Howto gpu passthrough

configure grub

add the following to /etc/default/grub:

for intel:

GRUB_CMDLINE_LINUX_DEFAULT="quiet ... intel_iommu=on"

for amd:

GRUB_CMDLINE_LINUX_DEFAULT="quiet ... amd_iommu=on"

re-configure your grub:

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

isolating gpu

find the device id of the gpu:

lspci -nn |grep -E NVIDIA

command output:

1:00.0 VGA compatible controller [0300]: NVIDIA Corporation GA104 [GeForce RTX 3070] [10de:2484] (rev a1)
01:00.1 Audio device [0403]: NVIDIA Corporation GA104 High Definition Audio Controller [10de:228b] (rev a1)

edit /etc/modprobe.d/vfio.conf file and adding the following line with your ids:

options vfio-pci ids=10de:2484,10de:228b

if using the nvidia drivers add the following to /etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="vfio-pci.ids=10de:2484,10de:228b" 

re-configure your grub:

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

edit /etc/mkinitcpio.conf and add the following:

MODULES="vfio vfio_iommu_type1 vfio_pci"

In the same file, also add modconf to the HOOKS line:

HOOKS="modconf"

backup your existing initramsfs image:

cp /boot/initramfs-linux.img /boot/default-initramfs-linux.img

rebuild initramfs:

mkinitcpio -g /boot/initramfs-linux.img -c /etc/mkinitcpio.conf

reboot your system:

reboot now

find your gpu and ensure that under “Kernel driver in use:” vfio-pci is displayed:

lspci -nnk

create bridge interface

create the bridge interface:

nmcli connection add type bridge autoconnect yes con-name br0 ifname br0

add device to bridge:

nmcli connection add type bridge-slave autoconnect yes con-name br0-eth0 ifname eth0 master br0

add ip address to bridge interface:

nmcli connection modify br0 ipv4.address 10.44.1.1 ipv4.method manual

active bridge interface:

nmcli connection up br0

share internet from wifi to windows

create script with iptables rules:

cat > /usr/local/bin/sharenet-wlan0 << EOF
#!/bin/bash
echo "1" > /proc/sys/net/ipv4/ip_forward
iptables -I INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -I FORWARD  -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -t nat -I POSTROUTING -o wlan0 -j MASQUERADE
EOF

fix permissions:

chmod +x /usr/local/bin/sharenet-wlan0

run the script:

/usr/local/bin/sharenet-wlan0

configure libvirtd

install virt-manager and ovmf:

pacman -S libvirt virt-manager ovmf qemu

edit /etc/libvirt/qemu.conf and add the following:

nvram = [
	"/usr/share/ovmf/x64/OVMF_CODE.fd:/usr/share/ovmf/x64/OVMF_VARS.fd"
]

start and enable the following services:

systemctl start libvirtd.service 
systemctl start virtlogd.socket
systemctl enable libvirtd.service
systemctl enable virtlogd.socket

add yourself to the libvirt group:

gpasswd -a username libvirt

install windows

install virtio windows drivers:

yay -S virtio-win

looking glass

add the following to your libvirt machine configuration inside the ‘devices’ section by running:

<shmem name='looking-glass'>
  <model type='ivshmem-plain'/>
  <size unit='M'>32</size>
</shmem>

install looking glass client:

yay -S looking-glass

references

• https://github.com/vanities/GPU-Passthrough-Arch-Linux-to-Windows10