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>

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 974cf06..619900c 100644 (file)
--- 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(struct notifier_block *nb,
        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 mdev_device *mdev)
        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;