QEMU supports a bunch of CPUID features that are tied to the kvm CPUID
nodes rather than the processor's. They are "kvmclock",
"kvm_nopiodelay", "kvm_mmu", "kvm_asyncpf". These are not known to
libvirt and their CPUID leaf might move if (for example) the Hyper-V
extensions are enabled. Hence their handling would anyway require some
special-casing.
However, among these the most useful is kvmclock; an additional
"property" of this feature is that a <timer> element is a better model
than a CPUID feature. Although, creating part of the -cpu command-line
from something other than the <cpu> XML element introduces some
ugliness.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
