I would like to use kvm migration, not only for live migration, but also migration to a file, e.g. to be able to make a consistent copy, or maybe to freeze a domain during host reboot.

This gives a downtime of some seconds or maybe minutes. Afterwards, the domain's clocks have lost this time, date and hwclock. This could be corrected e.g. by logging into the domain and calling ntpdate.

Is there some best practice for the clock correction? Something non-interactive? Is it a bug that hwclock loses the time?

Host and domain are running Debian lenny, Kernel 2.6.26, clock paravirtualized. I do not call kvm and migrate directly, but through virsh save and restore.