From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v4 15/15] s390: doc: detailed specifications for AP virtualization Date: Tue, 17 Apr 2018 18:25:50 +0200 Message-ID: <53283f8e-52b5-5653-044c-843b5b033a1e@linux.vnet.ibm.com> References: <1523827345-11600-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1523827345-11600-16-git-send-email-akrowiak@linux.vnet.ibm.com> <04a0cf49-71a1-214a-7261-d8e55adee1de@linux.vnet.ibm.com> <65d3b123-7a0a-4de3-687f-5b6707e797f7@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <65d3b123-7a0a-4de3-687f-5b6707e797f7@linux.vnet.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Tony Krowiak , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, borntraeger@de.ibm.com, cohuck@redhat.com, kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com, alex.williamson@redhat.com, alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com, thuth@redhat.com, pasic@linux.vnet.ibm.com, berrange@redhat.com, fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com List-ID: On 17/04/2018 18:14, Tony Krowiak wrote: > On 04/16/2018 09:13 AM, Pierre Morel wrote: >> On 15/04/2018 23:22, Tony Krowiak wrote: >>> This patch provides documentation describing the AP architecture and >>> design concepts behind the virtualization of AP devices. It also >>> ...snip... >>> +The process for reserving an AP queue for use by a KVM guest is: >>> + >>> +* The vfio-ap driver during its initialization will perform the >>> following: >>> +  * Create the 'vfio_ap' root device - /sys/devices/vfio_ap >>> +  * Create the 'matrix' device in the 'vfio_ap' root >>> +  * Register the matrix device with the device core >>> +* Register with the ap_bus for AP queue devices of type CEX4, CEX5 and >>> +  CEX6 and to provide the vfio_ap driver's probe and remove >>> callback interfaces. >> >> I wonder why the type of card has anything to do with this driver. >> It should be transparent, the driver should be able to provide the >> matrix (APM/AQM/ADM) >> independently from the type of card in the slot. > > We've been down this road several times before. We are only supporting > virtualization of > CEX4 and newer cards. Also, the AP bus requires registering for > specific card types. Yes I know, but the AP BUS design may be not the optimal for the AP Matrix. The AP Matrix is device independent. We just write/clear bits in a matrix and we do not care what is plugged. So may be make clear that this device dependence is due to the actual AP BUS interface design. > >> >> >> Regards, >> >> Pierre >> > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany