1 files changed, 124 insertions, 0 deletions
diff --git a/OvmfPkg/PlatformPei/PlatformId.c b/OvmfPkg/PlatformPei/PlatformId.c
new file mode 100644
index 0000000000..afa2f811d9
--- /dev/null
+++ b/OvmfPkg/PlatformPei/PlatformId.c
@@ -0,0 +1,124 @@
+/**@file
+  PlatformId Event HOB creation
+
+  Copyright (c) 2024, Google LLC. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Base.h>
+#include <Guid/TcgEventHob.h>
+#include <IndustryStandard/UefiTcgPlatform.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/HobLib.h>
+#include <Library/PeiServicesLib.h>
+#include <Library/PrintLib.h>
+#include <Library/QemuFwCfgLib.h>
+
+#define DPREFIX  "sp800155evts: "
+
+/**
+ * Creates an EFI_HOB_TYPE_GUID_EXTENSION HOB for a given SP800155 event.
+ * Associates the string data with gTcg800155PlatformIdEventHobGuid. Any
+ * unused bytes or out-of-bounds event sizes are considered corrupted and
+ * are discarded.
+**/
+STATIC
+VOID
+PlatformIdRegisterSp800155 (
+  IN CONST EFI_PEI_SERVICES  **PeiServices,
+  IN       UINT8             *Evt,
+  IN       UINTN             EvtSize
+  )
+{
+  EFI_STATUS         Status;
+  VOID               *Hob;
+  EFI_HOB_GUID_TYPE  *GuidHob;
+  UINT8              *EvtDest;
+
+  Status = (*PeiServices)->CreateHob (
+                             PeiServices,
+                             EFI_HOB_TYPE_GUID_EXTENSION,
+                             sizeof (EFI_HOB_GUID_TYPE) + (UINT16)EvtSize,
+                             &Hob
+                             );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, DPREFIX "GUID HOB creation failed, skipping\n"));
+    return;
+  }
+
+  GuidHob = (EFI_HOB_GUID_TYPE *)Hob;
+  CopyGuid (&GuidHob->Name, &gTcg800155PlatformIdEventHobGuid);
+  EvtDest = (UINT8 *)GET_GUID_HOB_DATA (Hob);
+  CopyMem (EvtDest, Evt, EvtSize);
+  // Fill the remaining HOB padding bytes with 0s.
+  SetMem (EvtDest + EvtSize, GET_GUID_HOB_DATA_SIZE (Hob) - EvtSize, 0);
+}
+
+/**
+ * Reads the given path from the fw_cfg file and registers it as an
+ * EFI_HOB_GUID_EXTENSION HOB with gTcg800155PlatformIdEventHobGuid.
+ * Returns FALSE iff the file does not exist.
+**/
+BOOLEAN
+PlatformIdRegisterEvent (
+  IN CONST EFI_PEI_SERVICES  **PeiServices,
+  IN CONST CHAR8             *Path
+  )
+{
+  EFI_STATUS            Status;
+  UINTN                 NumPages;
+  EFI_PHYSICAL_ADDRESS  Pages;
+  FIRMWARE_CONFIG_ITEM  FdtItem;
+  UINTN                 FdtSize;
+  UINT8                 *Evt;
+
+  Status = QemuFwCfgFindFile (Path, &FdtItem, &FdtSize);
+  if (EFI_ERROR (Status)) {
+    return FALSE;
+  }
+
+  if (FdtSize > MAX_UINT16 - sizeof (EFI_HOB_GUID_TYPE)) {
+    DEBUG ((DEBUG_ERROR, DPREFIX "Eventdata too large for HOB, skipping\n"));
+    return TRUE;
+  }
+
+  NumPages = EFI_SIZE_TO_PAGES (FdtSize);
+  Status   = (*PeiServices)->AllocatePages (
+                               PeiServices,
+                               EfiBootServicesData,
+                               NumPages,
+                               &Pages
+                               );
+  if (EFI_ERROR (Status)) {
+    return TRUE;
+  }
+
+  Evt = (UINT8 *)(UINTN)Pages;
+  QemuFwCfgSelectItem (FdtItem);
+  QemuFwCfgReadBytes (FdtSize, Evt);
+  PlatformIdRegisterSp800155 (PeiServices, Evt, FdtSize);
+
+  Status = (*PeiServices)->FreePages (PeiServices, Pages, NumPages);
+  ASSERT_EFI_ERROR (Status);
+  return TRUE;
+}
+
+VOID
+PlatformIdInitialization (
+  IN CONST EFI_PEI_SERVICES  **PeiServices
+  )
+{
+  UINTN  Index;
+  CHAR8  Path[64];
+
+  for (Index = 0; ; Index++) {
+    AsciiSPrint (Path, sizeof (Path), "opt/org.tianocode/sp800155evt/%d", Index);
+    if (!PlatformIdRegisterEvent (PeiServices, Path)) {
+      break;
+    }
+  }
+}