Not a lot of meat on this, but it looks nice from glancing at all the bits. I would recommend that you read the CPUID bits from the real CPU and copy most of them over so that the kernel can enable features like SSE4.x, AVX/AVX2 and various others. Use KVM_GET_SUPPORTED_CPUID and then KVM_SET_CPUID2.

I would also set the CPU name to KVMKVMKVM and enable a few of the paravirtual devices like KVMCLOCK.

Good luck with your project!