# This is needed to support post-copy migration for QEMU run by libvirt,
# i.e., unprivileged, as userfaultfd is by default only available to
# privileged processes.
# It can be safely overridden by a file in /etc/sysctl.d/ in case post-copy
# migration is not used on the host.
-vm.unprivileged_userfaultfd = 1