Ubuntu 16.04.6 - Shared CEX7C cards defined in z/VM guest not established by zcrypt device driver

SRU Justification:
==================

[Impact]

* Ubuntu 16.04.6 systems on z15 with crypto CEX7C adapters under z/VM cannot see and make use of their hw crypto resources.

* The patch/backport adds CEX7 toleration support (by mapping it to CEX5) to kernel 4.4.

[Fix]

* Backport: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1848173/+attachment/5297314/+files/s390-zcrypt-CEX7-toleration-support.patch

[Test Case]

* Define a z/VM guest with 'apvirt' (hardware crypto adapter virtualization) having CryptoExpress 7S adapters attached to z/VM LPAR.

* Use lszcrypt command (ideally lszcrypt -VVV) from the s390-tools package to list the detected and available hardware crypto resources.

* Canonical can only do a toleration test: IBM needs to do the functional test (due to hardware availability).

[Regression Potential]

* The regression potential can be considered as moderate since this is purely s390x specific

* and limited to CryptoExpress 7S (CEX7) adapter cards

* and again if they running under z/VM (on z15) with 'apvirt' configured for the guest.

* and again only with 16.04.6's kernel 4.4.

[Other Info]

* The patch was already applied, kernel compiled and things tested on z15 und z/VM.

__________

System: IBM Z15 z/VM with shared CEX7C adapters
OS: Ubuntu 16.04.6 LTS ( 4.4.0-165-generic kernel ) with latest updates
Shared CEX7C adapters are not displayed on Ubuntu even though APAR 66266 had been installed onto the unterlying z/VM system.

Details
=======
Defined shared CEX7C CCA adapters to provide cryptographic accelerators based on CCA cards to a z/VM guest system running Ubuntu 16.04.6 LTS.

The adapters display all right under vm or when running vmcp commands under Linux.

lszcrypt -VVV does not display any adapter.

We observed that zcrypt_cex4 was not automatically loaded via dependency by modprobe ap. Explicitly loading by modprobe zcrypt_cex4 did not change card availability.

Please investigate.

Thanks.

Terminal output
==============
root@system:/sys/bus/ap/devices/card01# ls -l
total 0
-r--r--r-- 1 root root 4096 Oct 8 17:51 ap_functions
-r--r--r-- 1 root root 4096 Oct 8 17:51 depth
-r--r--r-- 1 root root 4096 Oct 8 17:51 hwtype
-r--r--r-- 1 root root 4096 Oct 8 17:51 interrupt
-r--r--r-- 1 root root 4096 Oct 8 17:51 modalias
-r--r--r-- 1 root root 4096 Oct 8 17:51 pendingq_count
drwxr-xr-x 2 root root 0 Oct 8 17:51 power
-r--r--r-- 1 root root 4096 Oct 8 17:51 raw_hwtype
-r--r--r-- 1 root root 4096 Oct 8 17:51 request_count
-r--r--r-- 1 root root 4096 Oct 8 17:51 requestq_count
-r--r--r-- 1 root root 4096 Oct 8 17:51 reset
lrwxrwxrwx 1 root root 0 Oct 8 17:51 subsystem -> ../../../bus/ap
-rw-r--r-- 1 root root 4096 Oct 8 17:50 uevent

# lszcrypt -V // < No output displayed >
# vmcp q v crypto
AP 001 CEX7C Domain 001 shared online

root@system:/sys/bus/ap/devices/card01# cat hwtype
13
root@system:/sys/bus/ap/devices/card01# cat raw_hwtype
13

# lsmod
Module Size Used by
ap 36864 0
ghash_s390 16384 0
prng 16384 0
aes_s390 20480 0
des_s390 16384 0
des_generic 28672 1 des_s390
sha512_s390 16384 0
qeth_l2 53248 1
sha256_s390 16384 0
sha1_s390 16384 0
sha_common 16384 3 sha256_s390,sha1_s390,sha512_s390
qeth 151552 1 qeth_l2
vmur 20480 0
ccwgroup 20480 1 qeth
dm_multipath 36864 0
zfcp 143360 0
dasd_eckd_mod 118784 8
qdio 73728 3 qeth,zfcp,qeth_l2
scsi_transport_fc 86016 1 zfcp
dasd_mod 135168 5 dasd_eckd_mod

# modprobe zcrypt_cex4
...
zcrypt_cex4 16384 0
zcrypt_api 36864 1 zcrypt_cex4
ap 36864 2 zcrypt_cex4,zcrypt_api
...

Contact Information = <email address hidden>

---uname output---
Linux system 4.4.0-164-generic #192-Ubuntu SMP Fri Sep 13 12:01:28 UTC 2019 s390x s390x s390x GNU/Linux

Machine Type = IBM Type: 8561 Model: 403 T01

---Debugger---
A debugger is not configured

---Steps to Reproduce---
 1.) Define shared CEX7 CCA cards to z/VM Guest
2.) boot up Ubuntu 16.04.6 LTS
3.) modprobe ap
4.) lszcrypt -VVV

Stack trace output:
 no

Oops output:
 no

System Dump Info:
  The system is not configured to capture a system dump.

Device driver error code:
 N/A

*Additional Instructions for <email address hidden>:
-Attach sysctl -a output output to the bug.

lszcrypt returns with

# lszcrypt -VVV ; echo RC=$?
RC=0

After investigating here a little ...
Ubuntu 16.04 has only toleration support for CEX6 and no support for CEX7.

Here is a patch which maps cex7 cards to cex5 cards.
Have a look into - it is just a 2 line code change which
extends the toleration patch for cex6 (mapped to cex5)
by the cex7 card - also mapped to cex5.

Code compiles and I've tested the kernel on a z15 with
lots of cex6 and cex7 cards - works fine.