Changeset 5610 in vbox for trunk/src/VBox/VMM

Timestamp:

Nov 2, 2007 11:10:07 AM (17 years ago)

Author:

vboxsync

Message:

Fixed boundary checks and support partial instruction updates (e.g. destination address of jmp instruction)

Location:

trunk/src/VBox/VMM/PATM

Files:

• PATM.cpp (modified) (3 diffs)
• PATMInternal.h (modified) (1 diff)
• VMMGC/PATMGC.cpp (modified) (1 diff)

trunk/src/VBox/VMM/PATM/PATM.cpp

@@ -4692 +4692 @@
             bool fValidPatchWrite = false;
 
+            /* Quick check to see if the write is in the patched part of the page */
+            if (    pPatchPage->pLowestAddrGC  > (RTGCPTR)((RTGCUINTPTR)GCPtr + cbWrite - 1)
+                ||  pPatchPage->pHighestAddrGC < GCPtr)
+            {
+                break;
+            }
+
             for (i=0;i<pPatchPage->cCount;i++)
             {
@@ -4719 +4726 @@
                         }
 
-                        pPatchInstrGC = patmGuestGCPtrToPatchGCPtr(pVM, pPatch, pGuestPtrGC);
+                        /* Find the closest instruction from below; the above quick check ensured that we are indeed in patched code */
+                        pPatchInstrGC = patmGuestGCPtrToClosestPatchGCPtr(pVM, pPatch, pGuestPtrGC);
+                        Assert(pPatchInstrGC);
                         if (pPatchInstrGC)
                         {
@@ -5624 +5633 @@
 }
 
+/* Converts Guest code GC ptr to Patch code GC ptr (or nearest from below if no identical match)
+ *
+ * @returns corresponding GC pointer in patch block
+ * @param   pVM         The VM to operate on.
+ * @param   pPatch      Current patch block pointer
+ * @param   pInstrGC    Guest context pointer to privileged instruction
+ *
+ */
+RTGCPTR patmGuestGCPtrToClosestPatchGCPtr(PVM pVM, PPATCHINFO pPatch, GCPTRTYPE(uint8_t*) pInstrGC)
+{
+        PRECGUESTTOPATCH pGuestToPatchRec = (PRECGUESTTOPATCH)RTAvlGCPtrGetBestFit(&pPatch->Guest2PatchAddrTree, pInstrGC, false);
+        if (pGuestToPatchRec)
+            return pVM->patm.s.pPatchMemGC + pGuestToPatchRec->PatchOffset;
+
+    return 0;
+}
+
 /* Converts Guest code GC ptr to Patch code GC ptr (if found)
  *

trunk/src/VBox/VMM/PATM/PATMInternal.h

@@ -524 +524 @@
 RTGCPTR patmPatchGCPtr2GuestGCPtr(PVM pVM, PPATCHINFO pPatch, GCPTRTYPE(uint8_t *) pPatchGC);
 RTGCPTR patmGuestGCPtrToPatchGCPtr(PVM pVM, PPATCHINFO pPatch, GCPTRTYPE(uint8_t*) pInstrGC);
+RTGCPTR patmGuestGCPtrToClosestPatchGCPtr(PVM pVM, PPATCHINFO pPatch, GCPTRTYPE(uint8_t*) pInstrGC);
 #endif
 

trunk/src/VBox/VMM/PATM/VMMGC/PATMGC.cpp

@@ -108 +108 @@
     if (pPatchPage)
     {
-        if (    pPatchPage->pLowestAddrGC  <= (RTGCPTR)((RTGCUINTPTR)GCPtr + cbWrite)
-            ||  pPatchPage->pHighestAddrGC > GCPtr)
+        if (    pPatchPage->pLowestAddrGC  > (RTGCPTR)((RTGCUINTPTR)GCPtr + cbWrite - 1)
+            ||  pPatchPage->pHighestAddrGC < GCPtr)
         {
             /* This part of the page was not patched; try to emulate the instruction. */