[edk2-devel] [PATCH v3 2/6] UefiCpuPkg: Adds SmmCpuSyncLib library class

["Wu, Jiaxin" <jiaxin.wu@intel.com>]

Intel is planning to provide different SMM CPU Sync implementation
along with some specific registers to improve the SMI performance,
hence need SmmCpuSyncLib Library for Intel.

This patch is to:
1.Adds SmmCpuSyncLib Library class in UefiCpuPkg.dec.
2.Adds SmmCpuSyncLib.h function declaration header file.

For the new SmmCpuSyncLib, it provides 3 sets of APIs:

1. ContextInit/ContextDeinit/ContextReset:
ContextInit() is called in driver's entrypoint to allocate and
initialize the SMM CPU Sync context. ContextDeinit() is called in
driver's unload function to deinitialize SMM CPU Sync context.
ContextReset() is called before CPU exist SMI, which allows CPU to
check into the next SMI from this point.

2. GetArrivedCpuCount/CheckInCpu/CheckOutCpu/LockDoor:
When SMI happens, all processors including BSP enter to SMM mode by
calling CheckInCpu(). The elected BSP calls LockDoor() so that
CheckInCpu() will return the error code after that. CheckOutCpu() can
be called in error handling flow for the CPU who calls CheckInCpu()
earlier. GetArrivedCpuCount() returns the number of checked-in CPUs.

3. WaitForAPs/ReleaseOneAp/WaitForBsp/ReleaseBsp
WaitForAPs() & ReleaseOneAp() are called from BSP to wait the number
of APs and release one specific AP. WaitForBsp() & ReleaseBsp() are
called from APs to wait and release BSP. The 4 APIs are used to
synchronize the running flow among BSP and APs. BSP and AP Sync flow
can be easy understand as below:
BSP: ReleaseOneAp  -->  AP: WaitForBsp
BSP: WaitForAPs    <--  AP: ReleaseBsp

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Zeng Star <star.zeng@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
---
 UefiCpuPkg/Include/Library/SmmCpuSyncLib.h | 275 +++++++++++++++++++++++++++++
 UefiCpuPkg/UefiCpuPkg.dec                  |   3 +
 2 files changed, 278 insertions(+)
 create mode 100644 UefiCpuPkg/Include/Library/SmmCpuSyncLib.h

diff --git a/UefiCpuPkg/Include/Library/SmmCpuSyncLib.h b/UefiCpuPkg/Include/Library/SmmCpuSyncLib.h
new file mode 100644
index 0000000000..0f9eb3414a
--- /dev/null
+++ b/UefiCpuPkg/Include/Library/SmmCpuSyncLib.h
@@ -0,0 +1,275 @@
+/** @file
+  Library that provides SMM CPU Sync related operations.
+  The lib provides 3 sets of APIs:
+  1. ContextInit/ContextDeinit/ContextReset:
+  ContextInit() is called in driver's entrypoint to allocate and initialize the SMM CPU Sync context.
+  ContextDeinit() is called in driver's unload function to deinitialize the SMM CPU Sync context.
+  ContextReset() is called before CPU exist SMI, which allows CPU to check into the next SMI from this point.
+
+  2. GetArrivedCpuCount/CheckInCpu/CheckOutCpu/LockDoor:
+  When SMI happens, all processors including BSP enter to SMM mode by calling CheckInCpu().
+  The elected BSP calls LockDoor() so that CheckInCpu() will return the error code after that.
+  CheckOutCpu() can be called in error handling flow for the CPU who calls CheckInCpu() earlier.
+  GetArrivedCpuCount() returns the number of checked-in CPUs.
+
+  3. WaitForAPs/ReleaseOneAp/WaitForBsp/ReleaseBsp
+  WaitForAPs() & ReleaseOneAp() are called from BSP to wait the number of APs and release one specific AP.
+  WaitForBsp() & ReleaseBsp() are called from APs to wait and release BSP.
+  The 4 APIs are used to synchronize the running flow among BSP and APs. BSP and AP Sync flow can be
+  easy understand as below:
+  BSP: ReleaseOneAp  -->  AP: WaitForBsp
+  BSP: WaitForAPs    <--  AP: ReleaseBsp
+
+  Copyright (c) 2023, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef SMM_CPU_SYNC_LIB_H_
+#define SMM_CPU_SYNC_LIB_H_
+
+#include <Uefi/UefiBaseType.h>
+
+//
+// Opaque structure for SMM CPU Sync context.
+//
+typedef struct SMM_CPU_SYNC_CONTEXT SMM_CPU_SYNC_CONTEXT;
+
+/**
+  Create and initialize the SMM CPU Sync context.
+
+  SmmCpuSyncContextInit() function is to allocate and initialize the SMM CPU Sync context.
+
+  @param[in]  NumberOfCpus          The number of Logical Processors in the system.
+  @param[out] SmmCpuSyncCtx         Pointer to the new created and initialized SMM CPU Sync context object.
+                                    NULL will be returned if any error happen during init.
+
+  @retval RETURN_SUCCESS            The SMM CPU Sync context was successful created and initialized.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx is NULL.
+  @retval RETURN_BUFFER_TOO_SMALL   Overflow happen
+  @retval RETURN_OUT_OF_RESOURCES   There are not enough resources available to create and initialize SMM CPU Sync context.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncContextInit (
+  IN   UINTN                 NumberOfCpus,
+  OUT  SMM_CPU_SYNC_CONTEXT  **SmmCpuSyncCtx
+  );
+
+/**
+  Deinit an allocated SMM CPU Sync context.
+
+  SmmCpuSyncContextDeinit() function is to deinitialize SMM CPU Sync context, the resources allocated in
+  SmmCpuSyncContextInit() will be freed.
+
+  Note: This function only can be called after SmmCpuSyncContextInit() return success.
+
+  @param[in,out]  SmmCpuSyncCtx     Pointer to the SMM CPU Sync context object to be deinitialized.
+
+  @retval RETURN_SUCCESS            The SMM CPU Sync context was successful deinitialized.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx is NULL.
+  @retval RETURN_UNSUPPORTED        Unsupported operation.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncContextDeinit (
+  IN OUT SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx
+  );
+
+/**
+  Reset SMM CPU Sync context.
+
+  SmmCpuSyncContextReset() function is to reset SMM CPU Sync context to the initialized state.
+
+  @param[in,out]  SmmCpuSyncCtx     Pointer to the SMM CPU Sync context object to be reset.
+
+  @retval RETURN_SUCCESS            The SMM CPU Sync context was successful reset.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx is NULL.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncContextReset (
+  IN OUT SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx
+  );
+
+/**
+  Get current number of arrived CPU in SMI.
+
+  For traditional CPU synchronization method, BSP might need to know the current number of arrived CPU in
+  SMI to make sure all APs in SMI. This API can be for that purpose.
+
+  @param[in]      SmmCpuSyncCtx     Pointer to the SMM CPU Sync context object.
+  @param[in,out]  CpuCount          Current count of arrived CPU in SMI.
+
+  @retval RETURN_SUCCESS            Get current number of arrived CPU in SMI successfully.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx or CpuCount is NULL.
+  @retval RETURN_UNSUPPORTED        Unsupported operation.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncGetArrivedCpuCount (
+  IN     SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx,
+  IN OUT UINTN                 *CpuCount
+  );
+
+/**
+  Performs an atomic operation to check in CPU.
+
+  When SMI happens, all processors including BSP enter to SMM mode by calling SmmCpuSyncCheckInCpu().
+
+  @param[in,out]  SmmCpuSyncCtx     Pointer to the SMM CPU Sync context object.
+  @param[in]      CpuIndex          Check in CPU index.
+
+  @retval RETURN_SUCCESS            Check in CPU (CpuIndex) successfully.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx is NULL.
+  @retval RETURN_ABORTED            Check in CPU failed due to SmmCpuSyncLockDoor() has been called by one elected CPU.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncCheckInCpu (
+  IN OUT SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx,
+  IN     UINTN                 CpuIndex
+  );
+
+/**
+  Performs an atomic operation to check out CPU.
+
+  CheckOutCpu() can be called in error handling flow for the CPU who calls CheckInCpu() earlier.
+
+  @param[in,out]  SmmCpuSyncCtx     Pointer to the SMM CPU Sync context object.
+  @param[in]      CpuIndex          Check out CPU index.
+
+  @retval RETURN_SUCCESS            Check out CPU (CpuIndex) successfully.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx is NULL.
+  @retval RETURN_NOT_READY          The CPU is not checked-in.
+  @retval RETURN_UNSUPPORTED        Unsupported operation.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncCheckOutCpu (
+  IN OUT SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx,
+  IN     UINTN                 CpuIndex
+  );
+
+/**
+  Performs an atomic operation lock door for CPU checkin or checkout.
+
+  After this function, CPU can not check in via SmmCpuSyncCheckInCpu().
+
+  The CPU specified by CpuIndex is elected to lock door.
+
+  @param[in,out]  SmmCpuSyncCtx     Pointer to the SMM CPU Sync context object.
+  @param[in]      CpuIndex          Indicate which CPU to lock door.
+  @param[in,out]  CpuCount          Number of arrived CPU in SMI after look door.
+
+  @retval RETURN_SUCCESS            Lock door for CPU successfully.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx or CpuCount is NULL.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncLockDoor (
+  IN OUT SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx,
+  IN     UINTN                 CpuIndex,
+  IN OUT UINTN                 *CpuCount
+  );
+
+/**
+  Used by the BSP to wait for APs.
+
+  The number of APs need to be waited is specified by NumberOfAPs. The BSP is specified by BspIndex.
+
+  Note: This function is blocking mode, and it will return only after the number of APs released by
+  calling SmmCpuSyncReleaseBsp():
+  BSP: WaitForAPs    <--  AP: ReleaseBsp
+
+  @param[in,out]  SmmCpuSyncCtx     Pointer to the SMM CPU Sync context object.
+  @param[in]      NumberOfAPs       Number of APs need to be waited by BSP.
+  @param[in]      BspIndex          The BSP Index to wait for APs.
+
+  @retval RETURN_SUCCESS            BSP to wait for APs successfully.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx is NULL or NumberOfAPs > total number of processors in system.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncWaitForAPs (
+  IN OUT SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx,
+  IN     UINTN                 NumberOfAPs,
+  IN     UINTN                 BspIndex
+  );
+
+/**
+  Used by the BSP to release one AP.
+
+  The AP is specified by CpuIndex. The BSP is specified by BspIndex.
+
+  @param[in,out]  SmmCpuSyncCtx     Pointer to the SMM CPU Sync context object.
+  @param[in]      CpuIndex          Indicate which AP need to be released.
+  @param[in]      BspIndex          The BSP Index to release AP.
+
+  @retval RETURN_SUCCESS            BSP to release one AP successfully.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx is NULL or CpuIndex is same as BspIndex.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncReleaseOneAp   (
+  IN OUT SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx,
+  IN     UINTN                 CpuIndex,
+  IN     UINTN                 BspIndex
+  );
+
+/**
+  Used by the AP to wait BSP.
+
+  The AP is specified by CpuIndex. The BSP is specified by BspIndex.
+
+  Note: This function is blocking mode, and it will return only after the AP released by
+  calling SmmCpuSyncReleaseOneAp():
+  BSP: ReleaseOneAp  -->  AP: WaitForBsp
+
+  @param[in,out]  SmmCpuSyncCtx    Pointer to the SMM CPU Sync context object.
+  @param[in]      CpuIndex         Indicate which AP wait BSP.
+  @param[in]      BspIndex         The BSP Index to be waited.
+
+  @retval RETURN_SUCCESS            AP to wait BSP successfully.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx is NULL or CpuIndex is same as BspIndex.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncWaitForBsp (
+  IN OUT SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx,
+  IN     UINTN                 CpuIndex,
+  IN     UINTN                 BspIndex
+  );
+
+/**
+  Used by the AP to release BSP.
+
+  The AP is specified by CpuIndex. The BSP is specified by BspIndex.
+
+  @param[in,out]  SmmCpuSyncCtx     Pointer to the SMM CPU Sync context object.
+  @param[in]      CpuIndex          Indicate which AP release BSP.
+  @param[in]      BspIndex          The BSP Index to be released.
+
+  @retval RETURN_SUCCESS            AP to release BSP successfully.
+  @retval RETURN_INVALID_PARAMETER  SmmCpuSyncCtx is NULL or CpuIndex is same as BspIndex.
+
+**/
+RETURN_STATUS
+EFIAPI
+SmmCpuSyncReleaseBsp (
+  IN OUT SMM_CPU_SYNC_CONTEXT  *SmmCpuSyncCtx,
+  IN     UINTN                 CpuIndex,
+  IN     UINTN                 BspIndex
+  );
+
+#endif
diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec
index 0b5431dbf7..20ab079219 100644
--- a/UefiCpuPkg/UefiCpuPkg.dec
+++ b/UefiCpuPkg/UefiCpuPkg.dec
@@ -62,10 +62,13 @@
   CpuPageTableLib|Include/Library/CpuPageTableLib.h
 
   ## @libraryclass   Provides functions for manipulating smram savestate registers.
   MmSaveStateLib|Include/Library/MmSaveStateLib.h
 
+  ## @libraryclass   Provides functions for SMM CPU Sync Operation.
+  SmmCpuSyncLib|Include/Library/SmmCpuSyncLib.h
+
 [LibraryClasses.RISCV64]
   ##  @libraryclass  Provides functions to manage MMU features on RISCV64 CPUs.
   ##
   RiscVMmuLib|Include/Library/BaseRiscVMmuLib.h
 
-- 
2.16.2.windows.1



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