From: Farhan Ali <alifm@linux.ibm.com>
Subject: s390: vfio-ap: zeroize the AP queues
Patch-mainline: v4.20-rc1
Git-commit: 46a7263d4746a2659edafcb885e91e58bb6d3a2e
References: FATE#326370, LTC#169186, bsc#1113483

Summary:     kernel: AP Crypto Passthrough 
Description: This adds support for AP crypto passthrough for 
             kvm guests.

Upstream-Description:

             s390: vfio-ap: zeroize the AP queues

             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@linux.ibm.com>
             Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
             Tested-by: Michael Mueller <mimu@linux.ibm.com>
             Tested-by: Farhan Ali <alifm@linux.ibm.com>
             Reviewed-by: Cornelia Huck <cohuck@redhat.com>
             Message-Id: <20180925231641.4954-14-akrowiak@linux.vnet.ibm.com>
             Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/s390/crypto/vfio_ap_ops.c |   49 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -819,6 +819,54 @@ static int vfio_ap_mdev_group_notifier(s
 	return NOTIFY_OK;
 }
 
+static int vfio_ap_mdev_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:
+			/* things are really broken, give up */
+			return -EIO;
+		}
+	} while (retry--);
+
+	return -EBUSY;
+}
+
+static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
+{
+	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_mdev_reset_queue(apid, apqi, 1);
+			/*
+			 * Regardless whether a queue turns out to be busy, or
+			 * is not operational, we need to continue resetting
+			 * the remaining queues.
+			 */
+			if (ret)
+				rc = ret;
+		}
+	}
+
+	return rc;
+}
+
 static int vfio_ap_mdev_open(struct mdev_device *mdev)
 {
 	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
@@ -849,6 +897,7 @@ static void vfio_ap_mdev_release(struct
 	if (matrix_mdev->kvm)
 		kvm_arch_crypto_clear_masks(matrix_mdev->kvm);
 
+	vfio_ap_mdev_reset_queues(mdev);
 	vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
 	matrix_mdev->kvm = NULL;