Question about loading bare metal firmware

[Clément Chigot]

Hi all,

I'm wondering if there is an official way to load bare metal software
within qemu emulations.
I've seen a lot of people (including us) using -kernel. However, the
doc seems to imply that the generic loader would be a better approach
(cf [1]). I know that the compatibility with older Qemus is one of the
reasons why -kernel is still highly used. I've also seen that the
reset vector can be initialized automatically by -kernel unlike with
the generic loader (this is the case with RiscV AFAICT).
But is there any kind of official recommendation on that topic ?

I'm asking that because a recent change in RiscV Polarfire Soc is
forcing -dtb to be passed along -kernel. But in case of bare board
software, -dtb isn't needed (at least in our use case).
I've a patch that allows "-dtb" to be missing with "-kernel" only if
"-bios none" is provided. But I'm not sure if this is the right way to
say "it's a bare board software".

@Bin Meng you're the one that added this -kernel support in PolarFire
Soc. Thus, is my approach looking good for you or do you have a better
one in mind ?

[1] https://www.qemu.org/docs/master/system/qemu-manpage.html#hxtool-8

Thanks,
Clément