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 processors 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 processor 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 processors 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.
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Zeng Star <star.zeng@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Jiaxin Wu (6):
UefiCpuPkg/PiSmmCpuDxeSmm: Fix invalid InitializeMpSyncData call
UefiCpuPkg/PiSmmCpuDxeSmm: Replace mIsBsp by mBspApicId check
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 | 10 +-
.../SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf | 6 +-
UefiCpuPkg/Include/Guid/SmmBaseHob.h | 75 ++++++++
.../Library/SmmCpuFeaturesLib/CpuFeaturesLib.h | 2 +
.../SmmCpuFeaturesLib/IntelSmmCpuFeaturesLib.c | 25 ++-
.../SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf | 6 +-
.../SmmCpuFeaturesLib/SmmCpuFeaturesLibStm.inf | 3 +-
UefiCpuPkg/Library/SmmCpuFeaturesLib/SmmStm.c | 3 +-
.../StandaloneMmCpuFeaturesLib.inf | 6 +-
UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c | 31 +++-
UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c | 25 ++-
UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c | 193 ++++++++++++++++-----
UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h | 26 ++-
UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.inf | 3 +-
UefiCpuPkg/UefiCpuPkg.dec | 5 +-
15 files changed, 356 insertions(+), 63 deletions(-)
create mode 100644 UefiCpuPkg/Include/Guid/SmmBaseHob.h
--
2.16.2.windows.1
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