[PATCH v8 17/22] s390: vfio-ap: zeroize the AP queues.

[Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx>]

From: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>

Let's call PAPQ(ZAPQ) to zeroize a queue:

* For each queue configured for a mediated matrix device
  when it is released.

Zeroizing a queue resets the queue, clears all pending
messages for the queue entries and disables adapter interruptions
associated with the queue.

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Tested-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
Tested-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
 drivers/s390/crypto/vfio_ap_ops.c     |   29 ++++++++++++++++++++++++++++-
 drivers/s390/crypto/vfio_ap_private.h |   25 +++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 1 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 31e0dbe..e5c6dc1 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -761,6 +761,30 @@ static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,
 	return NOTIFY_OK;
 }
 
+static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev, bool force)
+{
+	int ret;
+	int rc = 0;
+	unsigned long apid, apqi;
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+	for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,
+			     matrix_mdev->matrix.apm_max + 1) {
+		for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
+				     matrix_mdev->matrix.aqm_max + 1) {
+			ret = vfio_ap_reset_queue(apid, apqi, 1);
+			if (ret) {
+				if (force)
+					rc = ret;
+				else
+					return ret;
+			}
+		}
+	}
+
+	return rc;
+}
+
 static int vfio_ap_mdev_open(struct mdev_device *mdev)
 {
 	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
@@ -788,7 +812,10 @@ static void vfio_ap_mdev_release(struct mdev_device *mdev)
 {
 	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
 
-	kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
+	if (matrix_mdev->kvm)
+		kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
+
+	vfio_ap_mdev_reset_queues(mdev, true);
 	vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
 	matrix_mdev->kvm = NULL;
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 6fa77cf..087e21a 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -78,4 +78,29 @@ struct ap_matrix_mdev {
 extern int vfio_ap_mdev_register(void);
 extern void vfio_ap_mdev_unregister(void);
 
+static inline int vfio_ap_reset_queue(unsigned int apid, unsigned int apqi,
+				      unsigned int retry)
+{
+	struct ap_queue_status status;
+
+	do {
+		status = ap_zapq(AP_MKQID(apid, apqi));
+		switch (status.response_code) {
+		case AP_RESPONSE_NORMAL:
+			return 0;
+		case AP_RESPONSE_RESET_IN_PROGRESS:
+		case AP_RESPONSE_BUSY:
+			msleep(20);
+			break;
+		default:
+			pr_warn("%s: error zeroizing %02x.%04x: response code %d\n",
+				VFIO_AP_MODULE_NAME, apid, apqi,
+				status.response_code);
+			return -EIO;
+		}
+	} while (retry--);
+
+	return -EBUSY;
+}
+
 #endif /* _VFIO_AP_PRIVATE_H_ */
-- 
1.7.1