the latest nightly. Update dev notes explaining GPU passthrough support.
I was able to configure everything in the GUI, virsh commands are no longer needed.
My system did not need IOMMU enabled so I am not sure this would help.

https://github.com/truenas/documentation/pull/819/files/7caea38c89e40099e6971cc00554a1f58f86048a