Index: /trunk/src/VBox/HostDrivers/Support/SUPDrv.cpp
===================================================================
--- /trunk/src/VBox/HostDrivers/Support/SUPDrv.cpp	(revision 56492)
+++ /trunk/src/VBox/HostDrivers/Support/SUPDrv.cpp	(revision 56493)
@@ -3760,4 +3760,8 @@
  *
  * @remarks Must be called with preemption disabled.
+ *          The caller is also expected to check that the CPU is an Intel (or
+ *          VIA) CPU -and- that it supports VT-x.  Otherwise, this function
+ *          might throw a #GP fault as it tries to read/write MSRs that may not
+ *          be present!
  */
 SUPR0DECL(int) SUPR0GetVmxUsability(bool *pfIsSmxModeAmbiguous)