[PATCH v8 2/2] MdeModulePkg/DxeCore: Filter out all paging capabilities

[Jian J Wang <jian.j.wang@intel.com>]

> v8:
>   Remove merge code but keep code to remain MemoryMapStart

> v7:
>   Merge memory map after filtering code

> v6:
>   Add code filter out all paging capabilities

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>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
---
 MdeModulePkg/Core/Dxe/Mem/Page.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c
index 2034b64cd7..962ae90d3d 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 +1897,25 @@ 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);
+  }
+
   Status = EFI_SUCCESS;
 
 Done:
-- 
2.14.1.windows.1