If the backend is domain 0, which is the most common configuration, then host-wide operations may be starved, or the host may crash (Host Denial-of-Service). External References: https://xenbits.xen.org/xsa/advisory-300.html
Acknowledgments: Name: Julien Grall (ARM)
Created xen tracking bugs for this issue: Affects: fedora-all [bug 1731864]