> > C) When you could go: > > > > DT -> Discover Xen -> Xen-specific stuff -> Xen-specific EFI/ACPI discovery > > I take you mean discovering Xen with the usual Xen hypervisor node on > device tree. I think that C) is a good option actually. I like it. Not > sure why we didn't think about this earlier. Is there anything EFI or > ACPI which is needed before Xen support is discovered by > arch/arm64/kernel/setup.c:setup_arch -> xen_early_init()? Currently lots (including the memory map). With the stuff to support SPCR, the ACPI discovery would be moved before xen_early_init(). > If not, we could just go for this. A lot of complexity would go away. I suspect this would still be fairly complex, but would at least prevent the Xen-specific EFI handling from adversely affecting the native case. > > D) If you want to be generic: > > EFI -> EFI application -> EFI tables -> ACPI tables -> Xen-specific stuff > > \------------------------------------------/ > > (virtualize these, provide shims to Dom0, but handle > > everything in Xen itself) > > I think that this is good in theory but could turn out to be a lot of > work in practice. We could probably virtualize the RuntimeServices but > the BootServices are troublesome. What's troublesome with the boot services? What can't be simulated? > > E) Partially-generic option: > > EFI -> EFI application -> Xen detected by registered GUID -> Xen-specific EFI bootloader stuff -> OS in Xen-specific configuration > > > > > > > > > In any case this should be separate from the shim ABI discussion. > > > > > > > > I disagree; I think this is very much relevant to the ABI discussion. > > > > That's not to say that I insist on a particular approach, but I think > > > > that they need to be considered together. > > > > > > Let's suppose Xen didn't expose any RuntimeServices at all, would that > > > make it easier to discuss about the EFI stub parameters? > > > > It would simply the protocol specific to Xen, certainly. > > > > > In the grant scheme of things, they are not that important, as Ian > > > wrote what is important is how to pass the RSDP. > > > > Unfortunately we're still going to have to care about this eventually, > > even if for something like kexec. So we still need to spec out the state > > of things if this is going to be truly generic. > > Fair enough. My position is that if we restrict this to RuntimeServices, > it might be possible, but I still prefer C). Regardless of what we do we still need a well-defined state here, which brings us back to the initial problem eventually. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
