diff --git a/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciHostBridge.c b/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciHostBridge.c
index e3d3988..9fa3f84 100644
--- a/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciHostBridge.c
+++ b/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciHostBridge.c
@@ -839,6 +839,7 @@ NotifyPhase(
 
   case EfiPciHostBridgeEndEnumeration:
     PCIE_DEBUG("Case EfiPciHostBridgeEndEnumeration\n");
+    EnlargeAtuConfig0 (This);
     break;
 
   case EfiPciHostBridgeBeginBusAllocation:
diff --git a/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciHostBridge.h b/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciHostBridge.h
index cddda6b..c04361f 100644
--- a/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciHostBridge.h
+++ b/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciHostBridge.h
@@ -401,6 +401,9 @@ PreprocessController (
 #define EFI_RESOURCE_NONEXISTENT   0xFFFFFFFFFFFFFFFFULL
 #define EFI_RESOURCE_LESS          0xFFFFFFFFFFFFFFFEULL
 
+#define	INVALID_CAPABILITY_00       0x00
+#define	INVALID_CAPABILITY_FF       0xFF
+#define	PCI_CAPABILITY_POINTER_MASK 0xFC
 
 //
 // Driver Instance Data Prototypes
@@ -518,4 +521,8 @@ RootBridgeConstructor (
   IN UINT32                             Seg
   );
 
+VOID
+EnlargeAtuConfig0 (
+  IN EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL *This
+  );
 #endif
diff --git a/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciRootBridgeIo.c b/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciRootBridgeIo.c
index 10d766a..b57bd51 100644
--- a/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciRootBridgeIo.c
+++ b/Silicon/Hisilicon/Drivers/PciHostBridgeDxe/PciRootBridgeIo.c
@@ -14,6 +14,7 @@
  **/
 
 #include "PciHostBridge.h"
+#include <IndustryStandard/PciExpress30.h>
 #include <Library/DevicePathLib.h>
 #include <Library/DmaLib.h>
 #include <Library/PciExpressLib.h>
@@ -2322,3 +2323,81 @@ RootBridgeIoConfiguration (
   return EFI_SUCCESS;
 }
 
+BOOLEAN
+PcieCheckAriFwdEn (
+  UINTN  PciBaseAddr
+  )
+{
+  UINT8   PciPrimaryStatus;
+  UINT8   CapabilityOffset;
+  UINT8   CapId;
+  UINT8   TempData;
+
+  PciPrimaryStatus = MmioRead16 (PciBaseAddr + PCI_PRIMARY_STATUS_OFFSET);
+
+  if (PciPrimaryStatus & EFI_PCI_STATUS_CAPABILITY) {
+    CapabilityOffset = MmioRead8 (PciBaseAddr + PCI_CAPBILITY_POINTER_OFFSET);
+    CapabilityOffset &= PCI_CAPABILITY_POINTER_MASK;
+
+    while ((CapabilityOffset != INVALID_CAPABILITY_00) && (CapabilityOffset != INVALID_CAPABILITY_FF)) {
+      CapId = MmioRead8 (PciBaseAddr + CapabilityOffset);
+      if (CapId == EFI_PCI_CAPABILITY_ID_PCIEXP) {
+        break;
+      }
+      CapabilityOffset = MmioRead8 (PciBaseAddr + CapabilityOffset + 1);
+      CapabilityOffset &= PCI_CAPABILITY_POINTER_MASK;
+    }
+  } else {
+    PCIE_DEBUG ("[%a:%d] - No PCIE Capability.\n", __FUNCTION__, __LINE__);
+    return FALSE;
+  }
+
+  if ((CapabilityOffset == INVALID_CAPABILITY_FF) || (CapabilityOffset == INVALID_CAPABILITY_00)) {
+    PCIE_DEBUG ("[%a:%d] - No PCIE Capability.\n", __FUNCTION__, __LINE__);
+    return FALSE;
+  }
+
+  TempData = MmioRead16 (PciBaseAddr + CapabilityOffset +
+                          EFI_PCIE_CAPABILITY_DEVICE_CONTROL_2_OFFSET);
+  TempData &= EFI_PCIE_CAPABILITY_DEVICE_CAPABILITIES_2_ARI_FORWARDING;
+
+  if (TempData == EFI_PCIE_CAPABILITY_DEVICE_CAPABILITIES_2_ARI_FORWARDING) {
+    return TRUE;
+  } else {
+    return FALSE;
+  }
+}
+
+VOID
+EnlargeAtuConfig0 (
+  IN EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL *This
+  )
+{
+  UINTN                           RbPciBase;
+  UINT64                          MemLimit;
+  LIST_ENTRY                      *List;
+  PCI_HOST_BRIDGE_INSTANCE        *HostBridgeInstance;
+  PCI_ROOT_BRIDGE_INSTANCE        *RootBridgeInstance;
+
+  PCIE_DEBUG ("In Enlarge RP iatu Config 0.\n");
+
+  HostBridgeInstance = INSTANCE_FROM_RESOURCE_ALLOCATION_THIS (This);
+  List = HostBridgeInstance->Head.ForwardLink;
+
+  while (List != &HostBridgeInstance->Head) {
+    PCIE_DEBUG ("HostBridge has data.\n");
+    RootBridgeInstance = DRIVER_INSTANCE_FROM_LIST_ENTRY (List);
+
+    RbPciBase = RootBridgeInstance->RbPciBar;
+
+    // Those ARI FWD Enable Root Bridge, need enlarge iatu window.
+    if (PcieCheckAriFwdEn (RbPciBase)) {
+      MemLimit = GetPcieCfgAddress (RootBridgeInstance->Ecam,
+                                    RootBridgeInstance->BusBase + 2, 0, 0, 0)
+	               - 1;
+      MmioWrite32 (RbPciBase + IATU_OFFSET + IATU_VIEW_POINT, 1);
+      MmioWrite32 (RbPciBase + IATU_OFFSET + IATU_REGION_BASE_LIMIT, (UINT32) MemLimit);
+    }
+    List = List->ForwardLink;
+  }
+}
