From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Wed, 11 Jul 2012 22:43:04 +0000
Subject: Re: [Qemu-ppc] [RFC PATCH 12/17] PowerPC: booke64: Add DO_KVM kernel hooks
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To: Alexander Graf <agraf@suse.de>
Cc: Caraman Mihai Claudiu-B02008 <B02008@freescale.com>, "<kvm-ppc@vger.kernel.org>" <kvm-ppc@vger.kernel.org>, KVM list <kvm@vger.kernel.org>, linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, "qemu-ppc@nongnu.org List" <qemu-ppc@nongnu.org>

On Thu, 2012-07-12 at 00:35 +0200, Alexander Graf wrote:
> > On Thu, 2012-07-12 at 00:25 +0200, Alexander Graf wrote:
> >> Or just free up another register early on, like here.
> > 
> > If you're going to do that, you want to measure the impact on null
> > syscall performance though.
> 
> That should hold true for any change in that code, no?

Yes, but adding a gpr save is more invasive (you have to also load it
back later on & put it on the stack).

Cheers,
Ben.