VFIO Helper Script

#!/bin/bash

# Which device and which related HDMI audio device. They're usually in pairs.
export VGA_DEVICE=0000:01:00.0
export AUDIO_DEVICE=0000:01:00.1

# Placeholders. For radeon and shit.
export VGA_DRIVER=nvidia
export AUDIO_DRIVER=snd_hda_intel

# Passing through USB devices. Querying bus address and feeding that to QEMU
# instead of the device ID, so you can yank and replug the keyboard to regain
# control.
export KEYBOARD="04d9:4545"
export MOUSE="1532:0043"

vfiobind() {
    DEV="$1"

    echo -n Binding VFIO to ${DEV}...

    echo ${DEV} > /sys/bus/pci/devices/${DEV}/driver/unbind
    sleep 0.2

    echo vfio-pci > /sys/bus/pci/devices/${DEV}/driver_override
    echo ${DEV} > /sys/bus/pci/drivers/vfio-pci/bind
    echo > /sys/bus/pci/devices/${DEV}/driver_override
    sleep 0.5

    echo OK!
}

vfiounbind() {
    DEV="$1"

    echo -n Unbinding VFIO from ${DEV}...

    echo ${DEV} > /sys/bus/pci/drivers/vfio-pci/unbind
    sleep 0.2

    echo ${DEV} > /sys/bus/pci/drivers_probe
    sleep 0.5

    echo OK!
}

# Xorg shouldn't run.
if [ -n "$( ps -C xinit | grep xinit )" ];
then
    echo Don\'t run this inside Xorg!
    exit 1
fi

# Unbind specified graphics card and audio device.
echo Pulling the plug on the specified passthrough devices...

vfiobind $VGA_DEVICE
vfiobind $AUDIO_DEVICE

# Meh.
export QEMU_AUDIO_DRV=pa

# Get the bus addresses for keyboard and mouse.
export QEMU_KEYB=$( lsusb | sed -n 's/Bus \([0-9]*\) Device \([0-9]*\): ID '$KEYBOARD'.*/-device usb-host,bus=xhci.0,hostbus=\1,hostaddr=\2/p' )
export QEMU_MOUS=$( lsusb | sed -n 's/Bus \([0-9]*\) Device \([0-9]*\): ID '$MOUSE'.*/-device usb-host,bus=xhci.0,hostbus=\1,hostaddr=\2/p' )

echo Starting virtual machine...

# Run pulseaudio as root but not system daemon. Hack.
pulseaudio --start

# QEMU stuff
qemu-system-x86_64 \
    -machine type=q35,accel=kvm,kernel_irqchip=on \
    -rtc base=localtime \
    -enable-kvm \
    -cpu host,kvm=off,hv_relaxed,hv_spinlocks=0x1fff,hv_vapic,hv_time,hv-vendor-id=servo,hv-vpindex,hv-synic,hv-reset,hv-stimer,hv-runtime,hv-crash \
    -smp 8,sockets=1,cores=4,threads=2 \
    -m 12288 \
    -device ioh3420,bus=pcie.0,addr=1c.0,multifunction=on,port=1,chassis=1,id=root.1 \
    -object iothread,id=io1 \
    -device virtio-blk-pci,id=blk0,drive=drive0,iothread=io1,bus="pcie.0" \
    -drive if=none,id=drive0,file=/dev/bcache/by-uuid/84ea4a08-eed7-4651-93b6-24d5ed6d570a,format=raw,aio=threads,cache=none,cache.direct=on \
    -vga none \
    -drive if=pflash,format=raw,readonly,file=/usr/share/edk2.git/ovmf-x64/OVMF_CODE-pure-efi.fd \
    -drive if=pflash,format=raw,file=/usr/share/edk2.git/ovmf-x64/OVMF_VARS-pure-efi.fd \
    -display none \
    -device vfio-pci,host=01:00.0,bus="root.1" \
    -usb \
    -device nec-usb-xhci,id=xhci,bus="pcie.0" \
    $QEMU_KEYB \
    $QEMU_MOUS \
    -device virtio-net,netdev=net0,mac=de:ad:be:ef:33:4a,bus="pcie.0" \
    -netdev tap,id=net0,ifname=vmtap0,script=./qemu-ifup,downscript=./qemu-ifdown \
    -device ich9-intel-hda,bus="pcie.0",id=sound0 \
    -device hda-duplex,cad=0,bus=sound0.0 \
    -parallel none -serial none

# Kill pulseaudio instance started earlier.
pulseaudio --kill

# Rebind the devices for the host.
echo Adios vfio, reloading the host drivers for the passedthrough devices...

vfiounbind $AUDIO_DEVICE
vfiounbind $VGA_DEVICE