Re: HVMLite / PVHv2 - using x86 EFI boot entry

["Luis R. Rodriguez" <mcgrof@kernel.org>]

On Wed, Apr 06, 2016 at 01:11:30PM +0200, Daniel Kiper wrote:
> On Wed, Apr 06, 2016 at 04:40:27AM +0200, Luis R. Rodriguez wrote:
> > Boris sent out the first HVMLite series of patches to add a new Xen guest type
> > February 1, 2016 [0]. We've been talking off list with a few folks now over
> > the prospect of instead of adding yet-another-boot-entry we instead fixate
> > HVMLite to use the x86 EFI boot entry. There's a series of reasons to consider
> > this, likewise there are reasons to question the effort required and if its
> > really needed. We'd like some more public review of this proposal, and see if
> > others can come up with other ideas, both in favor or against this proposal.
> >
> > This in particular is also a good time to get x86 Linux folks to chime on on
> > the general design proposal of HVMLite design, given that outside of the boot
> > entry discussion it would seem including myself that we didn't get the memo
> > over the proposed architecture review [1]. At least on my behalf perhaps the
> > only sticking thorns of the design was the new boot entry, which came to me
> > as a surprise, and this thread addresses and the lack of addressing semantics
> > for early boot (which we may seem to need to address; some of this is being
> > addressing in parallels through other work). The HVMLite document talks about
> > using ACPI_FADT_NO_VGA -- we don't use this yet upstream but I have some pending
> > changes which should make it easy to integrate its use on HVMLite. Perhaps
> > there are others that may have some other points they may want to raise now...
> >
> > A huge summary of the discussion over EFI boot option for HVMLite is now on a
> > wiki [2], below I'll just provide the outline of the discussion. Consider this a
> > request for more public review, feel free to take any of the items below and
> > elaborate on it as you see fit.
> >
> > Worth mentioning also is that this topic will be discussed at the 2016 Xen
> > Hackathon April 18-19 [3] at the ARM Cambridge, UK Headquarters so if you can
> > attend and this topic interests you, consider attending.
> 
> I hope that you will be there as one of the biggest proponents of EFI entry point.

It would be a last minute trip to prepare for...

> If you does not it will be difficult or impossible to discuss this issue without you.
> In the worst case I can raise this topic on behalf of you and then we should organize
> phone call if possible (and accepted by others). However, to do that I must know your
> plans in advance.

I understand, I'd like to make it clear I am taking simply a neutral position
on this topic, even though it may seem I'm a die-hard on this idea, this was
simply an architectural question that came up, and I have been just
dissatisfied with the answers against the architectural questions I had over
this.

To help better evaluate how neutral really a discussion like this can be
can someone please help chime in on the question of if there are pressures to
just complete HVMLite design already ? How strong are those ? Are we really
able to have a very neutral technical discussion on this ?

  Luis