VFIO "GPU Passthrough" Guide for Proxmox

BIOS Settings:

Disable Above 4G
Disable ReBAR
Disable SR-IOV (Leave this enabled if using a Quadro or other SR-IOV enabled graphics accelerator)
Enable IOMMU Support
Enable VT-D
Ensure primary output in BIOS is set to iGPU (NOT AUTO)

Proxmox Kernel Version:

Ensure Proxmox is running on kernel version 6.0.2 or later -
```
pveversion -v
```
Ensure Proxmox is running on the latest kernel -
```
apt update
apt dist-upgrade
reboot
```

Proxmox Config:

Update the Proxmox Kernel Commandline to boot with IOMMU Support

nano /etc/kernel/cmdline
root=ZFS=rpool/ROOT/pve-1 boot=zfs
Change to:
For Intel:
root=ZFS=rpool/ROOT/pve-1 boot=zfs quiet intel_iommu=on
For AMD:
root=ZFS=rpool/ROOT/pve-1 boot=zfs quiet intel_iommu=on

Enable IOMMU in Proxmox

nano /etc/default/grub
Comment out #GRUB_CMDLINE_LINUX_DEFAULT="quiet"
Replace with
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on" - For Intel
GRUB_CMDLINE_LINUX_DEFAULT="quiet AMD_iommu=on" - For AMD
Save
update-grub

Add Kernel Modules

nano /etc/modules
vfio
vfio_iommu_type1
vfio_pci
vfio_virqfd

Blacklist GPU drivers from loading on root Proxmox (may be needed)

nano /etc/modprobe.d/blacklist.conf
blacklist nvidia
blacklist nouveau
blacklist radeon
blacklist amd

Ensure your GPU is in a SEPARATE IOMMU GROUP

lspci -v
- Find the group number with your GPU
find /sys/kernel/iommu_groups/ -type l
If you do notice that the GPU you’re using is in the same group as another device, run the command below to attempt to isolate the device then reboot Proxmox and run the steps above again to verify.
echo "options vfio_iommu_type1 allow_unsafe_interrupts=1" > /etc/modprobe.d/iommu_unsafe_interrupts.conf