Re: [Xen-devel] Re: [PATCH] xen: events: do not unmask polled ipis on restore.

[Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>]

On Fri, 2010-10-29 at 18:42 +0100, Jeremy Fitzhardinge wrote:
> On 10/29/2010 10:35 AM, Ian Campbell wrote:
> > On Fri, 2010-10-29 at 17:44 +0100, Jeremy Fitzhardinge wrote:
> >> On 10/29/2010 01:33 AM, Ian Campbell wrote:
> >>> The Xen PV spinlock backend attempts to setup an IPI to IRQ binding
> >>> which is only to be used via xen_poll_irq rather received directly.
> >>>
> >>> Unfortunately restore_cpu_ipis unconditionally unmasks each IPI
> >>> leading to:
> >> Gosh I wonder why we hadn't seen this before?
> > I must admit I don't normally enable CONFIG_PARAVIRT_SPINLOCKS I
> > happened to be running someone else's config when I noticed this.
> >
> > Possibly relates to switching to the edge triggered handler and the
> > related mask/unmask vs clear etc frobbing?
> 
> Possibly.  Did you see my comment further down?

No! Going back now...

Ian.



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