Bug#776450: Xen PVH support for grub-xen in Buster

[Colin Watson]

On Mon, Jan 07, 2019 at 09:53:36PM +0100, Hans van Kranenburg wrote:
> Note that:
> 
> Installing for x86_64-xen platform.
> grub-install: warning: no hints available for your platform. Expect
> reduced performance.
> Installation finished. No error reported.
> 
> ...which means that it only has /boot/grub/x86_64-xen with a copy of the
> modules. Maybe that's something to think about for the part of the story
> that actually expects those modules to be there? Maybe just always throw
> all of the three different types in there?

Oh right, I indeed forgot that bit.  I've pushed a fix (though no need
to retest).  i386-xen can only boot a 32-bit kernel and so isn't usable
with an amd64 userspace, but i386-xen_pvh can be used either way.

> Anyway, the first thing we're testing doesn't rely on that, so let's
> continue. In the xen config file, I use...
> 
> ---- >8 ----
> kernel = "/usr/lib/grub-xen/grub-i386-xen_pvh.bin"
> type = "pvh"
> ---- >8 ----
> 
> ...and yes, blue grub screen and it boots.

Excellent; thanks a lot for the test!

> Suggestion:
> 
> From usability point of view, it would actually also be nice if
> console=hvc0 would be added by default in the GRUB_CMDLINE_LINUX_DEFAULT
> for inside the Xen domU.
> 
> The default is now "quiet", but if you remove "quiet", it stays as
> quiet, and for a new user, it doesn't have to be super obvious what to
> do in this case.

It would be helpful not to collect too many not-very-closely-related
issues into this single bug.  In any case, if you install via the Debian
installer then it arranges for this to happen; we could look into doing
it somewhere else if there were a compelling reason to do so, but I'm a
little wary of shuffling all that fairly delicate machinery around as we
approach release, and d-i already sets up a number of other similar
things so is in a good position to do this.

-- 
Colin Watson                                       [cjwatson at debian.org]