From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: [PATCH v3 1/2] KVM: kvm-io: support cookies
Date: Wed, 3 Jul 2013 17:26:03 +0300
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 <20130703161439.579c3a0f@gondolin>
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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>
To: Cornelia Huck <cornelia.huck@de.ibm.com>
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On Wed, Jul 03, 2013 at 04:14:39PM +0200, Cornelia Huck wrote:
> 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.
It is certainly not right now.

--
			Gleb.