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GPU Passthrough Guide

reference : reddit

1. Enable IOMMU in BIOS

  • Reboot your system and enter BIOS/UEFI settings.
  • Look for options related to VT-d (Intel) or AMD-Vi (AMD).
  • Enable IOMMU or VT-d.
  • Save and exit the BIOS.

2. Enable IOMMU in Proxmox GRUB Configuration

Edit the GRUB configuration: 

nano /etc/default/grub

Change this line: 

GRUB_CMDLINE_LINUX_DEFAULT="quiet"
to:

  • For Intel CPUs: 
    GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on iommu=pt"
  • For AMD CPUs: 
    GRUB_CMDLINE_LINUX_DEFAULT="quiet amd_iommu=on iommu=pt"

Save and update GRUB: 

update-grub

3. Load IOMMU Kernel Modules

Edit the modules file: 

nano /etc/modules
Add the following lines at the bottom: 
vfio
vfio_pci
vfio_iommu_type1
vfio_virqfd
Save and exit.

Update the initramfs: 

update-initramfs -u

4. Verify IOMMU is Enabled

Step 1: Reboot

reboot

Step 2: Check IOMMU Status

dmesg | grep -i iommu
Expected output: 
DMAR: IOMMU enabled
AMD-Vi: Enabling IOMMU at 0000:00:00.2

Step 3: Verify PCI Devices

lspci -nnk | grep -i -A3 "vga\|gpu"
If your GPU or PCI device appears, IOMMU is successfully enabled.