1 files changed, 89 insertions, 0 deletions
diff --git a/OvmfPkg/Library/MemDebugLogLib/MemDebugLogPei.c b/OvmfPkg/Library/MemDebugLogLib/MemDebugLogPei.c
new file mode 100644
index 0000000..cbdab6c
--- /dev/null
+++ b/OvmfPkg/Library/MemDebugLogLib/MemDebugLogPei.c
@@ -0,0 +1,89 @@
+/** @file
+ *
+  Memory Debug Log Library - PEI Phase
+
+  Copyright (C) 2025, Oracle and/or its affiliates.
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <PiPei.h>
+#include <Library/PeiServicesLib.h>
+#include <Library/QemuFwCfgSimpleParserLib.h>
+#include <Library/MemDebugLogLib.h>
+
+EFI_PHYSICAL_ADDRESS  mMemDebugLogBufAddr;
+BOOLEAN               mMemDebugLogBufAddrInit;
+
+EFI_STATUS
+EFIAPI
+MemDebugLogWrite (
+  IN  CHAR8  *Buffer,
+  IN  UINTN  Length
+  )
+{
+  EFI_STATUS  Status;
+
+  if (!mMemDebugLogBufAddrInit) {
+    //
+    // Obtain the Memory Debug Log buffer addr from HOB
+    // NOTE: This is expected to fail until the HOB is created.
+    //
+    Status = MemDebugLogAddrFromHOB (&mMemDebugLogBufAddr);
+    if (EFI_ERROR (Status)) {
+      mMemDebugLogBufAddr = 0;
+    } else {
+      mMemDebugLogBufAddrInit = TRUE;
+    }
+  }
+
+  if (mMemDebugLogBufAddr) {
+    Status = MemDebugLogWriteBuffer (mMemDebugLogBufAddr, Buffer, Length);
+  } else {
+    //
+    // HOB has not yet been created, so
+    // write to the early debug log buffer.
+    //
+    if (FixedPcdGet32 (PcdOvmfEarlyMemDebugLogBase) != 0x0) {
+      Status = MemDebugLogWriteBuffer (
+                 (EFI_PHYSICAL_ADDRESS)(UINTN)FixedPcdGet32 (PcdOvmfEarlyMemDebugLogBase),
+                 Buffer,
+                 Length
+                 );
+    } else {
+      Status = EFI_NOT_FOUND;
+    }
+  }
+
+  return Status;
+}
+
+UINT32
+EFIAPI
+MemDebugLogPages (
+  VOID
+  )
+{
+  UINT32      FwCfg_MemDebugLogPages;
+  UINT32      MemDebugLogBufPages;
+  EFI_STATUS  Status;
+
+  //
+  // Allow FwCfg value to override Pcd.
+  //
+  Status = QemuFwCfgParseUint32 ("opt/ovmf/MemDebugLogPages", TRUE, &FwCfg_MemDebugLogPages);
+  if (Status == EFI_SUCCESS) {
+    MemDebugLogBufPages = FwCfg_MemDebugLogPages;
+  } else {
+    MemDebugLogBufPages = FixedPcdGet32 (PcdMemDebugLogPages);
+  }
+
+  //
+  // Cap max memory debug log size at MAX_MEM_DEBUG_LOG_PAGES
+  //
+  if (MemDebugLogBufPages > MAX_MEM_DEBUG_LOG_PAGES) {
+    MemDebugLogBufPages = MAX_MEM_DEBUG_LOG_PAGES;
+  }
+
+  return MemDebugLogBufPages;
+}