Re: [PATCH v7 1/2] MdeModulePkg/DxeCore: Filter out all paging capabilities

["Zeng, Star" <star.zeng@intel.com>]

Reviewed-by: Star Zeng <star.zeng@intel.com>

-----Original Message-----
From: Wang, Jian J 
Sent: Tuesday, November 21, 2017 2:17 PM
To: edk2-devel@lists.01.org
Cc: Yao, Jiewen <jiewen.yao@intel.com>; Zeng, Star <star.zeng@intel.com>; Laszlo Ersek <lersek@redhat.com>; Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: [PATCH v7 1/2] MdeModulePkg/DxeCore: Filter out all paging capabilities

> v7:
>   Merge memory map after filtering code

Some OSs will treat EFI_MEMORY_DESCRIPTOR.Attribute as really set attributes and change memory paging attribute accordingly.
But current EFI_MEMORY_DESCRIPTOR.Attribute is assigned by value from Capabilities in GCD memory map. This might cause boot problems. Clearing all paging related capabilities can workaround it. The code added in this patch is supposed to be removed once the usage of EFI_MEMORY_DESCRIPTOR.Attribute is clarified in UEFI spec and adopted by both EDK-II Core and all supported OSs.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
---
 MdeModulePkg/Core/Dxe/DxeMain.h              | 18 ++++++++++++++++++
 MdeModulePkg/Core/Dxe/Mem/Page.c             | 21 +++++++++++++++++++++
 MdeModulePkg/Core/Dxe/Misc/PropertiesTable.c |  1 -
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Core/Dxe/DxeMain.h b/MdeModulePkg/Core/Dxe/DxeMain.h index 1a0babba71..07b86ba696 100644
--- a/MdeModulePkg/Core/Dxe/DxeMain.h
+++ b/MdeModulePkg/Core/Dxe/DxeMain.h
@@ -2948,4 +2948,22 @@ ApplyMemoryProtectionPolicy (
   IN  UINT64                Length
   );
 
+/**
+  Merge continous memory map entries whose have same attributes.
+
+  @param  MemoryMap       A pointer to the buffer in which firmware places
+                          the current memory map.
+  @param  MemoryMapSize   A pointer to the size, in bytes, of the
+                          MemoryMap buffer. On input, this is the size of
+                          the current memory map.  On output,
+                          it is the size of new memory map after merge.
+  @param  DescriptorSize  Size, in bytes, of an individual EFI_MEMORY_DESCRIPTOR.
+**/
+VOID
+MergeMemoryMap (
+  IN OUT EFI_MEMORY_DESCRIPTOR  *MemoryMap,
+  IN OUT UINTN                  *MemoryMapSize,
+  IN UINTN                      DescriptorSize
+  );
+
 #endif
diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c
index f1e4a37f2a..9ff73efdfa 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Page.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Page.c
@@ -1687,6 +1687,7 @@ CoreGetMemoryMap (
   EFI_GCD_MAP_ENTRY                 MergeGcdMapEntry;
   EFI_MEMORY_TYPE                   Type;
   EFI_MEMORY_DESCRIPTOR             *MemoryMapStart;
+  EFI_MEMORY_DESCRIPTOR             *MemoryMapEnd;
 
   //
   // Make sure the parameters are valid @@ -1896,6 +1897,26 @@ CoreGetMemoryMap (
   //
   BufferSize = ((UINT8 *)MemoryMap - (UINT8 *)MemoryMapStart);
 
+  //
+  // Note: Some OSs will treat EFI_MEMORY_DESCRIPTOR.Attribute as really
+  //       set attributes and change memory paging attribute accordingly.
+  //       But current EFI_MEMORY_DESCRIPTOR.Attribute is assigned by
+  //       value from Capabilities in GCD memory map. This might cause
+  //       boot problems. Clearing all paging related capabilities can
+  //       workaround it. Following code is supposed to be removed once
+  //       the usage of EFI_MEMORY_DESCRIPTOR.Attribute is clarified in
+  //       UEFI spec and adopted by both EDK-II Core and all supported
+  //       OSs.
+  //
+  MemoryMapEnd = MemoryMap;
+  MemoryMap = MemoryMapStart;
+  while (MemoryMap < MemoryMapEnd) {
+    MemoryMap->Attribute &= ~(UINT64)(EFI_MEMORY_RP | EFI_MEMORY_RO |
+                                      EFI_MEMORY_XP);
+    MemoryMap = NEXT_MEMORY_DESCRIPTOR (MemoryMap, Size);  }  
+ MergeMemoryMap (MemoryMapStart, &BufferSize, Size);
+
   Status = EFI_SUCCESS;
 
 Done:
diff --git a/MdeModulePkg/Core/Dxe/Misc/PropertiesTable.c b/MdeModulePkg/Core/Dxe/Misc/PropertiesTable.c
index 6cf5edcbe5..75d9b14c1f 100644
--- a/MdeModulePkg/Core/Dxe/Misc/PropertiesTable.c
+++ b/MdeModulePkg/Core/Dxe/Misc/PropertiesTable.c
@@ -182,7 +182,6 @@ SortMemoryMap (
                                  it is the size of new memory map after merge.
   @param  DescriptorSize         Size, in bytes, of an individual EFI_MEMORY_DESCRIPTOR.
 **/
-STATIC
 VOID
 MergeMemoryMap (
   IN OUT EFI_MEMORY_DESCRIPTOR  *MemoryMap,
--
2.14.1.windows.1