### **Enable IOMMU**
***Set the kernel paramater depending on your CPU.*** \
For GRUB user, 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
```
Reboot your system for the changes to take effect.
### **Verify IOMMU**
***If you don't see any output when running following command, IOMMU is not functioning.***
```sh
dmesg | grep 'IOMMU enabled'
```
### **Install required tools**
< details >
< summary > < b > Gentoo Linux< / b > < / summary >
```sh
emerge -av qemu virt-manager libvirt ebtables dnsmasq
```
< / details >
< details >
< summary > < b > Arch Linux< / b > < / summary >
```sh
pacman -S qemu libvirt edk2-ovmf virt-manager dnsmasq ebtables
```
< / details >
< details >
< summary > < b > Fedora< / b > < / summary >
```sh
dnf install @virtualization
```
< / details >
### **Enable required services**
< details >
< summary > < b > SystemD< / b > < / summary >
```sh
systemctl enable --now libvirtd
```
< / details >
< details >
< summary > < b > OpenRC< / b > < / summary >
```sh
rc-update add libvirtd default
rc-service libvirtd start
```
< / details >
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*** \
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.
### **Attaching PCI devices**
Remove Channel Spice, Display Spice, Video XQL, 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 \
Some GPU vBIOS needs to be patched for UEFI Support. \
***----- TODO: vBIOS patching ------*** \
To use patched vBIOS, edit VM's configuration to include patched vBIOS inside ** *hostdev*** block of VGA
```sh
mkdir /etc/libvirt/hooks
touch /etc/libvirt/hooks/qemu
chmod +x /etc/libvirt/hooks/qemu
```
< table >
< tr >
< th >
virsh edit win10
< / th >
< / tr >
< tr >
< td >
```xml
...
< hostdev mode = 'subsystem' type = 'pci' managed = 'yes' >
< source >
...
< / source >
< rom file = '/home/me/patched.rom' / >
...
< / hostdev >
...
```
< / td >
< / tr >
< / table >
### 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/ )
< details >
< summary > < b > Create Libvirt Hook< / b > < / summary >
```sh
mkdir /etc/libvirt/hooks
touch /etc/libvirt/hooks/qemu
chmod +x /etc/libvirt/hooks/qemu
```
< table >
< tr >
< th >
/etc/libvirt/hooks/qemu
< / th >
< / tr >
< tr >
< td >
```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
```
< / td >
< / tr >
< / table >
< / details >
< details >
< summary > < b > Create Start Script< / b > < / summary >
```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
```
< table >
< tr >
< th >
/etc/libvirt/hooks/qemu.d/win10/prepare/begin/start.sh
< / th >
< / tr >
< tr >
< td >
```sh
#!/bin/bash
set -x
# Stop display manager
systemctl stop display-manager
# rc-service display-manager stop
# 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
```
< / td >
< / tr >
< / table >
< / details >
< details >
< summary > < b > Create Stop Script< / b > < / summary >
```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
```
< table >
< tr >
< th >
/etc/libvirt/hooks/qemu.d/win10/release/end/stop.sh
< / th >
< / tr >
< tr >
< td >
```sh
#!/bin/bash
set -x
# Unload vfio module
modprobe -r vfio-pci
# 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
# 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
# Load AMD kernel module
# modprobe amdgpu
# Restart Display Manager
systemctl start display-manager
# rc-service display-manager start
```
< / td >
< / tr >
< / table >
< / details >
### Keyboard/Mouse Passthrough
Modify libvirt configuration of your VM. Change first line to:
< table >
< tr >
< th >
virsh edit win10
< / th >
< / tr >
< tr >
< td >
```xml
< domain type = 'kvm' xmlns:qemu = 'http://libvirt.org/schemas/domain/qemu/1.0' >
```
< / td >
< / tr >
< / table >
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 `</domain>` tag. \
Replace ** *MOUSE_NAME*** and ** *KEYBOARD_NAME*** with your device id.
< table >
< tr >
< th >
virsh edit win10
< / th >
< / tr >
< tr >
< td >
```xml
...
< qemu:commandline >
< qemu:arg value = '-object' / >
< qemu:arg value = 'input-linux,id=mouse1,evdev=/dev/input/by-id/MOUSE_NAME' / >
< qemu:arg value = '-object' / >
< qemu:arg value = 'input-linux,id=kbd1,evdev=/dev/input/by-id/KEYBOARD_NAME,grab_all=on,repeat=on' / >
< / qemu:commandline >
< / domain >
```
< / td >
< / tr >
< / table >
You need to include these devices in your qemu config.
< table >
< tr >
< th >
/etc/libvirt/qemu.conf
< / th >
< / tr >
< tr >
< td >
```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"
]
...
```
< / td >
< / tr >
< / table >
Also, switch from PS/2 devices to virtio devices. Add the devices inside ** *< devices > *** block
< table >
< tr >
< th >
virsh edit win10
< / th >
< / tr >
< tr >
< td >
```xml
...
< devices >
...
< input type = 'mouse' bus = 'virtio' / >
< input type = 'keyboard' bus = 'virtio' / >
...
< / devices >
...
```
< / td >
< / tr >
< / table >
### **Audio Passthrough**
VM's audio can be routed to the host. You need ** *Pulseaudio***. \
Modify the libvirt configuration of your VM.
< table >
< tr >
< th >
virsh edit win10
< / th >
< / tr >
< tr >
< td >
```xml
...
< qemu:commandline >
...
< qemu:arg value = "-device" / >
< qemu:arg value = "ich9-intel-hda,bus=pcie.0,addr=0x1b" / >
< qemu:arg value = "-device" / >
< qemu:arg value = "hda-micro,audiodev=hda" / >
< qemu:arg value = "-audiodev" / >
< qemu:arg value = "pa,id=hda,server=/run/user/1000/pulse/native" / >
< / qemu:commandline >
< / devices >
```
< / td >
< / tr >
< / table >
### Video card driver virtualisation detection
Video Card drivers refuse to run in Virtual Machine, so you need to spoof Hyper-V Vendor ID.
< table >
< tr >
< th >
virsh edit win10
< / th >
< / tr >
< tr >
< td >
```xml
...
< features >
...
< hyperv >
...
< vendor_id state = 'on' value = 'whatever' / >
...
< / hyperv >
...
< / features >
...
```
< / td >
< / tr >
< / table >
Nvidia guest drivers also require hiding the KVM CPU leaf:
< table >
< tr >
< th >
virsh edit win10
< / th >
< / tr >
< tr >
< td >
```xml
...
< features >
...
< kvm >
< hidden state = 'on' / >
< / kvm >
...
< / features >
...
```
< / td >
< / tr >
< / table >
### **See Also**
> [Single GPU Passthrough by joeknock90](https://github.com/joeknock90/Single-GPU-Passthrough)<br/>
> [Single GPU Passthrough by YuriAlek](https://gitlab.com/YuriAlek/vfio)<br/>
> [ArchLinux PCI Passthrough](https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF)<br/>
> [Gentoo GPU Passthrough](https://wiki.gentoo.org/wiki/GPU_passthrough_with_libvirt_qemu_kvm)<br/>
