Re: [Patch V4 02/21] UefiCpuPkg/CpuPageTableLib: Add check for input Length

["Ni, Ray" <ray.ni@intel.com>]

Reviewed-by: Ray Ni <ray.ni@intel.com>

> -----Original Message-----
> From: Tan, Dun <dun.tan@intel.com>
> Sent: Thursday, March 23, 2023 3:41 PM
> To: devel@edk2.groups.io
> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; Kumar,
> Rahul R <rahul.r.kumar@intel.com>; Gerd Hoffmann <kraxel@redhat.com>
> Subject: [Patch V4 02/21] 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>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Rahul Kumar <rahul1.kumar@intel.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  UefiCpuPkg/Include/Library/CpuPageTableLib.h         | 4 ++--
>  UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c | 6 +++++-
>  2 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/UefiCpuPkg/Include/Library/CpuPageTableLib.h
> b/UefiCpuPkg/Include/Library/CpuPageTableLib.h
> index 2dc9b7d18e..5f44ece548 100644
> --- a/UefiCpuPkg/Include/Library/CpuPageTableLib.h
> +++ b/UefiCpuPkg/Include/Library/CpuPageTableLib.h
> @@ -1,7 +1,7 @@
>  /** @file
>    Public include file for PageTableLib library.
> 
> -  Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
> +  Copyright (c) 2022 - 2023, Intel Corporation. All rights reserved.<BR>
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>  **/
> @@ -81,7 +81,7 @@ typedef enum {
>    @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
> 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.
> --
> 2.31.1.windows.1