Xen through 4.7.x allows local ARM guest OS users to cause a denial of service (host crash) via vectors involving an asynchronous abort while at EL2.
https://security.gentoo.org/glsa/201612-56
http://xenbits.xen.org/xsa/xsa201-2.patch
http://xenbits.xen.org/xsa/advisory-201.html
http://www.securitytracker.com/id/1037358
http://www.securityfocus.com/bid/94581