[edk2-devel] [PATCH v4 0/5] Simplify SMM Relocation Process

[Wu, Jiaxin]

Thanks Ray, I will update all.

> -----Original Message-----
> From: Ni, Ray <ray.ni at intel.com>
> Sent: Friday, February 10, 2023 8:57 PM
> To: devel at edk2.groups.io; Wu, Jiaxin <jiaxin.wu at intel.com>
> Subject: RE: [edk2-devel] [PATCH v4 0/5] Simplify SMM Relocation Process
> 
> Jiaxin,
> I provide separate review comments for each patch.
> 
> Can you please make sure the copy right year is updated for every file
> change?
> I may not emphasize this for each patch.
> 
> > -----Original Message-----
> > From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Wu,
> Jiaxin
> > Sent: Friday, February 10, 2023 2:05 PM
> > To: devel at edk2.groups.io
> > Subject: [edk2-devel] [PATCH v4 0/5] Simplify SMM Relocation Process
> >
> > Existing SMBASE Relocation is in the PiSmmCpuDxeSmm driver, which
> > will relocate the SMBASE of each processor by setting the SMBASE
> > field in the saved state map (at offset 7EF8h) to a new value.
> > The RSM instruction reloads the internal SMBASE register with the
> > value in SMBASE field when each time it exits SMM. All subsequent
> > SMI requests will use the new SMBASE to find the starting address
> > for the SMI handler (at SMBASE + 8000h).
> >
> > Due to the default SMBASE for all x86 processors is 0x30000, the
> > APs' 1st SMI for rebase has to be executed one by one to avoid
> > the CPUs over-writing each other's SMM Save State Area (see
> > existing SmmRelocateBases() function), which means the next AP has
> > to wait for the previous AP to finish its 1st SMI, then it can call
> > into its 1st SMI for rebase via Smi Ipi command, thus leading the
> > existing SMBASE Relocation has to be running in series. Besides, it
> > needs very complex code to handle the AP exit semaphore
> > (mRebased[Index]), which will hook return address of SMM Save State
> > so that semaphore code can be executed immediately after AP exits
> > SMM for SMBASE relocation (see existing SemaphoreHook() function).
> >
> > This series is to add the new SMM Base HOB for any PEI module to do
> > the SmBase relocation ahead of PiSmmCpuDxeSmm driver and store the
> > relocated SmBase address in array for each Processors. When the
> > SMBASE relocation happens in a PEI module, the PEI module shall
> > produce the SMM_BASE_HOB in HOB database which tells the
> > PiSmmCpuDxeSmm driver (runs at a later phase) about the new SMBASE
> > for each CPU thread. PiSmmCpuDxeSmm driver installs the SMI handler
> > at the SMM_BASE_HOB.SmBase[Index]+0x8000 for CPU thread Index.
> When
> > the HOB doesn't exist, PiSmmCpuDxeSmm driver shall relocate and
> > program the new SMBASE itself (keep existing SMBASE Relocation way).
> >
> > With SMM Base Hob support, PiSmmCpuDxeSmm does not need the RSM
> > instruction to do the SMBASE Relocation. SMBASE Register for each
> > processors have already been programmed and all SMBASE address have
> > recorded in SMM Base Hob. So the same default SMBASE Address
> > (0x30000) will not be used, thus the CPUs over-writing each other's
> > SMM Save State Area will not happen in PiSmmCpuDxeSmm driver. This
> > way makes the first SMI init can be executed in parallel and save
> > boot time on multi-core system. Besides, Semaphore Hook code logic
> > is also not required, which will greatly simplify the SMBASE
> > Relocation flow.
> >
> > Note:
> > This is the new way that firmware can program the SMBASE
> > independently of the RSM instruction. The PEI code performing
> > this logic will not be open sourced, similarly to other things
> > that are kept binary-only in the FSP. Due to the register
> > difference in different vender, and it has not been documented
> > in the Intel SDM yet, we need a new binary-only interface for
> > SMM Base HOB.
> >
> > Jiaxin Wu (5):
> >   UefiCpuPkg/PiSmmCpuDxeSmm: Fix invalid InitializeMpSyncData call
> >   UefiCpuPkg/SmmBaseHob.h: Add SMM Base HOB Data
> >   UefiCpuPkg/PiSmmCpuDxeSmm: Consume SMM Base Hob for SmBase
> info
> >   UefiCpuPkg/SmmCpuFeaturesLib: Skip SMBASE configuration
> >   OvmfPkg/SmmCpuFeaturesLib: Check SmBase relocation supported or
> not
> >
> >  .../Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c  |   8 +
> >  .../SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf        |   4 +
> >  UefiCpuPkg/Include/Guid/SmmBaseHob.h               |  64 +++++++
> >  .../Library/SmmCpuFeaturesLib/CpuFeaturesLib.h     |   2 +
> >  .../SmmCpuFeaturesLib/IntelSmmCpuFeaturesLib.c     |  23 ++-
> >  .../SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf        |   4 +
> >  .../SmmCpuFeaturesLib/SmmCpuFeaturesLibStm.inf     |   1 +
> >  UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmStm.c      |   1 -
> >  .../StandaloneMmCpuFeaturesLib.inf                 |   4 +
> >  UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c                  |  29 +++-
> >  UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c              |  23 +++
> >  UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c         | 191
> > ++++++++++++++++-----
> >  UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h         |  24 +++
> >  UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.inf       |   1 +
> >  UefiCpuPkg/UefiCpuPkg.dec                          |   3 +
> >  15 files changed, 332 insertions(+), 50 deletions(-)
> >  create mode 100644 UefiCpuPkg/Include/Guid/SmmBaseHob.h
> >
> > --
> > 2.16.2.windows.1
> >
> >
> >
> > 
> >



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