Sometime ago I learnt, from Paolo Bonzini (upstream KVM maintainer), about this little debugging utility –
x86info (written by Dave Jones) which captures detailed information about CPU diagnostics — TLB, cache sizes, CPU feature flags, model-specific registers, etc. Take a look at its man page for specifics.
$ yum install x86info -y
Run it and capture the output in a file:
$ x86info -a 2>&1 | tee stdout-x86info.txt
As part of debugging KVM-based nested virtualization issues, here I captured
x86info of L0 (bare metal, Intel Haswell), L1 (guest hypervisor), L2 (nested guest, running on L1).