[fireball] 51120: [NTOS/KE] - Remove VirtualBox SYSENTER-hack added in r50991. - Bring back NT-compatible SYSENTER support detection changed in r50991.

Author: fireball
Date: Tue Mar 22 16:35:51 2011
New Revision: 51120

URL: http://svn.reactos.org/svn/reactos?rev=51120&view=rev
Log:
[NTOS/KE]
- Remove VirtualBox SYSENTER-hack added in r50991.
- Bring back NT-compatible SYSENTER support detection changed in r50991.

Modified:
    trunk/reactos/ntoskrnl/ke/i386/cpu.c

Modified: trunk/reactos/ntoskrnl/ke/i386/cpu.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ke/i386/cpu.c?rev=...
==============================================================================
--- trunk/reactos/ntoskrnl/ke/i386/cpu.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/ke/i386/cpu.c [iso-8859-1] Tue Mar 22 16:35:51 2011
@@ -303,17 +303,10 @@
                 /* Remove support for correct PTE support. */
                 FeatureBits &= ~KF_WORKING_PTE;
             }
-            
-            /* Virtualbox claims to have no SYSENTER support,
-             * which is false for processors >= Pentium Pro */
-            if(Prcb->CpuType >= 6)
-            {
-                Reg[3] |= 0x800;
-            }
-
-            /* Check if the CPU is too old to support SYSENTER,
-             * See Intel CPUID instruction manual for details*/
-            if ((Reg[0] & 0x0FFF3FFF) < 0x00000633)
+
+            /* Check if the CPU is too old to support SYSENTER */
+            if ((Prcb->CpuType < 6) ||
+                ((Prcb->CpuType == 6) && (Prcb->CpuStep < 0x0303)))
             {
                 /* Disable it */
                 Reg[3] &= ~0x800;