On 3/3/19 9:09 PM, Halil Pasic wrote:
On Fri, 22 Feb 2019 16:29:56 +0100
Pierre Morel <pmo...@linux.ibm.com> wrote:

We need to associate the ap_vfio_queue, which will hold the
per queue information for interrupt with a matrix mediated device
which hold the configuration and the way to the CRYCB.
[..]
+static int vfio_ap_get_all_domains(struct ap_matrix_mdev *matrix_mdev, int 
apid)
+{
+       int apqi, apqn;
+       int ret = 0;
+       struct vfio_ap_queue *q;
+       struct list_head q_list;
+
+       INIT_LIST_HEAD(&q_list);
+
+       for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS) {
+               apqn = AP_MKQID(apid, apqi);
+               q = vfio_ap_get_queue(apqn, &matrix_dev->free_list);
+               if (!q) {
+                       ret = -EADDRNOTAVAIL;
+                       goto rewind;
+               }
+               if (q->matrix_mdev) {
+                       ret = -EADDRINUSE;

You tried to get the q from matrix_dev->free_list thus modulo races
q->matrix_mdev should be 0. This change breaks the error codes in a
sense that it becomes impossible to provoke EADDRINUSE (the proper
error code for taken by another matrix_mdev).

I don't understand what you are saying here. AFIU, the idea here is to
pull the q from the free list. If there is no q for the apqn on the free
list, then that would indicate the queue has not been bound to a driver
in which case the appropriate rc is EADDRNOTAVAIL. If the queue has
been bound, then a check is done to see whether the queue has been
associated with an mdev device. If so, the rc is -EADDRINUSE, which is
also appropriate. What am I missing?


+                       goto rewind;
+               }
+               list_move(&q->list, &q_list);
+       }
+       move_and_set(&q_list, &matrix_mdev->qlist, matrix_mdev);
        return 0;
+rewind:
+       move_and_set(&q_list, &matrix_dev->free_list, NULL);
+       return ret;
  }
-
  /**
- * vfio_ap_mdev_verify_no_sharing
+ * vfio_ap_get_all_cards:
   *
- * Verifies that the APQNs derived from the cross product of the AP adapter IDs
- * and AP queue indexes comprising the AP matrix are not configured for another
- * mediated device. AP queue sharing is not allowed.
+ * @matrix_mdev: the matrix mediated device for which we want to associate
+ *              all available queues with a given apqi.
+ * @apqi:       The apqi which associated with all defined APID of the
+ *              mediated device will define a AP queue.
   *
- * @matrix_mdev: the mediated matrix device
+ * We define a local list to put all queues we find on the matrix device
+ * free list when associating the apqi with all already defined apid for
+ * this matrix mediated device.
   *
- * Returns 0 if the APQNs are not shared, otherwise; returns -EADDRINUSE.
+ * If we can get all the devices we roll them to the mediated device list
+ * If we get errors we unroll them to the free list.
   */
-static int vfio_ap_mdev_verify_no_sharing(struct ap_matrix_mdev *matrix_mdev)
+static int vfio_ap_get_all_cards(struct ap_matrix_mdev *matrix_mdev, int apqi)
  {
-       struct ap_matrix_mdev *lstdev;
-       DECLARE_BITMAP(apm, AP_DEVICES);
-       DECLARE_BITMAP(aqm, AP_DOMAINS);
-
-       list_for_each_entry(lstdev, &matrix_dev->mdev_list, node) {
-               if (matrix_mdev == lstdev)
-                       continue;
-
-               memset(apm, 0, sizeof(apm));
-               memset(aqm, 0, sizeof(aqm));
-
-               /*
-                * We work on full longs, as we can only exclude the leftover
-                * bits in non-inverse order. The leftover is all zeros.
-                */
-               if (!bitmap_and(apm, matrix_mdev->matrix.apm,
-                               lstdev->matrix.apm, AP_DEVICES))
-                       continue;
-
-               if (!bitmap_and(aqm, matrix_mdev->matrix.aqm,
-                               lstdev->matrix.aqm, AP_DOMAINS))
-                       continue;
-
-               return -EADDRINUSE;
+       int apid, apqn;
+       int ret = 0;
+       struct vfio_ap_queue *q;
+       struct list_head q_list;
+       struct ap_matrix_mdev *tmp = NULL;
+
+       INIT_LIST_HEAD(&q_list);
+
+       for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, AP_DEVICES) {
+               apqn = AP_MKQID(apid, apqi);
+               q = vfio_ap_get_queue(apqn, &matrix_dev->free_list);
+               if (!q) {
+                       ret = -EADDRNOTAVAIL;
+                       goto rewind;
+               }
+               if (q->matrix_mdev) {
+                       ret = -EADDRINUSE;

Same here!

Regards,
Halil

+                       goto rewind;
+               }
+               list_move(&q->list, &q_list);
        }

[..]


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