ACK/Cmnt: [SRU][F][PATCH 0/1] Support/enhancement of NVMe IPL (LP: 1902179)

[Stefan Bader]

On 03.11.20 19:31, frank.heimes at canonical.com wrote:
> BugLink: https://bugs.launchpad.net/bugs/1902179
> 
> SRU Justification:
> 
> [Impact]
> 
> * The base for being able to IPL (boot) NVMe devices on s390x was introduced with kernel 5.8.
> 
> * This got now requested (for hardware enablement reasons) for Ubuntu 20.04 LTS as well.
> 
> * On top a brand new commit got upstream accepted that introduces support for NVMe IPL kernel parameters, which is not yet in groovy.
> 
> [Fix]
> 
> * cherry pick of commit 3737e8ee4f2fc7e77994d1a8bd618a9dda5a5514 3737e8ee4f2f "s390: nvme ipl"
> 
> * cherry pick of commit 23a457b8d57dc8d0cc1dbd1882993dd2fcc4b0c0 23a457b8d57d "s390: nvme reipl"
>   does not apply cleanly, hence the following backport:
>   https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1902179/+attachment/5430310/+files/0002-s390-nvme-reipl.patch
> 
> * cherry pick of commit 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.
> 
> * Install the patched kernel on focal/20.04 installation and make sure that zipl re-ran (the patched version of zipl with the s390-tools commit mentioned in this LP bug - or take the s390-tools version for groovy for testing purposes).
> 
> * If everything is in place (means patched kernel, as well as patched s390-tools/zipl) an installation from scratch on an NVMe devices should be possible - in case everything needed landed on an updated image.
>   With the 20.04.2 image that should be the case.
> 
> [Regression Potential]
> 
> * There is a certain regression risk with these patches, because:
> 
> * the 'zipl' (s390x-specific) boot-loader is touched
> 
> * if something is wrong there, in worst-case systems where the modified zipl ran may no longer be bootable!
> 
> * The modifications are targetted towards nvme devices ('blkext' driver), but they are closely related to zFCP devices and share some code parts,
> 
> * hence in worst case they could have an impact on zFCP devices, too.
> 
> * But this is very unlikely, since a (largely) separate IPL type 'nvme' got introduced and NVMe ipl is handled in separate case statements and functions.
> 
> * The patches are all upstream accepted (the first two with 5.8, that last with v5.10-rc1, hence the latter one is as of today in linux-next).
> 
> * A patched focal kernel was build and shared for further testing. I did some regression testing with the patched kernel on non-NVMe systems - the NVMe based tests need to be done by IBM (due to the lack of hardware).
> 
> * All modifications are limited to the s390x architecture and there again to the unique way of booting aka IPL (arch/s390/include/asm/ipl.h, arch/s390/include/uapi/asm/ipl.h, arch/s390/kernel/ipl.c and arch/s390/boot/ipl_parm.c).
> 
> [Other]
> 
> * The general NVMe ipl (boot) functionality in given with 3737e8ee4f2f "s390: nvme ipl" and 23a457b8d57d "s390: nvme reipl" and is already proven to work with groovy.
> 
> * New for groovy AND focal is only "s390/ipl: support NVMe IPL kernel parameters".
> 
> * The entire set of commits/patches is only new for focal.
> 
> * The SRU for SRUing "s390/ipl: support NVMe IPL kernel parameters" to groovy/20.10 was handled by a separate request.
> 
> Alexander Egorenkov (1):
>   s390/ipl: support NVMe IPL kernel parameters
> 
> Jason J. Herne (2):
>   s390: nvme ipl
>   s390: nvme reipl
> 
>  arch/s390/boot/ipl_parm.c        |  31 +++--
>  arch/s390/include/asm/ipl.h      |  11 ++
>  arch/s390/include/uapi/asm/ipl.h |  25 ++++
>  arch/s390/kernel/ipl.c           | 209 +++++++++++++++++++++++++++++++
>  4 files changed, 268 insertions(+), 8 deletions(-)
> 
With dropping linux-next on patch #3 and it looks like the kernel and the tools
part are not hard dependencies which need to be handled...

Acked-by: Stefan Bader <stefan.bader at canonical.com>

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