Ubuntu 10.04 + Xen + Simics

The goal of my previous posts were to create a Xen 4.0.1 + Ubuntu 10.04 and run it on top of Simics 3. Well everything works great until I got to Simics and then I would get a dreaded triple fault due to MSR 0x8000020 or MSR_EFER, which appears to be a MSR for 64-bit CPUs. It does not exist on Pentium 4 machines, Simics x86 cpu, and it is unclear why that instruction was being executed. After figuring out the stack trace in Simics, I disassembled Linux and Xen and could not find a matching set of instructions. That meant the only other possibility was that grub was at fault. It seems that during the booting of a multiboot the instruction was being called. After installing grub1 onto the machine, the machine boots in Simics.