RFC: allow specifying CPU microcode binaries in jobs
The Linux kernel provides a mechanism to load CPU microcodes in the early boot stages. This may be useful for some target platforms that need certain ucode updates to enable vulnerability mitigation mechanisms or other specific CPU features.
The most flexible method to load them (at boot time) is to prepend the cpio'd ucode binary to the initrd image. Having an optional "deploy" key for this that makes LAVA concatenate the ucode binary with the repackaged initrd (after the overlays have been applied) would allow to boot Linux with additional CPU ucodes in certain platforms, configurable in a per-job basis without having to change anything in the kernel image or the initrd.
I tried to do this myself but I couldn't find how to modify the job definition schema so that the validation won't warn about the extra key. All guidance is welcome.