UefiCpuPkg/MpInitLib: Always use AP Create if GhcbApicIds HOB is present

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654

Currently, the first time an AP is started for an SEV-SNP guest, it relies
on the VMSA as set by the hypervisor. If the list of APIC IDs has been
retrieved, this is not necessary. The list of APIC IDs will be identified
by a GUIDed HOB. If the GUIDed HOB is present, use the SEV-SNP AP Create
protocol to start the AP for the first time and each time thereafter.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Ray Ni <ray.ni@intel.com>

6 files changed, 112 insertions, 13 deletions

diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
index 407f4988b5..15c10b3060 100644
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
@@ -77,6 +77,7 @@
   gEfiEventExitBootServicesGuid                 ## CONSUMES  ## Event

   gEfiEventLegacyBootGuid                       ## SOMETIMES_CONSUMES  ## Event

   gEdkiiMicrocodePatchHobGuid                   ## SOMETIMES_CONSUMES  ## HOB

+  gGhcbApicIdsGuid                              ## SOMETIMES_CONSUMES  ## HOB

 

 [Guids.LoongArch64]

   gProcessorResourceHobGuid                     ## SOMETIMES_CONSUMES  ## HOB

diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c b/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
index c83144285b..0478e92317 100644
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/AmdSev.c
@@ -2,7 +2,7 @@
 

   AMD SEV helper function.

 

-  Copyright (c) 2021, AMD Incorporated. All rights reserved.<BR>

+  Copyright (c) 2021 - 2024, AMD Incorporated. All rights reserved.<BR>

 

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

@@ -68,3 +68,22 @@ SevSnpRmpAdjust (
   //

   return RETURN_UNSUPPORTED;

 }

+

+/**

+  Determine if the SEV-SNP AP Create protocol should be used.

+

+  @param[in]  CpuMpData  Pointer to CPU MP Data

+

+  @retval     TRUE       Use SEV-SNP AP Create protocol

+  @retval     FALSE      Do not use SEV-SNP AP Create protocol

+**/

+BOOLEAN

+CanUseSevSnpCreateAP (

+  IN  CPU_MP_DATA  *CpuMpData

+  )

+{

+  //

+  // SEV-SNP is not supported on 32-bit build.

+  //

+  return FALSE;

+}

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 9bac62f289..d724456502 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -2,7 +2,7 @@
   CPU MP Initialize Library common functions.

 

   Copyright (c) 2016 - 2022, Intel Corporation. All rights reserved.<BR>

-  Copyright (c) 2020, AMD Inc. All rights reserved.<BR>

+  Copyright (c) 2020 - 2024, AMD Inc. All rights reserved.<BR>

 

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

@@ -1303,9 +1303,10 @@ WakeUpAP (
       //

       // Wakeup all APs

       //   Must use the INIT-SIPI-SIPI method for initial configuration in

-      //   order to obtain the APIC ID.

+      //   order to obtain the APIC ID if not an SEV-SNP guest and the

+      //   list of APIC IDs is not available.

       //

-      if (CpuMpData->SevSnpIsEnabled && (CpuMpData->InitFlag != ApInitConfig)) {

+      if (CanUseSevSnpCreateAP (CpuMpData)) {

         SevSnpCreateAP (CpuMpData, -1);

       } else {

         if ((CpuMpData->InitFlag == ApInitConfig) && FixedPcdGetBool (PcdFirstTimeWakeUpAPsBySipi)) {

@@ -1415,7 +1416,7 @@ WakeUpAP (
         SetSevEsJumpTable (ExchangeInfo->BufferStart);

       }

 

-      if (CpuMpData->SevSnpIsEnabled && (CpuMpData->InitFlag != ApInitConfig)) {

+      if (CanUseSevSnpCreateAP (CpuMpData)) {

         SevSnpCreateAP (CpuMpData, (INTN)ProcessorNumber);

       } else {

         SendInitSipiSipi (

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index d26035559f..65e05c4806 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -2,7 +2,7 @@
   Common header file for MP Initialize Library.

 

   Copyright (c) 2016 - 2023, Intel Corporation. All rights reserved.<BR>

-  Copyright (c) 2020, AMD Inc. All rights reserved.<BR>

+  Copyright (c) 2020 - 2024, AMD Inc. All rights reserved.<BR>

 

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

@@ -925,6 +925,19 @@ SevSnpCreateAP (
   );

 

 /**

+  Determine if the SEV-SNP AP Create protocol should be used.

+

+  @param[in]  CpuMpData  Pointer to CPU MP Data

+

+  @retval     TRUE       Use SEV-SNP AP Create protocol

+  @retval     FALSE      Do not use SEV-SNP AP Create protocol

+**/

+BOOLEAN

+CanUseSevSnpCreateAP (

+  IN  CPU_MP_DATA  *CpuMpData

+  );

+

+/**

   Get pointer to CPU MP Data structure from GUIDed HOB.

 

   @param[in] CpuMpData  The pointer to CPU MP Data structure.

diff --git a/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf b/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
index 3ba15c149e..6c75b96fdc 100644
--- a/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
+++ b/UefiCpuPkg/Library/MpInitLib/PeiMpInitLib.inf
@@ -85,6 +85,7 @@
 [Guids]

   gEdkiiS3SmmInitDoneGuid

   gEdkiiMicrocodePatchHobGuid

+  gGhcbApicIdsGuid                       ## SOMETIMES_CONSUMES

 

 [Guids.LoongArch64]

   gProcessorResourceHobGuid              ## SOMETIMES_CONSUMES  ## HOB

diff --git a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
index c9f0984f41..bd12a5ee2f 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
+++ b/UefiCpuPkg/Library/MpInitLib/X64/AmdSev.c
@@ -2,7 +2,7 @@
 

   AMD SEV helper function.

 

-  Copyright (c) 2021, AMD Incorporated. All rights reserved.<BR>

+  Copyright (c) 2021 - 2024, AMD Incorporated. All rights reserved.<BR>

 

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

@@ -268,20 +268,55 @@ SevSnpCreateAP (
   IN INTN         ProcessorNumber

   )

 {

-  CPU_INFO_IN_HOB  *CpuInfoInHob;

-  CPU_AP_DATA      *CpuData;

-  UINTN            Index;

-  UINT32           ApicId;

+  CPU_INFO_IN_HOB    *CpuInfoInHob;

+  CPU_AP_DATA        *CpuData;

+  UINTN              Index;

+  UINTN              MaxIndex;

+  UINT32             ApicId;

+  EFI_HOB_GUID_TYPE  *GuidHob;

+  GHCB_APIC_IDS      *GhcbApicIds;

 

   ASSERT (CpuMpData->MpCpuExchangeInfo->BufferStart < 0x100000);

 

   CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;

 

   if (ProcessorNumber < 0) {

-    for (Index = 0; Index < CpuMpData->CpuCount; Index++) {

+    if (CpuMpData->InitFlag == ApInitConfig) {

+      //

+      // APs have not been started, so CpuCount is not "known" yet. Use the

+      // retrieved APIC IDs to start the APs and fill out the MpLib CPU

+      // information properly. CanUseSevSnpCreateAP() guarantees we have a

+      // HOB when InitFlag is ApInitConfig.

+      //

+      GuidHob     = GetFirstGuidHob (&gGhcbApicIdsGuid);

+      GhcbApicIds = (GHCB_APIC_IDS *)(*(UINTN *)GET_GUID_HOB_DATA (GuidHob));

+      MaxIndex    = MIN (GhcbApicIds->NumEntries, PcdGet32 (PcdCpuMaxLogicalProcessorNumber));

+    } else {

+      //

+      // APs have been previously started.

+      //

+      MaxIndex = CpuMpData->CpuCount;

+    }

+

+    for (Index = 0; Index < MaxIndex; Index++) {

       if (Index != CpuMpData->BspNumber) {

         CpuData = &CpuMpData->CpuData[Index];

-        ApicId  = CpuInfoInHob[Index].ApicId,

+

+        if (CpuMpData->InitFlag == ApInitConfig) {

+          ApicId = GhcbApicIds->ApicIds[Index];

+

+          //

+          // For the first boot, use the BSP register information.

+          //

+          CopyMem (

+            &CpuData->VolatileRegisters,

+            &CpuMpData->CpuData[0].VolatileRegisters,

+            sizeof (CpuData->VolatileRegisters)

+            );

+        } else {

+          ApicId = CpuInfoInHob[Index].ApicId;

+        }

+

         SevSnpCreateSaveArea (CpuMpData, CpuData, ApicId);

       }

     }

@@ -325,3 +360,32 @@ SevSnpRmpAdjust (
 

   return AsmRmpAdjust ((UINT64)PageAddress, 0, Rdx);

 }

+

+/**

+  Determine if the SEV-SNP AP Create protocol should be used.

+

+  @param[in]  CpuMpData  Pointer to CPU MP Data

+

+  @retval     TRUE       Use SEV-SNP AP Create protocol

+  @retval     FALSE      Do not use SEV-SNP AP Create protocol

+**/

+BOOLEAN

+CanUseSevSnpCreateAP (

+  IN  CPU_MP_DATA  *CpuMpData

+  )

+{

+  //

+  // The AP Create protocol is used for an SEV-SNP guest if

+  //   - The initial configuration has been performed already or

+  //   - The APIC IDs GUIDed HOB is non-zero.

+  //

+  if (!CpuMpData->SevSnpIsEnabled) {

+    return FALSE;

+  }

+

+  if ((CpuMpData->InitFlag == ApInitConfig) && (GetFirstGuidHob (&gGhcbApicIdsGuid) == NULL)) {

+    return FALSE;

+  }

+

+  return TRUE;

+}