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Proxmox GPU Passthrough

Ron

PCI passthrough allows a VM to directly control a physical device (GPU, NIC, etc.).

1. Requirements (non-negotiable)

  • CPU with IOMMU:
    • Intel → VT-d
    • AMD → AMD-Vi
  • BIOS:
    • Enable VT-d / IOMMU
    • Enable Above 4G Decoding (important for GPUs)
  • GPU:
    • Dedicated GPU for VM (don’t use host GPU unless you know what you're doing)

2. Enable IOMMU (Host)

Edit GRUB:

 
sudo nano /etc/default/grub
 

Intel:

 
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on iommu=pt"
 

AMD:

 
GRUB_CMDLINE_LINUX_DEFAULT="quiet amd_iommu=on iommu=pt"
 

Update:

 
sudo update-grub

3. Enable VFIO modules

 
sudo nano /etc/modules
 

Add:

 
vfio
vfio_iommu_type1
vfio_pci
vfio_virqfd
 

4. Blacklist host GPU drivers

 
sudo nano /etc/modprobe.d/blacklist.conf
 

Add:

 
blacklist nouveau
blacklist nvidia
blacklist nvidiafb

5. Bind GPU to VFIO

Get GPU IDs:

 
lspci -nn | grep -i nvidia

Bind them:

 
sudo nano /etc/modprobe.d/vfio.conf
 
 
options vfio-pci ids=10de:1c81,10de:0fb9
 

6. Update initramfs

 
sudo update-initramfs -u -k all
reboot

7. Verify isolation

 
dmesg | grep -e IOMMU
 
 
lspci -nnk | grep -A3 -i nvidia
 

You should see:

 
Kernel driver in use: vfio-pci

8. Configure VM (Proxmox GUI)

Edit VM:

Hardware:

  • Machine: q35
  • BIOS: OVMF (UEFI)
  • Add → PCI Device

9. Optional (fix NVIDIA Code 43 / stability)

Edit VM config:

 
nano /etc/pve/qemu-server/<VMID>.conf
 

Add:

 
cpu: host,hidden=1
args: -cpu host,kvm=off

 10. Inside VM (Ubuntu)

Install driver:

sudo ubuntu-drivers autoinstall
sudo reboot

Test:

nvidia-smi

Reference :https://pve.proxmox.com/wiki/PCI_Passthrough

Hi, I’m Ron

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