Re: [edk2-devel] [PATCH v2 1/1] UefiCpuPkg: PiSmmCpuDxeSmm: Not to Change Bitwidth During Static Paging

["Kun Qin" <kuqin12@gmail.com>]

Hi Ray,

Would you please provide feedback for this patch?

It is already reviewed by Laszlo here: 
https://edk2.groups.io/g/devel/message/74122. Could you please let me 
know what it takes after your review? I can send a v3 for reviewed-by 
tags if necessary.

Thanks in advance,
Kun

On 04/14/2021 13:25, Kun Qin via groups.io wrote:
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3300
> 
> Current implementation of SetStaticPageTable routine in PiSmmCpuDxeSmm
> driver will check a global variable mPhysicalAddressBits, and eventually
> cap any value larger than 39 at 39.
> 
> This global variable is used in ConvertMemoryPageAttributes, which backs
> SmmSetMemoryAttributes and SmmClearMemoryAttributes. Thus for a processor
> that supports more than 39 bits width, trying to mark page table regions
> higher than 39-bit will always return EFI_UNSUPPROTED.
> 
> This change updated the interface of SetStaticPageTable function to take
> PhysicalAddressBits as an input parameter, in order to avoid changing/
> accessing the global variable.
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Rahul Kumar <rahul1.kumar@intel.com>
> 
> Fixes: 4eee0cc7cc0db74489b99c19eba056b53eda6358
> Signed-off-by: Kun Qin <kuqin12@gmail.com>
> ---
> 
> Notes:
>      v2:
>      - SetStaticPageTable interface update [Ray]
>      - Commit message updates, variable type change [Laszlo]
> 
>   UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c | 30 +++++++++++---------
>   1 file changed, 16 insertions(+), 14 deletions(-)
> 
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> index 6902584b1fbd..d6f8dd94d303 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> @@ -211,11 +211,13 @@ CalculateMaximumSupportAddress (
>   /**
>     Set static page table.
>   
> -  @param[in] PageTable     Address of page table.
> +  @param[in] PageTable              Address of page table.
> +  @param[in] PhysicalAddressBits    The maximum physical address bits supported.
>   **/
>   VOID
>   SetStaticPageTable (
> -  IN UINTN               PageTable
> +  IN UINTN               PageTable,
> +  IN UINT8               PhysicalAddressBits
>     )
>   {
>     UINT64                                        PageAddress;
> @@ -237,26 +239,26 @@ SetStaticPageTable (
>     // IA-32e paging translates 48-bit linear addresses to 52-bit physical addresses
>     //  when 5-Level Paging is disabled.
>     //
> -  ASSERT (mPhysicalAddressBits <= 52);
> -  if (!m5LevelPagingNeeded && mPhysicalAddressBits > 48) {
> -    mPhysicalAddressBits = 48;
> +  ASSERT (PhysicalAddressBits <= 52);
> +  if (!m5LevelPagingNeeded && PhysicalAddressBits > 48) {
> +    PhysicalAddressBits = 48;
>     }
>   
>     NumberOfPml5EntriesNeeded = 1;
> -  if (mPhysicalAddressBits > 48) {
> -    NumberOfPml5EntriesNeeded = (UINTN) LShiftU64 (1, mPhysicalAddressBits - 48);
> -    mPhysicalAddressBits = 48;
> +  if (PhysicalAddressBits > 48) {
> +    NumberOfPml5EntriesNeeded = (UINTN) LShiftU64 (1, PhysicalAddressBits - 48);
> +    PhysicalAddressBits = 48;
>     }
>   
>     NumberOfPml4EntriesNeeded = 1;
> -  if (mPhysicalAddressBits > 39) {
> -    NumberOfPml4EntriesNeeded = (UINTN) LShiftU64 (1, mPhysicalAddressBits - 39);
> -    mPhysicalAddressBits = 39;
> +  if (PhysicalAddressBits > 39) {
> +    NumberOfPml4EntriesNeeded = (UINTN) LShiftU64 (1, PhysicalAddressBits - 39);
> +    PhysicalAddressBits = 39;
>     }
>   
>     NumberOfPdpEntriesNeeded = 1;
> -  ASSERT (mPhysicalAddressBits > 30);
> -  NumberOfPdpEntriesNeeded = (UINTN) LShiftU64 (1, mPhysicalAddressBits - 30);
> +  ASSERT (PhysicalAddressBits > 30);
> +  NumberOfPdpEntriesNeeded = (UINTN) LShiftU64 (1, PhysicalAddressBits - 30);
>   
>     //
>     // By architecture only one PageMapLevel4 exists - so lets allocate storage for it.
> @@ -438,7 +440,7 @@ SmmInitPageTable (
>       // When access to non-SMRAM memory is restricted, create page table
>       // that covers all memory space.
>       //
> -    SetStaticPageTable ((UINTN)PTEntry);
> +    SetStaticPageTable ((UINTN)PTEntry, mPhysicalAddressBits);
>     } else {
>       //
>       // Add pages to page pool
>