UefiCpuPkg: Combine branch for non-present and leaf ParentEntry

Combine 'if' condition branch for non-present and leaf Parent
Entry in PageTableLibMapInLevel. Most steps of these two condition
are the same. This commit doesn't change any functionality.

Signed-off-by: Dun Tan <dun.tan@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
index 11cca8ccbcdc9efc93189bf325fe351de98077a7..0d576ce39a974d848a000f6ffbc9830eeb681bc8 100644 (file)
--- a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
+++ b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
@@ -351,68 +351,45 @@ PageTableLibMapInLevel (
   // ParentPagingEntry ONLY is deferenced for checking Present and MustBeOne bits\r
   // when Modify is FALSE.\r
   //\r
-\r
-  if (ParentPagingEntry->Pce.Present == 0) {\r
-    //\r
-    // [LinearAddress, LinearAddress + Length] contains non-present range.\r
-    //\r
-    Status = IsAttributesAndMaskValidForNonPresentEntry (Attribute, Mask);\r
-    if (RETURN_ERROR (Status)) {\r
-      return Status;\r
-    }\r
-\r
-    //\r
-    // Check the attribute in ParentPagingEntry is equal to attribute calculated by input Attribue and Mask.\r
-    //\r
-    PleBAttribute.Uint64 = PageTableLibGetPleBMapAttribute (&ParentPagingEntry->PleB, ParentAttribute);\r
-    if ((IA32_MAP_ATTRIBUTE_ATTRIBUTES (&PleBAttribute) & IA32_MAP_ATTRIBUTE_ATTRIBUTES (Mask))\r
-        == (IA32_MAP_ATTRIBUTE_ATTRIBUTES (Attribute) & IA32_MAP_ATTRIBUTE_ATTRIBUTES (Mask)))\r
-    {\r
-      return RETURN_SUCCESS;\r
-    }\r
-\r
+  if ((ParentPagingEntry->Pce.Present == 0) || IsPle (ParentPagingEntry, Level + 1)) {\r
     //\r
-    // The parent entry is CR3 or PML5E/PML4E/PDPTE/PDE.\r
+    // When ParentPagingEntry is non-present, parent entry is CR3 or PML5E/PML4E/PDPTE/PDE.\r
     // It does NOT point to an existing page directory.\r
+    // When ParentPagingEntry is present, parent entry is leaf PDPTE_1G or PDE_2M. Split to 2M or 4K pages.\r
+    // Note: it's impossible the parent entry is a PTE_4K.\r
     //\r
-    ASSERT (Buffer == NULL || *BufferSize >= SIZE_4KB);\r
-    CreateNew    = TRUE;\r
-    *BufferSize -= SIZE_4KB;\r
-\r
-    if (Modify) {\r
-      ParentPagingEntry->Uintn = (UINTN)Buffer + *BufferSize;\r
-      ZeroMem ((VOID *)ParentPagingEntry->Uintn, SIZE_4KB);\r
-      //\r
-      // Set default attribute bits for PML5E/PML4E/PDPTE/PDE.\r
-      //\r
-      PageTableLibSetPnle (&ParentPagingEntry->Pnle, &NopAttribute, &AllOneMask);\r
-    } else {\r
+    PleBAttribute.Uint64 = PageTableLibGetPleBMapAttribute (&ParentPagingEntry->PleB, ParentAttribute);\r
+    if (ParentPagingEntry->Pce.Present == 0) {\r
       //\r
-      // Just make sure Present and MustBeZero (PageSize) bits are accurate.\r
+      // [LinearAddress, LinearAddress + Length] contains non-present range.\r
       //\r
+      Status = IsAttributesAndMaskValidForNonPresentEntry (Attribute, Mask);\r
+      if (RETURN_ERROR (Status)) {\r
+        return Status;\r
+      }\r
+\r
       OneOfPagingEntry.Pnle.Uint64 = 0;\r
+    } else {\r
+      PageTableLibSetPle (Level, &OneOfPagingEntry, 0, &PleBAttribute, &AllOneMask);\r
     }\r
-  } else if (IsPle (ParentPagingEntry, Level + 1)) {\r
-    //\r
-    // The parent entry is a PDPTE_1G or PDE_2M. Split to 2M or 4K pages.\r
-    // Note: it's impossible the parent entry is a PTE_4K.\r
-    //\r
+\r
     //\r
-    // Use NOP attributes as the attribute of grand-parents because CPU will consider\r
-    // the actual attributes of grand-parents when determing the memory type.\r
+    // Check if the attribute, the physical address calculated by ParentPagingEntry is equal to\r
+    // the attribute, the physical address calculated by input Attribue and Mask.\r
     //\r
-    PleBAttribute.Uint64 = PageTableLibGetPleBMapAttribute (&ParentPagingEntry->PleB, ParentAttribute);\r
     if ((IA32_MAP_ATTRIBUTE_ATTRIBUTES (&PleBAttribute) & IA32_MAP_ATTRIBUTE_ATTRIBUTES (Mask))\r
         == (IA32_MAP_ATTRIBUTE_ATTRIBUTES (Attribute) & IA32_MAP_ATTRIBUTE_ATTRIBUTES (Mask)))\r
     {\r
-      //\r
-      // This function is called when the memory length is less than the region length of the parent level.\r
-      // No need to split the page when the attributes equal.\r
-      //\r
       if ((Mask->Bits.PageTableBaseAddressLow == 0) && (Mask->Bits.PageTableBaseAddressHigh == 0)) {\r
         return RETURN_SUCCESS;\r
       }\r
 \r
+      //\r
+      // Non-present entry won't reach there since:\r
+      // 1.When map non-present entry to present, the attribute must be different.\r
+      // 2.When still map non-present entry to non-present, PageTableBaseAddressLow and High in Mask must be 0.\r
+      //\r
+      ASSERT (ParentPagingEntry->Pce.Present == 1);\r
       PhysicalAddrInEntry = IA32_MAP_ATTRIBUTE_PAGE_TABLE_BASE_ADDRESS (&PleBAttribute) + MultU64x32 (RegionLength, (UINT32)PagingEntryIndex);\r
       PhysicalAddrInAttr  = (IA32_MAP_ATTRIBUTE_PAGE_TABLE_BASE_ADDRESS (Attribute) + Offset) & (~RegionMask);\r
       if (PhysicalAddrInEntry == PhysicalAddrInAttr) {\r
@@ -423,17 +400,19 @@ PageTableLibMapInLevel (
     ASSERT (Buffer == NULL || *BufferSize >= SIZE_4KB);\r
     CreateNew    = TRUE;\r
     *BufferSize -= SIZE_4KB;\r
-    PageTableLibSetPle (Level, &OneOfPagingEntry, 0, &PleBAttribute, &AllOneMask);\r
+\r
     if (Modify) {\r
-      //\r
-      // Create 512 child-level entries that map to 2M/4K.\r
-      //\r
       PagingEntry = (IA32_PAGING_ENTRY *)((UINTN)Buffer + *BufferSize);\r
       ZeroMem (PagingEntry, SIZE_4KB);\r
 \r
-      for (SubOffset = 0, Index = 0; Index < 512; Index++) {\r
-        PagingEntry[Index].Uint64 = OneOfPagingEntry.Uint64 + SubOffset;\r
-        SubOffset                += RegionLength;\r
+      if (ParentPagingEntry->Pce.Present) {\r
+        //\r
+        // Create 512 child-level entries that map to 2M/4K.\r
+        //\r
+        for (SubOffset = 0, Index = 0; Index < 512; Index++) {\r
+          PagingEntry[Index].Uint64 = OneOfPagingEntry.Uint64 + SubOffset;\r
+          SubOffset                += RegionLength;\r
+        }\r
       }\r
 \r
       //\r