Unfortunately, QEMU itself doesn't emulate the Intel Galileo Gen 1 hardware. Instead it emulates the I440FX or ICH9 chips. (Diagrams are available here http://wiki.qemu.org/Features/Q35)
You may run Rocket under QEMU for x86 and QEMU for ARM, however you won't be able to access the GPIO chips as they aren't implemented in QEMU.
As an alternative to QEMU, I wonder if the Simics based Galilio Simulation on Helix LabCloud would be helpful?
It's not Gen 1 specific but you may want to take a look anyway. Helix LabCloud is pretty slick and it gets better every day.