Some tools, such as virt-manager, prefers having the default USB
controller explicit in the XML document. This patch makes sure there
is one. With this patch, it is now possible to switch from USB1 to
USB2 from the release 0.9.1 of virt-manager.
Fix tests to pass with this change.
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>