VMware is rejigging the way it shares memory among virtual machines, after turning off Transparent Page Sharing (TPS) because academics identified insecurities in the technology.

The academic paper is entitled “Wait a minute! A fast, Cross-VM attack on AES”
https://eprint.iacr.org/2014/435.pdf

slightly different opinions
http://vsphere-land.com/news/why-the-vmware-vsphere-tps-vulnerability-is-a-big-deal.html
http://wahlnetwork.com/2014/10/20/tps-vulnerability/