libvirt/src/cpu_map/x86_cpu64-rhel6.xml

<cpus>
  <model name='cpu64-rhel6'>
    <decode host='on' guest='on'/>
    <feature name='apic'/>
    <feature name='clflush'/>
    <feature name='cmov'/>
    <feature name='cx16'/>
    <feature name='cx8'/>
    <feature name='de'/>
    <feature name='fpu'/>
    <feature name='fxsr'/>
    <feature name='lahf_lm'/>
    <feature name='lm'/>
    <feature name='mca'/>
    <feature name='mce'/>
    <feature name='mmx'/>
    <feature name='msr'/>
    <feature name='mtrr'/>
    <feature name='nx'/>
    <feature name='pae'/>
    <feature name='pat'/>
    <feature name='pge'/>
    <feature name='pni'/>
    <feature name='pse'/>
    <feature name='pse36'/>
    <feature name='sep'/>
    <feature name='sse'/>
    <feature name='sse2'/>
    <feature name='syscall'/>
    <feature name='tsc'/>
  </model>
</cpus>