Changeset 61211 in vbox

Timestamp:

May 26, 2016 2:12:15 PM (9 years ago)

Author:

vboxsync

Message:

pgmPoolMonitorIsReused: Cross page stuff == reused, as does unaligned 8+ byte writes.

File:

• trunk/src/VBox/VMM/VMMAll/PGMAllPool.cpp (modified) (2 diffs)

trunk/src/VBox/VMM/VMMAll/PGMAllPool.cpp

@@ -793 +793 @@
             return false;
     }
+
+    /*
+     * Anything having ESP on the left side means stack writes.
+     */
     if (    (    (pDis->Param1.fUse & DISUSE_REG_GEN32)
              ||  (pDis->Param1.fUse & DISUSE_REG_GEN64))
@@ -798 +802 @@
     {
         Log4(("pgmPoolMonitorIsReused: ESP\n"));
+        return true;
+    }
+
+    /*
+     * Page table updates are very very unlikely to be crossing page boundraries,
+     * and we don't want to deal with that in pgmPoolMonitorChainChanging and such.
+     */
+    uint32_t const cbWrite = DISGetParamSize(pDis, &pDis->Param1);
+    if ( (((uintptr_t)pvFault + cbWrite) >> X86_PAGE_SHIFT) != ((uintptr_t)pvFault >> X86_PAGE_SHIFT) )
+    {
+        Log4(("pgmPoolMonitorIsReused: cross page write\n"));
+        return true;
+    }
+
+    /*
+     * Nobody does an unaligned 8 byte write to a page table, right.
+     */
+    if (cbWrite >= 8 && ((uintptr_t)pvFault & 7) != 0)
+    {
+        Log4(("pgmPoolMonitorIsReused: Unaligned 8+ byte write\n"));
         return true;
     }