I use qemu for development of embedded systems. Lately I had a need to
check ACPI related kernel module, but I have seen that there isn't any
support in the version 0.7.1 that I use.
I have checked also 0.7.2 and found no support.
A patch that I have found on www.h7.dion.ne.jp/~qemu-win/ for x86_64 by F.Navara seemed like close enough.
I have applied it (after adaptation, since it didn't go smooth for 0.7.1 or 0.7.2).
The system booted, but running dmesg | grep ACPI inside the embedded system on the qemu gave: