Pkg xen devel - Sep 2021 - The kernel's dropping of 32-bit PV guest support should be mentioned in bullseye's i386 release notes

Hi,

Over the last 24 hours two of my customers have tried to
dist-upgrade from buster to bullseye. As they were running PV mode
32-bit guests this appeared to work fine until they tried to reboot
into bullseye, and then the kernel wouldn't boot. As we know that is
because the Linux kernel dropped support for 32-bit PV mode guests
at 5.9.

Now, clearly 32-bit PV is a bad idea and nobody should be running
that any more and any hosting setup that has these should have been
getting people to switch to PVH or HVM. And we have, but always there
are some people that don't get the message. They won't look into the
Xen Project documentation on that either.

I think that the bullseye i386 release notes should mention that if
you're upgrading from a buster Xen PV guest then you need to switch
it to PVH or HVM mode, or go to 64-bit. People who have managed to
go this far without realising they need to switch away from 32-bit
probably won't read Debian's release notes, but all persons
upgrading from one version of Debian to another are supposed to read
them so I think it's a good place.

I opened bug 995397 against release-notes to suggest this be added
and if maintainer agrees then I am happy to suggest some text.

Cheers,
Andy