[SRU][G][H][PATCH 0/1] Support/enhancement of NVMe IPL (LP: 1902179)

[frank.heimes at canonical.com]

BugLink: https://bugs.launchpad.net/bugs/1902179

SRU Justification:

[Impact]

* The basics for being able to IPL (boot) from NVMe devices on s390x were introduced with kernel 5.8.

* This was tested and is proven to work with groovy.

* Now a patch was requested to be added to groovy that introduces support for NVMe IPL kernel parameters.

[Fix]

* d9f12e48d08ec08ace574050a838e001e442ee38 d9f12e48d08e "s390/ipl: support NVMe IPL kernel parameters"

[Test Case]

* IBM z15 or LinuxONE III hardware is needed with an NVMe device attached to a LPAR.

* Just check if NVMe kernel parameters can be passed over.

* Due to the lack of hardware this test needs to be done by IBM.

[Regression Potential]

* There is a certain regression risk with this patch, since:

* The handling of 'scpdata' is changed, and with that the way how kernel cmd-line parameters are extracted from the NVMe IPL block,
  that is passed by the firmware to the kernel at boot time.

* If broken such a hand over will not work for NVMe anymore,
  which wouldn't be a very big problem for now, since booting w/o still works fine (as it does today).

* But in worst case it could break the hand over of cmd-line parameters for FCP devices, since some code is shared or even harm ipl in general.

* The patch is upstream accepted (with v5.10-rc1 - as of today in linux-next) and a patched groovy kernel was build and shared for further testing.

* All modifications are limited to the s390x architecture and there again to the unique way of booting aka IPL (s390/boot/ipl*).

[Other]

* This is in preparation for getting IPL (boot) from NVMe device support on s390x backported to focal (for hardware enablement reasons).

* Without having this patch in groovy, one may face a regression during upgrade from groovy to focal.

* Since it's planned to have the hirsute kernel on 5.1x, it will have this patch sooner or later.

* However, since the today's hirsute kernel is just based on groovy, I've added hirsute to the SRU.

Alexander Egorenkov (1):
  s390/ipl: support NVMe IPL kernel parameters

 arch/s390/boot/ipl_parm.c | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

-- 
2.25.1