Re: [PATCH] powerpc/mpic: Remove WHOAMI readback after EOI

From: Scott Wood
Date: Wed May 13 2015 - 12:34:16 EST


On Wed, 2015-05-13 at 15:23 +0300, Purcareata Bogdan wrote:
> Ping?
>
> On 24.03.2015 12:43, Bogdan Purcareata wrote:
> > After previous discussions regarding the subject [1][2], there's no clear
> > explanation or reason why the call was needed in the first place. The sensible
> > argument is some sort of synchronization between the CPU and the MPIC, which
> > hasn't been pointed out precisely and is no longer required (at least on BookE
> > platforms).
> >
> > The benefit of this change is saving a MMIO trap per interrupt when running in a
> > KVM guest.
> >
> > [1] https://patchwork.ozlabs.org/patch/429098/
> > [2] https://patchwork.ozlabs.org/patch/433557/
> >
> > Signed-off-by: Bogdan Purcareata <bogdan.purcareata@xxxxxxxxxxxxx>
> > ---
> > arch/powerpc/sysdev/mpic.c | 1 -
> > 1 file changed, 1 deletion(-)

Don't top-post.

This is commit 56302c53d3dc477b8360954fc92c1dfc4fc0ec54 in Linus's tree.

-Scott


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