KVM TSC trapping

Zachary Amsden
2011-01-06T10:10:50Z

On top of my last patchset, I now implement TSC trapping and
a flexible migration scheme for maintaining stable TSC across
migration. Since it is administratively configured, it can
be selectively enabled only for VMs which require it. In
particular, VMs which use KVM clock probably do not want it.

We will need some administrative controls in qemu and in libvirt
to make full use of this, but the design allows flexible and
fairly simple control. In addition, users can override these
settings with module parameters to forcibly disable or enable
TSC trapping globally, for testing, workarounds, or performance.

This may be slightly out of date, but I would like to solicit
feedback about the patches, #2 especially.

--Zach