Re: Xen 4.4 development update

[Daniel Kiper <daniel.kiper@oracle.com>]

On Thu, Aug 08, 2013 at 04:51:51PM -0400, Eric Shelton wrote:
> On Thu, Aug 8, 2013 at 3:55 PM, Konrad Rzeszutek Wilk
> <konrad.wilk@oracle.com> wrote:
> . . .
> > Rework them. The maintainer would like it done differently - that was my
> > recollection last year when I chatted with him (Matthew Garret).
> >
> > Daniel will know more - but he is right now making multiboot2 work with
> > Xen and then attacking this.
>
> Back then (https://lkml.org/lkml/2012/2/9/299), Matthew said:
>
> > Hm. Is there absolutely no way to do this by replacing efi_call_*? It'd
> > really be nice to avoid yet another set of duplicate functions here -
> > the ia64/x86 situation is already bad enough. Ideally this would be
> > sufficiently generic that arm can also plug into it.
>
> It looks like the arm patches are just now nearing commit worthiness,
> with V2 just posted a couple of days ago:
>
> https://lkml.org/lkml/2013/8/6/584
>
> It looks like Garrett's goal of merging arm and x86 EFI code is being
> realized, and that I will need to refactor my patchset to keep up with
> these changes.  Roy Franz seems to be doing the heavy lifting on arm
> EFI, with Matt Fleming serving as the maintainer.

I have not dug very deep but it looks that it is only EFI loader
patch series (called stub in Linux Kernel). It is not related to
Xen EFI stuff in Linux Kernel.

> Related to this, is the Xen hypervisor booting under EFI for arm
> already?  I assume not, if Linux currently lacks the needed
> hypercalls.  Does anything arm-specific need to happen in an
> EFI-friendly dom0 kernel, given that it is hypercall driven?  Is there
> a platform for test?

IIRC there is no EFI support in Xen on ARM. However, you should ask
Stefano and/or Ian Campbell for more details. They are ARM maintainers
for Xen.

As Konrad said I am working on multiboot2 protocol support for Xen.
It is needed to load Xen from e.g. GRUB2 loader on EFI platforms.
I would like to finish this first because there are some interests
in that project. Then I will be working on EFI support for Xen
in Linux Kernel. However, if you like to work on this stuff go
ahead. I do no have any objections. Just drop me line then I would
not duplicate your efforts.

Daniel