Re: multiboot2 and module2 boot issues via GRUB2

[Andrew Cooper]

On 06/04/2021 09:19, Jan Beulich wrote:
> On 01.04.2021 21:43, Andrew Cooper 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.
> Well, I wasn't suggesting anywhere to concatenate random things.
> Instead I was envisioning a command line option giving us the
> context we need (e.g. "initrd=3+5").

That's a massive layering violation, and incredibly fragile to the order
of lines in the boot stanza.

Either fix it by using a single monolithic initrd, which has worked
perfectly well for the past 2 decades, or add a feature to grub to get
initrd-like behaviour for MB2 too.  I will object very strongly to any
Xen patches trying to do this.

~Andrew