Changeset 62334 in vbox

Timestamp:

Jul 19, 2016 4:03:23 PM (9 years ago)

Author:

vboxsync

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

108871

Message:

VMX: Force host state VMCS updates when moving away from magic 64-on-32 switcher.

File:

• trunk/src/VBox/VMM/VMMR0/HMVMXR0.cpp (modified) (4 diffs)

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

@@ -4903 +4903 @@
                the rest of the VM run (until VM reset). See @bugref{8432#c7}. */
             pVCpu->hm.s.vmx.fSwitchedTo64on32 = true;
+            Log4(("Load[%RU32]: hmR0VmxSetupVMRunHandler: selected 64-bit switcher\n", pVCpu->idCpu));
         }
 #else
@@ -4924 +4925 @@
 # ifdef VBOX_ENABLE_64_BITS_GUESTS
         /* Keep using the 64-bit switcher even though we're in 32-bit because of bad Intel design. See @bugref{8432#c7}.
-         * Except if Real-on-V86 is active, clear the 64-bit switcher flag because now we know the guest is in a sane
-         * state where it's safe to use the 32-bit switcher again.
+         * If Real-on-V86 is active, clear the 64-bit switcher flag because now we know the guest is in a sane
+         * state where it's safe to use the 32-bit switcher. Otherwise check the guest state if it's safe to use
+         * the much faster 32-bit switcher again.
          */
-        if (pVCpu->hm.s.vmx.RealMode.fRealOnV86Active)
-            pVCpu->hm.s.vmx.fSwitchedTo64on32 = false;
-
         if (!pVCpu->hm.s.vmx.fSwitchedTo64on32)
+        {
+            if (pVCpu->hm.s.vmx.pfnStartVM != VMXR0StartVM32)
+                Log4(("Load[%RU32]: hmR0VmxSetupVMRunHandler: selected 32-bit switcher\n", pVCpu->idCpu));
             pVCpu->hm.s.vmx.pfnStartVM = VMXR0StartVM32;
+        }
         else
         {
-            Assert(!pVCpu->hm.s.vmx.RealMode.fRealOnV86Active);
             Assert(pVCpu->hm.s.vmx.pfnStartVM == VMXR0SwitcherStartVM64);
-            if (hmR0VmxIs32BitSwitcherSafe(pVCpu, pMixedCtx))
+            if (pVCpu->hm.s.vmx.RealMode.fRealOnV86Active || hmR0VmxIs32BitSwitcherSafe(pVCpu, pMixedCtx))
             {
                 pVCpu->hm.s.vmx.fSwitchedTo64on32 = false;
                 pVCpu->hm.s.vmx.pfnStartVM = VMXR0StartVM32;
-            }
+                HMCPU_CF_SET(pVCpu, HM_CHANGED_GUEST_EFER_MSR | HM_CHANGED_VMX_ENTRY_CTLS | HM_CHANGED_VMX_EXIT_CTLS | HM_CHANGED_HOST_CONTEXT);
+                Log4(("Load[%RU32]: hmR0VmxSetupVMRunHandler: selected 32-bit switcher (safe)\n", pVCpu->idCpu));
+            } 
         }
 # else
@@ -8750 +8754 @@
      * Load the host state bits as we may've been preempted (only happens when
      * thread-context hooks are used or when hmR0VmxSetupVMRunHandler() changes pfnStartVM).
+     * Note that the 64-on-32 switcher saves the (64-bit) host state into the VMCS and
+     * if we change the switcher back to 32-bit, we *must* save the 32-bit host state here.
+     * See @bugref{8432}.
      */
-    /** @todo Why should hmR0VmxSetupVMRunHandler() changing pfnStartVM have
-     *        any effect to the host state needing to be saved? */
     if (HMCPU_CF_IS_PENDING(pVCpu, HM_CHANGED_HOST_CONTEXT))
     {
-        /* This ASSUMES that pfnStartVM has been set up already. */
         int rc = hmR0VmxSaveHostState(pVM, pVCpu);
         AssertRC(rc);
@@ -8898 +8902 @@
     pVCpu->hm.s.vmx.fRestoreHostFlags |= VMX_RESTORE_HOST_REQUIRED;   /* Host state messed up by VT-x, we must restore. */
 #endif
+#if HC_ARCH_BITS == 32 && defined(VBOX_ENABLE_64_BITS_GUESTS)
+    /* The 64-on-32 switcher maintains uVmcsState on its own and we need to leave it alone here. */
+    if (pVCpu->hm.s.vmx.pfnStartVM != VMXR0SwitcherStartVM64)
+        pVCpu->hm.s.vmx.uVmcsState |= HMVMX_VMCS_STATE_LAUNCHED;      /* Use VMRESUME instead of VMLAUNCH in the next run. */
+#else
     pVCpu->hm.s.vmx.uVmcsState |= HMVMX_VMCS_STATE_LAUNCHED;          /* Use VMRESUME instead of VMLAUNCH in the next run. */
+#endif
 #ifdef VBOX_STRICT
     hmR0VmxCheckHostEferMsr(pVCpu);                                   /* Verify that VMRUN/VMLAUNCH didn't modify host EFER. */