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https://github.com/QaidVoid/Complete-Single-GPU-Passthrough

Single GPU VFIO Passthrough Guide
https://github.com/QaidVoid/Complete-Single-GPU-Passthrough

gpu libvirt-hooks linux passthrough qemu-kvm vfio-pci virtio

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Single GPU VFIO Passthrough Guide

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README 

        
## **Table Of Contents**

* **[IOMMU Setup](#enable--verify-iommu)**

* **[Installing Packages](#install-required-tools)**

* **[Enabling Services](#enable-required-services)**

* **[Guest Setup](#setup-guest-os)**

* **[Attching PCI Devices](#attaching-pci-devices)**

* **[Libvirt Hooks](#libvirt-hooks)**

* **[Keyboard/Mouse Passthrough](#keyboardmouse-passthrough)**

* **[Video Card Virtualisation Detection](#video-card-driver-virtualisation-detection)**

* **[Audio Passthrough](#audio-passthrough)**

* **[GPU vBIOS Patching](#vbios-patching)**



### **Enable & Verify IOMMU**

***BIOS Settings*** \

Enable ***Intel VT-d*** or ***AMD-Vi*** in BIOS settings. If these options are not present, it is likely that your hardware does not support IOMMU.



Disable ***Resizable BAR Support*** in BIOS settings. 

Cards that support Resizable BAR can cause problems with black screens following driver load if Resizable BAR is enabled in UEFI/BIOS. There doesn't seem to be a large performance penalty for disabling it, so turn it off for now until ReBAR support is available for KVM. 



***Set the kernel paramater depending on your CPU.***



  GRUB



***Edit GRUB configuration***

| /etc/default/grub |

| ----- |

| `GRUB_CMDLINE_LINUX_DEFAULT="... intel_iommu=on iommu=pt ..."` |

| OR |

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



***Generate grub.cfg***

```sh

grub-mkconfig -o /boot/grub/grub.cfg

```



  Systemd Boot



***Edit boot entry.***

| /boot/loader/entries/*.conf |

| ----- |

| `options root=UUID=...intel_iommu=on iommu=pt..` |

| OR |

| `options root=UUID=...amd_iommu=on iommu=pt..` |



Reboot your system for the changes to take effect.



***To verify IOMMU, run the following command.***

```sh

dmesg | grep IOMMU

```

The output should include the message `Intel-IOMMU: enabled` for Intel CPUs or `AMD-Vi: AMD IOMMUv2 loaded and initialized` for AMD CPUs.



To view the IOMMU groups and attached devices, run the following script:

```sh

#!/bin/bash

shopt -s nullglob

for g in `find /sys/kernel/iommu_groups/* -maxdepth 0 -type d | sort -V`; do

    echo "IOMMU Group ${g##*/}:"

    for d in $g/devices/*; do

        echo -e "\t$(lspci -nns ${d##*/})"

    done;

done;

```



When using passthrough, it is necessary to pass every device in the group that includes your GPU. \

You can avoid having to pass everything by using [ACS override patch](https://wiki.archlinux.org/title/PCI_passthrough_via_OVMF#Bypassing_the_IOMMU_groups_(ACS_override_patch)).



### **Install required tools**



  Gentoo Linux



  ```sh

  emerge -av qemu virt-manager libvirt ebtables dnsmasq

  ```



  Arch Linux



  ```sh

  pacman -S qemu libvirt edk2-ovmf virt-manager dnsmasq ebtables

  ```



  Fedora



  ```sh

  dnf install @virtualization

  ```



  Ubuntu



  ```sh

  apt install qemu-kvm qemu-utils libvirt-daemon-system libvirt-clients bridge-utils virt-manager ovmf

  ```



### **Enable required services**



  SystemD



  ```sh

  systemctl enable --now libvirtd

  ```



  OpenRC



  ```sh

  rc-update add libvirtd default

  rc-service libvirtd start

  ```



Sometimes, you might need to start default network manually.

```sh

virsh net-start default

virsh net-autostart default

```



### **Setup Guest OS**

***NOTE: You should replace win10 with your VM's name where applicable*** \

You should add your user to ***libvirt*** group to be able to run VM without root. And, ***input*** and ***kvm*** group for passing input devices.

```sh

usermod -aG kvm,input,libvirt username

```



Download [virtio](https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/stable-virtio/virtio-win.iso) driver. \

Launch ***virt-manager*** and create a new virtual machine. Select ***Customize before install*** on Final Step. \

In ***Overview*** section, set ***Chipset*** to ***Q35***, and ***Firmware*** to ***UEFI*** \

In ***CPUs*** section, set ***CPU model*** to ***host-passthrough***, and ***CPU Topology*** to whatever fits your system. \

For ***SATA*** disk of VM, set ***Disk Bus*** to ***virtio***. \

In ***NIC*** section, set ***Device Model*** to ***virtio*** \

Add Hardware > CDROM: virtio-win.iso \

Now, ***Begin Installation***. Windows can't detect the ***virtio disk***, so you need to ***Load Driver*** and select ***virtio-iso/amd64/win10*** when prompted. \

After successful installation of Windows, install virtio drivers from virtio CDROM. You can then remove virtio iso.



### **Attaching PCI devices**

Remove Channel Spice, Display Spice, Video QXL, Sound ich* and other unnecessary devices. \

Now, click on ***Add Hardware***, select ***PCI Devices*** and add the PCI Host devices for your GPU's VGA and HDMI Audio.



### **Libvirt Hooks**

Libvirt hooks automate the process of running specific tasks during VM state change. \

More info at: [PassthroughPost](https://passthroughpo.st/simple-per-vm-libvirt-hooks-with-the-vfio-tools-hook-helper/)



**Note**: Comment Unbind/rebind EFI framebuffer line from start and stop script if you're using AMD 6000 series cards (https://github.com/QaidVoid/Complete-Single-GPU-Passthrough/issues/9).

Also, move the line to unload AMD kernal module below detaching devices from host. These might also apply to older AMD cards.



  Create Libvirt Hook



  ```sh

  mkdir /etc/libvirt/hooks

  touch /etc/libvirt/hooks/qemu

  chmod +x /etc/libvirt/hooks/qemu

  ```

  

  

  

    /etc/libvirt/hooks/qemu

  

  



  

  



  ```sh

  #!/bin/bash



GUEST_NAME="$1"

HOOK_NAME="$2"

STATE_NAME="$3"

MISC="${@:4}"



BASEDIR="$(dirname $0)"



HOOKPATH="$BASEDIR/qemu.d/$GUEST_NAME/$HOOK_NAME/$STATE_NAME"

set -e # If a script exits with an error, we should as well.



if [ -f "$HOOKPATH" ]; then

  eval \""$HOOKPATH"\" "$@"

elif [ -d "$HOOKPATH" ]; then

  while read file; do

    eval \""$file"\" "$@"

  done <<< "$(find -L "$HOOKPATH" -maxdepth 1 -type f -executable -print;)"

fi

  ```



  

  

  



  Create Start Script

  

  ```sh

  mkdir -p /etc/libvirt/hooks/qemu.d/win10/prepare/begin

  touch /etc/libvirt/hooks/qemu.d/win10/prepare/begin/start.sh

  chmod +x /etc/libvirt/hooks/qemu.d/win10/prepare/begin/start.sh

  ```

**Note**: If you're on KDE Plasma (Wayland), you need to terminate user services alongside display-manager (https://github.com/QaidVoid/Complete-Single-GPU-Passthrough/issues/31).



  

  

  

    /etc/libvirt/hooks/qemu.d/win10/prepare/begin/start.sh

  

  



  

  



  ```sh

#!/bin/bash

set -x



# Stop display manager

systemctl stop display-manager

# systemctl --user -M YOUR_USERNAME@ stop plasma*



# Unbind VTconsoles: might not be needed

echo 0 > /sys/class/vtconsole/vtcon0/bind

echo 0 > /sys/class/vtconsole/vtcon1/bind



# Unbind EFI Framebuffer

echo efi-framebuffer.0 > /sys/bus/platform/drivers/efi-framebuffer/unbind



# Unload NVIDIA kernel modules

modprobe -r nvidia_drm nvidia_modeset nvidia_uvm nvidia



# Unload AMD kernel module

# modprobe -r amdgpu



# Detach GPU devices from host

# Use your GPU and HDMI Audio PCI host device

virsh nodedev-detach pci_0000_01_00_0

virsh nodedev-detach pci_0000_01_00_1



# Load vfio module

modprobe vfio-pci

  ```



  

  

  



  Create Stop Script



  ```sh

  mkdir -p /etc/libvirt/hooks/qemu.d/win10/release/end

  touch /etc/libvirt/hooks/qemu.d/win10/release/end/stop.sh

  chmod +x /etc/libvirt/hooks/qemu.d/win10/release/end/stop.sh

  ```

  

  

  

    /etc/libvirt/hooks/qemu.d/win10/release/end/stop.sh

  

  



  

  



  ```sh

#!/bin/bash

set -x



# Attach GPU devices to host

# Use your GPU and HDMI Audio PCI host device

virsh nodedev-reattach pci_0000_01_00_0

virsh nodedev-reattach pci_0000_01_00_1



# Unload vfio module

modprobe -r vfio-pci



# Load AMD kernel module

#modprobe amdgpu



# Rebind framebuffer to host

echo "efi-framebuffer.0" > /sys/bus/platform/drivers/efi-framebuffer/bind



# Load NVIDIA kernel modules

modprobe nvidia_drm

modprobe nvidia_modeset

modprobe nvidia_uvm

modprobe nvidia



# Bind VTconsoles: might not be needed

echo 1 > /sys/class/vtconsole/vtcon0/bind

echo 1 > /sys/class/vtconsole/vtcon1/bind



# Restart Display Manager

systemctl start display-manager

```



  

  

  



### **Keyboard/Mouse Passthrough**

In order to be able to use keyboard/mouse in the VM, you can either passthrough the USB Host device or use Evdev passthrough.



Using USB Host Device is simple, \

***Add Hardware*** > ***USB Host Device***, add your keyboard and mouse device.



For Evdev passthrough, follow these steps: \

Modify libvirt configuration of your VM. \

**Note**: Save only after adding keyboard and mouse devices or the changes gets lost. \

Change first line to:



virsh edit win10



```xml



```



Find your keyboard and mouse devices in ***/dev/input/by-id***. You'd generally use the devices ending with ***event-kbd*** and ***event-mouse***. And the devices in your configuration right before closing ***``*** tag. \

Replace ***MOUSE_NAME*** and ***KEYBOARD_NAME*** with your device id.



virsh edit win10



```xml

...

  

    

    

    

    

  



```



You need to include these devices in your qemu config.



/etc/libvirt/qemu.conf



```sh

...

user = "YOUR_USERNAME"

group = "kvm"

...

cgroup_device_acl = [

    "/dev/input/by-id/KEYBOARD_NAME",

    "/dev/input/by-id/MOUSE_NAME",

    "/dev/null", "/dev/full", "/dev/zero",

    "/dev/random", "/dev/urandom",

    "/dev/ptmx", "/dev/kvm", "/dev/kqemu",

    "/dev/rtc","/dev/hpet", "/dev/sev"

]

...

```



Also, switch from PS/2 devices to virtio devices. Add the devices inside ***``*** block



virsh edit win10



```xml

...



  ...

  

  

  ...



...

```



### **Audio Passthrough**

VM's audio can be routed to the host using ***Pipewire*** or ***Pulseaudio***. \

You can also use [Scream](https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF#Passing_VM_audio_to_host_via_Scream) instead.



    Pipewire



From [ArchWiki](https://wiki.archlinux.org/title/PCI_passthrough_via_OVMF#Passing_audio_from_virtual_machine_to_host_via_JACK_and_PipeWire)



You need to have Pipewire with JACK support.



***Note***: You may use [Carla](https://kx.studio//Applications:Carla) to figure out appropriate input/output. Replace `1000` with your current user id.



virsh edit win10



```xml

...

  

    ...

    

      

      

    

  

  

    

    

  



```



    Pulseaudio



***Note***: Replace `1000` with your current user id.



virsh edit win10



```xml

...

  

    ...

    

    

    

    

    

    

  



```



### **Video card driver virtualisation detection**

Video Card drivers refuse to run in Virtual Machine, so you need to spoof Hyper-V Vendor ID.



virsh edit win10



```xml

...



  ...

  

    ...

    

    ...

  

  ...



...

```



NVIDIA guest drivers also require hiding the KVM CPU leaf:



virsh edit win10



```xml

...



  ...

  

    

  

  ...



...

```



### **vBIOS Patching**

***NOTE: You are only making changes on dumped ROM file. Your hardware is safe.*** \

While most of the GPU can be passed with stock vBIOS, some GPU requires vBIOS patching to passthrough. \

In order to patch vBIOS, you need to first dump the GPU vBIOS from your system. \

If you have Windows installed, you can use [GPU-Z](https://www.techpowerup.com/gpuz) to dump vBIOS. \

To dump vBIOS on Linux, you can use following command (replace PCI id with yours):

```sh

echo 1 > /sys/bus/pci/devices/0000:01:00.0/rom

cat /sys/bus/pci/devices/0000:01:00.0/rom > path/to/dump/vbios.rom

echo 0 > /sys/bus/pci/devices/0000:01:00.0/rom

```

If you're not in root shell, you should use the above commands with sudo as:

```sh

echo 1 | sudo tee /sys/bus/pci/devices/0000:01:00.0/rom

sudo cat /sys/bus/pci/devices/0000:01:00.0/rom > path/to/dump/vbios.rom

echo 0 | sudo tee /sys/bus/pci/devices/0000:01:00.0/rom

```

To patch vBIOS, you need to use Hex Editor (eg., [Okteta](https://utils.kde.org/projects/okteta)) and trim unnecessary header. \

For NVIDIA GPU, using hex editor, search string “VIDEO”, and remove everything before HEX value 55. \

I'm not sure about AMD, but the process should be similar.



To use patched vBIOS, edit VM's configuration to include patched vBIOS inside ***hostdev*** block of VGA



  

  

  

  virsh edit win10

  

  



  

  



  ```xml

  ...

  

    

      ...

    

    

    ...

  

  ...

  ```



  

  

  



### **See Also**

> [Single GPU Passthrough Troubleshooting](https://docs.google.com/document/d/17Wh9_5HPqAx8HHk-p2bGlR0E-65TplkG18jvM98I7V8)


> [Single GPU Passthrough by joeknock90](https://github.com/joeknock90/Single-GPU-Passthrough)


> [Single GPU Passthrough by YuriAlek](https://gitlab.com/YuriAlek/vfio)


> [Single GPU Passthrough by wabulu](https://github.com/wabulu/Single-GPU-passthrough-amd-nvidia)


> [ArchLinux PCI Passthrough](https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF)


> [Gentoo GPU Passthrough](https://wiki.gentoo.org/wiki/GPU_passthrough_with_libvirt_qemu_kvm)