147 lines
3.1 KiB
Markdown
147 lines
3.1 KiB
Markdown
# GPU Passthrough (VFIO) Notes
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Host/guest checklist for GPU passthrough (or virtual GPU) when building Debian VMs in Proxmox / virt-manager style setups.
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---
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## Host: Pick GPU and enable passthrough
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List GPUs on the host:
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```bash
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lspci | egrep -i 'vga|3d|display'
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```
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Note the PCI ID of the card you want to pass, e.g. `0000:01:00.0`.
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On the host, enable IOMMU and passthrough (Proxmox/virt-manager style):
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- Add appropriate kernel params (example Intel):
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```text
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intel_iommu=on iommu=pt
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```
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- Reboot and verify:
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```bash
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dmesg | egrep -i 'iommu|dmar'
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```
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Bind the GPU to `vfio` (or equivalent passthrough driver) on the host so the VM can own it exclusively.
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---
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## Host: Create the VM with a VGA/GPU device
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Create a new VM (Proxmox or virt-manager):
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- **Firmware**: UEFI/OVMF if possible
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- **Machine type**: Q35/modern
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- **CPU**: host-passthrough (or similar)
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Add GPU to the VM:
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- Add PCI device: select your GPU (and its audio function if present)
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- For a purely virtual GPU instead (no passthrough), pick Virtio GPU or QXL as the display adapter
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Add display channel:
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- If you want a normal graphical console, use SPICE (virt-manager) or Proxmox’s standard console display
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- Add a Channel (spice) device for clipboard/resize when using SPICE
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---
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## Guest: Verify what GPU the VM sees
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Inside the guest OS (your Debian VM):
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```bash
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lspci | egrep -i 'vga|3d|display'
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lsmod | egrep 'nvidia|amdgpu|radeon|virtio_gpu'
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```
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Interpretation:
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- `NVIDIA Corporation ...` → real NVIDIA passthrough
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- `Advanced Micro Devices, Inc. [AMD/ATI] ...` → AMD passthrough
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- `Red Hat, Inc. Virtio GPU` or `QXL` → virtual GPU only
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---
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## Guest: Install and test drivers
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### If NVIDIA passthrough
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Install driver and tools:
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```bash
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sudo apt update
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sudo apt install nvidia-driver-535 nvidia-smi
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```
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(Adjust version to what Debian suggests.)
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Test:
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```bash
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nvidia-smi
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watch -n 1 nvidia-smi
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```
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The watch line must be `watch -n 1 nvidia-smi`.
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Quick 3D check:
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```bash
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sudo apt install mesa-utils
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glxgears
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```
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GPU utilization should rise in `nvidia-smi` while `glxgears` runs.
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### If AMD passthrough
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Inspect and ensure `amdgpu` is used:
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```bash
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sudo lshw -c video
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lsmod | grep amdgpu
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```
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Install tools:
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```bash
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sudo apt install mesa-utils
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# optionally:
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sudo apt install amdgpu-tools # or ROCm SMI tools if available
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```
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Monitor:
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```bash
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watch -n 1 sudo amd-smi
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```
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(Or the ROCm SMI CLI in your distro.)
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### If only Virtio/QXL is present
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- You have a virtual GPU, not the physical one.
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- You can still use `glxgears` and basic acceleration, but host GPU usage is not controlled directly from inside this VM.
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- To use the physical card, change the VM to PCI passthrough as above.
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---
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## Guest: Console and SPICE/GUI behavior
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- With SPICE display and the spice channel present, dynamic resolution and clipboard should work once guest tools are installed.
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- If a graphical display manager (e.g. LightDM) misbehaves, you can force a TTY-only boot:
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```bash
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sudo systemctl set-default multi-user.target
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sudo systemctl disable --now lightdm.service
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```
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This gives you a reliable text console, and you can work purely over SSH for GPU workloads.
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