Re: multiboot2 and module2 boot issues via GRUB2

[Daniel Kiper]

On Thu, Apr 01, 2021 at 08:43:46PM +0100, Andrew Cooper via Grub-devel wrote:
> On 01/04/2021 09:44, Roger Pau Monné wrote:
> > On Thu, Apr 01, 2021 at 09:31:07AM +0200, Jan Beulich wrote:
> >> On 01.04.2021 03:06, Roman Shaposhnik wrote:
> >>> And the obvious next question: is my EVE usecase esoteric enough that
> >>> I should just go ahead and do a custom GRUB patch or is there a more
> >>> general interest in this?
> >> Not sure if it ought to be a grub patch - the issue could as well
> >> be dealt with in Xen, by concatenating modules to form a monolithic
> >> initrd.
> > I would rather have it done in the loader than Xen, mostly because
> > it's a Linux boot specific format, and hence I don't think Xen should
> > have any knowledge about it.
> >
> > If it turns out to be impossible to implement on the loader side we
> > should consider doing it in Xen, but that's not my first option.
>
> Concatenating random things which may or may not be initrds is
> absolutely not something Xen should do.  We don't have enough context to
> do it safely/sensibly.
>
> Honestly, I like the idea of supporting something like this generally in
> grub.  Linux already commonly has initrd preparation prepending an
> uncompressed microcode CPIO archive, and I can see a usability advantage
> from maintaining the initrd fragments separately.
>
> Looking at the grub manual, this behaviour of the `initrd` command isn't
> even documented.  Perhaps that should be fixed first, and then maybe
> `module2_multi` added too?

I am OK with additional Multiboot2 command. Though I would do
s/module2_multi/module2_concat/. Additionally, it should look for "--"
and interpret everything after it as a command line argument for
a concatenated module.

Daniel