Bug#995397: Dropped support for 32-bit Xen PV guests should be mentioned in i386 release notes

[Andy Smith <andy@strugglers.net>]

Hi Paul,

On Thu, Sep 30, 2021 at 10:21:42PM +0200, Paul Gevers wrote:
> This indeed sounds like something that could be mentioned under the
> "issues to be aware of" section. A proposal text would help the process
> forward.

Thanks. I am not sure whether it fits in "Items not limited to the
upgrade process" or under "Obsolescence and deprecation", but how
about:

    The Linux kernel no longer provides support for 32-bit Xen
    guests in PV mode.

    Users of 32-bit Xen guests should check that they are running in
    either PVH or HVM mode before upgrading to bullseye, since as of
    v5.9 the Linux kernel will not boot as a 32-bit Xen PV mode
    guest.

    You can check which type of Xen guest you are running as
    follows:

    <pre>
    $ cat /sys/hypervisor/guest_type
    PV
    </pre>

    If you see <b>PVH</b> or <b>HVM</b> here then you should be safe
    to upgrade to bullseye.

    If it is a requirement to continue using PV mode, the least
    disruptive option may be to <a
    href="https://wiki.debian.org/CrossGrading";>switch to an amd64
    (64-bit) kernel</a>. It is not necessary to cross-grade the
    entire system to amd64.

Not sure if the last paragraph is appropriate as I'm not sure if
cross-grading like that is considered supported, even though I
suppose multiarch is considered supported, so why not?

Anyway, all of this is only for the i386 release notes as amd64
support has not been dropped.

Thanks!
Andy