s390/vfio-ap: Fix memory allocation for mdev_types array

The vfio-ap crypto driver fails to allocate memory for an array of
pointers used to pass supported mdev types to mdev_register_parent().

Since we only support a single mdev type, the fix is to allocate a
single entry in the ap_matrix_dev->mdev_types array.

Link: https://lore.kernel.org/r/[email protected]
Fixes: da44c34 ("vfio/mdev: simplify mdev_type handling")
Cc: [email protected]
Cc: Tony Krowiak <[email protected]>
Reported-by: Christian Borntraeger <[email protected]>
Reviewed-by: Matthew Rosato <[email protected]>
Signed-off-by: Jason J. Herne <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

Author: Jason J. Herne

drivers/s390/crypto/vfio_ap_private.h

@@ -52,7 +52,7 @@ struct ap_matrix_dev {
 	struct mutex guests_lock; /* serializes access to each KVM guest */
 	struct mdev_parent parent;
 	struct mdev_type mdev_type;
-	struct mdev_type *mdev_types[];
+	struct mdev_type *mdev_types[1];
 };
 
 extern struct ap_matrix_dev *matrix_dev;