Re: [Qemu-devel] [PATCH 1/1] s390: IPL device for s390

[Christian Borntraeger <borntraeger@de.ibm.com>]

>> Anthony, this is the prototype of the IPL device that we have talked about some weeks
>> ago. Is an external device to do the IPL process for s390 still ok with you?
> 
> Even with an external IPL, we should still be able to detect that a guest provides 
> its own virtio-zipl code that contains a boot menu and execute that instead of directly
> booting into the first entry, right?

This is something that we can argue about to find a way to cover all our use cases
Some of my goals are
- make it possible to install the boot loader in lpar/vm and boot in kvm and vice versa
- follow the real HW ipl process (which I do for FCP, but not for dasd/eckd)
- be able to choose a boot device (-boot <x> is not the right thing for s390)
- be able to choose an program (loadparm)
- get a disk booted no matter if FCP, ECKD CDL, ECKD LDL, block size etc as long as this
  configuration can exist with the current tool sets (that includes ipling disks prepared
  with the sles11 tools)
- have some code that can be extended to non-disk boot devices (s390-ipl takes a qdev id
  as parameter)

Can you clarify what you need? the code should be modular enough to add a detection, a switch
or something else to make that possible.

Christian 

PS: long term we probably also want to have real ECKD dasd passthrough as an alternative to 
virtio for dasds. Then the IPL process will also include interpretation of ipl ccws, but this is 
something that wont be ready anytime soon