Index: /trunk/src/VBox/Main/idl/VirtualBox.xidl
===================================================================
--- /trunk/src/VBox/Main/idl/VirtualBox.xidl	(revision 75918)
+++ /trunk/src/VBox/Main/idl/VirtualBox.xidl	(revision 75919)
@@ -1353,4 +1353,5 @@
     <const name="NestedPaging"      value="3"/>
     <const name="UnrestrictedGuest" value="4"/>
+    <const name="NestedHWVirt"      value="5"/>
   </enum>
 
Index: /trunk/src/VBox/Main/src-server/HostImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/src-server/HostImpl.cpp	(revision 75918)
+++ /trunk/src/VBox/Main/src-server/HostImpl.cpp	(revision 75919)
@@ -218,4 +218,5 @@
                             fNestedPagingSupported,
                             fUnrestrictedGuestSupported,
+                            fNestedHWVirtSupported,
                             fRecheckVTSupported;
 
@@ -300,4 +301,5 @@
     m->fNestedPagingSupported = false;
     m->fUnrestrictedGuestSupported = false;
+    m->fNestedHWVirtSupported = false;
     m->fRecheckVTSupported = false;
 
@@ -388,9 +390,15 @@
                 else
                     Assert(m->fUnrestrictedGuestSupported == false);
+                /** @todo r=klaus put accurate condition here and update it as
+                 * the feature becomes available with VT-x. */
+                if (   (fVTCaps & SUPVTCAPS_AMD_V)
+                    && m->fNestedPagingSupported)
+                    m->fNestedHWVirtSupported = true;
             }
             else
             {
                 LogRel(("SUPR0QueryVTCaps -> %Rrc\n", rc));
-                m->fVTSupported = m->fNestedPagingSupported = m->fUnrestrictedGuestSupported = false;
+                m->fVTSupported = m->fNestedPagingSupported = m->fUnrestrictedGuestSupported
+                    = m->fNestedHWVirtSupported = false;
             }
             rc = SUPR3Term(false);
@@ -1017,4 +1025,5 @@
         case ProcessorFeature_NestedPaging:
         case ProcessorFeature_UnrestrictedGuest:
+        case ProcessorFeature_NestedHWVirt:
             break;
         default:
@@ -1032,5 +1041,6 @@
             && (   aFeature == ProcessorFeature_HWVirtEx
                 || aFeature == ProcessorFeature_NestedPaging
-                || aFeature == ProcessorFeature_UnrestrictedGuest)
+                || aFeature == ProcessorFeature_UnrestrictedGuest
+                || aFeature == ProcessorFeature_NestedHWVirt)
            )
         {
@@ -1057,9 +1067,15 @@
                     else
                         Assert(m->fUnrestrictedGuestSupported == false);
+                    /** @todo r=klaus put accurate condition here and update it as
+                     * the feature becomes available with VT-x. */
+                    if (   (fVTCaps & SUPVTCAPS_AMD_V)
+                        && m->fNestedPagingSupported)
+                        m->fNestedHWVirtSupported = true;
                 }
                 else
                 {
                     LogRel(("SUPR0QueryVTCaps -> %Rrc\n", rc));
-                    m->fVTSupported = m->fNestedPagingSupported = m->fUnrestrictedGuestSupported = false;
+                    m->fVTSupported = m->fNestedPagingSupported = m->fUnrestrictedGuestSupported
+                        = m->fNestedHWVirtSupported = false;
                 }
                 rc = SUPR3Term(false);
@@ -1091,4 +1107,8 @@
             case ProcessorFeature_UnrestrictedGuest:
                 *aSupported = m->fUnrestrictedGuestSupported;
+                break;
+
+            case ProcessorFeature_NestedHWVirt:
+                *aSupported = m->fNestedHWVirtSupported;
                 break;