From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755108AbeDQQ0A (ORCPT ); Tue, 17 Apr 2018 12:26:00 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:53228 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753848AbeDQQZ6 (ORCPT ); Tue, 17 Apr 2018 12:25:58 -0400 Subject: Re: [PATCH v4 15/15] s390: doc: detailed specifications for AP virtualization 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 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> From: Pierre Morel Date: Tue, 17 Apr 2018 18:25:50 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <65d3b123-7a0a-4de3-687f-5b6707e797f7@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18041716-0044-0000-0000-00000549445F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18041716-0045-0000-0000-0000288953AE Message-Id: <53283f8e-52b5-5653-044c-843b5b033a1e@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-17_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804170143 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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