UefiCpuPkg/PiSmmCpu: relax superpage protection on page split.

PiSmmCpu driver may split page for page attribute request.
Current logic not only propagates the super page attribute to
the leaf page attribut, but also to the directory page attribute.

However, the later might be wrong because we cannot clear protection
without touching directory page attribute.
The effective protection is the strictest combination
across the levels.

We should always clear protection on directory page and set
protection on leaf page for easy clearing later.

Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiewen Yao <jiewen.yao@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
index c85e025424218b75f041aa112f7c2c3b756dbb6f..d841dd014c4bfb236874d440a800dc2d0604d12d 100644 (file)
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
@@ -299,7 +299,7 @@ SplitPage (
       for (Index = 0; Index < SIZE_4KB / sizeof(UINT64); Index++) {\r
         NewPageEntry[Index] = BaseAddress + SIZE_4KB * Index + ((*PageEntry) & PAGE_PROGATE_BITS);\r
       }\r
-      (*PageEntry) = (UINT64)(UINTN)NewPageEntry + ((*PageEntry) & PAGE_PROGATE_BITS);\r
+      (*PageEntry) = (UINT64)(UINTN)NewPageEntry + PAGE_ATTRIBUTE_BITS;\r
       return RETURN_SUCCESS;\r
     } else {\r
       return RETURN_UNSUPPORTED;\r
@@ -320,7 +320,7 @@ SplitPage (
       for (Index = 0; Index < SIZE_4KB / sizeof(UINT64); Index++) {\r
         NewPageEntry[Index] = BaseAddress + SIZE_2MB * Index + IA32_PG_PS + ((*PageEntry) & PAGE_PROGATE_BITS);\r
       }\r
-      (*PageEntry) = (UINT64)(UINTN)NewPageEntry + ((*PageEntry) & PAGE_PROGATE_BITS);\r
+      (*PageEntry) = (UINT64)(UINTN)NewPageEntry + PAGE_ATTRIBUTE_BITS;\r
       return RETURN_SUCCESS;\r
     } else {\r
       return RETURN_UNSUPPORTED;\r