506720a2da | 9 months ago | |
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.github | 9 months ago | |
README.md | 9 months ago |
README.md
Table Of Contents
- IOMMU Setup
- Installing Packages
- Enabling Services
- Guest Setup
- Attching PCI Devices
- Libvirt Hooks
- Keyboard/Mouse Passthrough
- Video Card Virtualisation Detection
- Audio Passthrough
- GPU 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.
For GRUB user, edit grub configuration.
/etc/default/grub |
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GRUB_CMDLINE_LINUX_DEFAULT="... intel_iommu=on iommu=pt ..." |
OR |
GRUB_CMDLINE_LINUX_DEFAULT="... amd_iommu=on iommu=pt ..." |
Generate grub.cfg
grub-mkconfig -o /boot/grub/grub.cfg
Reboot your system for the changes to take effect.
To verify IOMMU, run the following command.
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:
#!/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.
Install required tools
Gentoo Linux
emerge -av qemu virt-manager libvirt ebtables dnsmasq
Arch Linux
pacman -S qemu libvirt edk2-ovmf virt-manager dnsmasq ebtables
Fedora
dnf install @virtualization
Ubuntu
apt install qemu-kvm qemu-utils libvirt-daemon-system libvirt-clients bridge-utils virt-manager ovmf
Enable required services
SystemD
systemctl enable --now libvirtd
OpenRC
rc-update add libvirtd default
rc-service libvirtd start
Sometimes, you might need to start default network manually.
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.
usermod -aG kvm,input,libvirt username
Download virtio 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
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
mkdir /etc/libvirt/hooks
touch /etc/libvirt/hooks/qemu
chmod +x /etc/libvirt/hooks/qemu
/etc/libvirt/hooks/qemu |
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Create Start Script
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 |
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Create Stop Script
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 |
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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 |
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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.
virsh edit win10 |
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You need to include these devices in your qemu config.
/etc/libvirt/qemu.conf |
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Also, switch from PS/2 devices to virtio devices. Add the devices inside <devices>
block
virsh edit win10 |
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Audio Passthrough
VM's audio can be routed to the host. You need Pulseaudio. It's hit or miss.
You can also use Scream instead of Pulseaudio.
Modify the libvirt configuration of your VM.
virsh edit win10 |
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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 |
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NVIDIA guest drivers also require hiding the KVM CPU leaf:
virsh edit win10 |
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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 to dump vBIOS.
To dump vBIOS on Linux, you can use following command (replace PCI id with yours):
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:
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) 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 |
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See Also
Single GPU Passthrough Troubleshooting
Single GPU Passthrough by joeknock90
Single GPU Passthrough by YuriAlek
Single GPU Passthrough by wabulu
ArchLinux PCI Passthrough
Gentoo GPU Passthrough