Changeset 95793 in vbox

Timestamp:

Jul 25, 2022 11:07:54 AM (3 years ago)

Author:

vboxsync

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

152514

Message:

VMM/CPUM: Clear NX if no PAE, as it is causing trouble for 32-bit Windows 7. Followup to r151799. bugref:9898

Location:

trunk/src/VBox/VMM

Files:

• VMMR3/CPUM.cpp (modified) (1 diff)
• VMMR3/CPUMR3CpuId.cpp (modified) (1 diff)
• include/CPUMInternal.h (modified) (1 diff)

trunk/src/VBox/VMM/VMMR3/CPUM.cpp

@@ -4394 +4394 @@
             cpumR3MsrRegStats(pVM);
 
+            /* There shouldn't be any more calls to CPUMR3SetGuestCpuIdFeature and
+               CPUMR3ClearGuestCpuIdFeature now, so do some final CPUID polishing (NX). */
+            cpumR3CpuIdRing3InitDone(pVM);
+
             /* Create VMX-preemption timer for nested guests if required.  Must be
                done here as CPUM is initialized before TM. */

trunk/src/VBox/VMM/VMMR3/CPUMR3CpuId.cpp

@@ -3725 +3725 @@
 
 
+/**
+ * Do some final polishing after all calls to CPUMR3SetGuestCpuIdFeature and
+ * CPUMR3ClearGuestCpuIdFeature are (probably) done.
+ *
+ * @param   pVM             The cross context VM structure.
+ */
+void cpumR3CpuIdRing3InitDone(PVM pVM)
+{
+    /*
+     * Do not advertise NX w/o PAE, seems to confuse windows 7 (black screen very
+     * early in real mode).
+     */
+    PCPUMCPUIDLEAF pStdLeaf = cpumCpuIdGetLeaf(pVM, UINT32_C(0x00000001));
+    PCPUMCPUIDLEAF pExtLeaf = cpumCpuIdGetLeaf(pVM, UINT32_C(0x80000001));
+    if (pStdLeaf && pExtLeaf)
+    {
+        if (   !(pStdLeaf->uEdx & X86_CPUID_FEATURE_EDX_PAE)
+            && (pExtLeaf->uEdx & X86_CPUID_EXT_FEATURE_EDX_NX))
+            pExtLeaf->uEdx &= ~X86_CPUID_EXT_FEATURE_EDX_NX;
+    }
+}
+
+
 /*
  *

trunk/src/VBox/VMM/include/CPUMInternal.h

@@ -502 +502 @@
 int                 cpumR3InitCpuIdAndMsrs(PVM pVM, PCCPUMMSRS pHostMsrs);
 void                cpumR3InitVmxGuestFeaturesAndMsrs(PVM pVM, PCVMXMSRS pHostVmxMsrs, PVMXMSRS pGuestVmxMsrs);
+void                cpumR3CpuIdRing3InitDone(PVM pVM);
 void                cpumR3SaveCpuId(PVM pVM, PSSMHANDLE pSSM);
 int                 cpumR3LoadCpuId(PVM pVM, PSSMHANDLE pSSM, uint32_t uVersion, PCCPUMMSRS pGuestMsrs);