[iommufd PATCH v2 2/2] vfio/ap: validate iova during dma_unmap and trigger irq disable

[Yi Liu <yi.l.liu@intel.com>]

From: Matthew Rosato <mjrosato@linux.ibm.com>

Currently, each mapped iova is stashed in its associated vfio_ap_queue;
when we get an unmap request, validate that it matches with one or more
of these stashed values before attempting unpins.

Each stashed iova represents IRQ that was enabled for a queue.  Therefore,
if a match is found, trigger IRQ disable for this queue to ensure that
underlying firmware will no longer try to use the associated pfn after
the page is unpinned. IRQ disable will also handle the associated unpin.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 0b4cc8c597ae..8bf353d46820 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1535,13 +1535,29 @@ static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev,
 	return 0;
 }
 
+static void unmap_iova(struct ap_matrix_mdev *matrix_mdev, u64 iova, u64 length)
+{
+	struct ap_queue_table *qtable = &matrix_mdev->qtable;
+	struct vfio_ap_queue *q;
+	int loop_cursor;
+
+	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode) {
+		if (q->saved_iova >= iova && q->saved_iova < iova + length)
+			vfio_ap_irq_disable(q);
+	}
+}
+
 static void vfio_ap_mdev_dma_unmap(struct vfio_device *vdev, u64 iova,
 				   u64 length)
 {
 	struct ap_matrix_mdev *matrix_mdev =
 		container_of(vdev, struct ap_matrix_mdev, vdev);
 
-	vfio_unpin_pages(&matrix_mdev->vdev, iova, 1);
+	mutex_lock(&matrix_dev->mdevs_lock);
+
+	unmap_iova(matrix_mdev, iova, length);
+
+	mutex_unlock(&matrix_dev->mdevs_lock);
 }
 
 /**
-- 
2.34.1