From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 24 Apr 2020 05:33:38 +0200 From: Halil Pasic Subject: Re: [PATCH v7 03/15] s390/zcrypt: driver callback to indicate resource in use In-Reply-To: <20200416113721.124f9843.cohuck@redhat.com> References: <20200407192015.19887-1-akrowiak@linux.ibm.com> <20200407192015.19887-4-akrowiak@linux.ibm.com> <20200414145851.562867ae.cohuck@redhat.com> <35d8c3cb-78bb-8f84-41d8-c6e59d201ba0@linux.ibm.com> <20200416113721.124f9843.cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Message-Id: <20200424053338.658b2a05.pasic@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: To: Cornelia Huck Cc: Tony Krowiak , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, freude@linux.ibm.com, borntraeger@de.ibm.com, mjrosato@linux.ibm.com, pmorel@linux.ibm.com, alex.williamson@redhat.com, kwankhede@nvidia.com, jjherne@linux.ibm.com, fiuczy@linux.ibm.com On Thu, 16 Apr 2020 11:37:21 +0200 Cornelia Huck wrote: > On Wed, 15 Apr 2020 13:10:10 -0400 > Tony Krowiak wrote: > > > On 4/14/20 8:58 AM, Cornelia Huck wrote: > > > On Tue, 7 Apr 2020 15:20:03 -0400 > > > Tony Krowiak wrote: > > > >> + > > >> + if (ap_drv->in_use) > > >> + if (ap_drv->in_use(newapm, ap_perms.aqm)) > > > Can we log the offending apm somewhere, preferably with additional info > > > that allows the admin to figure out why an error was returned? > > > > One of the things on my TODO list is to add logging to the vfio_ap > > module which will track all significant activity within the device > > driver. I plan to do that with a patch or set of patches specifically > > put together for that purpose. Having said that, the best place to > > log this would be in the in_use callback in the vfio_ap device driver > > (see next patch) where the APQNs that are in use can be identified. > > For now, I will log a message to the dmesg log indicating which > > APQNs are in use by the matrix mdev. > > Sounds reasonable. My main issue was what an admin was supposed to do > until logging was in place :) Logging may not be the right answer here. Imagine somebody wants to build a nice web-tool for managing this stuff at scale -- e.g. something HMC. I don't think the solution is to let this tool parse the kernel messages and try to relate that to its own transactions. But I do agree, having a way to report why "won't do" to the end user is important for usability. Regards, Halil > > > > > > > > >> + rc = -EADDRINUSE; > > >> + > > >> + module_put(drv->owner); > > >> + > > >> + return rc; > > >> +} >