"Q: How is this different from previous VM escape vulnerabilities?
A: Most VM escape vulnerabilities discovered in the past were only exploitable in non-default configurations or in configurations that wouldn’t be used in secured environments. Other VM escape vulnerabilities only applied to a single virtualization platform, or didn’t directly allow for arbitrary code execution."
"Q: How is this different from previous VM escape vulnerabilities?
A: Most VM escape vulnerabilities discovered in the past were only exploitable in non-default configurations or in configurations that wouldn’t be used in secured environments. Other VM escape vulnerabilities only applied to a single virtualization platform, or didn’t directly allow for arbitrary code execution."
Edit: Xen advisory: http://xenbits.xen.org/xsa/advisory-133.html