UefiCpuPkg/PiSmmCpuDxeSmm: Use NonSmm BSP as default SMM BSP.

Currently, if BSP election is not enabled, will use Core0 as SMM BSP.
However, Core0 does not always have the highest performance.
So, we can used NonSmm BSP as default BSP.
This will take effect in normal SMM init flow and S3 boot flow.
In normal SMM flow, the code is executed before first SMI.
In S3 flow, the code is executed in Non-SMM BSP's first SMI, where the
gSmmCpuPrivate keeps the data from last boot.

Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
index 25d058c5b9..b279f5dfcc 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
@@ -1953,6 +1953,16 @@ InitializeMpSyncData (
       // Enable BSP election by setting BspIndex to -1

       //

       mSmmMpSyncData->BspIndex = (UINT32)-1;

+    } else {

+      //

+      // Use NonSMM BSP as SMM BSP

+      //

+      for (CpuIndex = 0; CpuIndex < gSmmCpuPrivate->SmmCoreEntryContext.NumberOfCpus; CpuIndex++) {

+        if (GetApicId () == gSmmCpuPrivate->ProcessorInfo[CpuIndex].ProcessorId) {

+          mSmmMpSyncData->BspIndex = (UINT32)CpuIndex;

+          break;

+        }

+      }

     }

 

     mSmmMpSyncData->EffectiveSyncMode = mCpuSmmSyncMode;