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

[Christian Borntraeger]

On 04/05/12 15:53, Alexander Graf wrote:
> 
> On 04.05.2012, at 15:44, Christian Borntraeger wrote:
> 
>> An IPL (booting) on s390 of SCSI disks is done by a firmware component.
>> Lets implement this scheme as an qemu device that also allows to
>> configure the IPL like the HMC. We have a parameter iplid that
>> refers to a disk device and a load parm that specifies the entry
>> on the disk to be ipled. We also provide a default device
>> if no -device s390-ipl statement is given.
> 
> Any reason we can't do this in guest firmware code?

Conceptually guest firmware does not exist in the guest address space
on s390. It is separate in a storage area called HSA. 
(you could say the existing hardware is semi-hosted, you cant buy it bare 
metal.
Doing the boot code in guest address space will fail if the guest firmware
address  collides with the addresses specified by a bootmap.

Christian