Re: How to write a zIPL section in IPL2 record on a raw disk

[Thomas Huth <thuth@redhat.com>]

On 12/04/2023 04.22, Mike Stramba wrote:
> I have a CKD file, created with the Hercules dasdinit program.
> It's a  (hercules) 3350 uncompressed file.
> I've put a small "hello world" IPL program on it, and it works fine with 
> Hercules
> 
> When I try to run it with qemu-system-s390x I get :
> 
> LOADPARM=[        ]
> Using virtio-blk.
> Using guessed DASD geometry.
> Using ECKD scheme (block size  4096), CDL
> No zIPL section in IPL2 record.   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
> zIPL load failed.
> Could not find a suitable boot device (none specified)
> Failed to load OS from hard disk
> 
> The qemu script is :
> qemu-system-s390x -m 16 -drive format=raw,file=test-ipl.3350.un,if=virtio 
> -nographic

  Hi Mike!

I guess you're the first person who's trying to do this ;-) ...
QEMU's s390x emulation has been developed with only Linux guests in mind, so 
the boot "firmware" also only supports disks that have been prepared by the 
bootloader that is used for loading Linux on s390x - i.e. zipl.

FWIW, you can find the sources of the "firmware" in the pc-bios/s390-ccw/ 
folder of the QEMU source tree if you want to have a look.

But if you just want to load a small kernel into QEMU, you're maybe better 
off by using the "-kernel" option to load an ELF file.

> I found this link re:  the zipl command.
> https://www.ibm.com/docs/en/linux-on-systems?topic=u-modes-syntax-overview 
> 
> Where is that command   and  / or its source ?

zipl is part of the s390-tools that are available here:

  https://github.com/ibm-s390-linux/s390-tools

(there should also be a package for this in each decent s390x Linux distro).

  HTH,
   Thomas