[edk2-devel] [PATCH v1 3/3] MdeModulePkg/DxeIpl: Align Page table Level setting with previous level.

[Wu, Jiaxin]

System paging 5 level enabled or not can be checked via CR4.LA57, system
preferred Page table Level (PcdUse5LevelPageTable) must align
with previous level for X64 mode.

This patch is to do the wise check:
If X64, Page table Level setting in PcdUse5LevelPageTable must align with
previous level.
If IA32, Page table Level is decided by PcdUse5LevelPageTable and feature
capability.

Change-Id: Ia7f7e365c7354cc49f971209bfcbc5af5aded062
Cc: Dandan Bi <dandan...@intel.com>
Cc: Liming Gao <gaolim...@byosoft.com.cn>
Cc: Eric Dong <eric.d...@intel.com>
Cc: Ray Ni <ray...@intel.com>
Cc: Zeng Star <star.z...@intel.com>
Cc: Gerd Hoffmann <kra...@redhat.com>
Cc: Rahul Kumar <rahul1.ku...@intel.com>
Signed-off-by: Jiaxin Wu <jiaxin...@intel.com>
---
 MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 39 ++++++++++++++++--------
 1 file changed, 27 insertions(+), 12 deletions(-)

diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c 
b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
index 18b121d768..301e200cd8 100644
--- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
+++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
@@ -737,22 +737,37 @@ CreateIdentityMappingPageTables (
     } else {
       PhysicalAddressBits = 36;
     }
   }
 
-  Page5LevelSupport = FALSE;
-  if (PcdGetBool (PcdUse5LevelPageTable)) {
-    AsmCpuidEx (
-      CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS,
-      CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS_SUB_LEAF_INFO,
-      NULL,
-      NULL,
-      &EcxFlags.Uint32,
-      NULL
-      );
-    if (EcxFlags.Bits.FiveLevelPage != 0) {
-      Page5LevelSupport = TRUE;
+  //
+  // Check run in X64 or IA32
+  //
+  if (sizeof (UINTN) == sizeof (UINT64)) {
+    //
+    // If X64, Page table Level must align with previous level.
+    //
+    Cr4.UintN = AsmReadCr4 ();
+    Page5LevelSupport = Cr4.Bits.LA57 ? TRUE : FALSE;
+    ASSERT (PcdGetBool (PcdUse5LevelPageTable) == Page5LevelSupport);
+  } else {
+    //
+    // If IA32, Page table Level is decided by PCD and feature capbility.
+    //
+    Page5LevelSupport = FALSE;
+    if (PcdGetBool (PcdUse5LevelPageTable)) {
+      AsmCpuidEx (
+        CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS,
+        CPUID_STRUCTURED_EXTENDED_FEATURE_FLAGS_SUB_LEAF_INFO,
+        NULL,
+        NULL,
+        &EcxFlags.Uint32,
+        NULL
+        );
+      if (EcxFlags.Bits.FiveLevelPage != 0) {
+        Page5LevelSupport = TRUE;
+      }
     }
   }
 
   DEBUG ((DEBUG_INFO, "AddressBits=%u 5LevelPaging=%u 1GPage=%u\n", 
PhysicalAddressBits, Page5LevelSupport, Page1GSupport));
 
-- 
2.16.2.windows.1



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