Re: [edk2-devel] [Patch V3 0/8] Create page table by CpuPageTableLib in DxeIpl

["Michael D Kinney" <michael.d.kinney@intel.com>]

Hi Ard,

Thanks for the feedback.  Let's work on this approach.

Are there similar needs for CPU related services in the DXE Core before
the CPU AP is loaded?

If we are going to define a new lib class to abstract DXE IPL requirements,
it would be good to cover DXE Core requirements too.

Mike

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ard Biesheuvel
> Sent: Monday, April 24, 2023 10:24 AM
> To: devel@edk2.groups.io; Tan, Dun <dun.tan@intel.com>
> Subject: Re: [edk2-devel] [Patch V3 0/8] Create page table by CpuPageTableLib in DxeIpl
> 
> On Mon, 24 Apr 2023 at 12:06, duntan <dun.tan@intel.com> wrote:
> >
> > In V3 patch set:
> > 1. Add a new patch 'MdePkg: Move CpuPageTableLib defination to MdePkg' to Move CpuPageTableLib defination from UefiCpuPkg to
> MdePkg.
> >    So that MdeModulePkg doesn't need to depend on UefiCpuPkg.
> 
> As I replied to the other patch, I think adding CpuPageTableLib to
> MdePkg in its current form (even only the interface) is not the right
> approach here. The function protoypes and enums exposed by this
> library are highly specific to a particular implementation.
> 
> There is a clear use case here, which is the DXE IPL code, and as has
> been suggested in the other thread, it would be more appropriate to
> define an abstraction regarding this use case, and define it as a
> library class (with a NULL implementation) in MdeModulePkg. That way,
> UefiCpuPkg can provide the x86 implementation based on
> CpuPageTableLilb, and other architectures can do likewise.
> 
> Please refer to the patch below, which illustrates why there are other
> requirements in this area:
> 
> https://edk2.groups.io/g/devel/message/101122
> 
> --
> Ard.
> 
> 
> 
> 
> > 2. Modify the patch 'MdeModulePkg/DxeIpl: Create page table by CpuPageTableLib' to set GHCB page to be mapped as unencrypted
> for each CPU for AMD SEV feature.
> >
> > Dun Tan (8):
> >   MdePkg: Move CpuPageTableLib defination to MdePkg
> >   EmulatorPkg: Add CpuPageTableLib required by DxeIpl in DSC
> >   IntelFsp2Pkg: Add CpuPageTableLib required by DxeIpl in DSC
> >   MdeModulePkg: Add CpuPageTableLib required by DxeIpl in DSC
> >   OvmfPkg: Add CpuPageTableLib required by DxeIpl in DSC file
> >   MdeModulePkg/DxeIpl: Create page table by CpuPageTableLib
> >   MdeModulePkg/DxeIpl: Remove duplicated code to enable NX
> >   MdeModulePkg/DxeIpl: Refinement to the code to set PageTable as RO
> >
> >  EmulatorPkg/EmulatorPkg.dsc                              |   3 ++-
> >  IntelFsp2Pkg/Tools/Tests/QemuFspPkg.dsc                  |   3 ++-
> >  MdeModulePkg/Core/DxeIplPeim/DxeIpl.h                    |   3 ++-
> >  MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf                  |   5 ++++-
> >  MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c          | 112 ++++----------------------------------------------------------
> --------------------------------------------------
> >  MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c           |   5 +++--
> >  MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c         | 720
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> ++++++++++++++++++++++++++++++++++++++++----------------------------------------------------------------------------------------
> --------------------------------------------------------------------------------------------------------------------------------
> --------------------------------------------------------------------------------------------------------------------------------
> --------------------------------------------------------------------------------------------------------------------------------
> --------------------------------------------------------------------------------
> >  MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h         | 182 ++++++++++----------------------------------------------------
> ------------------------------------------------------------------------------------------------------------------------
> >  MdeModulePkg/MdeModulePkg.dsc                            |   3 ++-
> >  {UefiCpuPkg => MdePkg}/Include/Library/CpuPageTableLib.h |   0
> >  MdePkg/MdePkg.dec                                        |   5 ++++-
> >  OvmfPkg/AmdSev/AmdSevX64.dsc                             |   2 +-
> >  OvmfPkg/Bhyve/BhyveX64.dsc                               |   3 ++-
> >  OvmfPkg/CloudHv/CloudHvX64.dsc                           |   2 +-
> >  OvmfPkg/Microvm/MicrovmX64.dsc                           |   2 +-
> >  OvmfPkg/OvmfPkgIa32.dsc                                  |   3 ++-
> >  OvmfPkg/OvmfPkgIa32X64.dsc                               |   2 +-
> >  OvmfPkg/OvmfPkgX64.dsc                                   |   2 +-
> >  OvmfPkg/OvmfXen.dsc                                      |   2 +-
> >  UefiCpuPkg/UefiCpuPkg.dec                                |   3 ---
> >  20 files changed, 211 insertions(+), 851 deletions(-)
> >  rename {UefiCpuPkg => MdePkg}/Include/Library/CpuPageTableLib.h (100%)
> >
> > --
> > 2.31.1.windows.1
> >
> >
> >
> >
> >
> >
> 
> 
> 
>