Finally was able to recreate this behaviour locally. Using CentOS 5.3 as dom0, then I took a current oneiric ec2 image for domU, started a javajdk-6-jdk install and got the endless look of multicall failed messages in domU. Meanwhile I could see in dom0 that there was a matching stream of "mm.c:694:* Bad L3 flags 6" messages (6 == _PAGE_RW | _PAGE_USER). Using exactly the same domU image in a CentOS 5,4 and later dom0 works without problems.
Though I could not yet find out what exactly the change is between 5.3 and 5.4 that fixes the issue.
Finally was able to recreate this behaviour locally. Using CentOS 5.3 as dom0, then I took a current oneiric ec2 image for domU, started a javajdk-6-jdk install and got the endless look of multicall failed messages in domU. Meanwhile I could see in dom0 that there was a matching stream of "mm.c:694:* Bad L3 flags 6" messages (6 == _PAGE_RW | _PAGE_USER). Using exactly the same domU image in a CentOS 5,4 and later dom0 works without problems.
Though I could not yet find out what exactly the change is between 5.3 and 5.4 that fixes the issue.