Below is an example command-line a user would run from the host Linux to start virt virtual machine booting a Linux guest:
qemu-system-aarch64 -smp 8 -m 1024 -cpu host -machine type=virt,gic-version=3 -kernel /boot/Image -enable-kvm -display none -serial tcp::4446,server,telnet -drive if=none,file=rootfs__ubuntu__arm64.ext4,id=foo,format=raw -device virtioblk-device,drive=foo -append 'root=/dev/vda rw console=ttyAMA0 rootwait earlyprintk' -monitor stdio
