Re: [edk2-devel] [PATCH v1 08/13] OvmfPkg/PlatformInitLib: Create gEfiSmmSmramMemoryGuid

["Ni, Ray" <ray.ni@intel.com>]

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I think the commit message can have more details to help OVMF developers understand the needs of this patch.
E.g.:
  Before using SmmRelocationLib, the PiSmmCpuDxeSmm driver allocates the SMRAM to be used for SMI handler + save state area of each processor from Smst->AllocatePages().
  With SmmRelocationLib, the SMRAM allocation for SMI handlers and save state areas is moved to early PEI phase when the Smst->AllocatePages() service is not available. So, the allocation is done by
  splitting the SMRAM out of the SMRAM regions reported from Guid HOB (gEfiSmmSMramMemoryGuid).
  However, OVMF platform does not produce the GUID HOB. This patch produces the HOB......

Thanks,
Ray

________________________________
From: Wu, Jiaxin <jiaxin.wu@intel.com>
Sent: Wednesday, April 10, 2024 21:57
To: devel@edk2.groups.io <devel@edk2.groups.io>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>; Yao, Jiewen <jiewen.yao@intel.com>; Gerd Hoffmann <kraxel@redhat.com>; Ni, Ray <ray.ni@intel.com>
Subject: [PATCH v1 08/13] OvmfPkg/PlatformInitLib: Create gEfiSmmSmramMemoryGuid

SmmRelocationLib instance will reserve the memory from
gEfiSmmSmramMemoryGuid for the smbase relocation.

So, system must produce the gEfiSmmSmramMemoryGuid.

This patch is for the OVMF to produce the
gEfiSmmSmramMemoryGuid 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>
---
 OvmfPkg/Library/PlatformInitLib/MemDetect.c        | 97 +++++++++++++---------
 .../Library/PlatformInitLib/PlatformInitLib.inf    |  5 +-
 2 files changed, 64 insertions(+), 38 deletions(-)

diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
index 7b6e5102ad..8b98256225 100644
--- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c
+++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
@@ -1,9 +1,9 @@
 /**@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:

   MemDetect.c
@@ -41,10 +41,12 @@ Module Name:
 #include <Library/QemuFwCfgSimpleParserLib.h>
 #include <Library/TdxLib.h>

 #include <Library/PlatformInitLib.h>

+#include <Guid/SmramMemoryReserve.h>
+
 #define MEGABYTE_SHIFT  20

 VOID
 EFIAPI
 PlatformQemuUc32BaseInitialization (
@@ -1027,52 +1029,73 @@ PlatformQemuInitializeRam (
   //
   // Determine total memory size available
   //
   PlatformGetSystemMemorySizeBelow4gb (PlatformInfoHob);

-  if (PlatformInfoHob->BootMode == BOOT_ON_S3_RESUME) {
-    //
-    // Create the following memory HOB as an exception on the S3 boot path.
+  //
+  // 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;
+    UINTN                           BufferSize;
+    UINT8                           SmramRanges;
+    EFI_PEI_HOB_POINTERS            Hob;
+    EFI_SMRAM_HOB_DESCRIPTOR_BLOCK  *SmramHobDescriptorBlock;
+
+    TsegSize = PlatformInfoHob->Q35TsegMbytes * SIZE_1MB;
+    PlatformAddMemoryRangeHob (BASE_1MB, PlatformInfoHob->LowMemory - TsegSize);
+    PlatformAddReservedMemoryBaseSizeHob (
+      PlatformInfoHob->LowMemory - TsegSize,
+      TsegSize,
+      TRUE
+      );
+
+    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;
+
     //
-    // 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.
+    // Create first SMRAM descriptor, which contains data structures used in S3 resume.
+    // One page is enough for the data structure
     //
-    // 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.
+    SmramHobDescriptorBlock->Descriptor[0].PhysicalStart = PlatformInfoHob->LowMemory - TsegSize;
+    SmramHobDescriptorBlock->Descriptor[0].CpuStart      = PlatformInfoHob->LowMemory - TsegSize;
+    SmramHobDescriptorBlock->Descriptor[0].PhysicalSize  = EFI_PAGE_SIZE;
+    SmramHobDescriptorBlock->Descriptor[0].RegionState   = EFI_SMRAM_CLOSED | EFI_CACHEABLE | EFI_ALLOCATED;
+
     //
-    // 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 second SMRAM descriptor, which is free and will be used by SMM foundation.
     //
-    QemuInitializeRamBelow1gb (PlatformInfoHob);
+    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  = TsegSize - EFI_PAGE_SIZE;
+    SmramHobDescriptorBlock->Descriptor[1].RegionState   = EFI_SMRAM_CLOSED | EFI_CACHEABLE;
   } 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
     // memory size read from the CMOS.
     //
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
@@ -1,10 +1,10 @@
 ## @file
 #  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
 #
 ##

@@ -54,10 +54,13 @@
   PeiHardwareInfoLib

 [LibraryClasses.X64]
   TdxLib

+[Guids]
+  gEfiSmmSmramMemoryGuid
+
 [Pcd]
   gEfiMdePkgTokenSpaceGuid.PcdPciExpressBaseAddress
   gEfiMdeModulePkgTokenSpaceGuid.PcdUse1GPageTable

 [FixedPcd]
--
2.16.2.windows.1



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