Comment 35 for bug 1790457

And just for the records, the kernel part already landed in xenial, too:
xenial updates kernel today: 4.4.0.137.
$ git log --oneline | grep "s390: detect etoken facility"
c32821c s390: detect etoken facility
$ git tag --contains c32821c
Ubuntu-4.4.0-136.162
Ubuntu-4.4.0-137.163
Ubuntu-4.4.0-138.164
Ubuntu-raspi2-4.4.0-1099.107
Ubuntu-snapdragon-4.4.0-1103.108