[edk2-devel] [PATCH v2 5/5] UefiCpuPkg/MpInitLib: Add support for multiple HOBs to SaveCpuMpData()

["Gerd Hoffmann" <kraxel@redhat.com>]

Add support for splitting Hand-Off data into multiple HOBs.  This is
required for VMs with thousands of CPUs.  The actual CPU count per HOB
is much smaller (128) for better test coverage.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 UefiCpuPkg/Library/MpInitLib/PeiMpLib.c | 44 +++++++++++++++----------
 1 file changed, 27 insertions(+), 17 deletions(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
index f80e00edcff3..8a916a218016 100644
--- a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
@@ -126,35 +126,45 @@ SaveCpuMpData (
   IN CPU_MP_DATA  *CpuMpData
   )
 {
+  UINT32           MaxCpusPerHob, CpusInHob;
   UINT64           Data64;
-  UINTN            Index;
+  UINT32           Index, HobBase;
   CPU_INFO_IN_HOB  *CpuInfoInHob;
   MP_HAND_OFF      *MpHandOff;
   UINTN            MpHandOffSize;
 
+  MaxCpusPerHob = (MAX_UINT16 - sizeof (EFI_HOB_GUID_TYPE) - sizeof (MP_HAND_OFF)) / sizeof (PROCESSOR_HAND_OFF);
+
   //
   // When APs are in a state that can be waken up by a store operation to a memory address,
   // report the MP_HAND_OFF data for DXE to use.
   //
-  CpuInfoInHob  = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
-  MpHandOffSize = sizeof (MP_HAND_OFF) + sizeof (PROCESSOR_HAND_OFF) * CpuMpData->CpuCount;
-  MpHandOff     = (MP_HAND_OFF *)BuildGuidHob (&mMpHandOffGuid, MpHandOffSize);
-  ASSERT (MpHandOff != NULL);
-  ZeroMem (MpHandOff, MpHandOffSize);
-  MpHandOff->ProcessorIndex = 0;
+  CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
 
-  MpHandOff->CpuCount = CpuMpData->CpuCount;
-  if (CpuMpData->ApLoopMode != ApInHltLoop) {
-    MpHandOff->StartupSignalValue    = MP_HAND_OFF_SIGNAL;
-    MpHandOff->WaitLoopExecutionMode = sizeof (VOID *);
-  }
+  for (Index = 0; Index < CpuMpData->CpuCount; Index++) {
+    if (Index % MaxCpusPerHob == 0) {
+      HobBase   = Index;
+      CpusInHob = MIN (CpuMpData->CpuCount - HobBase, MaxCpusPerHob);
 
-  for (Index = 0; Index < MpHandOff->CpuCount; Index++) {
-    MpHandOff->Info[Index].ApicId = CpuInfoInHob[Index].ApicId;
-    MpHandOff->Info[Index].Health = CpuInfoInHob[Index].Health;
+      MpHandOffSize = sizeof (MP_HAND_OFF) + sizeof (PROCESSOR_HAND_OFF) * CpusInHob;
+      MpHandOff     = (MP_HAND_OFF *)BuildGuidHob (&mMpHandOffGuid, MpHandOffSize);
+      ASSERT (MpHandOff != NULL);
+      ZeroMem (MpHandOff, MpHandOffSize);
+
+      MpHandOff->ProcessorIndex = HobBase;
+      MpHandOff->CpuCount       = CpusInHob;
+
+      if (CpuMpData->ApLoopMode != ApInHltLoop) {
+        MpHandOff->StartupSignalValue    = MP_HAND_OFF_SIGNAL;
+        MpHandOff->WaitLoopExecutionMode = sizeof (VOID *);
+      }
+    }
+
+    MpHandOff->Info[Index-HobBase].ApicId = CpuInfoInHob[Index].ApicId;
+    MpHandOff->Info[Index-HobBase].Health = CpuInfoInHob[Index].Health;
     if (CpuMpData->ApLoopMode != ApInHltLoop) {
-      MpHandOff->Info[Index].StartupSignalAddress    = (UINT64)(UINTN)CpuMpData->CpuData[Index].StartupApSignal;
-      MpHandOff->Info[Index].StartupProcedureAddress = (UINT64)(UINTN)&CpuMpData->CpuData[Index].ApFunction;
+      MpHandOff->Info[Index-HobBase].StartupSignalAddress    = (UINT64)(UINTN)CpuMpData->CpuData[Index].StartupApSignal;
+      MpHandOff->Info[Index-HobBase].StartupProcedureAddress = (UINT64)(UINTN)&CpuMpData->CpuData[Index].ApFunction;
     }
   }
 
-- 
2.43.2



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