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

["Andi Kleen" <andi@xxxxxxxxxxxxxx>]

> But, erm, does that even make sense?  I'm assuming the NMI reason port
> tells the CPU why it got an NMI.  If multiple CPUs can get NMIs and
> there's only a single reason port, then doesn't that mean that either 1)
> they all got the NMI for the same reason, or 2) having a single port is
> inherently racy?  How does the locking actually work there?

All the code to determine NMI reasons is inherently racy,
and each new NMI user makes it worse.

-Andi


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