Re: [Xen-devel] High CPU temp, suspend problem - xen 4.1.5-pre, linux 3.7.x

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 26.03.13 at 19:50, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
> So vector e9 doesn't appear to be programmed in anywhere.

Quite obviously, as it's the 8259A vector for IRQ 9. The question
really is why an IRQ appears on that vector in the first place. The
8259A resume code _should_ leave all IRQs masked on a fully
IO-APIC system (see my question raised yesterday).

And that's also why I suggested, for an experiment, to fiddle with
the loop exit condition to exclude legacy vectors (which wouldn't
be a final solution, but would at least tell us whether the direction
is the right one). In the end, besides understanding why an
interrupt on vector E9 gets raised at all, we may also need to
tweak the IRQ migration logic to not do anything on legacy IRQs,
but that would need to happen earlier than in
smp_irq_move_cleanup_interrupt(). Considering that 4.3
apparently doesn't have this problem, we may need to go hunt for
a change that isn't directly connected to this, yet deals with the
problem as a side effect (at least I don't recall any particular fix
since 4.2). One aspect here is the double mapping of legacy IRQs
(once to their IO-APIC vector, and once to their legacy vector,
i.e. vector_irq[] having two entries pointing to the same IRQ).

Jan


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