Changeset 82159 in vbox

Timestamp:

Nov 25, 2019 10:18:41 AM (5 years ago)

Author:

vboxsync

Message:

VMM/HMVMXR0: Fix single-stepping in the hypervisor debugger using MTF when the guest is also single-stepping (using EFLAGS.TF).

File:

• trunk/src/VBox/VMM/VMMR0/HMVMXR0.cpp (modified) (5 diffs)

trunk/src/VBox/VMM/VMMR0/HMVMXR0.cpp

@@ -5805 +5805 @@
          * executing guest code so they'll trigger at the right time.
          */
+        HMVMX_CPUMCTX_ASSERT(pVCpu, CPUMCTX_EXTRN_DR7);
         if (pVCpu->cpum.GstCtx.dr[7] & (X86_DR7_ENABLED_MASK | X86_DR7_GD))
         {
@@ -8820 +8821 @@
             AssertRC(rc);
         }
-        else if (pVCpu->cpum.GstCtx.eflags.u32 & X86_EFL_TF)
+        else
         {
             /*
-             * We must not deliver a debug exception when single-stepping in the hypervisor debugger
-             * using EFLAGS.T. Instead, clear interrupt inhibition.
+             * We must not deliver a debug exception when single-stepping over STI/Mov-SS in the
+             * hypervisor debugger using EFLAGS.TF but rather clear interrupt inhibition. However,
+             * we take care of this case in hmR0VmxExportSharedDebugState and also the case if
+             * we use MTF, so just make sure it's called before executing guest-code.
              */
-            Assert(!(pVCpu->CTX_SUFF(pVM)->hm.s.vmx.Msrs.ProcCtls.n.allowed1 & VMX_PROC_CTLS_MONITOR_TRAP_FLAG));
-            fIntrState = 0;
+            ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_GUEST_DR_MASK);
         }
     }
@@ -10828 +10830 @@
             hmR0VmxReadAllRoFieldsVmcs(pVmxTransient);
 #endif
-#if defined(HMVMX_ALWAYS_SYNC_FULL_GUEST_STATE) || defined(HMVMX_ALWAYS_SAVE_FULL_GUEST_STATE)
-            rc = hmR0VmxImportGuestState(pVCpu, pVmcsInfo, HMVMX_CPUMCTX_EXTRN_ALL);
-            AssertRC(rc);
-#elif defined(HMVMX_ALWAYS_SAVE_GUEST_RFLAGS)
-            rc = hmR0VmxImportGuestState(pVCpu, pVmcsInfo, HMVMX_CPUMCTX_EXTRN_RFLAGS);
-            AssertRC(rc);
-#else
+
             /*
              * Import the guest-interruptibility state always as we need it while evaluating
@@ -10843 +10839 @@
              * mode changes wrt CR0 are intercepted.
              */
-            rc = hmR0VmxImportGuestState(pVCpu, pVmcsInfo, CPUMCTX_EXTRN_HM_VMX_INT_STATE);
+            uint64_t const fImportMask = CPUMCTX_EXTRN_HM_VMX_INT_STATE
+#if defined(HMVMX_ALWAYS_SYNC_FULL_GUEST_STATE) || defined(HMVMX_ALWAYS_SAVE_FULL_GUEST_STATE)
+                                       | HMVMX_CPUMCTX_EXTRN_ALL
+#elif defined(HMVMX_ALWAYS_SAVE_GUEST_RFLAGS)
+                                       | CPUMCTX_EXTRN_RFLAGS
+#endif
+                                       ;
+            rc = hmR0VmxImportGuestState(pVCpu, pVmcsInfo, fImportMask);
             AssertRC(rc);
-#endif
 
             /*
@@ -13740 +13742 @@
     PCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
     if (!pVmxTransient->fIsNestedGuest)
+    {
         rc = DBGFRZTrap01Handler(pVCpu->CTX_SUFF(pVM), pVCpu, CPUMCTX2CORE(pCtx), uDR6, pVCpu->hm.s.fSingleInstruction);
+
+        /*
+         * Prevents stepping twice over the same instruction when the guest is stepping using
+         * EFLAGS.TF and the hypervisor debugger is stepping using MTF.
+         * Testcase: DOSQEMM, break (using "ba x 1") at cs:rip 0x70:0x774 and step (using "t").
+         */
+        if (   rc == VINF_EM_DBG_STEPPED
+            && (pVmxTransient->pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_MONITOR_TRAP_FLAG))
+        {
+            Assert(pVCpu->hm.s.fSingleInstruction);
+            rc = VINF_EM_RAW_GUEST_TRAP;
+        }
+    }
     else
         rc = VINF_EM_RAW_GUEST_TRAP;