At DayJob(tm), we run several older AMD-based KVM VM hosting platforms, running AMD FX 8150 CPUs on Gigabyte 990FXA-D3 motherboards.
This is a companion discussion topic for the original entry at https://www.funkypenguin.co.nz/note/kvm-vms-on-kernel-2-6-32-696-30-1-el6-x86-64-on-amd-based-hypervisor-fail-to-boot/