[PATCH v6 1/2] MdeModulePkg/DxeCore: Filter out all paging capabilities

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

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>
---
 MdeModulePkg/Core/Dxe/Mem/Page.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c
index c9219cc068..783b576e35 100644
--- a/MdeModulePkg/Core/Dxe/Mem/Page.c
+++ b/MdeModulePkg/Core/Dxe/Mem/Page.c
@@ -1829,6 +1829,23 @@ CoreGetMemoryMap (
   //
   BufferSize = ((UINT8 *)MemoryMap - (UINT8 *)MemoryMapStart);
 
+  //
+  // WORKAROUND: 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.
+  //
+  while (MemoryMapStart < MemoryMap) {
+    MemoryMapStart->Attribute &= ~(UINT64)(EFI_MEMORY_RP | EFI_MEMORY_RO |
+                                           EFI_MEMORY_XP);
+    MemoryMapStart = NEXT_MEMORY_DESCRIPTOR(MemoryMapStart, Size);
+  }
+
   Status = EFI_SUCCESS;
 
 Done:
-- 
2.14.1.windows.1