[hbelusca] 62305: [NTVDM]: Limit the number of CPU recursion calls (not more than 32).

Author: hbelusca
Date: Sun Feb 23 15:54:20 2014
New Revision: 62305

URL: http://svn.reactos.org/svn/reactos?rev=62305&view=rev
Log:
[NTVDM]: Limit the number of CPU recursion calls (not more than 32).

Modified:
    branches/ntvdm/subsystems/ntvdm/callback.c
    branches/ntvdm/subsystems/ntvdm/clock.c
    branches/ntvdm/subsystems/ntvdm/emulator.c

Modified: branches/ntvdm/subsystems/ntvdm/callback.c
URL:
http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/callback…
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/callback.c	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/callback.c	[iso-8859-1] Sun Feb 23 15:54:20 2014
@@ -102,7 +102,7 @@
 
     DPRINT("Call16(0x%04X, 0x%04X)\n", Segment, Offset);
 
-    /* Start simulation */
+    /* Start CPU simulation */
     EmulatorSimulate();
 
     /* Restore CS:IP */

Modified: branches/ntvdm/subsystems/ntvdm/clock.c
URL:
http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/clock.c?…
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/clock.c	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/clock.c	[iso-8859-1] Sun Feb 23 15:54:20 2014
@@ -59,6 +59,7 @@
 
 VOID ClockUpdate(VOID)
 {
+    extern BOOLEAN CpuSimulate;
     UINT i;
 
 #ifdef WORKING_TIMER
@@ -127,7 +128,7 @@
     VgaHorizontalRetrace();
 
     /* Continue CPU emulation */
-    for (i = 0; (i < STEPS_PER_CYCLE) && VdmRunning; i++)
+    for (i = 0; VdmRunning && CpuSimulate && (i < STEPS_PER_CYCLE);
i++)
     {
         EmulatorStep();
 #ifdef IPS_DISPLAY

Modified: branches/ntvdm/subsystems/ntvdm/emulator.c
URL:
http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/emulator…
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/emulator.c	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/emulator.c	[iso-8859-1] Sun Feb 23 15:54:20 2014
@@ -30,6 +30,12 @@
 /* PRIVATE VARIABLES **********************************************************/
 
 FAST486_STATE EmulatorContext;
+BOOLEAN CpuSimulate = FALSE;
+
+/* No more than 'MaxCpuCallLevel' recursive CPU calls are allowed */
+const static INT MaxCpuCallLevel = 32;
+static INT CpuCallLevel = 0;
+
 LPVOID  BaseAddress = NULL;
 BOOLEAN VdmRunning  = TRUE;
 
@@ -177,18 +183,31 @@
 
 VOID EmulatorSimulate(VOID)
 {
-    // FIXME: Do not mix VdmRunning (i.e. ntvdm running) and CpuSimulate!!
-    while (VdmRunning) ClockUpdate();
+    if (CpuCallLevel > MaxCpuCallLevel)
+    {
+        DisplayMessage(L"Too many CPU levels of recursion (%d, expected maximum
%d)",
+                       CpuCallLevel, MaxCpuCallLevel);
+
+        /* Stop the VDM */
+        VdmRunning = FALSE;
+        return;
+    }
+    CpuCallLevel++;
+
+    CpuSimulate = TRUE;
+    while (VdmRunning && CpuSimulate) ClockUpdate();
+
+    CpuCallLevel--;
+    if (CpuCallLevel < 0) CpuCallLevel = 0;
 
     /* This takes into account for reentrance */
-    VdmRunning = TRUE;
+    CpuSimulate = TRUE;
 }
 
 VOID EmulatorUnsimulate(VOID)
 {
     /* Stop simulation */
-    // FIXME: Do not mix VdmRunning (i.e. ntvdm running) and CpuSimulate!!
-    VdmRunning = FALSE;
+    CpuSimulate = FALSE;
 }
 
 VOID EmulatorInterrupt(BYTE Number)