Re: [PATCH 0/2] Introducing hyperlaunch capability design (formerly: DomB mode of dom0less)

[Jan Beulich <jbeulich@xxxxxxxx>]

On 16.03.2021 04:56, Daniel P. Smith wrote:
> To assist in reading, please find attached rendered copies of the design
> docs. It should be noted that due to poor rendering by pandoc, we forced
> the tables to stay as ASCII tables in the patches whereas the attached
> docs have the tables rendered properly by rst2pdf.

In section 3.6 I found "As a result, on x86 the hyperlaunch capability does
not rely on nor preclude any specific BIOS boot protocol, i.e legacy BIOS
boot or UEFI boot. The only requirement is that the boot loader supports
the Multiboot2 (MB2) protocol." I'm afraid the two sentences contradict
one another, as UEFI on its own doesn't provide MB2 functionality. It is
my understanding that you don't require this anyway - what you need is a
way to load modules beyond just Dom0 kernel and an initrd.

I'm also struggling to see how you mean to associate the (MB2) modules
passed to Xen with the individual functions. I.e. I don't see how it will
be ensure that the embedded mb-index is in sync with the order or modules
actually supplied.

As to modules - iirc there are placement restrictions by at least some
boot loaders (below 4Gb). If that's correct, do you have any thoughts
towards dealing with the limited space available to hold these modules?
I've seem systems with lots of memory, but with as little as just 1Gb
below the 4Gb boundary.

Jan