Fetch the latest kernel and build a bootable x86 or ARM64 image along with a busybox userspace.
To run, set the QEMU_BUILD_DIR environment variable in the run.sh script to your qemu build directory before running it as follows.
$ ./run.sh x86 build or
$ ./run.sh arm64 build
You need the build argument only the first time you run. You can remove it for subsequent runs.