Messages in this thread | | | Subject | Re: [PATCH v3 6/9] vfio: ap: register IOMMU VFIO notifier | From | Pierre Morel <> | Date | Tue, 19 Feb 2019 20:04:22 +0100 |
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On 19/02/2019 10:59, Halil Pasic wrote: > On Fri, 15 Feb 2019 17:55:35 -0500 > Tony Krowiak <akrowiak@linux.ibm.com> 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 <pmorel@linux.ibm.com> >>> --- >>> 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 > > [..] >
Since I will rework the vfio_ap_queue life cycle, I will study this. But I find the creation / deletion in probe/remove and the link/unlimk to the matrix device in assign/un_assign as suggested by Tony more logical.
Regards, Pierre
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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