Table of Contents

Proxmox - GPU Passthrough - Configure Proxmox

Update Grub

SSH directly into the Proxmox server.

Edit /etc/default/grub file.

Change the line:

/etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet"

For an Intel CPU

/etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on"

For an AMD CPU

/etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet amd_iommu=on"

NOTE: Additional commands may be needed as well in this line, if the passthrough ends up failing.

For example: 

GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on iommu=pt pcie_acs_override=downstream,multifunction nofb nomodeset video=vesafb:off,efifb:off"

When editing is finished run this command: 

update-grub

VFIO Modules

Add a few VFIO (Virtual Function I/O) modules to your Proxmox system.

Add the following to the /etc/modules file:

/etc/modules
vfio
vfio_iommu_type1
vfio_pci
vfio_virqfd

Save and exit.

IOMMU interrupt remapping

Run the following commands: 

echo "options vfio_iommu_type1 allow_unsafe_interrupts=1" > /etc/modprobe.d/iommu_unsafe_interrupts.conf
echo "options kvm ignore_msrs=1" > /etc/modprobe.d/kvm.conf

Blacklist Drivers

To prevent the Proxmox host system utilizing the GPU(s), some drivers need to be blacklisted. 

echo "blacklist radeon" >> /etc/modprobe.d/blacklist.conf
echo "blacklist nouveau" >> /etc/modprobe.d/blacklist.conf
echo "blacklist nvidia" >> /etc/modprobe.d/blacklist.conf

Adding GPU to VFIO

Determine the GPU

lspci -v

returns: 

01:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1) (prog-if 00 [VGA controller])
01:00.1 Audio device: NVIDIA Corporation GP104 High Definition Audio Controller (rev a1)

NOTE: Look for the line(s) that show the video card.

Make note of the first set of numbers (e.g. 01:00.0 and 01:00.1).

Determine the GPU Vendor IDs

Run the command below.

NOTE: Replace 01:00 with whatever number was next to your GPU when you ran the previous command: 

lspci -n -s 01:00

returns: 

01:00.0 0000: 10de:1b81 (rev a1)
01:00.1 0000: 10de:10f0 (rev a1)

NOTE: This should output the GPU Vendor IDs, usually one ID for the GPU and one ID for the Audio bus.

Make a note of the vendor id codes: 10de:1b81 and 10de:10f0.

Add the GPU Vendor IDs to the VFIO

echo "options vfio-pci ids=10de:1b81,10de:10f0 disable_vga=1"> /etc/modprobe.d/vfio.conf

Update images

update-initramfs -u

NOTE: initramfs is a tiny version of the OS that gets loaded by the bootloader, right after the kernel.

  • It lives in RAM, and it provides just enough tools and instructions to tell the kernel how to set up the real filesystem, mount the HDD read/write, and start loading all the system services.
  • It includes the stub of init, PID #1.
  • If your initramfs is broken, your boot fails.

update-initramfs is a script that updates initramfs to work with a new kernel.

Updating the initramfs prevents some modules from being loaded.

Restart

sudo reboot

NOTE: The Proxmox host should be ready to passthrough GPUs!