Re: [Xen-devel] Early ACPI events prevent subsequent ACPI functionality on xen 4.3 + HVM domU

[Diana Crisan <dcrisan@xxxxxxxxxxxx>]

George,

On 21/05/13 17:09, George Dunlap wrote:
> On 05/21/2013 04:59 PM, Alex Bligh wrote:
> > George,
> >
> > --On 21 May 2013 16:23:00 +0100 George Dunlap
> > <george.dunlap@xxxxxxxxxxxxx> wrote:
> >
> > > On 05/21/2013 04:16 PM, Alex Bligh wrote:
> > > > George,
> > > >
> > > > --On 21 May 2013 14:39:55 +0100 George Dunlap
> > > > <George.Dunlap@xxxxxxxxxxxxx> wrote:
> > > >
> > > > > So this appears to be an xl toolstack thing.  I managed to reproduce
> > > > > your results using "xl shutdown -F [domain]"; but if you then do "xl
> > > > > trigger [domian] power", the domain shuts down as normal.
> > > > OK. But doesn't the power thing yank the power rather than send a
> > > > clean shutdown?
> > > No -- if you push the button just once on most modern hardware it will
> > > send an ACPI "poweroff" event that the OS handles gracefully. That's
> > > what gets sent when you do "xl trigger [domain] power".  If the OS
> > > ignores it (either on real hardware or virtual hardware) nothing 
> > > happens.
> > > On real hardware you have to then hold down the button for 5 seconds 
> > > for
> > > a hard-shutdown, with xl you have to do "xl destroy".
> > OK, great. I am guessing the reason why 'xl shutdown' doesn't do
> > that is to cope with (a) non-HVM domains, and (b) old fashioned
> > HVM domains with PV support but not ACPI support. Correct?
> >
> > > > We are using libxl here (admittedly having looked carefully at
> > > > the xl code for guidance) and get the same problem.
> > > The relevant xl code is here:
> > >
> > >      rc=libxl_domain_shutdown(ctx, domid);
> > >      if (rc == ERROR_NOPARAVIRT) {
> > >          if (fallback_trigger) {
> > >              fprintf(stderr, "PV control interface not available:"
> > >                      " sending ACPI power button event.\n");
> > >              rc = libxl_send_trigger(ctx, domid, 
> > > LIBXL_TRIGGER_POWER, 0);
> > >          } else {
> > >              fprintf(stderr, "PV control interface not available:"
> > >                      " external graceful shutdown not possible.\n");
> > >              fprintf(stderr, "Use \"-F\" to fallback to ACPI power
> > > event.\n");
> > >          }
> > >      }
> > >
> > > It looks like libxl_domain_shutdown() will only use the PV shutdown
> > > method.  If that method is not available, then it will call
> > > libxl_send_trigger().
> > OK. Well if that's the case, why is it not working? i.e. how
> > is using 'xl trigger power' a workaround? As our testing was
> > on xl (as well as libxl). Perhaps libxl_domain_shutdown
> > is returning an error other than ERROR_NOPARAVIRT or no error
> > at all?
> xl/libxl is working as designed. xl tried libxl_domain_shutdown() 
> first.  libxl saw that there were PV drivers available, so it sent the 
> PV shutdown signal over xenstore and returned success.  libxl and xl 
> have no way of knowing that the signal was never received, so it never 
> falls back to ACPI.
> "xl trigger power" is a work-around because when you detect that a 
> guest is stuck, you should be able to issue an ACPI shutdown and get a 
> clean shutdown, even when the PV shutdown path is stuck.
> (In fact, as a short-term solution, you might consider just replacing 
> "xl shutdown $d" with "xl trigger $d power" in your control framework.)
I am having problems replicating the short-term solution reliably on our 
end, even with xl/libxl. It seems that issuing an "xl trigger dom power" 
does not make the domain shutdown, even after a 10 minute wait. 
Subsequent ones tend to do the same and after issuing quite a few I 
managed to get the domU to power off.
This happens even if I do not issue the shutdown early in the boot 
process, but rather issue directly an xl trigger dom power.
> > Does xl trigger reset do the same thing (i.e. a graceful shutdown)?
> > If not we'd also (I think) have to recode reboots to do a power trigger
> > then a restart.
> Hmm, this is what I get:
>
> # xl trigger h0 reset
> libxl: error: libxl.c:4639:libxl_send_trigger: Send trigger 'reset' 
> failed: Function not implemented
> YMMV...
>
>  -George
--
Diana Crisan

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel