[PATCH 3/6] UefiCpuPkg/CpuDxe: clear NX attr for page directory

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

If PcdDxeNxMemoryProtectionPolicy is set to enable protection for memory
of EfiBootServicesCode, EfiConventionalMemory and EfiReservedMemoryType,
the BIOS will hang at a page fault exception randomly.

The root cause is that the memory allocation for driver images (actually
a memory type conversion from free memory, type of EfiConventionalMemory,
to code memory, type of EfiBootServicesCode/EfiRuntimeServicesCode)
will get memory with NX set, because the CpuDxe driver will keep the NX
attribute (with free memory) in page directory during page table splitting
and then override the NX attribute of all its entries.

This patch fixes this issue by not inheriting NX attribute when turning
a page entry into a page directory during page granularity split.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
---
 UefiCpuPkg/CpuDxe/CpuPageTable.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/UefiCpuPkg/CpuDxe/CpuPageTable.c b/UefiCpuPkg/CpuDxe/CpuPageTable.c
index a9c9bc9d5e..1654e71103 100644
--- a/UefiCpuPkg/CpuDxe/CpuPageTable.c
+++ b/UefiCpuPkg/CpuDxe/CpuPageTable.c
@@ -528,7 +528,7 @@ SplitPage (
       for (Index = 0; Index < SIZE_4KB / sizeof(UINT64); Index++) {
         NewPageEntry[Index] = (BaseAddress + SIZE_4KB * Index) | AddressEncMask | ((*PageEntry) & PAGE_PROGATE_BITS);
       }
-      (*PageEntry) = (UINT64)(UINTN)NewPageEntry | AddressEncMask | ((*PageEntry) & PAGE_PROGATE_BITS);
+      (*PageEntry) = (UINT64)(UINTN)NewPageEntry | AddressEncMask | ((*PageEntry) & PAGE_ATTRIBUTE_BITS);
       return RETURN_SUCCESS;
     } else {
       return RETURN_UNSUPPORTED;
@@ -549,7 +549,7 @@ SplitPage (
       for (Index = 0; Index < SIZE_4KB / sizeof(UINT64); Index++) {
         NewPageEntry[Index] = (BaseAddress + SIZE_2MB * Index) | AddressEncMask | IA32_PG_PS | ((*PageEntry) & PAGE_PROGATE_BITS);
       }
-      (*PageEntry) = (UINT64)(UINTN)NewPageEntry | AddressEncMask | ((*PageEntry) & PAGE_PROGATE_BITS);
+      (*PageEntry) = (UINT64)(UINTN)NewPageEntry | AddressEncMask | ((*PageEntry) & PAGE_ATTRIBUTE_BITS);
       return RETURN_SUCCESS;
     } else {
       return RETURN_UNSUPPORTED;
@@ -979,7 +979,7 @@ RefreshGcdMemoryAttributesFromPaging (
                         );
         ASSERT_EFI_ERROR (Status);
         DEBUG ((
-          DEBUG_INFO,
+          DEBUG_VERBOSE,
           "Updated memory space attribute: [%lu] %016lx - %016lx (%016lx -> %016lx)\r\n",
           (UINT64)Index, BaseAddress, BaseAddress + Length - 1,
           MemorySpaceMap[Index].Attributes,
-- 
2.15.1.windows.2