I've been using vftool with arm64 Ubuntu server cloudimg. Directly uses the virtualization framework, easy to work with once you get it going.

https://github.com/evansm7/vftool

my command: vftool -k vmlinuz -i initrd -d disk.img -p 4 -m 2048 -a "console=hvc0 irqaffinity=0 root=/dev/vda"