Description of problem: I'm not sure what the default downstream of driftfix is, but it should be slew to prevent Windows from BSOD. See http://lists.gnu.org/archive/html/qemu-devel/2012-06/msg03341.html RHEV/oVirt sets this option in the QEMU command line. Version-Release number of selected component (if applicable): Essex How reproducible: Steps to Reproduce: 1. 2. 3. Actual results: Expected results: Additional info: http://lists.gnu.org/archive/html/qemu-devel/2012-06/msg03341.html
This was included in Folsom: commit 3114a97ba188895daff4a3d337b2c73855d4632d Author: Daniel P. Berrange <berrange> Date: Mon Jun 11 17:16:10 2012 +0100 Update default policies for KVM guest PIT & RTC timers The default policies for the KVM guest PIT and RTC timers are not very good at maintaining reliable time in guest operating systems. In particular Windows 7 guests will often crash with the default KVM timer policies, and old Linux guests will have very bad time drift Set the PIT such that missed ticks are injected at the normal rate, ie they are delayed Set the RTC such that missed ticks are injected at a higher rate to "catch up" This corresponds to the following libvirt XML <clock offset='utc'> <timer name='pit' tickpolicy='delay'/> <timer name='rtc' tickpolicy='catchup'/> </clock> And the following KVM options -no-kvm-pit-reinjection -rtc base=utc,driftfix=slew This should provide a default configuration that works acceptably for most OS types. In the future this will likely need to be made configurable per-guest OS type. Fixes LP bug #1011848 Change-Id: Iafb0e2192b5f3c05b6395ffdfa14f86a98ce3d1f Signed-off-by: Daniel P. Berrange <berrange>