UefiCpuPkg: Enable Tdx support in MpInitLib

RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429

In TDVF BSP and APs are simplified. BSP is the vCPU-0, while the others
are treated as APs.

So MP intialization is rather simple. ApWorker is not supported, BSP is
always the working processor, while the APs are just in a
wait-for-precedure state.

Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

UefiCpuPkg/Library/MpInitLib/MpLib.c

@@ -9,9 +9,11 @@
 **/
 
 #include "MpLib.h"
+#include "MpIntelTdx.h"
 #include <Library/VmgExitLib.h>
 #include <Register/Amd/Fam17Msr.h>
 #include <Register/Amd/Ghcb.h>
+#include <ConfidentialComputingGuestAttr.h>
 
 EFI_GUID  mCpuInitMpLibHobGuid = CPU_INIT_MP_LIB_HOB_GUID;
 
@@ -1803,6 +1805,10 @@ MpInitLibInitialize (
   UINTN                    BackupBufferAddr;
   UINTN                    ApIdtBase;
 
+  if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
+    return EFI_SUCCESS;
+  }
+
   OldCpuMpData = GetCpuMpDataFromGuidedHob ();
   if (OldCpuMpData == NULL) {
     MaxLogicalProcessorNumber = PcdGet32 (PcdCpuMaxLogicalProcessorNumber);
@@ -2073,6 +2079,10 @@ MpInitLibGetProcessorInfo (
   CPU_INFO_IN_HOB  *CpuInfoInHob;
   UINTN            OriginalProcessorNumber;
 
+  if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
+    return TdxMpInitLibGetProcessorInfo (ProcessorNumber, ProcessorInfoBuffer, HealthData);
+  }
+
   CpuMpData    = GetCpuMpData ();
   CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
 
@@ -2167,6 +2177,10 @@ SwitchBSPWorker (
   BOOLEAN                      OldInterruptState;
   BOOLEAN                      OldTimerInterruptState;
 
+  if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
+    return EFI_UNSUPPORTED;
+  }
+
   //
   // Save and Disable Local APIC timer interrupt
   //
@@ -2307,6 +2321,10 @@ EnableDisableApWorker (
   CPU_MP_DATA  *CpuMpData;
   UINTN        CallerNumber;
 
+  if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
+    return EFI_UNSUPPORTED;
+  }
+
   CpuMpData = GetCpuMpData ();
 
   //
@@ -2367,6 +2385,11 @@ MpInitLibWhoAmI (
     return EFI_INVALID_PARAMETER;
   }
 
+  if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
+    *ProcessorNumber = 0;
+    return EFI_SUCCESS;
+  }
+
   CpuMpData = GetCpuMpData ();
 
   return GetProcessorNumber (CpuMpData, ProcessorNumber);
@@ -2405,12 +2428,16 @@ MpInitLibGetNumberOfProcessors (
   UINTN        EnabledProcessorNumber;
   UINTN        Index;
 
-  CpuMpData = GetCpuMpData ();
-
   if ((NumberOfProcessors == NULL) && (NumberOfEnabledProcessors == NULL)) {
     return EFI_INVALID_PARAMETER;
   }
 
+  if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
+    return TdxMpInitLibGetNumberOfProcessors (NumberOfProcessors, NumberOfEnabledProcessors);
+  }
+
+  CpuMpData = GetCpuMpData ();
+
   //
   // Check whether caller processor is BSP
   //
@@ -2490,13 +2517,16 @@ StartupAllCPUsWorker (
   BOOLEAN      HasEnabledAp;
   CPU_STATE    ApState;
 
-  CpuMpData = GetCpuMpData ();
-
   if (FailedCpuList != NULL) {
     *FailedCpuList = NULL;
   }
 
-  if ((CpuMpData->CpuCount == 1) && ExcludeBsp) {
+  Status = MpInitLibGetNumberOfProcessors (&ProcessorCount, NULL);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  if ((ProcessorCount == 1) && ExcludeBsp) {
     return EFI_NOT_STARTED;
   }
 
@@ -2504,6 +2534,22 @@ StartupAllCPUsWorker (
     return EFI_INVALID_PARAMETER;
   }
 
+  if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
+    //
+    // For Td guest ExcludeBsp must be FALSE. Otherwise it will return in above checks.
+    //
+    ASSERT (!ExcludeBsp);
+
+    //
+    // Start BSP.
+    //
+    Procedure (ProcedureArgument);
+
+    return EFI_SUCCESS;
+  }
+
+  CpuMpData = GetCpuMpData ();
+
   //
   // Check whether caller processor is BSP
   //
@@ -2643,6 +2689,13 @@ StartupThisAPWorker (
   CPU_AP_DATA  *CpuData;
   UINTN        CallerNumber;
 
+  //
+  // In Td guest, startup of AP is not supported in current stage.
+  //
+  if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr))) {
+    return EFI_UNSUPPORTED;
+  }
+
   CpuMpData = GetCpuMpData ();
 
   if (Finished != NULL) {