IOMMU activation.

After finishing up my newest small factor and low power consumption NAS Server, because both my NUC and my NAS were now booting off a ZFS mirror SSD stripe, I had to go through extra hoops in order to activate IOMMU for PCI pass-through in Proxmox VMs.

It really isn't that hard and I'll write it here step-by-step just so I don't forget about it, lol!

-Legacy Systems; Add IOMMU Support-

nano /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on"

- OR -

GRUB_CMDLINE_LINUX_DEFAULT="quiet amd_iommu=on"

Save file and close (ctrl + X, Y -if you're using nano)

update-grub

-EFI Boot Systems; Add IOMMU Support-

nano /etc/kernel/cmdline

intel_iommu=on

- OR -

amd_iommu=on

Save file and close (ctrl + X, Y -if you're using nano)

proxmox-boot-tool refresh

-Load VFIO modules at boot-

nano /etc/modules

add the following lines to the modules file

vfio
vfio_iommu_type1
vfio_pci
vfio_virqfd

Save file and close (ctrl + X, Y -if you're using nano)

-Apply all changes-

update-initramfs -u -k all
reboot

Now, if everything goes alright, hopefully after the reboot, you will have IOMMU activated and ready to go!
Have fun!