Description of problem:
Libvirt should pass this cmdline:
instead of only -etc base=utc.
Libvirt should also abundant the old -rtc-td-hack
Libvirt won't hardcode time keeping options, but it will pass whatever command line is configured for the guest. To get that particular set of options you need to configure
<timer name='rtc' tickpolicy='catchup' track='wall'/>
For compatibility with old QEMU, libvirt will use -rtc-td-hack if it is present, but -rtc is not present.