Again, performance gains leak sensitive data and the solution is to disable some features (and loose performance as well). Seems that Intel chose between performance x security, and security lost.
> Intel DDIO is enabled by default on all Intel Xeon processor E5 family and Intel Xeon processor E7 v2 family platforms. (from https://www.intel.com/content/www/us/en/io/data-direct-i-o-t...)
Seems that it was used in 2012-2014 processors, so it's an attack on 5-years-old processors. Perhaps the impact isn't that great nowadays, but I couldn't find it the same attack can be made in more recent CPUs.
> Yes, DDIO is enabled transparently by default in all Intel server-grade processors since 2012 (Intel Xeon E5, E7 and SP families).