virt-2.12 has been deprecated for a while and is probably going to be removed eventually.

Without highmem=off, we can't handle the PCI mappings and various other things.

With highmem=off, we still run into an issue with the cpus DTB entry as it has a cpu-map node that we mishandle.

As a first pass, probably checking that the node we are looking at actually has a reg field would help: https://github.com/klange/toaruos/blob/master/kernel/arch/aarch64/smp.c#L106

It would also be nice to be able to disable SMP entirely, like we do for x86-64: https://github.com/klange/toaruos/blob/master/kernel/arch/x86_64/smp.c#L393