[Xen-devel] RE: Genapic testing

["Puthiyaparambil, Aravindh" <aravindh.puthiyaparambil@xxxxxxxxxx>]

> > On an 8-way ES7000, Xen boots successfully but the system loops on
the
> > "Time went backwards" message while Dom0 comes up.
> 
> Does it just happen during boot, or carry on forever? Is dom0 UP or
> SMP? It sounds like IRQ0 is not getting through -- we bump time via

Dom0 is UP. It does not complete booting. It loops infinitely on the
"Time went backwards" message. The boot does not continue from that
point on. I am attaching the boot output.
If IRQ0 does not get through then won't check_timer() in io_apic.c fail?
That seems to be working which indicates that IRQ0 is indeed getting
through.

> I suggest adding tracing to timer_interrupt() in xen/arch/x86/time.c
> and see whether or not it is getting executed.

I added some trace to the function and it is being called. Any idea
where to go from here?

> > The other thing I noticed was that
> > specifying "apic=verbose" on the Xen command line in grub causes the
> > default driver to be loaded initially which is alright as the check
for
> > the ES7000 happens later on.
> 
> It seems that Linux has a cmdline conflict between genapic and apic.c
> tracing as to who owns "apic=". Does our behaviour differ from that of
> native Linux? I could change the parameter name of one or the other
> within Xen -- any suggestions for which and to what?

The same thing happens with native Linux (SLES9 SP1). I would suggest
adding a new "genapic" command line option so that it can be separate
from the "apic" option. Or we can add a check in generic_apic_probe() to
ignore apic=verbose/debug.

Aravindh

Attachment: xen3-genapic-es7000.txt
Description: xen3-genapic-es7000.txt

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