diff --git a/OvmfPkg/Include/Library/PlatformInitLib.h b/OvmfPkg/Include/Library/PlatformInitLib.h
index 6152a43d0d..2987a367cc 100644
--- a/OvmfPkg/Include/Library/PlatformInitLib.h
+++ b/OvmfPkg/Include/Library/PlatformInitLib.h
@@ -220,4 +220,18 @@ ProcessTdxHobList (
   VOID
   );
 
+/**
+  In Tdx guest, the system memory is passed in TdHob by host VMM. So
+  the major task of PlatformTdxPublishRamRegions is to walk thru the
+  TdHob list and transfer the ResourceDescriptorHob and MemoryAllocationHob
+  to the hobs in DXE phase.
+
+  MemoryAllocationHob should also be created for Mailbox and Ovmf work area.
+**/
+VOID
+EFIAPI
+PlatformTdxPublishRamRegions (
+  VOID
+  );
+
 #endif // PLATFORM_INIT_LIB_H_
diff --git a/OvmfPkg/Library/PlatformInitLib/IntelTdx.c b/OvmfPkg/Library/PlatformInitLib/IntelTdx.c
index e9196b7ffa..c6d7c8bb6e 100644
--- a/OvmfPkg/Library/PlatformInitLib/IntelTdx.c
+++ b/OvmfPkg/Library/PlatformInitLib/IntelTdx.c
@@ -512,3 +512,52 @@ TransferTdxHobList (
     Hob.Raw = GET_NEXT_HOB (Hob);
   }
 }
+
+/**
+  In Tdx guest, the system memory is passed in TdHob by host VMM. So
+  the major task of PlatformTdxPublishRamRegions is to walk thru the
+  TdHob list and transfer the ResourceDescriptorHob and MemoryAllocationHob
+  to the hobs in DXE phase.
+
+  MemoryAllocationHob should also be created for Mailbox and Ovmf work area.
+**/
+VOID
+EFIAPI
+PlatformTdxPublishRamRegions (
+  VOID
+  )
+{
+  if (!TdIsEnabled ()) {
+    return;
+  }
+
+  TransferTdxHobList ();
+
+  //
+  // The memory region defined by PcdOvmfSecGhcbBackupBase is pre-allocated by
+  // host VMM and used as the td mailbox at the beginning of system boot.
+  //
+  BuildMemoryAllocationHob (
+    FixedPcdGet32 (PcdOvmfSecGhcbBackupBase),
+    FixedPcdGet32 (PcdOvmfSecGhcbBackupSize),
+    EfiACPIMemoryNVS
+    );
+
+  if (FixedPcdGet32 (PcdOvmfWorkAreaSize) != 0) {
+    //
+    // Reserve the work area.
+    //
+    // Since this memory range will be used by the Reset Vector on S3
+    // resume, it must be reserved as ACPI NVS.
+    //
+    // If S3 is unsupported, then various drivers might still write to the
+    // work area. We ought to prevent DXE from serving allocation requests
+    // such that they would overlap the work area.
+    //
+    BuildMemoryAllocationHob (
+      (EFI_PHYSICAL_ADDRESS)(UINTN)FixedPcdGet32 (PcdOvmfWorkAreaBase),
+      (UINT64)(UINTN)FixedPcdGet32 (PcdOvmfWorkAreaSize),
+      EfiBootServicesData
+      );
+  }
+}
diff --git a/OvmfPkg/Library/PlatformInitLib/IntelTdxNull.c b/OvmfPkg/Library/PlatformInitLib/IntelTdxNull.c
index af90e0866e..3ebe582af8 100644
--- a/OvmfPkg/Library/PlatformInitLib/IntelTdxNull.c
+++ b/OvmfPkg/Library/PlatformInitLib/IntelTdxNull.c
@@ -28,3 +28,19 @@ ProcessTdxHobList (
 {
   return EFI_UNSUPPORTED;
 }
+
+/**
+  In Tdx guest, the system memory is passed in TdHob by host VMM. So
+  the major task of PlatformTdxPublishRamRegions is to walk thru the
+  TdHob list and transfer the ResourceDescriptorHob and MemoryAllocationHob
+  to the hobs in DXE phase.
+
+  MemoryAllocationHob should also be created for Mailbox and Ovmf work area.
+**/
+VOID
+EFIAPI
+PlatformTdxPublishRamRegions (
+  VOID
+  )
+{
+}
diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
index 911c0906cb..4c1dedf863 100644
--- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c
+++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
@@ -37,6 +37,8 @@ Module Name:
 #include <Library/MtrrLib.h>
 #include <Library/QemuFwCfgLib.h>
 #include <Library/QemuFwCfgSimpleParserLib.h>
+#include <Library/TdxLib.h>
+
 #include <Library/PlatformInitLib.h>
 
 VOID
@@ -528,7 +530,19 @@ PlatformAddressWidthInitialization (
     PhysMemAddressWidth = 36;
   }
 
+ #if defined (MDE_CPU_X64)
+  if (TdIsEnabled ()) {
+    if (TdSharedPageMask () == (1ULL << 47)) {
+      PhysMemAddressWidth = 48;
+    } else {
+      PhysMemAddressWidth = 52;
+    }
+  }
+
+  ASSERT (PhysMemAddressWidth <= 52);
+ #else
   ASSERT (PhysMemAddressWidth <= 48);
+ #endif
 
   PlatformInfoHob->FirstNonAddress     = FirstNonAddress;
   PlatformInfoHob->PhysMemAddressWidth = PhysMemAddressWidth;
diff --git a/OvmfPkg/Library/PlatformInitLib/Platform.c b/OvmfPkg/Library/PlatformInitLib/Platform.c
index c4fa7d4453..101074f610 100644
--- a/OvmfPkg/Library/PlatformInitLib/Platform.c
+++ b/OvmfPkg/Library/PlatformInitLib/Platform.c
@@ -136,7 +136,9 @@ PlatformMemMapInitialization (
   //
   // Video memory + Legacy BIOS region
   //
-  PlatformAddIoMemoryRangeHob (0x0A0000, BASE_1MB);
+  if (!TdIsEnabled ()) {
+    PlatformAddIoMemoryRangeHob (0x0A0000, BASE_1MB);
+  }
 
   if (PlatformInfoHob->HostBridgeDevId == 0xffff /* microvm */) {
     PlatformAddIoMemoryBaseSizeHob (MICROVM_GED_MMIO_BASE, SIZE_4KB);