On 04.07.2010, at 11:10, Avi Kivity wrote: > On 07/04/2010 12:04 PM, Alexander Graf wrote: >> >> My biggest concern about putting things in the device-tree is that I was >> trying to keep things as separate as possible. Why does the firmware have to >> know that it's running in KVM? > > It doesn't need to know about kvm, it needs to know that a particular > hypercall protocol is available.
Considering how the parts of the draft that I read about sound like, that's not the inventor's idea. PPC people love to see the BIOS be part of the virtualization solution. I don't. That's the biggest difference here and reason for us going different directions. I think what they thought of is something like if (in_kvm()) { device_tree_put("/hypervisor/exit", EXIT_TYPE_MAGIC); device_tree_put("/hypervisor/exit_magic", EXIT_MAGIC); } which then the OS reads out. But that's useless, as the hypercalls are hypervisor specific. So why make the detection on the Linux side generic? > >> Why do I have to patch 3 projects (Linux, OpenBIOS, Qemu) when I could go >> with patching a single one (Linux)? >> > > That's not a valid argument. You patch as many projects as it takes to get > it right (not that I have an opinion in this particular discussion). If you can put code in Linux that touches 3 submaintainer's directories or one submaintainer's directory with both ending up being functionally equivalent, which way would you go? > > At the very least you have to patch qemu for reasons described before > (backwards compatible live migration). There is no live migration on PPC (yet). That point is completely moot atm. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html