oVirt 4.3 contains just one Debian version defined which is "Debian 7" which is a really old version. The most recent version of Debian is 10: https://www.debian.org/releases/buster/ We should add this version and remove Debian 7 since it's EoL for more than a year: https://www.debian.org/News/2018/20180601 PS: same for Ubuntu: oVirt lists a bunch of old versions that are no longer supported including non-LTS ones.
This is specifically covered under rhbz#1341161 -- we're not going to update the list for every release, so "Other Linux (Kernel 4.x)" is a catch-all for versions which use modern virtual hardware. *** This bug has been marked as a duplicate of bug 1341161 ***