From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v5 10/13] s390: vfio-ap: sysfs interface to view matrix mdev matrix Date: Tue, 5 Jun 2018 14:40:44 +0200 Message-ID: <32340d2a-bea6-bdb1-38a6-76afe3d54672@linux.ibm.com> References: <1525705912-12815-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1525705912-12815-11-git-send-email-akrowiak@linux.vnet.ibm.com> <53275110-45fb-d50f-c97e-93141378f094@linux.vnet.ibm.com> <89bda651-d465-af50-a737-1900a54b01c8@linux.ibm.com> <6f67a282-773d-3fca-5b36-cc23ad49ba5b@linux.vnet.ibm.com> Reply-To: pmorel@linux.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <6f67a282-773d-3fca-5b36-cc23ad49ba5b@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, pmorel@linux.vnet.ibm.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 30/05/2018 16:28, Tony Krowiak wrote: > On 05/24/2018 05:10 AM, Pierre Morel wrote: >> On 23/05/2018 16:38, Tony Krowiak wrote: >>> On 05/16/2018 03:55 AM, Pierre Morel wrote: >>>> On 07/05/2018 17:11, Tony Krowiak wrote: >>>>> Provides a sysfs interface to view the AP matrix configured for the >>>>> mediated matrix device. >>>>> >>>>> The relevant sysfs structures are: >>>>> >>>>> /sys/devices/vfio_ap >>>>> ... [matrix] >>>>> ...... [mdev_supported_types] >>>>> ......... [vfio_ap-passthrough] >>>>> ............ [devices] >>>>> ...............[$uuid] >>>>> .................. matrix >>>>> >>>>> To view the matrix configured for the mediated matrix device, >>>>> print the matrix file: >>>> >>>> This is the configured matrix, not the one used by the guest. >>>> Nothing in the patches protect against binding a queue and assigning >>>> a new AP when the guest runs. >>>> The card and queue will be showed by this entry. >>> >>> Of course, as stated above, this is the matrix configured for the >>> mediated matrix device. Are you suggesting here that the driver >>> should prevent assigning a new adapter or domain while a guest is >>> running? Couldn't this be a step in the process for hot (un)plugging >>> AP queues? >> >> No, I mean what is the point to show this? >> It is not what the guest sees. >> Has it any use case? > > The point is to display the matrix so one can view the AP queues that > have been assigned to the mediated matrix device. This is the only way > to view the matrix. Do you not find value in being able to see what > has been assigned to the mediated matrix device? Two things: 1) I think it is better to retrieve the individual masks 2) As I said above, what you show is not the effective mask used by the guest -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany