UefiCpuPkg/CpuPageTableLib: Add check for input Length

Add check for input Length in PageTableMap (). Return
RETURN_SUCCESS when input Length is 0.

Signed-off-by: Dun Tan <dun.tan@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
index 52535e5a8d..218068a3e1 100644
--- a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
+++ b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
@@ -544,7 +544,7 @@ PageTableLibMapInLevel (
   @retval RETURN_BUFFER_TOO_SMALL   The buffer is too small for page table creation/updating.

                                     BufferSize is updated to indicate the expected buffer size.

                                     Caller may still get RETURN_BUFFER_TOO_SMALL with the new BufferSize.

-  @retval RETURN_SUCCESS            PageTable is created/updated successfully.

+  @retval RETURN_SUCCESS            PageTable is created/updated successfully or the input Length is 0.

 **/

 RETURN_STATUS

 EFIAPI

@@ -567,6 +567,10 @@ PageTableMap (
   IA32_PAGE_LEVEL     MaxLeafLevel;

   IA32_MAP_ATTRIBUTE  ParentAttribute;

 

+  if (Length == 0) {

+    return RETURN_SUCCESS;

+  }

+

   if ((PagingMode == Paging32bit) || (PagingMode == PagingPae) || (PagingMode >= PagingModeMax)) {

     //

     // 32bit paging is never supported.