+++ This bug was initially created as a clone of Bug #541921 +++
This bug is for the changes needed on the management layer to allow "backward migration", when the newer version of KVM has fixes that make the savevm format incompatible with previous versions (e.g. the fix for bug 531701).
KVM will be changed to allow an older savevm version to be requested, by using the machine-type argument to define the savevm version (Bug #541731), and VDSM (and maybe the higher layers) need to be able to use that feature when there is the need to allow backward migration.
--- Additional comment from dlaor on 2009-11-30 08:44:46 EDT ---
or all rhel5.4.* incarnations, we'll always use -M rhel5.4 as a default, unless instructed differently by mgmt.
So, newer vdsm should start using rhel5.4.x for newer VMs, otherwise ATM pvclock will drift.
---
The exact similar implementation is needed in libvirt.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.
http://rhn.redhat.com/errata/RHBA-2010-0205.html