On 08.05.2012, at 14:32, Christian Borntraeger wrote: > 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?
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? Alex
