[jgardou] 58852: [NTOSKRNL] - Handle VME for the PUSHF and POPF instruction in virtual mode - There is no reason to set interrupt flag when handling POPF - Fix a typo in POPF case : mask out the ri...

Author: jgardou
Date: Thu Apr 25 21:29:59 2013
New Revision: 58852

URL: http://svn.reactos.org/svn/reactos?rev=58852&view=rev
Log:
[NTOSKRNL]
 - Handle VME for the PUSHF and POPF instruction in virtual mode
 - There is no reason to set interrupt flag when handling POPF
 - Fix a typo in POPF case : mask out the right variable
See http://www.rcollins.org/articles/vme1/ for reference

Modified:
    trunk/reactos/ntoskrnl/ke/i386/v86vdm.c

Modified: trunk/reactos/ntoskrnl/ke/i386/v86vdm.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ke/i386/v86vdm.c?r...
==============================================================================
--- trunk/reactos/ntoskrnl/ke/i386/v86vdm.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/ke/i386/v86vdm.c [iso-8859-1] Thu Apr 25 21:29:59 2013
@@ -53,16 +53,22 @@
 {
     ULONG Esp, V86EFlags, TrapEFlags;

-    /* Check for VME support */
-    ASSERT(KeI386VirtualIntExtensions == FALSE);
-
     /* Get current V8086 flags and mask out interrupt flag */
     V86EFlags = *KiNtVdmState;
     V86EFlags &= ~EFLAGS_INTERRUPT_MASK;

-    /* Get trap frame EFLags and leave only align, nested task and interrupt */
+    /* Get trap frame EFLags */
     TrapEFlags = TrapFrame->EFlags;
-    V86EFlags &= (EFLAGS_ALIGN_CHECK | EFLAGS_NESTED_TASK | EFLAGS_INTERRUPT_MASK);
+    /* Check for VME support */
+    if(KeI386VirtualIntExtensions)
+    {
+        /* Copy the virtual interrupt flag to the interrupt flag */
+        TrapEFlags &= ~EFLAGS_INTERRUPT_MASK;
+        if(TrapEFlags & EFLAGS_VIF)
+            TrapEFlags |= EFLAGS_INTERRUPT_MASK;
+    }
+    /* Leave only align, nested task and interrupt */
+    TrapEFlags &= (EFLAGS_ALIGN_CHECK | EFLAGS_NESTED_TASK | EFLAGS_INTERRUPT_MASK);

/* Add in those flags if they exist, and add in the IOPL flag */
     V86EFlags |= TrapEFlags;
@@ -133,10 +139,20 @@
     TrapEFlags = TrapFrame->EFlags;

/* Check for VME support */
-    ASSERT(KeI386VirtualIntExtensions == FALSE);
-
-    /* Add V86 and Interrupt flag */
-    V86EFlags |= EFLAGS_V86_MASK | EFLAGS_INTERRUPT_MASK;
+    if(KeI386VirtualIntExtensions)
+    {
+        /* Copy the IF flag into the VIF one */
+        V86EFlags &= ~EFLAGS_VIF;
+        if(V86EFlags & EFLAGS_INTERRUPT_MASK)
+        {
+            V86EFlags |= EFLAGS_VIF;
+            /* Don't set the interrupt flag */
+            V86EFlags &= ~EFLAGS_INTERRUPT_MASK;
+        }
+    }
+
+    /* Add V86 flag */
+    V86EFlags |= EFLAGS_V86_MASK;

/* Update EFlags in trap frame */
     TrapFrame->EFlags = V86EFlags;