Init CPU_HOT_EJECT_DATA, exposed via PcdCpuHotEjectDataAddress. This is
owned by PiSmmCpuDxeSmm,  managed in OvmfPkg/SmmCpuFeaturesLib, and is
consumed in OvmfPkg/CpuHotPlugSmm which sets up CPU_HOT_EJECT_DATA->Handler
which handles the mechanics of CPU ejection.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Aaron Young <aaron.young@oracle.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3132
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
 .../Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c  | 68 ++++++++++++++++++++++
 .../SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf        |  3 +
 2 files changed, 71 insertions(+)

diff --git a/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c b/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c
index 7ef7ed98342e..5e7f2de25911 100644
--- a/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c
+++ b/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c
@@ -14,6 +14,7 @@
 #include <Library/PcdLib.h>
 #include <Library/SmmCpuFeaturesLib.h>
 #include <Library/SmmServicesTableLib.h>
+#include <Library/MemoryAllocationLib.h>                 // AllocatePool()
 #include <Library/UefiBootServicesTableLib.h>
 #include <PiSmm.h>
 #include <Register/Intel/SmramSaveStateMap.h>
@@ -171,6 +172,61 @@ SmmCpuFeaturesHookReturnFromSmm (
   return OriginalInstructionPointer;
 }
 
+//
+// The PCD corresponding to CPU_HOT_EJECT_DATA is owned by UefiCpuPkg
+// but we allocate and set it up here because it is needed from
+// SmmCpuFeaturesRendezvousExit() on all CPUs exiting SMI and
+// simultaneous PcdGet64() on multiple CPUs is not supported.
+//
+
+GLOBAL_REMOVE_IF_UNREFERENCED
+CPU_HOT_EJECT_DATA *mCpuHotEjectData;
+
+STATIC
+VOID
+EFIAPI
+SmmCpuFeaturesSmmInitHotEject(
+  VOID
+  )
+{
+  UINT32 mMaxNumberOfCpus;
+  EFI_STATUS Status;
+
+  if (!FeaturePcdGet (PcdCpuHotPlugSupport)) {
+    return;
+  }
+
+  // PcdCpuHotPlugSupport => PcdCpuMaxLogicalProcessorNumber
+  mMaxNumberOfCpus = PcdGet32 (PcdCpuMaxLogicalProcessorNumber);
+
+  // No spare CPUs to eject
+  if (mMaxNumberOfCpus == 1) {
+    return;
+  }
+
+  mCpuHotEjectData =
+    (CPU_HOT_EJECT_DATA *)AllocatePool (sizeof (*mCpuHotEjectData));
+  ASSERT (mCpuHotEjectData != NULL);
+
+  //
+  // Allocate buffer for pointers to array in CPU_HOT_EJECT_DATA.
+  //
+  mCpuHotEjectData->Revision = CPU_HOT_EJECT_DATA_REVISION_1;   // Revision
+  mCpuHotEjectData->ArrayLength = mMaxNumberOfCpus;             // Array Length of APIC ID
+  mCpuHotEjectData->ApicIdMap =                                 // CpuIndex -> APIC ID map
+    (UINT64 *)AllocatePool (sizeof (UINT64) * mCpuHotEjectData->ArrayLength);
+  mCpuHotEjectData->Handler = NULL;                             // Hot Eject handler
+  mCpuHotEjectData->Handler = 0;                                // Reserved
+
+  ASSERT (mCpuHotEjectData->ApicIdMap != NULL);
+
+  //
+  // Expose address of CPU Hot eject Data structure
+  //
+  Status = PcdSet64S (PcdCpuHotEjectDataAddress, (UINT64)(VOID *)mCpuHotEjectData);
+  ASSERT_EFI_ERROR (Status);
+}
+
 /**
   Hook point in normal execution mode that allows the one CPU that was elected
   as monarch during System Management Mode initialization to perform additional
@@ -188,6 +244,9 @@ SmmCpuFeaturesSmmRelocationComplete (
   UINTN      MapPagesBase;
   UINTN      MapPagesCount;
 
+
+  SmmCpuFeaturesSmmInitHotEject();
+
   if (!MemEncryptSevIsEnabled ()) {
     return;
   }
@@ -375,6 +434,15 @@ SmmCpuFeaturesRendezvousExit (
   IN UINTN  CpuIndex
   )
 {
+  //
+  // CPU Hot eject not enabled.
+  //
+  if (mCpuHotEjectData == NULL ||
+      mCpuHotEjectData->Handler == NULL) {
+    return;
+  }
+
+  mCpuHotEjectData->Handler(CpuIndex);
 }
 
 /**
diff --git a/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf b/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf
index 97a10afb6e27..3043f02b2216 100644
--- a/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf
+++ b/OvmfPkg/Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf
@@ -36,3 +36,6 @@
 
 [Pcd]
   gUefiOvmfPkgTokenSpaceGuid.PcdQ35SmramAtDefaultSmbase
+  gUefiCpuPkgTokenSpaceGuid.PcdCpuHotPlugSupport
+  gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber
+  gUefiCpuPkgTokenSpaceGuid.PcdCpuHotEjectDataAddress
-- 
2.9.3



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