Re: [xen-unstable test] 77945: regressions - FAIL [and 2 more messages]

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 15/01/16 17:15, Jan Beulich wrote:
>>>> On 15.01.16 at 18:06, <ian.campbell@citrix.com> wrote:
>> On Thu, 2016-01-14 at 16:27 +0000, Ian Jackson wrote:
>>>  * I don't have a clear design proposal for the above but I think Doug
>>>    can probably provide one.  I'm hoping this is more a matter of
>>>    thinking carefully than of extensive build system programming!
>> I think we should:
>>
>> 1) Move /usr/lib/debug/xen-4.7-unstable.config to /boot. I previously
>> didn't care about what path it was, but the usecase of having grub be able
>> to react to the config (see below) is a strong reason to have it in /boot
>> IMHO. Jan has said he won't veto such a change, AFAICT everyone else is
>> happy with it.
>>
>> 2) Assume that grub (specifically the patch in http://savannah.gnu.org/bugs 
>> /?43420 and as used by osstest today) will at some point be modified to
>> look at /boot/xenconfig-$version to decide whether to create an XSM entry
>> or not instead of the presence of /boot/xenpolicy-$version. This step
>> belongs here logically but chronologically could come much later since
>> osstest will do the right thing even if there is a spurious
>> /boot/xenpolicy-$version file (which is to say it will ignore the spurious
>> entry and boot the right thing).
>>
>> 3) Have tools/* always build the FLASK+XSM tools _and_ the FLASK policy and
>> to always install both. Any related configure options can go away and we no
>> longer need to worry about synchronising the configuration of the tools and
>> xen trees, this is desirable because we would prefer to have one set of
>> tools which gracefully handles differing hypervisor configurations over
>> needing different sets of tools (FLASK+XSM was one of the few exceptions to
>> that rule AFAICT).
>>
>> I think with this plan there is no need to modify osstest.git, since it
>> already does the right thing (which is, it sets XSM for Xen builds, which
>> in turn enables FLASK and it does nothing for tools/* which is correct once
>> #3 above has happened).
>>
>> The only downside is a spurious /boot/xenpolicy-$version installed when the
>> corresponding Xen binary doesn't support XSM, however given the assumption
>> in #2 (which implies the user will never see a spurious grub entry, which
>> is the important thing) and the fact that it avoids the complexity of
>> having tools/* rely in some way on xen/.config I think that is a worthwhile
>> trade-off.
>>
>> Hopefully this simplifies a bunch of the arguments we have been having and
>> provides a path forwards?
>>
>> Objections?
> My opinion on 1 and 2 is known; 3 seems like a good step to me.

FWIW, I also prefer option 3.  It lends itself better to a toolstack
which functions in the same way, irrespective of hypervisor configuration.

~Andrew