From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cornelia Huck <cornelia.huck@de.ibm.com>
Subject: Re: [PATCH v3 1/2] KVM: kvm-io: support cookies
Date: Wed, 3 Jul 2013 16:14:39 +0200
Message-ID: <20130703161439.579c3a0f@gondolin>
References: <1372859439-18733-1-git-send-email-cornelia.huck@de.ibm.com>
	<1372859439-18733-2-git-send-email-cornelia.huck@de.ibm.com>
	<20130703135642.GC32123@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Return-path: <kvm-owner@vger.kernel.org>
In-Reply-To: <20130703135642.GC32123@redhat.com>
Sender: kvm-owner@vger.kernel.org
List-Archive: <https://lore.kernel.org/kvm/>
List-Post: <mailto:kvm@vger.kernel.org>
To: Gleb Natapov <gleb@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Christian Borntraeger <borntraeger@de.ibm.com>, Heiko Carstens <heiko.carstens@de.ibm.com>, Martin Schwidefsky <schwidefsky@de.ibm.com>, KVM <kvm@vger.kernel.org>, linux-s390 <linux-s390@vger.kernel.org>
List-ID: <linux-s390.vger.kernel.org>

On Wed, 3 Jul 2013 16:56:42 +0300
Gleb Natapov <gleb@redhat.com> wrote:

> On Wed, Jul 03, 2013 at 03:50:38PM +0200, Cornelia Huck wrote:
> > Add new functions kvm_io_bus_{read,write}_cookie() that allows users of
> > the kvm io infrastructure to use a cookie value to speed up lookup of a
> > device on an io bus.
> > 
> > kvm_io_bus_{read,write} now returns the index on the bus; existing callers
> > have been fixed up to accept return codes > 0.
> > 
> > Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> > ---
> >  arch/ia64/kvm/kvm-ia64.c   |   2 +-
> >  arch/powerpc/kvm/powerpc.c |   4 +-
> >  arch/x86/kvm/x86.c         |   6 +--
> >  include/linux/kvm_host.h   |   4 ++
> >  virt/kvm/kvm_main.c        | 102 ++++++++++++++++++++++++++++++++++++++-------
> >  5 files changed, 97 insertions(+), 21 deletions(-)
> > 
> > diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
> > index 5b2dc0d..465ab54 100644
> > --- a/arch/ia64/kvm/kvm-ia64.c
> > +++ b/arch/ia64/kvm/kvm-ia64.c
> > @@ -250,7 +250,7 @@ mmio:
> >  	else
> >  		r = kvm_io_bus_write(vcpu->kvm, KVM_MMIO_BUS, p->addr,
> >  				     p->size, &p->data);
> > -	if (r)
> > +	if (r < 0)
> No need to change kvm_io_bus_(read|write) return value now. Just do
> there:
> 
>   r = __kvm_io_bus_write(bus, &range, val);
>   return  r >=0 ? 0 : r;
> 

Well, if the index is not interesting for anything but the cookie code,
I can certainly drop it.