Hi, > SLOF is what is loaded from the very beginning, it configures PCI, cooks > the device tree and boots the guest system (directly or via yaboot/grub, > from disk, network or ram). Normal firmware, as usual. It knows all the > details about the machine so the guest system (linux) does not need to know > details about PCI host bus adapter or anything like this.
So pretty much like seabios on x86. > RTAS is an agent which always lives in RAM when the guest system (linux, > aix) is up and running. It is a light-weight version of SLOF which is left > in RAM by SLOF and can do board/machine specific tasks such as PCI config > space access or PCI hotplug - something what SLOF already knows about and > something what the guest does not want to know about in details. This came > from IBM pHyp (traditional server PPC64 hypervisor) and it is quite a big > firmware. In the case of KVM, it is very small stub which simply passes > requests to QEMU which does the rest. But it is still a separate binary > image even in the current QEMU. How that does get loaded? Is it there at machine init? Or does SLOF load RTAS from somewhere? thanks, Gerd
