Changeset 25556 in vbox for trunk/src/VBox/VMM/VMMGC

Timestamp:

Dec 22, 2009 12:19:11 PM (15 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

56233

Message:

Rewrote RDTSC #GP optimization as it's no longer safe to access the instruction opcode due to possibly stale code TLB entries.

File:

• trunk/src/VBox/VMM/VMMGC/TRPMGCHandlers.cpp (modified) (2 diffs)

trunk/src/VBox/VMM/VMMGC/TRPMGCHandlers.cpp

@@ -845 +845 @@
 
     /*
-     * Optimize RDTSC traps.
-     * Some guests (like Solaris) are using RDTSC all over the place and
-     * will end up trapping a *lot* because of that.
-     */
-    if (   !pRegFrame->eflags.Bits.u1VM
-        && ((uint8_t *)PC)[0] == 0x0f
-        && ((uint8_t *)PC)[1] == 0x31)
-    {
-        STAM_PROFILE_STOP(&pVM->trpm.s.StatTrap0dDisasm, a);
-        return trpmGCTrap0dHandlerRdTsc(pVM, pVCpu, pRegFrame);
-    }
-
-    /*
      * Disassemble the instruction.
      */
@@ -870 +857 @@
     }
     STAM_PROFILE_STOP(&pVM->trpm.s.StatTrap0dDisasm, a);
+
+    /*
+     * Optimize RDTSC traps.
+     * Some guests (like Solaris) are using RDTSC all over the place and
+     * will end up trapping a *lot* because of that.
+     *
+     * Note: it's no longer safe to access the instruction opcode directly due to possible stale code TLB entries
+     */
+    if (Cpu.pCurInstr->opcode == OP_RDTSC)
+    {
+        STAM_PROFILE_STOP(&pVM->trpm.s.StatTrap0dDisasm, a);
+        return trpmGCTrap0dHandlerRdTsc(pVM, pVCpu, pRegFrame);
+    }
 
     /*