6.1.5. Hafnium RAM disk

Hafnium expects to find the following files in the root directory of its RAM disk:

• manifest.dtb – configuration file in DeviceTree format (required)

• kernels for the VMs, whose names are described in the manifest (optional)

• initrd of the primary VM, whose name is described in the manifest (optional)

The manifest.dtb must be the first file in the RAM disk, to ensure that it is properly aligned. Hafnium will not be able to read it if it is not aligned to a 4 byte boundary.

Follow the preparing Linux instructions to produce vmlinuz and initrd.img for a basic Linux primary VM.

6.1.5.1. Create a RAM disk for Hafnium

Assuming that a subdirectory called initrd contains the files listed in the previous section, we can build initrd.img with the following command:

cd initrd; echo -e "./manifest.dtb\n$(find . -type f -not -name manifest.dtb)" | cpio -o -v > ../initrd.img; cd -