Re: [Xen-devel] [PATCH v1 2/2] xen/arm: Fix deadlock in on_selected_cpus function

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 28 Jan 2014, Ian Campbell wrote:
> On Mon, 2014-01-27 at 19:00 +0000, Stefano Stabellini wrote:
> > Alternatively, as Ian suggested, we could increase the priotiry of SGIs
> > but I am a bit wary of making that change at RC2.
> 
> I'm leaning the other way -- I'm wary of open coding magic locking
> primitives to work around this issue on a case by case basis. It's just
> too subtle IMHO.
> 
> The IPI and cross CPU calling primitives are basically predicated on
> those IPIs interrupting normal interrupt handlers.

The problem is that we don't know if we can context switch properly
nested interrupts. Also I would need to think harder whether everything
would work correctly without hitches with multiple SGIs happening
simultaneously (with more than 2 cpus involved).

On the other hand we know that both Oleksandr's and my solution should
work OK with no surprises if implemented correctly.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel