[Xen-devel] Re: [PATCH 08/13] xen/pvticketlock: disable interrupts while blocking

[Don Zickus <dzickus@xxxxxxxxxx>]

On Wed, Sep 14, 2011 at 10:00:07AM +0300, Avi Kivity wrote:
> On 09/13/2011 10:21 PM, Don Zickus wrote:
> >Or are you saying an NMI in an idle system will have the same %rip thus
> >falsely detecting a back-to-back NMI?
> >
> >
> 
> That's easy to avoid - insert an instruction zeroing the last
> nmi_rip somewhere before or after hlt.  It's always okay to execute
> such an instruction (outside the nmi handler itself), since nmi_rip
> is meant to detect a "no instructions executed" condition.

Ah. Like a touch_nmi_watchdog() type of thing.  Interesting.  I'll poke
around the idle code.  Need to instrument a reproducer first.

Thanks,
Don

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