Changeset 13381 in vbox for trunk/src

Timestamp:

Oct 17, 2008 8:40:48 PM (16 years ago)

Author:

vboxsync

Message:

EM: experimental fix for #DE loop during ubuntu boot w/ busted apic: Check for CPL=0 traps in patch code and hand them on to emR3PatchTrap.

File:

• trunk/src/VBox/VMM/EM.cpp (modified) (12 diffs)

trunk/src/VBox/VMM/EM.cpp

@@ -98 +98 @@
 static int emR3ForcedActions(PVM pVM, int rc);
 static int emR3RawGuestTrap(PVM pVM);
+static int emR3PatchTrap(PVM pVM, PCPUMCTX pCtx, int gcret);
 
 
@@ -1430 +1431 @@
     }
 
-    /* Traps can be directly forwarded in hardware accelerated mode. */
+    /*
+     * Traps can be directly forwarded in hardware accelerated mode.
+     */
     if (HWACCMR3IsActive(pVM))
     {
@@ -1440 +1443 @@
     }
 
-    /** Scan kernel code that traps; we might not get another chance. */
+#if 1 /* Experimental: Review, disable if it causes trouble. */
+    /*
+     * Handle traps in patch code first.
+     *
+     * We catch a few of these cases in RC before returning to R3 (#PF, #GP, #BP)
+     * but several traps isn't handled specially by TRPM in RC and we end up here
+     * instead. One example is #DE.
+     */
+    uint32_t uCpl = CPUMGetGuestCPL(pVM, CPUMCTX2CORE(pCtx));
+    if (    uCpl == 0
+        &&  PATMIsPatchGCAddr(pVM, (RTGCPTR)pCtx->eip))
+    {
+        LogFlow(("emR3RawGuestTrap: trap %#x in patch code; eip=%08x\n", u8TrapNo, pCtx->eip));
+        return emR3PatchTrap(pVM, pCtx, rc);
+    }
+#endif
+
+    /*
+     * If the guest gate is marked unpatched, then we will check again if we can patch it.
+     * (This assumes that we've already tried and failed to dispatch the trap in
+     * RC for the gates that already has been patched. Which is true for most high
+     * volume traps, because these are handled specially, but not for odd ones like #DE.)
+     */
+    if (TRPMR3GetGuestTrapHandler(pVM, u8TrapNo) == TRPM_INVALID_HANDLER)
+    {
+        CSAMR3CheckGates(pVM, u8TrapNo, 1);
+        Log(("emR3RawHandleRC: recheck gate %x -> valid=%d\n", u8TrapNo, TRPMR3GetGuestTrapHandler(pVM, u8TrapNo) != TRPM_INVALID_HANDLER));
+
+        /* If it was successful, then we could go back to raw mode. */
+        if (TRPMR3GetGuestTrapHandler(pVM, u8TrapNo) != TRPM_INVALID_HANDLER)
+        {
+            /* Must check pending forced actions as our IDT or GDT might be out of sync. */
+            rc = EMR3CheckRawForcedActions(pVM);
+            AssertRCReturn(rc, rc);
+
+            TRPMERRORCODE enmError = uErrorCode != ~0U
+                                   ? TRPM_TRAP_HAS_ERRORCODE
+                                   : TRPM_TRAP_NO_ERRORCODE;
+            rc = TRPMForwardTrap(pVM, CPUMCTX2CORE(pCtx), u8TrapNo, uErrorCode, enmError, TRPM_TRAP, -1);
+            if (rc == VINF_SUCCESS /* Don't use VBOX_SUCCESS */)
+            {
+                TRPMResetTrap(pVM);
+                return VINF_EM_RESCHEDULE_RAW;
+            }
+            AssertMsg(rc == VINF_EM_RAW_GUEST_TRAP, ("%Rrc\n", rc));
+        }
+    }
+
+    /*
+     * Scan kernel code that traps; we might not get another chance.
+     */
+    /** @todo move this up before the dispatching? */
     if (    (pCtx->ss & X86_SEL_RPL) <= 1
         &&  !pCtx->eflags.Bits.u1VM)
@@ -1448 +1502 @@
     }
 
+    /*
+     * Trap specific handling.
+     */
     if (u8TrapNo == 6) /* (#UD) Invalid opcode. */
     {
+        /*
+         * If MONITOR & MWAIT are supported, then interpret them here.
+         */
         DISCPUSTATE cpu;
-
-        /* If MONITOR & MWAIT are supported, then interpret them here. */
         rc = CPUMR3DisasmInstrCPU(pVM, pCtx, pCtx->rip, &cpu, "Guest Trap (#UD): ");
         if (    VBOX_SUCCESS(rc)
             && (cpu.pCurInstr->opcode == OP_MONITOR || cpu.pCurInstr->opcode == OP_MWAIT))
         {
-            uint32_t u32Dummy, u32Features, u32ExtFeatures, size;
-
+            uint32_t u32Dummy, u32Features, u32ExtFeatures;
             CPUMGetGuestCpuId(pVM, 1, &u32Dummy, &u32Dummy, &u32ExtFeatures, &u32Features);
-
             if (u32ExtFeatures & X86_CPUID_FEATURE_ECX_MONITOR)
             {
@@ -1466 +1522 @@
                 AssertRC(rc);
 
-                rc = EMInterpretInstructionCPU(pVM, &cpu, CPUMCTX2CORE(pCtx), 0, &size);
+                uint32_t opsize;
+                rc = EMInterpretInstructionCPU(pVM, &cpu, CPUMCTX2CORE(pCtx), 0, &opsize);
                 if (VBOX_SUCCESS(rc))
                 {
@@ -1478 +1535 @@
     else if (u8TrapNo == 13) /* (#GP) Privileged exception */
     {
+        /*
+         * Handle I/O bitmap?
+         */
+        /** @todo We're not supposed to be here with a false guest trap concerning
+         *        I/O access. We can easily handle those in RC.  */
         DISCPUSTATE cpu;
-
         rc = CPUMR3DisasmInstrCPU(pVM, pCtx, pCtx->rip, &cpu, "Guest Trap: ");
-        if (VBOX_SUCCESS(rc) && (cpu.pCurInstr->optype & OPTYPE_PORTIO))
+        if (    VBOX_SUCCESS(rc)
+            &&  (cpu.pCurInstr->optype & OPTYPE_PORTIO))
         {
             /*
@@ -1576 +1638 @@
 }
 
+
 /**
  * Handle a trap (\#PF or \#GP) in patch code
@@ -1584 +1647 @@
  * @param   gcret   GC return code
  */
-int emR3PatchTrap(PVM pVM, PCPUMCTX pCtx, int gcret)
+static int emR3PatchTrap(PVM pVM, PCPUMCTX pCtx, int gcret)
 {
     uint8_t         u8TrapNo;
@@ -2094 +2157 @@
                 break;
             }
-
-            Assert(TRPMHasTrap(pVM));
-            Assert(!PATMIsPatchGCAddr(pVM, (RTGCPTR)pCtx->eip));
-
-            if (TRPMHasTrap(pVM))
-            {
-                uint8_t         u8Interrupt;
-                RTGCUINT        uErrorCode;
-                TRPMERRORCODE   enmError = TRPM_TRAP_NO_ERRORCODE;
-
-                rc = TRPMQueryTrapAll(pVM, &u8Interrupt, NULL, &uErrorCode, NULL);
-                AssertRC(rc);
-
-                if (uErrorCode != ~0U)
-                    enmError = TRPM_TRAP_HAS_ERRORCODE;
-
-                /* If the guest gate is marked unpatched, then we will check again if we can patch it. */
-                if (TRPMR3GetGuestTrapHandler(pVM, u8Interrupt) == TRPM_INVALID_HANDLER)
-                {
-                    CSAMR3CheckGates(pVM, u8Interrupt, 1);
-                    Log(("emR3RawHandleRC: recheck gate %x -> valid=%d\n", u8Interrupt, TRPMR3GetGuestTrapHandler(pVM, u8Interrupt) != TRPM_INVALID_HANDLER));
-
-                    /** If it was successful, then we could go back to raw mode. */
-                    if (TRPMR3GetGuestTrapHandler(pVM, u8Interrupt) != TRPM_INVALID_HANDLER)
-                    {
-                        /* Must check pending forced actions as our IDT or GDT might be out of sync */
-                        EMR3CheckRawForcedActions(pVM);
-
-                        rc = TRPMForwardTrap(pVM, CPUMCTX2CORE(pCtx), u8Interrupt, uErrorCode, enmError, TRPM_TRAP, -1);
-                        if (rc == VINF_SUCCESS /* Don't use VBOX_SUCCESS */)
-                        {
-                            TRPMResetTrap(pVM);
-                            return VINF_EM_RESCHEDULE_RAW;
-                        }
-                    }
-                }
-            }
             rc = emR3RawGuestTrap(pVM);
             break;
@@ -2219 +2245 @@
         case VINF_EM_RAW_INTERRUPT_PENDING:
         case VINF_EM_RAW_RING_SWITCH_INT:
-        {
-            uint8_t u8Interrupt;
-
             Assert(TRPMHasTrap(pVM));
             Assert(!PATMIsPatchGCAddr(pVM, (RTGCPTR)pCtx->eip));
@@ -2227 +2250 @@
             if (TRPMHasTrap(pVM))
             {
-                u8Interrupt = TRPMGetTrapNo(pVM);
-
                 /* If the guest gate is marked unpatched, then we will check again if we can patch it. */
+                uint8_t u8Interrupt = TRPMGetTrapNo(pVM);
                 if (TRPMR3GetGuestTrapHandler(pVM, u8Interrupt) == TRPM_INVALID_HANDLER)
                 {
@@ -2239 +2261 @@
             rc = VINF_EM_RESCHEDULE_REM;
             break;
-        }
 
         /*