[PATCH v8 03/16] s390/vfio-ap: manage link between queue struct and matrix mdev

[Tony Krowiak <akrowiak@linux.ibm.com>]

A vfio_ap_queue structure is created for each queue device probed. To
ensure that the matrix mdev to which a queue's APQN is assigned is linked
to the queue structure as long as the queue device is bound to the vfio_ap
device driver, let's go ahead and manage these links when the queue device
is probed and removed as well as whenever an adapter or domain is assigned
to or unassigned from the matrix mdev.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 93 +++++++++++++++++++++++++++++--
 1 file changed, 88 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 7c96b6fd9f70..21b98a392f36 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -160,7 +160,6 @@ struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q)
 		  status.response_code);
 end_free:
 	vfio_ap_free_aqic_resources(q);
-	q->matrix_mdev = NULL;
 	return status;
 }
 
@@ -262,7 +261,6 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
 	struct vfio_ap_queue *q;
 	struct ap_queue_status qstatus = {
 			       .response_code = AP_RESPONSE_Q_NOT_AVAIL, };
-	struct ap_matrix_mdev *matrix_mdev;
 
 	/* If we do not use the AIV facility just go to userland */
 	if (!(vcpu->arch.sie_block->eca & ECA_AIV))
@@ -273,14 +271,11 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
 
 	if (!vcpu->kvm->arch.crypto.pqap_hook)
 		goto out_unlock;
-	matrix_mdev = container_of(vcpu->kvm->arch.crypto.pqap_hook,
-				   struct ap_matrix_mdev, pqap_hook);
 
 	q = vfio_ap_get_queue(apqn);
 	if (!q)
 		goto out_unlock;
 
-	q->matrix_mdev = matrix_mdev;
 	status = vcpu->run->s.regs.gprs[1];
 
 	/* If IR bit(16) is set we enable the interrupt */
@@ -548,6 +543,67 @@ static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev)
 	return 0;
 }
 
+enum qlink_type {
+	LINK_APID,
+	LINK_APQI,
+	UNLINK_APID,
+	UNLINK_APQI,
+};
+
+/**
+ * vfio_ap_mdev_link_queues
+ *
+ * @matrix_mdev: The matrix mdev to link.
+ * @type:	 The type of link.
+ * @qlink_id:	 The APID or APQI of the queues to link.
+ *
+ * Sets the link from the queues with the specified @qlink_id (i.e., APID or
+ * APQI) to @matrix_mdev:
+ *	qlink_id == LINK_APID: Link @matrix_mdev to the queues with the
+ *		    specified APID>
+ *	qlink_id == UNLINK_APID: Unlink @matrix_mdev from the queues with the
+ *		    specified APID>
+ *	qlink_id == LINK_APQI: Link @matrix_mdev to the queues with the
+ *		    specified APQI>
+ *	qlink_id == UNLINK_APQI: Unlink @matrix_mdev from the queues with the
+ *		    specified APQI>
+ */
+static void vfio_ap_mdev_link_queues(struct ap_matrix_mdev *matrix_mdev,
+				     enum qlink_type type,
+				     unsigned long qlink_id)
+{
+	unsigned long id;
+	struct vfio_ap_queue *q;
+
+	switch (type) {
+	case LINK_APID:
+	case UNLINK_APID:
+		for_each_set_bit_inv(id, matrix_mdev->matrix.aqm,
+				     matrix_mdev->matrix.aqm_max + 1) {
+			q = vfio_ap_get_queue(AP_MKQID(qlink_id, id));
+			if (q) {
+				if (type == LINK_APID)
+					q->matrix_mdev = matrix_mdev;
+				else
+					q->matrix_mdev = NULL;
+			}
+		}
+		break;
+	default:
+		for_each_set_bit_inv(id, matrix_mdev->matrix.apm,
+				     matrix_mdev->matrix.apm_max + 1) {
+			q = vfio_ap_get_queue(AP_MKQID(id, qlink_id));
+			if (q) {
+				if (type == LINK_APQI)
+					q->matrix_mdev = matrix_mdev;
+				else
+					q->matrix_mdev = NULL;
+			}
+		}
+		break;
+	}
+}
+
 /**
  * assign_adapter_store
  *
@@ -617,6 +673,7 @@ static ssize_t assign_adapter_store(struct device *dev,
 	if (ret)
 		goto share_err;
 
+	vfio_ap_mdev_link_queues(matrix_mdev, LINK_APID, apid);
 	ret = count;
 	goto done;
 
@@ -668,6 +725,7 @@ static ssize_t unassign_adapter_store(struct device *dev,
 
 	mutex_lock(&matrix_dev->lock);
 	clear_bit_inv((unsigned long)apid, matrix_mdev->matrix.apm);
+	vfio_ap_mdev_link_queues(matrix_mdev, UNLINK_APID, apid);
 	mutex_unlock(&matrix_dev->lock);
 
 	return count;
@@ -758,6 +816,7 @@ static ssize_t assign_domain_store(struct device *dev,
 	if (ret)
 		goto share_err;
 
+	vfio_ap_mdev_link_queues(matrix_mdev, LINK_APQI, apqi);
 	ret = count;
 	goto done;
 
@@ -810,6 +869,7 @@ static ssize_t unassign_domain_store(struct device *dev,
 
 	mutex_lock(&matrix_dev->lock);
 	clear_bit_inv((unsigned long)apqi, matrix_mdev->matrix.aqm);
+	vfio_ap_mdev_link_queues(matrix_mdev, UNLINK_APQI, apqi);
 	mutex_unlock(&matrix_dev->lock);
 
 	return count;
@@ -1282,6 +1342,28 @@ void vfio_ap_mdev_unregister(void)
 	mdev_unregister_device(&matrix_dev->device);
 }
 
+/**
+ * vfio_ap_queue_link_mdev
+ *
+ * @q: The queue to link with the matrix mdev.
+ *
+ * Links @q with the matrix mdev to which the queue's APQN is assigned.
+ */
+static void vfio_ap_queue_link_mdev(struct vfio_ap_queue *q)
+{
+	unsigned long apid = AP_QID_CARD(q->apqn);
+	unsigned long apqi = AP_QID_QUEUE(q->apqn);
+	struct ap_matrix_mdev *matrix_mdev;
+
+	list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) {
+		if (test_bit_inv(apid, matrix_mdev->matrix.apm) &&
+		    test_bit_inv(apqi, matrix_mdev->matrix.aqm)) {
+			q->matrix_mdev = matrix_mdev;
+			break;
+		}
+	}
+}
+
 int vfio_ap_mdev_probe_queue(struct ap_queue *queue)
 {
 	struct vfio_ap_queue *q;
@@ -1294,6 +1376,7 @@ int vfio_ap_mdev_probe_queue(struct ap_queue *queue)
 	dev_set_drvdata(&queue->ap_dev.device, q);
 	q->apqn = queue->qid;
 	q->saved_isc = VFIO_AP_ISC_INVALID;
+	vfio_ap_queue_link_mdev(q);
 	mutex_unlock(&matrix_dev->lock);
 
 	return 0;
-- 
2.21.1