[PATCH v3 6/9] vfio: ap: register IOMMU VFIO notifier

Pierre Morel
2019-02-14T13:51:28Z

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
@@ -781,6 +781,36 @@ static const struct attribute_group *vfio_ap_mdev_attr_groups[] = {
};

/**
+ * vfio_ap_mdev_iommu_notifier: IOMMU notifier callback
+ *
+ * @nb: The notifier block
+ * @action: Action to be taken (VFIO_IOMMU_NOTIFY_DMA_UNMAP)
+ * @data: the specific unmap structure for vfio_iommu_type1
+ *
+ * Unpins the guest IOVA. (The NIB guest address we pinned before).
+ * Return NOTIFY_OK after unpining on a UNMAP request.
+ * otherwise, returns NOTIFY_DONE .
+ */
+static int vfio_ap_mdev_iommu_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct ap_matrix_mdev *matrix_mdev;
+
+ matrix_mdev = container_of(nb, struct ap_matrix_mdev, iommu_notifier);
+
+ if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
+ struct vfio_iommu_type1_dma_unmap *unmap = data;
+ unsigned long g_pfn = unmap->iova >> PAGE_SHIFT;
+
+ vfio_unpin_pages(mdev_dev(matrix_mdev->mdev), &g_pfn, 1);
+ return NOTIFY_OK;
+ }
+
+ return NOTIFY_DONE;
+}
+
+
+/**
* vfio_ap_mdev_set_kvm
*
* @matrix_mdev: a mediated matrix device
@@ -904,8 +934,7 @@ static void vfio_ap_dissociate_queues(struct ap_matrix_mdev *matrix_mdev)
* In the case a queue could not be found return -ENODEV.
* Otherwise return 0.
*/
-static __attribute__((unused))
- int vfio_ap_associate_queues(struct ap_matrix_mdev *matrix_mdev)
+static int vfio_ap_associate_queues(struct ap_matrix_mdev *matrix_mdev)
{
unsigned long apid, apqi;
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;

return 0;
+
+err_associate:
+ vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+ &matrix_mdev->iommu_notifier);
+err_iommu:
+ vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
+ &matrix_mdev->group_notifier);
+err_group:
+ module_put(THIS_MODULE);
+ return ret;
}

static void vfio_ap_mdev_release(struct mdev_device *mdev)
@@ -985,6 +1034,9 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev)
vfio_ap_mdev_reset_queues(mdev);
vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
&matrix_mdev->group_notifier);
+ vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY,
+ &matrix_mdev->iommu_notifier);
+ vfio_ap_dissociate_queues(matrix_mdev);
matrix_mdev->kvm = NULL;
module_put(THIS_MODULE);
}
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 10bc8b5..2781720 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -80,7 +80,9 @@ struct ap_matrix_mdev {
struct list_head node;
struct ap_matrix matrix;
struct notifier_block group_notifier;
+ struct notifier_block iommu_notifier;
struct kvm *kvm;
+ struct mdev_device *mdev;
};

extern int vfio_ap_mdev_register(void);
--
2.7.4