The HVMOP_set_mem_access HVM control operations in Xen 4.1.x for 32-bit and 4.1.x through 4.4.x for 64-bit allow local guest administrators to cause a denial of service (CPU consumption) by leveraging access to certain service domains for HVM guests and a large input.
http://xenbits.xen.org/xsa/advisory-89.html
http://www.securitytracker.com/id/1029956
http://www.securityfocus.com/bid/66407
http://www.openwall.com/lists/oss-security/2014/03/25/2
http://www.openwall.com/lists/oss-security/2014/03/25/1
http://www.debian.org/security/2014/dsa-3006
http://security.gentoo.org/glsa/glsa-201407-03.xml
http://lists.opensuse.org/opensuse-security-announce/2014-10/msg00002.html