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

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

Hi Laszlo,

I kept the renames and only replaced the original local variable 
assignment with input argument. Thanks for your review.

Regards,
Kun

On 04/15/2021 03:41, Laszlo Ersek wrote:
> On 04/14/21 22:25, Kun Qin 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
>>
> 
> Last time I checked the variable renames carefully, now I'm trusting
> that those have not been broken/modified since v1.
> 
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
>