From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cornelia Huck Subject: Re: [PATCH 2/2] vfio: ccw: validate the count field of a ccw before pinning Date: Mon, 16 Oct 2017 11:14:20 +0200 Message-ID: <20171016111420.4a8ca1af.cohuck@redhat.com> References: <20171011023822.42948-1-bjsdjshi@linux.vnet.ibm.com> <20171011023822.42948-3-bjsdjshi@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, borntraeger@de.ibm.com, pasic@linux.vnet.ibm.com, pmorel@linux.vnet.ibm.com To: Dong Jia Shi Return-path: In-Reply-To: <20171011023822.42948-3-bjsdjshi@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Wed, 11 Oct 2017 04:38:22 +0200 Dong Jia Shi wrote: > If the count field of a ccw is zero, there is no need to > try to pin page(s) for it. Let's check the count value > before starting pinning operations. > > Reviewed-by: Pierre Morel > Signed-off-by: Dong Jia Shi > --- > drivers/s390/cio/vfio_ccw_cp.c | 18 +++++++++++++++++- > 1 file changed, 17 insertions(+), 1 deletion(-) This sounds reasonable, and I could not spot anything in the architecture that speaks against simply setting the IDA flag. Hopefully there's nothing buried out of sight :)