title: TrustZone versus Hypervisor
body: <p>I am just reading <a href="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.prd29-genc-009492c/index.html" rel="nofollow">this document</a> from ARM on <strong>TrustZone</strong> and some things are unclear to me.</p>
  
  <p>The fact that a <strong>Hypervisor</strong> offers a special CPU mode and that for the <strong>TrustZone</strong>, the processor comes with an extra <em>33rd bit</em>: Isn't mode also a particular bit setting? How is then an extra bit making all that difference in terms of security.  I do understand that the extra bit makes way for two separate 32 bit address spacing, but apart from that I am unable to put two and two together. Can someone clearly explain  why <strong>TrustZone</strong> is more secure than a Hypervisor??</p>