qemu_fifo.sh

#!/bin/bash

HCPUS=8-15,24-31
MCPUS=0-7,16-23
ACPUS=0-31

disable_isolation () {
    #vfio-isolate \
    #        cpuset-modify --cpus C$ACPUS /system.slice \
    #        cpuset-modify --cpus C$ACPUS /user.slice \
    #        irq-affinity mask C$ACPUS

    systemctl set-property --runtime -- user.slice AllowedCPUs=$ACPUS
    systemctl set-property --runtime -- system.slice AllowedCPUs=$ACPUS
    systemctl set-property --runtime -- init.scope AllowedCPUs=$ACPUS

    echo 950000 > /proc/sys/kernel/sched_rt_runtime_us

    taskset -pc $ACPUS 2  # kthreadd reset
}

enable_isolation () {
    chrt -a -f -p 99 $(pidof qemu-system-x86_64)
    echo "Set QEMU execution policy!"
    chrt -p $(pidof qemu-system-x86_64)

    vfio-isolate \
        drop-caches \
        cpuset-modify --cpus C$HCPUS /system.slice \
        cpuset-modify --cpus C$HCPUS /user.slice \
        move-tasks / /system.slice \
        compact-memory \
        irq-affinity mask C$MCPUS

    # schedule real-time processes to have more CPU time
    echo -1 > /proc/sys/kernel/sched_rt_runtime_us

    systemctl set-property --runtime -- user.slice AllowedCPUs=$HCPUS
    systemctl set-property --runtime -- system.slice AllowedCPUs=$HCPUS
    systemctl set-property --runtime -- init.scope AllowedCPUs=$HCPUS

    taskset -pc $HCPUS 2  # kthreadd only on host cores
}

arg="$1"
shift
if [ "$arg" == "--cleanup" ]; then
	ec\ho "Cleanup qemu fifo"
	disable_isolation
	exit 0
fi

if [[ $(sudo virsh list --all | grep running) ]]; then
  echo "VM running, performing action"
  enable_isolation
else
  echo "VM no longer running, aborting"
  disable_isolation
  exit 1
fi