OvmfPkg/PlatformInitLib: Create gEfiSmmSmramMemoryGuid

In the PiSmmCpuDxeSmm driver, SMRAM allocation for SMI
handlers and processor Save State areas was traditionally
performed using the Smst->AllocatePages() function during
the DXE phase. The introduction of SmmRelocationLib
changes this process by moving the allocation to the PEI
phase, where Smst->AllocatePages() is not accessible.
Instead, the allocation is now handled by partitioning
the SMRAM based on the information provided by a GUID HOB
(identified by gEfiSmmSMramMemoryGuid).

This patch is to ensure that OVMF produces the
gEfiSmmSMramMemoryGuid HOB, allowing SmmRelocationLib to
reserve the necessary memory for SMBASE relocation.

More info for the change:
1. The EFI_SMM_SMRAM_MEMORY_GUID HOB, as defined in the PI
specification, vol.3, section 5, which is used to describe
the SMRAM memory regions supported by the platform. This HOB
should be produced during the memory detection phase to
align with the PI spec.

2. In addition to the memory reserved for ACPI S3 resume,
an increasing number of features require reserving SMRAM
for specific purposes, such as SmmRelocation. Other
advanced features in Intel platforms also necessitate
this. The implementation of these features varies and is
entirely dependent on the platform. This is why an
increasing number of platforms are adopting the
EFI_SMM_SMRAM_MEMORY_GUID HOB for SMRAM description.

3. It is crucial that the SMRAM information remains
consistent when retrieved from the platform, whether
through the SMM ACCESS PPI/Protocol or the
EFI_SMM_SMRAM_MEMORY_GUID HOB. Inconsistencies can lead
to unexpected issues, most commonly memory region conflicts.

4. The SMM ACCESS PPI/Protocol can be naturally
implemented for general use. The common approach is to
utilize the EFI_SMM_SMRAM_MEMORY_GUID HOB. For reference,
see the existing implementation in the EDK2 repository at
edk2/UefiPayloadPkg/SmmAccessDxe/SmmAccessDxe.inf and
edk2-platforms/Silicon/Intel/IntelSiliconPkg/Feature/
SmmAccess/Library/PeiSmmAccessLib/PeiSmmAccessLib.inf.

Next patch will refine the OVMF SMM Access to consume
the EFI_SMM_SMRAM_MEMORY_GUID HOB.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Ray Ni <ray.ni@intel.com>
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>

2 files changed, 90 insertions, 40 deletions

diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
index 7b6e5102ad..19abb16e79 100644
--- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c
+++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
@@ -1,7 +1,7 @@
 /**@file

   Memory Detection for Virtual Machines.

 

-  Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>

+  Copyright (c) 2006 - 2024, Intel Corporation. All rights reserved.<BR>

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

 

 Module Name:

@@ -42,6 +42,7 @@ Module Name:
 #include <Library/TdxLib.h>

 

 #include <Library/PlatformInitLib.h>

+#include <Guid/SmramMemoryReserve.h>

 

 #define MEGABYTE_SHIFT  20

 

@@ -982,6 +983,57 @@ PlatformAddressWidthInitialization (
   PlatformInfoHob->PhysMemAddressWidth = PhysMemAddressWidth;

 }

 

+/**

+  Create gEfiSmmSmramMemoryGuid HOB defined in the PI specification Vol. 3,

+  section 5, which is used to describe the SMRAM memory regions supported

+  by the platform.

+

+  @param[in] StartAddress      StartAddress of smram.

+  @param[in] Size              Size of smram.

+

+**/

+STATIC

+VOID

+CreateSmmSmramMemoryHob (

+  IN EFI_PHYSICAL_ADDRESS  StartAddress,

+  IN UINT32                Size

+  )

+{

+  UINTN                           BufferSize;

+  UINT8                           SmramRanges;

+  EFI_PEI_HOB_POINTERS            Hob;

+  EFI_SMRAM_HOB_DESCRIPTOR_BLOCK  *SmramHobDescriptorBlock;

+

+  SmramRanges = 2;

+  BufferSize  = sizeof (EFI_SMRAM_HOB_DESCRIPTOR_BLOCK) + (SmramRanges - 1) * sizeof (EFI_SMRAM_DESCRIPTOR);

+

+  Hob.Raw = BuildGuidHob (

+              &gEfiSmmSmramMemoryGuid,

+              BufferSize

+              );

+  ASSERT (Hob.Raw);

+

+  SmramHobDescriptorBlock                             = (EFI_SMRAM_HOB_DESCRIPTOR_BLOCK *)(Hob.Raw);

+  SmramHobDescriptorBlock->NumberOfSmmReservedRegions = SmramRanges;

+

+  //

+  // 1. Create first SMRAM descriptor, which contains data structures used in S3 resume.

+  // One page is enough for the data structure

+  //

+  SmramHobDescriptorBlock->Descriptor[0].PhysicalStart = StartAddress;

+  SmramHobDescriptorBlock->Descriptor[0].CpuStart      = StartAddress;

+  SmramHobDescriptorBlock->Descriptor[0].PhysicalSize  = EFI_PAGE_SIZE;

+  SmramHobDescriptorBlock->Descriptor[0].RegionState   = EFI_SMRAM_CLOSED | EFI_CACHEABLE | EFI_ALLOCATED;

+

+  //

+  // 2. Create second SMRAM descriptor, which is free and will be used by SMM foundation.

+  //

+  SmramHobDescriptorBlock->Descriptor[1].PhysicalStart = SmramHobDescriptorBlock->Descriptor[0].PhysicalStart + EFI_PAGE_SIZE;

+  SmramHobDescriptorBlock->Descriptor[1].CpuStart      = SmramHobDescriptorBlock->Descriptor[0].CpuStart + EFI_PAGE_SIZE;

+  SmramHobDescriptorBlock->Descriptor[1].PhysicalSize  = Size - EFI_PAGE_SIZE;

+  SmramHobDescriptorBlock->Descriptor[1].RegionState   = EFI_SMRAM_CLOSED | EFI_CACHEABLE;

+}

+

 STATIC

 VOID

 QemuInitializeRamBelow1gb (

@@ -1029,48 +1081,43 @@ PlatformQemuInitializeRam (
   //

   PlatformGetSystemMemorySizeBelow4gb (PlatformInfoHob);

 

-  if (PlatformInfoHob->BootMode == BOOT_ON_S3_RESUME) {

-    //

-    // Create the following memory HOB as an exception on the S3 boot path.

-    //

-    // Normally we'd create memory HOBs only on the normal boot path. However,

-    // CpuMpPei specifically needs such a low-memory HOB on the S3 path as

-    // well, for "borrowing" a subset of it temporarily, for the AP startup

-    // vector.

-    //

-    // CpuMpPei saves the original contents of the borrowed area in permanent

-    // PEI RAM, in a backup buffer allocated with the normal PEI services.

-    // CpuMpPei restores the original contents ("returns" the borrowed area) at

-    // End-of-PEI. End-of-PEI in turn is emitted by S3Resume2Pei before

-    // transferring control to the OS's wakeup vector in the FACS.

+  //

+  // CpuMpPei saves the original contents of the borrowed area in permanent

+  // PEI RAM, in a backup buffer allocated with the normal PEI services.

+  // CpuMpPei restores the original contents ("returns" the borrowed area) at

+  // End-of-PEI. End-of-PEI in turn is emitted by S3Resume2Pei before

+  // transferring control to the OS's wakeup vector in the FACS.

+  //

+  // We expect any other PEIMs that "borrow" memory similarly to CpuMpPei to

+  // restore the original contents. Furthermore, we expect all such PEIMs

+  // (CpuMpPei included) to claim the borrowed areas by producing memory

+  // allocation HOBs, and to honor preexistent memory allocation HOBs when

+  // looking for an area to borrow.

+  //

+  QemuInitializeRamBelow1gb (PlatformInfoHob);

+

+  if (PlatformInfoHob->SmmSmramRequire) {

+    UINT32                TsegSize;

+    EFI_PHYSICAL_ADDRESS  TsegBase;

+

+    TsegSize = PlatformInfoHob->Q35TsegMbytes * SIZE_1MB;

+    TsegBase = PlatformInfoHob->LowMemory - TsegSize;

+    PlatformAddMemoryRangeHob (BASE_1MB, TsegBase);

+    PlatformAddReservedMemoryBaseSizeHob (

+      TsegBase,

+      TsegSize,

+      TRUE

+      );

+

     //

-    // We expect any other PEIMs that "borrow" memory similarly to CpuMpPei to

-    // restore the original contents. Furthermore, we expect all such PEIMs

-    // (CpuMpPei included) to claim the borrowed areas by producing memory

-    // allocation HOBs, and to honor preexistent memory allocation HOBs when

-    // looking for an area to borrow.

+    // Create gEfiSmmSmramMemoryGuid HOB

     //

-    QemuInitializeRamBelow1gb (PlatformInfoHob);

+    CreateSmmSmramMemoryHob (TsegBase, TsegSize);

   } else {

-    //

-    // Create memory HOBs

-    //

-    QemuInitializeRamBelow1gb (PlatformInfoHob);

-

-    if (PlatformInfoHob->SmmSmramRequire) {

-      UINT32  TsegSize;

-

-      TsegSize = PlatformInfoHob->Q35TsegMbytes * SIZE_1MB;

-      PlatformAddMemoryRangeHob (BASE_1MB, PlatformInfoHob->LowMemory - TsegSize);

-      PlatformAddReservedMemoryBaseSizeHob (

-        PlatformInfoHob->LowMemory - TsegSize,

-        TsegSize,

-        TRUE

-        );

-    } else {

-      PlatformAddMemoryRangeHob (BASE_1MB, PlatformInfoHob->LowMemory);

-    }

+    PlatformAddMemoryRangeHob (BASE_1MB, PlatformInfoHob->LowMemory);

+  }

 

+  if (PlatformInfoHob->BootMode != BOOT_ON_S3_RESUME) {

     //

     // If QEMU presents an E820 map, then create memory HOBs for the >=4GB RAM

     // entries. Otherwise, create a single memory HOB with the flat >=4GB

diff --git a/OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf b/OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf
index 5a79d95b68..2bb1c0296f 100644
--- a/OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf
+++ b/OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf
@@ -2,7 +2,7 @@
 #  Platform Initialization Lib

 #

 #  This module provides platform specific function to detect boot mode.

-#  Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>

+#  Copyright (c) 2006 - 2024, Intel Corporation. All rights reserved.<BR>

 #

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

 #

@@ -56,6 +56,9 @@
 [LibraryClasses.X64]

   TdxLib

 

+[Guids]

+  gEfiSmmSmramMemoryGuid

+

 [Pcd]

   gEfiMdePkgTokenSpaceGuid.PcdPciExpressBaseAddress

   gEfiMdeModulePkgTokenSpaceGuid.PcdUse1GPageTable