Re: [RFC v4 1/3] MdeModulePkg/PciHostBridgeDxe: Add support for address translation

[Guo Heyi <heyi.guo@linaro.org>]

Hi Ray,

Thanks for your comments. It seems comments 10 and 12 are the major issue; let's
discuss that first.

1. In current implementation, namely PciBusDxe and PciHostBridgeDxe both in
MdeModulePkg, Address parameter passed to RootBridgeIoMemRead comes from
PciIoMemRead().
2. In PciIoMemRead(), Offset is only an offset within selected BAR; then
PciIoDevice->PciBar[BarIndex].BaseAddress is added to Offset in
PciIoVerifyBarAccess().
3. So whether the "Address" passed to RootBridgeIoMemRead() is host address or
device address depends on the property of
PciIoDevice->PciBar[BarIndex].BaseAddress.
4. In PciBusDxe, we can see PciIoDevice->PciBar[BarIndex].BaseAddress simply
comes from the value read from BAR register, which is absolutely a device
address.
5. What we do in patch 3/3 is also to convert the device address in
PciBar[BarIndex].BaseAddress to host address before returning to the caller of
PciIoGetBarAttributes().

Please let me know your comments.

For other comments, I have no strong opinion and I can follow the conclusion of
the community.

Thanks and regards,

Heyi

On Tue, Feb 27, 2018 at 04:48:47PM +0800, Ni, Ruiyu wrote:
> On 2/27/2018 10:09 AM, Heyi Guo wrote:
> >PCI address translation is necessary for some non-x86 platforms. On
> >such platforms, address value (denoted as "device address" or "address
> >in PCI view") set to PCI BAR registers in configuration space might be
> >different from the address which is used by CPU to access the
> >registers in memory BAR or IO BAR spaces (denoted as "host address" or
> >"address in CPU view"). The difference between the two addresses is
> >called "Address Translation Offset" or simply "translation", and can
> >be represented by "Address Translation Offset" in ACPI QWORD Address
> >Space Descriptor (Offset 0x1E). However UEFI and ACPI differs on the
> >definitions of QWORD Address Space Descriptor, and we will follow UEFI
> >definition on UEFI protocols, such as PCI root bridge IO protocol and
> >PCI IO protocol. In UEFI 2.7, "Address Translation Offset" is "Offset
> >to apply to the Starting address to convert it to a PCI address". This
> >means:
> >
> >1. Translation = device address - host address.
> >
> >2. PciRootBridgeIo->Configuration should return CPU view address, as
> >well as PciIo->GetBarAttributes.
> >
> >Summary of addresses used:
> >
> >1. Base and Limit in PCI_ROOT_BRIDGE_APERTURE are device address, for
> >it is easy to check whether the address is below 4G or above 4G.
> >
> >2. Address returned by
> >EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL::GetProposedResources
> >is device address, or else PCI bus driver cannot set correct address
> >into PCI BAR registers.
> >
> >3. Address returned by PciRootBridgeIo->Configuration is host address
> >per UEFI 2.7 definition.
> >
> >4. Addresses used in GCD manipulation are host address.
> >
> >5. Addresses in ResAllocNode of PCI_ROOT_BRIDGE_INSTANCE are host
> >address, for they are allocated from GCD.
> >
> >6. Address passed to PciHostBridgeResourceConflict is host address,
> >for it comes from ResAllocNode.
> >
> >RESTRICTION: to simplify the situation, we require the alignment of
> >Translation must be larger than any BAR alignment in the same root
> >bridge, so that resource allocation alignment can be applied to both
> >device address and host address.
> (1). I'd like to see this restriction be reflected in code.
> Both assertion and if-check are needed to ensure debug firmware hang
> and release firmware return fail status from PciHostBridge driver.
> 
> >
> >Contributed-under: TianoCore Contribution Agreement 1.1
> >Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
> >Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> >Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> >Cc: Star Zeng <star.zeng@intel.com>
> >Cc: Eric Dong <eric.dong@intel.com>
> >Cc: Laszlo Ersek <lersek@redhat.com>
> >Cc: Michael D Kinney <michael.d.kinney@intel.com>
> >---
> >
> >Notes:
> >     v4:
> >     - Add ASSERT (FALSE) to default branch in GetTranslationByResourceType
> >       [Laszlo]
> >     - Fix bug when passing BaseAddress to gDS->AllocateIoSpace and
> >       gDS->AllocateMemorySpace [Laszlo]
> >     - Add comment for applying alignment to both device address and host
> >       address, and add NOTE for the alignment requirement of Translation,
> >       as well as in commit message [Laszlo][Ray]
> >     - Improve indention for the code in CreateRootBridge [Laszlo]
> >     - Improve comment for Translation in PCI_ROOT_BRIDGE_APERTURE
> >       definition [Laszlo]
> >     - Ignore translation of bus in CreateRootBridge
> >
> >  MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostResource.h |   2 +
> >  MdeModulePkg/Include/Library/PciHostBridgeLib.h         |  14 +++
> >  MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c   |  85 +++++++++++---
> >  MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c | 122 +++++++++++++++++---
> >  4 files changed, 194 insertions(+), 29 deletions(-)
> >
> >diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostResource.h b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostResource.h
> >index 8612c0c3251b..662c2dd59529 100644
> >--- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostResource.h
> >+++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostResource.h
> >@@ -38,6 +38,8 @@ typedef enum {
> >  typedef struct {
> >    PCI_RESOURCE_TYPE Type;
> >+  // Base is a host address instead of a device address when address translation
> >+  // exists and host address != device address
> (2). Coding style issue. The comments need to be in style like:
> //[EMPTY]
> // xxxx
> //[EMPTY]
> And how about just simply say Base is a host address. No matter address
> translation exists or not, Base is a host address actually.
> 
> >    UINT64            Base;
> >    UINT64            Length;
> >    UINT64            Alignment;
> >diff --git a/MdeModulePkg/Include/Library/PciHostBridgeLib.h b/MdeModulePkg/Include/Library/PciHostBridgeLib.h
> >index d42e9ecdd763..c842a4152e85 100644
> >--- a/MdeModulePkg/Include/Library/PciHostBridgeLib.h
> >+++ b/MdeModulePkg/Include/Library/PciHostBridgeLib.h
> >@@ -20,8 +20,22 @@
> >  // (Base > Limit) indicates an aperture is not available.
> >  //
> >  typedef struct {
> >+  // Base and Limit are the device address instead of host address when
> >+  // Translation is not zero
> (3). Similar comments to (2).
> >    UINT64 Base;
> >    UINT64 Limit;
> >+  // According to UEFI 2.7, Device Address = Host Address + Translation,
> >+  // so Translation = Device Address - Host Address.
> >+  // On platforms where Translation is not zero, the subtraction is probably to
> >+  // be performed with UINT64 wrap-around semantics, for we may translate an
> >+  // above-4G host address into a below-4G device address for legacy PCIe device
> >+  // compatibility.
> >+  // NOTE: The alignment of Translation is required to be larger than any BAR
> >+  // alignment in the same root bridge, so that the same alignment can be
> >+  // applied to both device address and host address, which simplifies the
> >+  // situation and makes the current resource allocation code in generic PCI
> >+  // host bridge driver still work.
> (4). Still I'd like to see the alignment requirement be reflected in code
> through assertion and if-check.
> 
> >+  UINT64 Translation;
> >  } PCI_ROOT_BRIDGE_APERTURE;
> >  typedef struct {
> >diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
> >index 1494848c3e8c..1e65faee9084 100644
> >--- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
> >+++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
> >@@ -32,6 +32,30 @@ EDKII_IOMMU_PROTOCOL        *mIoMmuProtocol;
> >  EFI_EVENT                   mIoMmuEvent;
> >  VOID                        *mIoMmuRegistration;
> >+STATIC
> (5). Can you remove STATIC? personal preference:)
> >+UINT64
> >+GetTranslationByResourceType (
> >+  IN  PCI_ROOT_BRIDGE_INSTANCE     *RootBridge,
> >+  IN  PCI_RESOURCE_TYPE            ResourceType
> >+  )
> >+{
> >+  switch (ResourceType) {
> >+    case TypeIo:
> >+      return RootBridge->Io.Translation;
> >+    case TypeMem32:
> >+      return RootBridge->Mem.Translation;
> >+    case TypePMem32:
> >+      return RootBridge->PMem.Translation;
> >+    case TypeMem64:
> >+      return RootBridge->MemAbove4G.Translation;
> >+    case TypePMem64:
> >+      return RootBridge->PMemAbove4G.Translation;
> >+    default:
> >+      ASSERT (FALSE);
> >+      return 0;
> >+  }
> >+}
> >+
> >  /**
> >    Ensure the compatibility of an IO space descriptor with the IO aperture.
> >@@ -366,6 +390,7 @@ InitializePciHostBridge (
> >    UINTN                       MemApertureIndex;
> >    BOOLEAN                     ResourceAssigned;
> >    LIST_ENTRY                  *Link;
> >+  UINT64                      TempHostAddress;
> (6). Just use name HostAddress?
> >    RootBridges = PciHostBridgeGetRootBridges (&RootBridgeCount);
> >    if ((RootBridges == NULL) || (RootBridgeCount == 0)) {
> >@@ -411,18 +436,24 @@ InitializePciHostBridge (
> >      }
> >      if (RootBridges[Index].Io.Base <= RootBridges[Index].Io.Limit) {
> >+      // Base and Limit in PCI_ROOT_BRIDGE_APERTURE are device address.
> >+      // According to UEFI 2.7, device address = host address + Translation.
> >+      // For GCD resource manipulation, we should use host address, so
> >+      // Translation is subtracted from device address here.
> (7). Please adjust the comment style to have two EMPTY line of comment above
> and below. Same to all comments in the patch.
> >        Status = AddIoSpace (
> >-                 RootBridges[Index].Io.Base,
> >+                 RootBridges[Index].Io.Base - RootBridges[Index].Io.Translation,
> >                   RootBridges[Index].Io.Limit - RootBridges[Index].Io.Base + 1
> >                   );
> >        ASSERT_EFI_ERROR (Status);
> >        if (ResourceAssigned) {
> >+        TempHostAddress = RootBridges[Index].Io.Base -
> >+          RootBridges[Index].Io.Translation;
> >          Status = gDS->AllocateIoSpace (
> >                          EfiGcdAllocateAddress,
> >                          EfiGcdIoTypeIo,
> >                          0,
> >                          RootBridges[Index].Io.Limit - RootBridges[Index].Io.Base + 1,
> >-                        &RootBridges[Index].Io.Base,
> >+                        &TempHostAddress,
> >                          gImageHandle,
> >                          NULL
> >                          );
> >@@ -443,14 +474,18 @@ InitializePciHostBridge (
> >      for (MemApertureIndex = 0; MemApertureIndex < ARRAY_SIZE (MemApertures); MemApertureIndex++) {
> >        if (MemApertures[MemApertureIndex]->Base <= MemApertures[MemApertureIndex]->Limit) {
> >+        // Base and Limit in PCI_ROOT_BRIDGE_APERTURE are device address.
> >+        // According to UEFI 2.7, device address = host address + Translation.
> >+        // For GCD resource manipulation, we should use host address, so
> >+        // Translation is subtracted from device address here.
> >          Status = AddMemoryMappedIoSpace (
> >-                   MemApertures[MemApertureIndex]->Base,
> >+                   MemApertures[MemApertureIndex]->Base - MemApertures[MemApertureIndex]->Translation,
> >                     MemApertures[MemApertureIndex]->Limit - MemApertures[MemApertureIndex]->Base + 1,
> >                     EFI_MEMORY_UC
> >                     );
> >          ASSERT_EFI_ERROR (Status);
> >          Status = gDS->SetMemorySpaceAttributes (
> >-                        MemApertures[MemApertureIndex]->Base,
> >+                        MemApertures[MemApertureIndex]->Base - MemApertures[MemApertureIndex]->Translation,
> >                          MemApertures[MemApertureIndex]->Limit - MemApertures[MemApertureIndex]->Base + 1,
> >                          EFI_MEMORY_UC
> >                          );
> >@@ -458,12 +493,14 @@ InitializePciHostBridge (
> >            DEBUG ((DEBUG_WARN, "PciHostBridge driver failed to set EFI_MEMORY_UC to MMIO aperture - %r.\n", Status));
> >          }
> >          if (ResourceAssigned) {
> >+          TempHostAddress = MemApertures[MemApertureIndex]->Base -
> >+            MemApertures[MemApertureIndex]->Translation;
> >            Status = gDS->AllocateMemorySpace (
> >                            EfiGcdAllocateAddress,
> >                            EfiGcdMemoryTypeMemoryMappedIo,
> >                            0,
> >                            MemApertures[MemApertureIndex]->Limit - MemApertures[MemApertureIndex]->Base + 1,
> >-                          &MemApertures[MemApertureIndex]->Base,
> >+                          &TempHostAddress,
> >                            gImageHandle,
> >                            NULL
> >                            );
> >@@ -654,6 +691,11 @@ AllocateResource (
> >    if (BaseAddress < Limit) {
> >      //
> >      // Have to make sure Aligment is handled since we are doing direct address allocation
> >+    // Strictly speaking, alignment requirement should be applied to device
> >+    // address instead of host address which is used in GCD manipulation below,
> >+    // but as we restrict the alignment of Translation to be larger than any BAR
> >+    // alignment in the root bridge, we can simplify the situation and consider
> >+    // the same alignment requirement is also applied to host address.
> >      //
> >      BaseAddress = ALIGN_VALUE (BaseAddress, LShiftU64 (1, BitsOfAlignment));
> >@@ -824,12 +866,17 @@ NotifyPhase (
> >            switch (Index) {
> >            case TypeIo:
> >+            // Base and Limit in PCI_ROOT_BRIDGE_APERTURE are device address.
> >+            // According to UEFI 2.7, device address = host address + Translation.
> >+            // For AllocateResource is manipulating GCD resource, we should use
> >+            // host address here, so Translation is subtracted from Base and
> >+            // Limit.
> >              BaseAddress = AllocateResource (
> >                              FALSE,
> >                              RootBridge->ResAllocNode[Index].Length,
> >                              MIN (15, BitsOfAlignment),
> >-                            ALIGN_VALUE (RootBridge->Io.Base, Alignment + 1),
> >-                            RootBridge->Io.Limit
> >+                            ALIGN_VALUE (RootBridge->Io.Base, Alignment + 1) - RootBridge->Io.Translation,
> >+                            RootBridge->Io.Limit - RootBridge->Io.Translation
> >                              );
> >              break;
> >@@ -838,8 +885,8 @@ NotifyPhase (
> (8). Add assertion and if-check here to make sure alignment of Translation
> is no less than the Alignment.
> >                              TRUE,
> >                              RootBridge->ResAllocNode[Index].Length,
> >                              MIN (63, BitsOfAlignment),
> >-                            ALIGN_VALUE (RootBridge->MemAbove4G.Base, Alignment + 1),
> >-                            RootBridge->MemAbove4G.Limit
> >+                            ALIGN_VALUE (RootBridge->MemAbove4G.Base, Alignment + 1) - RootBridge->MemAbove4G.Translation,
> >+                            RootBridge->MemAbove4G.Limit - RootBridge->MemAbove4G.Translation
> >                              );
> >              if (BaseAddress != MAX_UINT64) {
> >                break;
> >@@ -853,8 +900,8 @@ NotifyPhase (
> >                              TRUE,
> >                              RootBridge->ResAllocNode[Index].Length,
> >                              MIN (31, BitsOfAlignment),
> >-                            ALIGN_VALUE (RootBridge->Mem.Base, Alignment + 1),
> >-                            RootBridge->Mem.Limit
> >+                            ALIGN_VALUE (RootBridge->Mem.Base, Alignment + 1) - RootBridge->Mem.Translation,
> >+                            RootBridge->Mem.Limit - RootBridge->Mem.Translation
> >                              );
> >              break;
> >@@ -863,8 +910,8 @@ NotifyPhase (
> >                              TRUE,
> >                              RootBridge->ResAllocNode[Index].Length,
> >                              MIN (63, BitsOfAlignment),
> >-                            ALIGN_VALUE (RootBridge->PMemAbove4G.Base, Alignment + 1),
> >-                            RootBridge->PMemAbove4G.Limit
> >+                            ALIGN_VALUE (RootBridge->PMemAbove4G.Base, Alignment + 1) - RootBridge->PMemAbove4G.Translation,
> >+                            RootBridge->PMemAbove4G.Limit - RootBridge->PMemAbove4G.Translation
> >                              );
> >              if (BaseAddress != MAX_UINT64) {
> >                break;
> >@@ -877,8 +924,8 @@ NotifyPhase (
> >                              TRUE,
> >                              RootBridge->ResAllocNode[Index].Length,
> >                              MIN (31, BitsOfAlignment),
> >-                            ALIGN_VALUE (RootBridge->PMem.Base, Alignment + 1),
> >-                            RootBridge->PMem.Limit
> >+                            ALIGN_VALUE (RootBridge->PMem.Base, Alignment + 1) - RootBridge->PMem.Translation,
> >+                            RootBridge->PMem.Limit - RootBridge->PMem.Translation
> >                              );
> >              break;
> >@@ -1152,6 +1199,7 @@ StartBusEnumeration (
> >        Descriptor->AddrSpaceGranularity  = 0;
> >        Descriptor->AddrRangeMin          = RootBridge->Bus.Base;
> >        Descriptor->AddrRangeMax          = 0;
> >+      // Ignore translation offset for bus
> (9). Per PI spec on StartBusEnumeration, AddrRangeMax is ignored. So I don't
> think we need add comments here.
> >        Descriptor->AddrTranslationOffset = 0;
> >        Descriptor->AddrLen               = RootBridge->Bus.Limit - RootBridge->Bus.Base + 1;
> >@@ -1421,7 +1469,12 @@ GetProposedResources (
> >            Descriptor->Desc                  = ACPI_ADDRESS_SPACE_DESCRIPTOR;
> >            Descriptor->Len                   = sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) - 3;;
> >            Descriptor->GenFlag               = 0;
> >-          Descriptor->AddrRangeMin          = RootBridge->ResAllocNode[Index].Base;
> >+          // AddrRangeMin in Resource Descriptor here should be device address
> >+          // instead of host address, or else PCI bus driver cannot set correct
> >+          // address into PCI BAR registers.
> >+          // Base in ResAllocNode is a host address, so Translation is added.
> >+          Descriptor->AddrRangeMin          = RootBridge->ResAllocNode[Index].Base +
> >+              GetTranslationByResourceType (RootBridge, Index);
> (10). Do you think defining a PciHostBridgeDxe internal macro
> TO_HOST_ADDRESS(DeviceAddress, Offset) and TO_DEVICE_ADDRESS(HostAddress,
> Offset) is better?
> 
> >            Descriptor->AddrRangeMax          = 0;
> >            Descriptor->AddrTranslationOffset = (ResStatus == ResAllocated) ? EFI_RESOURCE_SATISFIED : PCI_RESOURCE_LESS;
> >            Descriptor->AddrLen               = RootBridge->ResAllocNode[Index].Length;
> >diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> >index dc06c16dc038..edaa0d48a441 100644
> >--- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> >+++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> >@@ -86,12 +86,28 @@ CreateRootBridge (
> >            (Bridge->AllocationAttributes & EFI_PCI_HOST_BRIDGE_COMBINE_MEM_PMEM) != 0 ? L"CombineMemPMem " : L"",
> >            (Bridge->AllocationAttributes & EFI_PCI_HOST_BRIDGE_MEM64_DECODE) != 0 ? L"Mem64Decode" : L""
> >            ));
> >+  // We don't see any scenario for bus translation, so translation for bus is just ignored.
> >    DEBUG ((EFI_D_INFO, "           Bus: %lx - %lx\n", Bridge->Bus.Base, Bridge->Bus.Limit));
> >-  DEBUG ((EFI_D_INFO, "            Io: %lx - %lx\n", Bridge->Io.Base, Bridge->Io.Limit));
> >-  DEBUG ((EFI_D_INFO, "           Mem: %lx - %lx\n", Bridge->Mem.Base, Bridge->Mem.Limit));
> >-  DEBUG ((EFI_D_INFO, "    MemAbove4G: %lx - %lx\n", Bridge->MemAbove4G.Base, Bridge->MemAbove4G.Limit));
> >-  DEBUG ((EFI_D_INFO, "          PMem: %lx - %lx\n", Bridge->PMem.Base, Bridge->PMem.Limit));
> >-  DEBUG ((EFI_D_INFO, "   PMemAbove4G: %lx - %lx\n", Bridge->PMemAbove4G.Base, Bridge->PMemAbove4G.Limit));
> >+  DEBUG ((
> >+    DEBUG_INFO, "            Io: %lx - %lx Translation=%lx\n",
> >+    Bridge->Io.Base, Bridge->Io.Limit, Bridge->Io.Translation
> >+    ));
> >+  DEBUG ((
> >+    DEBUG_INFO, "           Mem: %lx - %lx Translation=%lx\n",
> >+    Bridge->Mem.Base, Bridge->Mem.Limit, Bridge->Mem.Translation
> >+    ));
> >+  DEBUG ((
> >+    DEBUG_INFO, "    MemAbove4G: %lx - %lx Translation=%lx\n",
> >+    Bridge->MemAbove4G.Base, Bridge->MemAbove4G.Limit, Bridge->MemAbove4G.Translation
> >+    ));
> >+  DEBUG ((
> >+    DEBUG_INFO, "          PMem: %lx - %lx Translation=%lx\n",
> >+    Bridge->PMem.Base, Bridge->PMem.Limit, Bridge->PMem.Translation
> >+    ));
> >+  DEBUG ((
> >+    DEBUG_INFO, "   PMemAbove4G: %lx - %lx Translation=%lx\n",
> >+    Bridge->PMemAbove4G.Base, Bridge->PMemAbove4G.Limit, Bridge->PMemAbove4G.Translation
> >+    ));
> >    //
> >    // Make sure Mem and MemAbove4G apertures are valid
> >@@ -206,7 +222,15 @@ CreateRootBridge (
> >      }
> >      RootBridge->ResAllocNode[Index].Type     = Index;
> >      if (Bridge->ResourceAssigned && (Aperture->Limit >= Aperture->Base)) {
> >-      RootBridge->ResAllocNode[Index].Base   = Aperture->Base;
> >+      // Ignore translation for bus
> (11). How about we only make sure the TranslationOffset is 0 for TypeBus
> when getting the aperture from PciHostBridgeLib.
> So that later logic doesn't need to do special handling for the TypeBus.
> This way the code can be simpler.
> >+      if (Index == TypeBus) {
> >+        RootBridge->ResAllocNode[Index].Base   = Aperture->Base;
> >+      } else {
> >+        // Base in ResAllocNode is a host address, while Base in Aperture is a
> >+        // device address, so translation needs to be subtracted.
> >+        RootBridge->ResAllocNode[Index].Base   = Aperture->Base -
> >+          Aperture->Translation;
> (12). Still. Do you think using TO_HOST_ADDRESS() is better?
> >+      }
> >        RootBridge->ResAllocNode[Index].Length = Aperture->Limit - Aperture->Base + 1;
> >        RootBridge->ResAllocNode[Index].Status = ResAllocated;
> >      } else {
> >@@ -403,6 +427,28 @@ RootBridgeIoCheckParameter (
> >    return EFI_SUCCESS;
> >  }
> >+EFI_STATUS
> >+RootBridgeIoGetMemTranslationByAddress (
> >+  IN PCI_ROOT_BRIDGE_INSTANCE               *RootBridge,
> >+  IN UINT64                                 Address,
> >+  IN OUT UINT64                             *Translation
> >+  )
> >+{
> >+  if (Address >= RootBridge->Mem.Base && Address <= RootBridge->Mem.Limit) {
> >+    *Translation = RootBridge->Mem.Translation;
> >+  } else if (Address >= RootBridge->PMem.Base && Address <= RootBridge->PMem.Limit) {
> >+    *Translation = RootBridge->PMem.Translation;
> >+  } else if (Address >= RootBridge->MemAbove4G.Base && Address <= RootBridge->MemAbove4G.Limit) {
> >+    *Translation = RootBridge->MemAbove4G.Translation;
> >+  } else if (Address >= RootBridge->PMemAbove4G.Base && Address <= RootBridge->PMemAbove4G.Limit) {
> >+    *Translation = RootBridge->PMemAbove4G.Translation;
> >+  } else {
> >+    return EFI_INVALID_PARAMETER;
> >+  }
> >+
> >+  return EFI_SUCCESS;
> >+}
> >+
> >  /**
> >    Polls an address in memory mapped I/O space until an exit condition is met,
> >    or a timeout occurs.
> >@@ -658,13 +704,24 @@ RootBridgeIoMemRead (
> >    )
> >  {
> >    EFI_STATUS                             Status;
> >+  PCI_ROOT_BRIDGE_INSTANCE               *RootBridge;
> >+  UINT64                                 Translation;
> >    Status = RootBridgeIoCheckParameter (This, MemOperation, Width, Address,
> >                                         Count, Buffer);
> >    if (EFI_ERROR (Status)) {
> >      return Status;
> >    }
> >-  return mCpuIo->Mem.Read (mCpuIo, (EFI_CPU_IO_PROTOCOL_WIDTH) Width, Address, Count, Buffer);
> >+
> >+  RootBridge = ROOT_BRIDGE_FROM_THIS (This);
> >+  Status = RootBridgeIoGetMemTranslationByAddress (RootBridge, Address, &Translation);
> (13). Why do you think the Address is a Device Address?
> PciIo.GetBarAttributes() returns a HOST Address and the Translation Offset.
> I didn't see you change the PciIoMemRead() implementation.
> So it means the same HOST Address is passed into the this function.
> 
> >+  if (EFI_ERROR (Status)) {
> >+    return Status;
> >+  }
> >+
> >+  // Address passed to CpuIo->Mem.Read should be a host address instead of
> >+  // device address, so Translation should be subtracted.
> >+  return mCpuIo->Mem.Read (mCpuIo, (EFI_CPU_IO_PROTOCOL_WIDTH) Width, Address - Translation, Count, Buffer);
> >  }
> >  /**
> >@@ -705,13 +762,24 @@ RootBridgeIoMemWrite (
> >    )
> >  {
> >    EFI_STATUS                             Status;
> >+  PCI_ROOT_BRIDGE_INSTANCE               *RootBridge;
> >+  UINT64                                 Translation;
> >    Status = RootBridgeIoCheckParameter (This, MemOperation, Width, Address,
> >                                         Count, Buffer);
> >    if (EFI_ERROR (Status)) {
> >      return Status;
> >    }
> >-  return mCpuIo->Mem.Write (mCpuIo, (EFI_CPU_IO_PROTOCOL_WIDTH) Width, Address, Count, Buffer);
> >+
> >+  RootBridge = ROOT_BRIDGE_FROM_THIS (This);
> >+  Status = RootBridgeIoGetMemTranslationByAddress (RootBridge, Address, &Translation);
> >+  if (EFI_ERROR (Status)) {
> >+    return Status;
> >+  }
> >+
> >+  // Address passed to CpuIo->Mem.Write should be a host address instead of
> >+  // device address, so Translation should be subtracted.
> >+  return mCpuIo->Mem.Write (mCpuIo, (EFI_CPU_IO_PROTOCOL_WIDTH) Width, Address - Translation, Count, Buffer);
> (14). Same as (13)
> >  }
> >  /**
> >@@ -746,6 +814,8 @@ RootBridgeIoIoRead (
> >    )
> >  {
> >    EFI_STATUS                                    Status;
> >+  PCI_ROOT_BRIDGE_INSTANCE                      *RootBridge;
> >+
> >    Status = RootBridgeIoCheckParameter (
> >               This, IoOperation, Width,
> >               Address, Count, Buffer
> >@@ -753,7 +823,12 @@ RootBridgeIoIoRead (
> >    if (EFI_ERROR (Status)) {
> >      return Status;
> >    }
> >-  return mCpuIo->Io.Read (mCpuIo, (EFI_CPU_IO_PROTOCOL_WIDTH) Width, Address, Count, Buffer);
> >+
> >+  RootBridge = ROOT_BRIDGE_FROM_THIS (This);
> >+
> >+  // Address passed to CpuIo->Io.Read should be a host address instead of
> >+  // device address, so Translation should be subtracted.
> >+  return mCpuIo->Io.Read (mCpuIo, (EFI_CPU_IO_PROTOCOL_WIDTH) Width, Address - RootBridge->Io.Translation, Count, Buffer);
> (15). Same as (13)
> >  }
> >  /**
> >@@ -788,6 +863,8 @@ RootBridgeIoIoWrite (
> >    )
> >  {
> >    EFI_STATUS                                    Status;
> >+  PCI_ROOT_BRIDGE_INSTANCE                      *RootBridge;
> >+
> >    Status = RootBridgeIoCheckParameter (
> >               This, IoOperation, Width,
> >               Address, Count, Buffer
> >@@ -795,7 +872,12 @@ RootBridgeIoIoWrite (
> >    if (EFI_ERROR (Status)) {
> >      return Status;
> >    }
> >-  return mCpuIo->Io.Write (mCpuIo, (EFI_CPU_IO_PROTOCOL_WIDTH) Width, Address, Count, Buffer);
> >+
> >+  RootBridge = ROOT_BRIDGE_FROM_THIS (This);
> >+
> >+  // Address passed to CpuIo->Io.Write should be a host address instead of
> >+  // device address, so Translation should be subtracted.
> >+  return mCpuIo->Io.Write (mCpuIo, (EFI_CPU_IO_PROTOCOL_WIDTH) Width, Address - RootBridge->Io.Translation, Count, Buffer);
> (16). Same as (13)
> >  }
> >  /**
> >@@ -1615,25 +1697,39 @@ RootBridgeIoConfiguration (
> >      Descriptor->Desc = ACPI_ADDRESS_SPACE_DESCRIPTOR;
> >      Descriptor->Len  = sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) - 3;
> >+    // According to UEFI 2.7, RootBridgeIo->Configuration should return address
> >+    // range in CPU view (host address), and ResAllocNode->Base is already a CPU
> >+    // view address (host address).
> >      Descriptor->AddrRangeMin  = ResAllocNode->Base;
> >      Descriptor->AddrRangeMax  = ResAllocNode->Base + ResAllocNode->Length - 1;
> >      Descriptor->AddrLen       = ResAllocNode->Length;
> >      switch (ResAllocNode->Type) {
> >      case TypeIo:
> >-      Descriptor->ResType       = ACPI_ADDRESS_SPACE_TYPE_IO;
> >+      Descriptor->ResType               = ACPI_ADDRESS_SPACE_TYPE_IO;
> >+      Descriptor->AddrTranslationOffset = RootBridge->Io.Translation;
> (17). Can GetTranslationByResourceType() be used to simplify the code?
> >        break;
> >      case TypePMem32:
> >-      Descriptor->SpecificFlag = EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE;
> >+      Descriptor->SpecificFlag          = EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE;
> >+      Descriptor->AddrTranslationOffset = RootBridge->PMem.Translation;
> >+      Descriptor->ResType               = ACPI_ADDRESS_SPACE_TYPE_MEM;
> >+      Descriptor->AddrSpaceGranularity  = 32;
> >+      break;
> >+
> >      case TypeMem32:
> >+      Descriptor->AddrTranslationOffset = RootBridge->Mem.Translation;
> >        Descriptor->ResType               = ACPI_ADDRESS_SPACE_TYPE_MEM;
> >        Descriptor->AddrSpaceGranularity  = 32;
> >        break;
> >      case TypePMem64:
> >-      Descriptor->SpecificFlag = EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE;
> >+      Descriptor->SpecificFlag          = EFI_ACPI_MEMORY_RESOURCE_SPECIFIC_FLAG_CACHEABLE_PREFETCHABLE;
> >+      Descriptor->AddrTranslationOffset = RootBridge->PMemAbove4G.Translation;
> >+      Descriptor->ResType               = ACPI_ADDRESS_SPACE_TYPE_MEM;
> >+      Descriptor->AddrSpaceGranularity  = 64;
> >      case TypeMem64:
> >+      Descriptor->AddrTranslationOffset = RootBridge->MemAbove4G.Translation;
> >        Descriptor->ResType               = ACPI_ADDRESS_SPACE_TYPE_MEM;
> >        Descriptor->AddrSpaceGranularity  = 64;
> >        break;
> >
> 
> (18). Please remember to run BaseTools/Source/Python/Ecc/Ecc.py on the
> PciHostBridgeDxe driver to make sure coding style matches the requirement.
> 
> -- 
> Thanks,
> Ray