From mboxrd@z Thu Jan 1 00:00:00 1970 From: Halil Pasic Subject: Re: [PATCH v3 6/9] vfio: ap: register IOMMU VFIO notifier Date: Tue, 19 Feb 2019 10:59:46 +0100 Message-ID: <20190219105946.29e510a6@oc2783563651> References: <1550152269-6317-1-git-send-email-pmorel@linux.ibm.com> <1550152269-6317-7-git-send-email-pmorel@linux.ibm.com> <3ce0a3a0-22fb-c418-321d-7e6e3af5b66c@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3ce0a3a0-22fb-c418-321d-7e6e3af5b66c@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Tony Krowiak Cc: Pierre Morel , borntraeger@de.ibm.com, alex.williamson@redhat.com, cohuck@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com List-ID: On Fri, 15 Feb 2019 17:55:35 -0500 Tony Krowiak wrote: > On 2/14/19 8:51 AM, Pierre Morel wrote: > > To be able to use the VFIO interface to facilitate the > > mediated device memory pining/unpining we need to register > > a notifier for IOMMU. > > > > Signed-off-by: Pierre Morel > > --- > > drivers/s390/crypto/vfio_ap_ops.c | 64 +++++++++++++++++++++++++++++++---- > > drivers/s390/crypto/vfio_ap_private.h | 2 ++ > > 2 files changed, 60 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > > index 1851b24..6eddc2c 100644 > > --- a/drivers/s390/crypto/vfio_ap_ops.c > > +++ b/drivers/s390/crypto/vfio_ap_ops.c [..] struct vfio_ap_queue *q; > > @@ -967,12 +996,32 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev) > > > > ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, > > &events, &matrix_mdev->group_notifier); > > - if (ret) { > > - module_put(THIS_MODULE); > > - return ret; > > - } > > + if (ret) > > + goto err_group; > > + > > + matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier; > > + events = VFIO_IOMMU_NOTIFY_DMA_UNMAP; > > + > > + ret = vfio_register_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY, > > + &events, &matrix_mdev->iommu_notifier); > > + if (ret) > > + goto err_iommu; > > + > > + ret = vfio_ap_associate_queues(matrix_mdev); > > + if (ret) > > + goto err_associate; > > I think the matrix_mdev should be associated with queues when an > assignment of an adapter or domain is made to the mdev device via its > sysfs interfaces. I say this because assigning an adapter or domain to > an mdev device effectively grants ownership of any additional AP queues > added to the mdev device's AP matrix as a result of the assignment. It > only makes sense to assign ownership to the vfio_ap_queue objects > representing the queues at that time. If an adapter or domain is > dynamically assigned while a guest is using the affected queues, then > the associations will have to be made at that time and this code will > likely go bye bye. > Actually, we need the stuff in vfio_ap_queues only if the guest is offered to decides to use AP adaper interrupts. I would prefer to have it around only when needed: as long as we have the nib pinned for any given queue. Is there a reason why not to do so? Regards, Halil [..]