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

[Christian Borntraeger]

On 04/05/12 20:12, Alexander Graf wrote:
> 
> On 04.05.2012, at 16:02, Christian Borntraeger wrote:
> 
>> On 04/05/12 16:00, 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.
>>
>> Or in other words, this code is closer to the real s390 boxes.
> 
> Yeah, I see the point. I'd really like to get Anthony's comments on this one 
> first though.

Right.

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?

Christian