Re: [Xen-devel] [PATCH OSSTEST v2 11/19] Debian: Fixup UEFI boot order during install

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Fri, 2015-06-19 at 12:02 +0100, Ian Jackson wrote:
> Ian Campbell writes ("Re: [PATCH OSSTEST v2 11/19] Debian: Fixup UEFI boot 
> order during install"):
> > On Thu, 2015-06-18 at 18:57 +0100, Ian Jackson wrote:
> > > This seems a pretty serious bug.  Is there a way to avoid it ?
> > 
> > Unfortunately not as far as I can tell, it seems to be a major
> > shortcoming of the way UEFI boot order is managed both from the UEFI UI
> > and via the Linux command line tools. FWIW I was inspired by the way
> > XenRT has to do this too (so it is a problem for x86 too).
> > 
> > grub-installer happens pretty late in the install, so the gap until the
> > late command which repairs things is short, but not ideal I agree.
> 
> The real risk is, I think, that a marginal timeout results in the
> machine being powered off at the wrong moment.

Hrm, yes.

> We could reduce the risk of this by having the installer report back
> to the controller saying "I'm about to enter the critical region" and
> "I have now exited the critical region and am about to reboot", thus
> applying a separate timeout to the critical region.

Exiting the critical region is easy, it's the same script as I added
here.

Entering the critical region I'm not sure how to hook into,
grub-installer doesn't seem to provide any hooks of that sort.
early_hook seems like a rather too early lower bound.

Ian.


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