Sure, it's to align with the old behavior. Will add comments to explain it.
Thanks,
Dun
-----Original Message-----
From: Ni, Ray <ray...@intel.com>
Sent: Friday, June 2, 2023 11:31 AM
To: devel@edk2.groups.io; Tan, Dun <dun....@intel.com>
Cc: Dong, Eric <eric.d...@intel.com>; Kumar, Rahul R <rahul.r.ku...@intel.com>;
Gerd Hoffmann <kra...@redhat.com>
Subject: RE: [edk2-devel] [Patch V4 11/15] UefiCpuPkg: Use GenSmmPageTable() to
create Smm S3 page table
> - mSmmS3ResumeState->SmmS3Cr3 = (UINT32)(UINTN)PTEntry;
> + mSmmS3ResumeState->SmmS3Cr3 = (UINT32)GenSmmPageTable
> (Paging4Level, 32);
Why is "Paging4Level" used for S3 page table?
The S3 page table is used by S3Resume module:
if (SmmS3ResumeState->Signature == SMM_S3_RESUME_SMM_64) {
//
// Switch to long mode to complete resume.
//
......
AsmWriteCr3 ((UINTN)SmmS3ResumeState->SmmS3Cr3);
......
AsmEnablePaging64 (
0x38,
SmmS3ResumeState->SmmS3ResumeEntryPoint,
(UINT64)(UINTN)AcpiS3Context,
0,
SmmS3ResumeState->SmmS3StackBase + SmmS3ResumeState->SmmS3StackSize
);
The S3 page table is only used when PEI runs in 32bit mode, which revolves my
concern that CPU in 64bit mode cannot switch from 5-l paging to 4-l paging.
And I guess your code just aligns to the old behavior.
Can you add comments to above to explain the SmmS3Cr3 is only used by S3Resume
PEIM to switch CPU from 32bit to 64bit?
With that, Reviewed-by: Ray Ni <ray...@intel.com>
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