Prerequisites

GPU passthrough requires IOMMU support in both the CPU and motherboard firmware, plus a few system-level configuration steps.

1. Enable IOMMU

Add the appropriate kernel parameter for your CPU:

Intel:

intel_iommu=on iommu=pt

AMD:

amd_iommu=on iommu=pt

Edit /etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="... amd_iommu=on iommu=pt"

Apply and reboot:

sudo update-grub   # Debian/Ubuntu
sudo grub-mkconfig -o /boot/grub/grub.cfg  # Arch

Verify IOMMU is active after reboot:

dmesg | grep -i iommu | head -5

2. Load vfio-pci

Create /etc/modules-load.d/vfio.conf:

vfio
vfio_iommu_type1
vfio_pci

3. Join the vfio group

sudo usermod -aG vfio $USER

Log out and back in. Verify:

groups | grep vfio

4. Set unlimited locked memory

VFIO DMA-maps the entire guest RAM. The default memlock limit causes QEMU to fail:

vfio_container_dma_map(...) = -12 (Cannot allocate memory)

Fix:

sudo tee /etc/security/limits.d/vee-vfio.conf <<'EOF'
* - memlock unlimited
EOF

Log out and back in. Verify:

ulimit -l   # should print "unlimited"

5. Bind the GPU to vfio-pci

# List GPUs and their IOMMU groups
vee gpu list

# Bind to vfio-pci (run as root)
sudo vee gpu bind 08:00.0

# Verify — all devices in the IOMMU group should show vfio-pci
vee gpu status 08:00.0 --memory 16G

All devices in the IOMMU group (GPU + audio function) must be bound to vfio-pci together.