UefiCpuPkg/PiSmmCpuDxeSmm: Align BSP and AP sync logic for SMI exit

Below piece of code is the BSP and AP sync logic for SMI exit.
1. AP after finish the scheduled procedure:
  if (SmmCpuFeaturesNeedConfigureMtrrs ()) {
    SmmCpuSyncReleaseBsp ();
    SmmCpuSyncWaitForBsp ();
    ...
  }
  SmmCpuSyncReleaseBsp ();
  SmmCpuSyncWaitForBsp ();
  SmmCpuSyncReleaseBsp ();

2. BSP after return from SmmCoreEntry:
  SmmCpuSyncWaitForAPs ();
  if (SmmCpuFeaturesNeedConfigureMtrrs ()) {
    ReleaseAllAPs ();
    ...
    SmmCpuSyncWaitForAPs ();
  }
  ReleaseAllAPs ();
  SmmCpuSyncWaitForAPs();

This patch is to make BSP same as AP sync logic:
  if (SmmCpuFeaturesNeedConfigureMtrrs ()) {
    SmmCpuSyncWaitForAPs ();
    ReleaseAllAPs ();
    ...
  }
  SmmCpuSyncWaitForAPs ();
  ReleaseAllAPs ();
  SmmCpuSyncWaitForAPs();

With the change, it will be easy to understand the sync flow as
below:
BSP: SmmCpuSyncWaitForAPs  <--  AP: SmmCpuSyncReleaseBsp
BSP: ReleaseAllAPs         -->  AP: SmmCpuSyncWaitForBsp

This patch doesn't have function impact.

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>
Reviewed-by: Ray Ni <ray.ni@Intel.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
index 324e85d6b5..bd2c9f841b 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
@@ -627,13 +627,13 @@ BSPHandler (
   *mSmmMpSyncData->InsideSmm = FALSE;

   ReleaseAllAPs ();

 

-  //

-  // Wait for all APs to complete their pending tasks

-  //

-  SmmCpuSyncWaitForAPs (mSmmMpSyncData->SyncContext, ApCount, CpuIndex);

-

   if (SmmCpuFeaturesNeedConfigureMtrrs ()) {

     //

+    // Wait for all APs the readiness to program MTRRs

+    //

+    SmmCpuSyncWaitForAPs (mSmmMpSyncData->SyncContext, ApCount, CpuIndex);

+

+    //

     // Signal APs to restore MTRRs

     //

     ReleaseAllAPs ();

@@ -643,13 +643,13 @@ BSPHandler (
     //

     SmmCpuFeaturesReenableSmrr ();

     MtrrSetAllMtrrs (&Mtrrs);

-

-    //

-    // Wait for all APs to complete MTRR programming

-    //

-    SmmCpuSyncWaitForAPs (mSmmMpSyncData->SyncContext, ApCount, CpuIndex);

   }

 

+  //

+  // Wait for all APs to complete their pending tasks including MTRR programming if needed.

+  //

+  SmmCpuSyncWaitForAPs (mSmmMpSyncData->SyncContext, ApCount, CpuIndex);

+

   if (mSmmDebugAgentSupport) {

     //

     // Stop source level debug in BSP handler, the code below will not be