Changeset 81092 in vbox

Timestamp:

Oct 1, 2019 4:53:27 AM (5 years ago)

Author:

vboxsync

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

133698

Message:

VMM/HMSVMR0: Nested SVM: bugref:7243 Optimize run loop to avoid exits to ring-3 on every nested-guest VM-exit.

File:

• trunk/src/VBox/VMM/VMMR0/HMSVMR0.cpp (modified) (7 diffs)

trunk/src/VBox/VMM/VMMR0/HMSVMR0.cpp

@@ -2661 +2661 @@
     PCSVMVMCBSTATESAVE pVmcbGuest = &pVmcb->guest;
     PCSVMVMCBCTRL      pVmcbCtrl  = &pVmcb->ctrl;
-
-    Log4Func(("fExtrn=%#RX64 fWhat=%#RX64\n", pCtx->fExtrn, fWhat));
 
     /*
@@ -4100 +4098 @@
     {
         /* Pending PGM C3 sync. */
-        if (VMCPU_FF_IS_ANY_SET(pVCpu,VMCPU_FF_PGM_SYNC_CR3 | VMCPU_FF_PGM_SYNC_CR3_NON_GLOBAL))
+        if (VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_PGM_SYNC_CR3 | VMCPU_FF_PGM_SYNC_CR3_NON_GLOBAL))
         {
             int rc = PGMSyncCR3(pVCpu, pVCpu->cpum.GstCtx.cr0, pVCpu->cpum.GstCtx.cr3, pVCpu->cpum.GstCtx.cr4,
@@ -4183 +4181 @@
     int rc = hmR0SvmCheckForceFlags(pVCpu);
     if (rc != VINF_SUCCESS)
+    {
+        if (!CPUMIsGuestInSvmNestedHwVirtMode(pCtx))
+            STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchNstGstVmexit);
         return rc;
+    }
 
     if (TRPMHasTrap(pVCpu))
@@ -4192 +4194 @@
         if (    rcStrict != VINF_SUCCESS
             || !CPUMIsGuestInSvmNestedHwVirtMode(pCtx))
+        {
+            if (!CPUMIsGuestInSvmNestedHwVirtMode(pCtx))
+                STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchNstGstVmexit);
             return VBOXSTRICTRC_VAL(rcStrict);
+        }
     }
 
@@ -4314 +4320 @@
 
 #ifdef HMSVM_SYNC_FULL_GUEST_STATE
-    Assert(!(pVCpu->cpum.GstCtx->fExtrn & HMSVM_CPUMCTX_EXTRN_ALL));
+    Assert(!(pVCpu->cpum.GstCtx.fExtrn & HMSVM_CPUMCTX_EXTRN_ALL));
     ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_ALL_GUEST);
 #endif
@@ -4922 +4928 @@
         rc = hmR0SvmHandleExitNested(pVCpu, &SvmTransient);
         STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatExitHandling, x);
-        if (    rc != VINF_SUCCESS
-            || !CPUMIsGuestInSvmNestedHwVirtMode(pCtx))
-            break;
-        if (++(*pcLoops) >= pVCpu->CTX_SUFF(pVM)->hm.s.cMaxResumeLoops)
-        {
-            STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchMaxResumeLoops);
-            rc = VINF_EM_RAW_INTERRUPT;
-            break;
-        }
-        /** @todo NSTSVM: Add stat for StatSwitchNstGstVmexit. Re-arrange the above code to
-         *        be accurate when doing so, see the corresponding VT-x code. */
-
-        /** @todo handle single-stepping   */
+        if (rc == VINF_SUCCESS)
+        {
+            if (!CPUMIsGuestInSvmNestedHwVirtMode(pCtx))
+            {
+                STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchNstGstVmexit);
+                rc = VINF_SVM_VMEXIT;
+            }
+            else
+            {
+                if (++(*pcLoops) <= pVCpu->CTX_SUFF(pVM)->hm.s.cMaxResumeLoops)
+                    continue;
+                STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchMaxResumeLoops);
+                rc = VINF_EM_RAW_INTERRUPT;
+            }
+        }
+        else
+            Assert(rc != VINF_SVM_VMEXIT);
+        break;
+        /** @todo NSTSVM: handle single-stepping. */
     }
 
@@ -4959 +4971 @@
     uint32_t cLoops = 0;
     int      rc;
+    for (;;)
+    {
 #ifdef VBOX_WITH_NESTED_HWVIRT_SVM
-    if (!CPUMIsGuestInSvmNestedHwVirtMode(pCtx))
+        bool const fInNestedGuestMode = CPUMIsGuestInSvmNestedHwVirtMode(pCtx);
+#else
+        NOREF(pCtx);
+        bool const fInNestedGuestMode = false;
 #endif
-    {
-        if (!pVCpu->hm.s.fSingleInstruction)
-            rc = hmR0SvmRunGuestCodeNormal(pVCpu, &cLoops);
+        if (!fInNestedGuestMode)
+        {
+            if (!pVCpu->hm.s.fSingleInstruction)
+                rc = hmR0SvmRunGuestCodeNormal(pVCpu, &cLoops);
+            else
+                rc = hmR0SvmRunGuestCodeStep(pVCpu, &cLoops);
+        }
+#ifdef VBOX_WITH_NESTED_HWVIRT_SVM
         else
-            rc = hmR0SvmRunGuestCodeStep(pVCpu, &cLoops);
-    }
-#ifdef VBOX_WITH_NESTED_HWVIRT_SVM
-    else
-    {
-        rc = VINF_SVM_VMRUN;
-    }
-
-    /* Re-check the nested-guest condition here as we may be transitioning from the normal
-       execution loop into the nested-guest, hence this is not placed in the 'else' part above. */
-    if (rc == VINF_SVM_VMRUN)
-    {
-        rc = hmR0SvmRunGuestCodeNested(pVCpu, &cLoops);
+            rc = hmR0SvmRunGuestCodeNested(pVCpu, &cLoops);
+
+        if (rc == VINF_SVM_VMRUN)
+        {
+            Assert(CPUMIsGuestInSvmNestedHwVirtMode(pCtx));
+            continue;
+        }
         if (rc == VINF_SVM_VMEXIT)
-            rc = VINF_SUCCESS;
-    }
+        {
+            Assert(!CPUMIsGuestInSvmNestedHwVirtMode(pCtx));
+            continue;
+        }
 #endif
-
-    /** @todo NSTSVM: Continue in ring-0 after nested-guest \#VMEXIT. See VT-x code for
-     *        reference. */
+        break;
+    }
 
     /* Fixup error codes. */