]> git.proxmox.com Git - mirror_edk2.git/commitdiff
OvmfPkg/PciHostBridgeLibScan: create from PciHostBridgeLib
authorLaszlo Ersek <lersek@redhat.com>
Wed, 26 May 2021 20:14:32 +0000 (22:14 +0200)
committermergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Fri, 4 Jun 2021 16:01:50 +0000 (16:01 +0000)
Create an almost verbatim copy of the
"OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf" library instance.

The new PciHostBridgeLibScan instance will ultimately duplicate a
negligible amount of code from the original, and will be used by the Bhyve
and OvmfXen platforms.

List the new driver in "Maintainers.txt", in the "OvmfPkg: bhyve-related
modules" and "OvmfPkg: Xen-related modules" sections.

This patch should be reviewed with "git show --find-copies-harder".

Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Julien Grall <julien@xen.org>
Cc: Peter Grehan <grehan@freebsd.org>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Rebecca Cran <rebecca@bsdio.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2122
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20210526201446.12554-30-lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Maintainers.txt
OvmfPkg/Library/PciHostBridgeLibScan/PciHostBridge.h [new file with mode: 0644]
OvmfPkg/Library/PciHostBridgeLibScan/PciHostBridgeLib.c [new file with mode: 0644]
OvmfPkg/Library/PciHostBridgeLibScan/PciHostBridgeLibScan.inf [new file with mode: 0644]
OvmfPkg/Library/PciHostBridgeLibScan/XenSupport.c [new file with mode: 0644]

index 5d234f83f8712570d32bcf22fb34e4771e23bc1e..e0c3472b4b72cf7cc7f104e328633ca088ece3ea 100644 (file)
@@ -426,6 +426,7 @@ F: OvmfPkg/Include/Library/BhyveFwCtlLib.h
 F: OvmfPkg/Library/AcpiTimerLib/BaseAcpiTimerLibBhyve.c\r
 F: OvmfPkg/Library/AcpiTimerLib/BaseAcpiTimerLibBhyve.inf\r
 F: OvmfPkg/Library/BhyveFwCtlLib/\r
+F: OvmfPkg/Library/PciHostBridgeLibScan/\r
 F: OvmfPkg/Library/PlatformBootManagerLibBhyve/\r
 F: OvmfPkg/Library/ResetSystemLib/BaseResetShutdownBhyve.c\r
 F: OvmfPkg/Library/ResetSystemLib/BaseResetSystemLibBhyve.inf\r
@@ -484,6 +485,7 @@ F: OvmfPkg/Include/Library/XenPlatformLib.h
 F: OvmfPkg/Include/Protocol/XenBus.h\r
 F: OvmfPkg/Include/Protocol/XenIo.h\r
 F: OvmfPkg/Library/PciHostBridgeLib/XenSupport.c\r
+F: OvmfPkg/Library/PciHostBridgeLibScan/\r
 F: OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c\r
 F: OvmfPkg/Library/XenConsoleSerialPortLib/\r
 F: OvmfPkg/Library/XenHypercallLib/\r
diff --git a/OvmfPkg/Library/PciHostBridgeLibScan/PciHostBridge.h b/OvmfPkg/Library/PciHostBridgeLibScan/PciHostBridge.h
new file mode 100644 (file)
index 0000000..582b792
--- /dev/null
@@ -0,0 +1,14 @@
+/** @file\r
+  Header file of OVMF instance of PciHostBridgeLib.\r
+\r
+  Copyright (C) 2021, Red Hat, Inc.\r
+  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>\r
+\r
+  SPDX-License-Identifier: BSD-2-Clause-Patent\r
+\r
+**/\r
+\r
+PCI_ROOT_BRIDGE *\r
+ScanForRootBridges (\r
+  UINTN      *NumberOfRootBridges\r
+);\r
diff --git a/OvmfPkg/Library/PciHostBridgeLibScan/PciHostBridgeLib.c b/OvmfPkg/Library/PciHostBridgeLibScan/PciHostBridgeLib.c
new file mode 100644 (file)
index 0000000..6c2acc9
--- /dev/null
@@ -0,0 +1,133 @@
+/** @file\r
+  OVMF's instance of the PCI Host Bridge Library.\r
+\r
+  Copyright (C) 2016-2021, Red Hat, Inc.\r
+  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>\r
+\r
+  SPDX-License-Identifier: BSD-2-Clause-Patent\r
+\r
+**/\r
+#include <IndustryStandard/Pci.h>                     // PCI_MAX_BUS\r
+#include <IndustryStandard/Q35MchIch9.h>              // INTEL_Q35_MCH_DEVIC...\r
+#include <Library/BaseMemoryLib.h>                    // ZeroMem()\r
+#include <Library/PcdLib.h>                           // PcdGet64()\r
+#include <Library/PciHostBridgeLib.h>                 // PCI_ROOT_BRIDGE_APE...\r
+#include <Library/PciHostBridgeUtilityLib.h>          // PciHostBridgeUtilit...\r
+#include <Protocol/PciHostBridgeResourceAllocation.h> // EFI_PCI_HOST_BRIDGE...\r
+#include <Protocol/PciRootBridgeIo.h>                 // EFI_PCI_ATTRIBUTE_I...\r
+\r
+#include "PciHostBridge.h"\r
+\r
+STATIC PCI_ROOT_BRIDGE_APERTURE mNonExistAperture = { MAX_UINT64, 0 };\r
+\r
+\r
+/**\r
+  Return all the root bridge instances in an array.\r
+\r
+  @param Count  Return the count of root bridge instances.\r
+\r
+  @return All the root bridge instances in an array.\r
+          The array should be passed into PciHostBridgeFreeRootBridges()\r
+          when it's not used.\r
+**/\r
+PCI_ROOT_BRIDGE *\r
+EFIAPI\r
+PciHostBridgeGetRootBridges (\r
+  UINTN *Count\r
+  )\r
+{\r
+  UINT64               Attributes;\r
+  UINT64               AllocationAttributes;\r
+  PCI_ROOT_BRIDGE_APERTURE Io;\r
+  PCI_ROOT_BRIDGE_APERTURE Mem;\r
+  PCI_ROOT_BRIDGE_APERTURE MemAbove4G;\r
+\r
+  if (PcdGetBool (PcdPciDisableBusEnumeration)) {\r
+    return ScanForRootBridges (Count);\r
+  }\r
+\r
+  ZeroMem (&Io, sizeof (Io));\r
+  ZeroMem (&Mem, sizeof (Mem));\r
+  ZeroMem (&MemAbove4G, sizeof (MemAbove4G));\r
+\r
+  Attributes = EFI_PCI_ATTRIBUTE_IDE_PRIMARY_IO |\r
+    EFI_PCI_ATTRIBUTE_IDE_SECONDARY_IO |\r
+    EFI_PCI_ATTRIBUTE_ISA_IO_16 |\r
+    EFI_PCI_ATTRIBUTE_ISA_MOTHERBOARD_IO |\r
+    EFI_PCI_ATTRIBUTE_VGA_MEMORY |\r
+    EFI_PCI_ATTRIBUTE_VGA_IO_16 |\r
+    EFI_PCI_ATTRIBUTE_VGA_PALETTE_IO_16;\r
+\r
+  AllocationAttributes = EFI_PCI_HOST_BRIDGE_COMBINE_MEM_PMEM;\r
+  if (PcdGet64 (PcdPciMmio64Size) > 0) {\r
+    AllocationAttributes |= EFI_PCI_HOST_BRIDGE_MEM64_DECODE;\r
+    MemAbove4G.Base = PcdGet64 (PcdPciMmio64Base);\r
+    MemAbove4G.Limit = PcdGet64 (PcdPciMmio64Base) +\r
+                       PcdGet64 (PcdPciMmio64Size) - 1;\r
+  } else {\r
+    CopyMem (&MemAbove4G, &mNonExistAperture, sizeof (mNonExistAperture));\r
+  }\r
+\r
+  Io.Base = PcdGet64 (PcdPciIoBase);\r
+  Io.Limit = PcdGet64 (PcdPciIoBase) + (PcdGet64 (PcdPciIoSize) - 1);\r
+  Mem.Base = PcdGet64 (PcdPciMmio32Base);\r
+  Mem.Limit = PcdGet64 (PcdPciMmio32Base) + (PcdGet64 (PcdPciMmio32Size) - 1);\r
+\r
+  return PciHostBridgeUtilityGetRootBridges (\r
+    Count,\r
+    Attributes,\r
+    AllocationAttributes,\r
+    FALSE,\r
+    PcdGet16 (PcdOvmfHostBridgePciDevId) != INTEL_Q35_MCH_DEVICE_ID,\r
+    0,\r
+    PCI_MAX_BUS,\r
+    &Io,\r
+    &Mem,\r
+    &MemAbove4G,\r
+    &mNonExistAperture,\r
+    &mNonExistAperture\r
+    );\r
+}\r
+\r
+\r
+/**\r
+  Free the root bridge instances array returned from\r
+  PciHostBridgeGetRootBridges().\r
+\r
+  @param  The root bridge instances array.\r
+  @param  The count of the array.\r
+**/\r
+VOID\r
+EFIAPI\r
+PciHostBridgeFreeRootBridges (\r
+  PCI_ROOT_BRIDGE *Bridges,\r
+  UINTN           Count\r
+  )\r
+{\r
+  PciHostBridgeUtilityFreeRootBridges (Bridges, Count);\r
+}\r
+\r
+\r
+/**\r
+  Inform the platform that the resource conflict happens.\r
+\r
+  @param HostBridgeHandle Handle of the Host Bridge.\r
+  @param Configuration    Pointer to PCI I/O and PCI memory resource\r
+                          descriptors. The Configuration contains the resources\r
+                          for all the root bridges. The resource for each root\r
+                          bridge is terminated with END descriptor and an\r
+                          additional END is appended indicating the end of the\r
+                          entire resources. The resource descriptor field\r
+                          values follow the description in\r
+                          EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL\r
+                          .SubmitResources().\r
+**/\r
+VOID\r
+EFIAPI\r
+PciHostBridgeResourceConflict (\r
+  EFI_HANDLE                        HostBridgeHandle,\r
+  VOID                              *Configuration\r
+  )\r
+{\r
+  PciHostBridgeUtilityResourceConflict (Configuration);\r
+}\r
diff --git a/OvmfPkg/Library/PciHostBridgeLibScan/PciHostBridgeLibScan.inf b/OvmfPkg/Library/PciHostBridgeLibScan/PciHostBridgeLibScan.inf
new file mode 100644 (file)
index 0000000..4685938
--- /dev/null
@@ -0,0 +1,54 @@
+## @file\r
+#  OVMF's instance of the PCI Host Bridge Library.\r
+#\r
+#  Copyright (C) 2016-2021, Red Hat, Inc.\r
+#  Copyright (c) 2016 - 2018, Intel Corporation. All rights reserved.<BR>\r
+#\r
+#  SPDX-License-Identifier: BSD-2-Clause-Patent\r
+#\r
+#\r
+##\r
+\r
+[Defines]\r
+  INF_VERSION                    = 0x00010005\r
+  BASE_NAME                      = PciHostBridgeLibScan\r
+  FILE_GUID                      = c93f2411-9bf5-4894-b552-67fae0c3d291\r
+  MODULE_TYPE                    = DXE_DRIVER\r
+  VERSION_STRING                 = 1.0\r
+  LIBRARY_CLASS                  = PciHostBridgeLib\r
+\r
+#\r
+# The following information is for reference only and not required by the build\r
+# tools.\r
+#\r
+#  VALID_ARCHITECTURES           = IA32 X64 EBC\r
+#\r
+\r
+[Sources]\r
+  PciHostBridge.h\r
+  PciHostBridgeLib.c\r
+  XenSupport.c\r
+\r
+[Packages]\r
+  MdeModulePkg/MdeModulePkg.dec\r
+  MdePkg/MdePkg.dec\r
+  OvmfPkg/OvmfPkg.dec\r
+\r
+[LibraryClasses]\r
+  BaseLib\r
+  BaseMemoryLib\r
+  DebugLib\r
+  MemoryAllocationLib\r
+  PcdLib\r
+  PciHostBridgeUtilityLib\r
+  PciLib\r
+\r
+[Pcd]\r
+  gEfiMdeModulePkgTokenSpaceGuid.PcdPciDisableBusEnumeration\r
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId\r
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciIoBase\r
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciIoSize\r
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio32Base\r
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio32Size\r
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Base\r
+  gUefiOvmfPkgTokenSpaceGuid.PcdPciMmio64Size\r
diff --git a/OvmfPkg/Library/PciHostBridgeLibScan/XenSupport.c b/OvmfPkg/Library/PciHostBridgeLibScan/XenSupport.c
new file mode 100644 (file)
index 0000000..a4a61e5
--- /dev/null
@@ -0,0 +1,472 @@
+/** @file\r
+  Scan the entire PCI bus for root bridges to support OVMF above Xen.\r
+\r
+  Copyright (C) 2021, Red Hat, Inc.\r
+  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>\r
+\r
+  SPDX-License-Identifier: BSD-2-Clause-Patent\r
+\r
+**/\r
+\r
+#include <IndustryStandard/Pci.h>            // EFI_PCI_COMMAND_IO_SPACE\r
+#include <IndustryStandard/Q35MchIch9.h>     // INTEL_Q35_MCH_DEVICE_ID\r
+#include <Library/BaseLib.h>                 // DisableInterrupts()\r
+#include <Library/BaseMemoryLib.h>           // ZeroMem()\r
+#include <Library/DebugLib.h>                // ASSERT()\r
+#include <Library/MemoryAllocationLib.h>     // ReallocatePool()\r
+#include <Library/PcdLib.h>                  // PcdGet16()\r
+#include <Library/PciHostBridgeLib.h>        // PCI_ROOT_BRIDGE_APERTURE\r
+#include <Library/PciHostBridgeUtilityLib.h> // PciHostBridgeUtilityInitRoot...\r
+#include <Library/PciLib.h>                  // PciRead32()\r
+#include <Protocol/PciRootBridgeIo.h>        // EFI_PCI_ATTRIBUTE_ISA_IO\r
+\r
+#include "PciHostBridge.h"\r
+\r
+STATIC\r
+VOID\r
+PcatPciRootBridgeBarExisted (\r
+  IN  UINTN                          Address,\r
+  OUT UINT32                         *OriginalValue,\r
+  OUT UINT32                         *Value\r
+  )\r
+{\r
+  //\r
+  // Preserve the original value\r
+  //\r
+  *OriginalValue = PciRead32 (Address);\r
+\r
+  //\r
+  // Disable timer interrupt while the BAR is probed\r
+  //\r
+  DisableInterrupts ();\r
+\r
+  PciWrite32 (Address, 0xFFFFFFFF);\r
+  *Value = PciRead32 (Address);\r
+  PciWrite32 (Address, *OriginalValue);\r
+\r
+  //\r
+  // Enable interrupt\r
+  //\r
+  EnableInterrupts ();\r
+}\r
+\r
+#define PCI_COMMAND_DECODE ((UINT16)(EFI_PCI_COMMAND_IO_SPACE | \\r
+                                     EFI_PCI_COMMAND_MEMORY_SPACE))\r
+STATIC\r
+VOID\r
+PcatPciRootBridgeDecodingDisable (\r
+  IN  UINTN                          Address\r
+  )\r
+{\r
+  UINT16                             Value;\r
+\r
+  Value = PciRead16 (Address);\r
+  if (Value & PCI_COMMAND_DECODE) {\r
+    PciWrite16 (Address, Value & ~(UINT32)PCI_COMMAND_DECODE);\r
+  }\r
+}\r
+\r
+STATIC\r
+VOID\r
+PcatPciRootBridgeParseBars (\r
+  IN UINT16                         Command,\r
+  IN UINTN                          Bus,\r
+  IN UINTN                          Device,\r
+  IN UINTN                          Function,\r
+  IN UINTN                          BarOffsetBase,\r
+  IN UINTN                          BarOffsetEnd,\r
+  IN PCI_ROOT_BRIDGE_APERTURE       *Io,\r
+  IN PCI_ROOT_BRIDGE_APERTURE       *Mem,\r
+  IN PCI_ROOT_BRIDGE_APERTURE       *MemAbove4G\r
+\r
+)\r
+{\r
+  UINT32                            OriginalValue;\r
+  UINT32                            Value;\r
+  UINT32                            OriginalUpperValue;\r
+  UINT32                            UpperValue;\r
+  UINT64                            Mask;\r
+  UINTN                             Offset;\r
+  UINT64                            Base;\r
+  UINT64                            Length;\r
+  UINT64                            Limit;\r
+  PCI_ROOT_BRIDGE_APERTURE          *MemAperture;\r
+\r
+  // Disable address decoding for every device before OVMF starts sizing it\r
+  PcatPciRootBridgeDecodingDisable (\r
+    PCI_LIB_ADDRESS (Bus, Device, Function, PCI_COMMAND_OFFSET)\r
+  );\r
+\r
+  for (Offset = BarOffsetBase; Offset < BarOffsetEnd; Offset += sizeof (UINT32)) {\r
+    PcatPciRootBridgeBarExisted (\r
+      PCI_LIB_ADDRESS (Bus, Device, Function, Offset),\r
+      &OriginalValue, &Value\r
+    );\r
+    if (Value == 0) {\r
+      continue;\r
+    }\r
+    if ((Value & BIT0) == BIT0) {\r
+      //\r
+      // IO Bar\r
+      //\r
+      if (Command & EFI_PCI_COMMAND_IO_SPACE) {\r
+        Mask = 0xfffffffc;\r
+        Base = OriginalValue & Mask;\r
+        Length = ((~(Value & Mask)) & Mask) + 0x04;\r
+        if (!(Value & 0xFFFF0000)) {\r
+          Length &= 0x0000FFFF;\r
+        }\r
+        Limit = Base + Length - 1;\r
+\r
+        if (Base < Limit) {\r
+          if (Io->Base > Base) {\r
+            Io->Base = Base;\r
+          }\r
+          if (Io->Limit < Limit) {\r
+            Io->Limit = Limit;\r
+          }\r
+        }\r
+      }\r
+    } else {\r
+      //\r
+      // Mem Bar\r
+      //\r
+      if (Command & EFI_PCI_COMMAND_MEMORY_SPACE) {\r
+\r
+        Mask = 0xfffffff0;\r
+        Base = OriginalValue & Mask;\r
+        Length = Value & Mask;\r
+\r
+        if ((Value & (BIT1 | BIT2)) == 0) {\r
+          //\r
+          // 32bit\r
+          //\r
+          Length = ((~Length) + 1) & 0xffffffff;\r
+\r
+          MemAperture = Mem;\r
+        } else {\r
+          //\r
+          // 64bit\r
+          //\r
+          Offset += 4;\r
+          PcatPciRootBridgeBarExisted (\r
+            PCI_LIB_ADDRESS (Bus, Device, Function, Offset),\r
+            &OriginalUpperValue,\r
+            &UpperValue\r
+          );\r
+\r
+          Base = Base | LShiftU64 ((UINT64) OriginalUpperValue, 32);\r
+          Length = Length | LShiftU64 ((UINT64) UpperValue, 32);\r
+          Length = (~Length) + 1;\r
+\r
+          if (Base < BASE_4GB) {\r
+            MemAperture = Mem;\r
+          } else {\r
+            MemAperture = MemAbove4G;\r
+          }\r
+        }\r
+\r
+        Limit = Base + Length - 1;\r
+        if (Base < Limit) {\r
+          if (MemAperture->Base > Base) {\r
+            MemAperture->Base = Base;\r
+          }\r
+          if (MemAperture->Limit < Limit) {\r
+            MemAperture->Limit = Limit;\r
+          }\r
+        }\r
+      }\r
+    }\r
+  }\r
+}\r
+\r
+STATIC PCI_ROOT_BRIDGE_APERTURE mNonExistAperture = { MAX_UINT64, 0 };\r
+\r
+PCI_ROOT_BRIDGE *\r
+ScanForRootBridges (\r
+  UINTN      *NumberOfRootBridges\r
+  )\r
+{\r
+  UINTN      PrimaryBus;\r
+  UINTN      SubBus;\r
+  UINT8      Device;\r
+  UINT8      Function;\r
+  UINTN      NumberOfDevices;\r
+  UINTN      Address;\r
+  PCI_TYPE01 Pci;\r
+  UINT64     Attributes;\r
+  UINT64     Base;\r
+  UINT64     Limit;\r
+  UINT64     Value;\r
+  PCI_ROOT_BRIDGE_APERTURE Io, Mem, MemAbove4G, *MemAperture;\r
+  PCI_ROOT_BRIDGE *RootBridges;\r
+  UINTN      BarOffsetEnd;\r
+\r
+\r
+  *NumberOfRootBridges = 0;\r
+  RootBridges = NULL;\r
+\r
+  //\r
+  // After scanning all the PCI devices on the PCI root bridge's primary bus,\r
+  // update the Primary Bus Number for the next PCI root bridge to be this PCI\r
+  // root bridge's subordinate bus number + 1.\r
+  //\r
+  for (PrimaryBus = 0; PrimaryBus <= PCI_MAX_BUS; PrimaryBus = SubBus + 1) {\r
+    SubBus = PrimaryBus;\r
+    Attributes = 0;\r
+\r
+    ZeroMem (&Io, sizeof (Io));\r
+    ZeroMem (&Mem, sizeof (Mem));\r
+    ZeroMem (&MemAbove4G, sizeof (MemAbove4G));\r
+    Io.Base = Mem.Base = MemAbove4G.Base = MAX_UINT64;\r
+    //\r
+    // Scan all the PCI devices on the primary bus of the PCI root bridge\r
+    //\r
+    for (Device = 0, NumberOfDevices = 0; Device <= PCI_MAX_DEVICE; Device++) {\r
+\r
+      for (Function = 0; Function <= PCI_MAX_FUNC; Function++) {\r
+\r
+        //\r
+        // Compute the PCI configuration address of the PCI device to probe\r
+        //\r
+        Address = PCI_LIB_ADDRESS (PrimaryBus, Device, Function, 0);\r
+\r
+        //\r
+        // Read the Vendor ID from the PCI Configuration Header\r
+        //\r
+        if (PciRead16 (Address) == MAX_UINT16) {\r
+          if (Function == 0) {\r
+            //\r
+            // If the PCI Configuration Read fails, or a PCI device does not\r
+            // exist, then skip this entire PCI device\r
+            //\r
+            break;\r
+          } else {\r
+            //\r
+            // If PCI function != 0, VendorId == 0xFFFF, we continue to search\r
+            // PCI function.\r
+            //\r
+            continue;\r
+          }\r
+        }\r
+\r
+        //\r
+        // Read the entire PCI Configuration Header\r
+        //\r
+        PciReadBuffer (Address, sizeof (Pci), &Pci);\r
+\r
+        //\r
+        // Increment the number of PCI device found on the primary bus of the\r
+        // PCI root bridge\r
+        //\r
+        NumberOfDevices++;\r
+\r
+        //\r
+        // Look for devices with the VGA Palette Snoop enabled in the COMMAND\r
+        // register of the PCI Config Header\r
+        //\r
+        if ((Pci.Hdr.Command & EFI_PCI_COMMAND_VGA_PALETTE_SNOOP) != 0) {\r
+          Attributes |= EFI_PCI_ATTRIBUTE_VGA_PALETTE_IO;\r
+          Attributes |= EFI_PCI_ATTRIBUTE_VGA_PALETTE_IO_16;\r
+        }\r
+\r
+        BarOffsetEnd = 0;\r
+\r
+        //\r
+        // PCI-PCI Bridge\r
+        //\r
+        if (IS_PCI_BRIDGE (&Pci)) {\r
+          //\r
+          // Get the Bus range that the PPB is decoding\r
+          //\r
+          if (Pci.Bridge.SubordinateBus > SubBus) {\r
+            //\r
+            // If the subordinate bus number of the PCI-PCI bridge is greater\r
+            // than the PCI root bridge's current subordinate bus number,\r
+            // then update the PCI root bridge's subordinate bus number\r
+            //\r
+            SubBus = Pci.Bridge.SubordinateBus;\r
+          }\r
+\r
+          //\r
+          // Get the I/O range that the PPB is decoding\r
+          //\r
+          Value = Pci.Bridge.IoBase & 0x0f;\r
+          Base = ((UINT32) Pci.Bridge.IoBase & 0xf0) << 8;\r
+          Limit = (((UINT32) Pci.Bridge.IoLimit & 0xf0) << 8) | 0x0fff;\r
+          if (Value == BIT0) {\r
+            Base |= ((UINT32) Pci.Bridge.IoBaseUpper16 << 16);\r
+            Limit |= ((UINT32) Pci.Bridge.IoLimitUpper16 << 16);\r
+          }\r
+          if (Base < Limit) {\r
+            if (Io.Base > Base) {\r
+              Io.Base = Base;\r
+            }\r
+            if (Io.Limit < Limit) {\r
+              Io.Limit = Limit;\r
+            }\r
+          }\r
+\r
+          //\r
+          // Get the Memory range that the PPB is decoding\r
+          //\r
+          Base = ((UINT32) Pci.Bridge.MemoryBase & 0xfff0) << 16;\r
+          Limit = (((UINT32) Pci.Bridge.MemoryLimit & 0xfff0) << 16) | 0xfffff;\r
+          if (Base < Limit) {\r
+            if (Mem.Base > Base) {\r
+              Mem.Base = Base;\r
+            }\r
+            if (Mem.Limit < Limit) {\r
+              Mem.Limit = Limit;\r
+            }\r
+          }\r
+\r
+          //\r
+          // Get the Prefetchable Memory range that the PPB is decoding\r
+          // and merge it into Memory range\r
+          //\r
+          Value = Pci.Bridge.PrefetchableMemoryBase & 0x0f;\r
+          Base = ((UINT32) Pci.Bridge.PrefetchableMemoryBase & 0xfff0) << 16;\r
+          Limit = (((UINT32) Pci.Bridge.PrefetchableMemoryLimit & 0xfff0)\r
+                   << 16) | 0xfffff;\r
+          MemAperture = &Mem;\r
+          if (Value == BIT0) {\r
+            Base |= LShiftU64 (Pci.Bridge.PrefetchableBaseUpper32, 32);\r
+            Limit |= LShiftU64 (Pci.Bridge.PrefetchableLimitUpper32, 32);\r
+            MemAperture = &MemAbove4G;\r
+          }\r
+          if (Base < Limit) {\r
+            if (MemAperture->Base > Base) {\r
+              MemAperture->Base = Base;\r
+            }\r
+            if (MemAperture->Limit < Limit) {\r
+              MemAperture->Limit = Limit;\r
+            }\r
+          }\r
+\r
+          //\r
+          // Look at the PPB Configuration for legacy decoding attributes\r
+          //\r
+          if ((Pci.Bridge.BridgeControl & EFI_PCI_BRIDGE_CONTROL_ISA)\r
+              == EFI_PCI_BRIDGE_CONTROL_ISA) {\r
+            Attributes |= EFI_PCI_ATTRIBUTE_ISA_IO;\r
+            Attributes |= EFI_PCI_ATTRIBUTE_ISA_IO_16;\r
+            Attributes |= EFI_PCI_ATTRIBUTE_ISA_MOTHERBOARD_IO;\r
+          }\r
+          if ((Pci.Bridge.BridgeControl & EFI_PCI_BRIDGE_CONTROL_VGA)\r
+              == EFI_PCI_BRIDGE_CONTROL_VGA) {\r
+            Attributes |= EFI_PCI_ATTRIBUTE_VGA_PALETTE_IO;\r
+            Attributes |= EFI_PCI_ATTRIBUTE_VGA_MEMORY;\r
+            Attributes |= EFI_PCI_ATTRIBUTE_VGA_IO;\r
+            if ((Pci.Bridge.BridgeControl & EFI_PCI_BRIDGE_CONTROL_VGA_16)\r
+                != 0) {\r
+              Attributes |= EFI_PCI_ATTRIBUTE_VGA_PALETTE_IO_16;\r
+              Attributes |= EFI_PCI_ATTRIBUTE_VGA_IO_16;\r
+            }\r
+          }\r
+\r
+          BarOffsetEnd = OFFSET_OF (PCI_TYPE01, Bridge.Bar[2]);\r
+        } else {\r
+          //\r
+          // Parse the BARs of the PCI device to get what I/O Ranges, Memory\r
+          // Ranges, and Prefetchable Memory Ranges the device is decoding\r
+          //\r
+          if ((Pci.Hdr.HeaderType & HEADER_LAYOUT_CODE) == HEADER_TYPE_DEVICE) {\r
+            BarOffsetEnd = OFFSET_OF (PCI_TYPE00, Device.Bar[6]);\r
+          }\r
+        }\r
+\r
+        PcatPciRootBridgeParseBars (\r
+          Pci.Hdr.Command,\r
+          PrimaryBus,\r
+          Device,\r
+          Function,\r
+          OFFSET_OF (PCI_TYPE00, Device.Bar),\r
+          BarOffsetEnd,\r
+          &Io,\r
+          &Mem, &MemAbove4G\r
+        );\r
+\r
+        //\r
+        // See if the PCI device is an IDE controller\r
+        //\r
+        if (IS_CLASS2 (&Pci, PCI_CLASS_MASS_STORAGE,\r
+                       PCI_CLASS_MASS_STORAGE_IDE)) {\r
+          if (Pci.Hdr.ClassCode[0] & 0x80) {\r
+            Attributes |= EFI_PCI_ATTRIBUTE_IDE_PRIMARY_IO;\r
+            Attributes |= EFI_PCI_ATTRIBUTE_IDE_SECONDARY_IO;\r
+          }\r
+          if (Pci.Hdr.ClassCode[0] & 0x01) {\r
+            Attributes |= EFI_PCI_ATTRIBUTE_IDE_PRIMARY_IO;\r
+          }\r
+          if (Pci.Hdr.ClassCode[0] & 0x04) {\r
+            Attributes |= EFI_PCI_ATTRIBUTE_IDE_SECONDARY_IO;\r
+          }\r
+        }\r
+\r
+        //\r
+        // See if the PCI device is a legacy VGA controller or\r
+        // a standard VGA controller\r
+        //\r
+        if (IS_CLASS2 (&Pci, PCI_CLASS_OLD, PCI_CLASS_OLD_VGA) ||\r
+            IS_CLASS2 (&Pci, PCI_CLASS_DISPLAY, PCI_CLASS_DISPLAY_VGA)\r
+            ) {\r
+          Attributes |= EFI_PCI_ATTRIBUTE_VGA_PALETTE_IO;\r
+          Attributes |= EFI_PCI_ATTRIBUTE_VGA_PALETTE_IO_16;\r
+          Attributes |= EFI_PCI_ATTRIBUTE_VGA_MEMORY;\r
+          Attributes |= EFI_PCI_ATTRIBUTE_VGA_IO;\r
+          Attributes |= EFI_PCI_ATTRIBUTE_VGA_IO_16;\r
+        }\r
+\r
+        //\r
+        // See if the PCI Device is a PCI - ISA or PCI - EISA\r
+        // or ISA_POSITIVE_DECODE Bridge device\r
+        //\r
+        if (Pci.Hdr.ClassCode[2] == PCI_CLASS_BRIDGE) {\r
+          if (Pci.Hdr.ClassCode[1] == PCI_CLASS_BRIDGE_ISA ||\r
+              Pci.Hdr.ClassCode[1] == PCI_CLASS_BRIDGE_EISA ||\r
+              Pci.Hdr.ClassCode[1] == PCI_CLASS_BRIDGE_ISA_PDECODE) {\r
+            Attributes |= EFI_PCI_ATTRIBUTE_ISA_IO;\r
+            Attributes |= EFI_PCI_ATTRIBUTE_ISA_IO_16;\r
+            Attributes |= EFI_PCI_ATTRIBUTE_ISA_MOTHERBOARD_IO;\r
+          }\r
+        }\r
+\r
+        //\r
+        // If this device is not a multi function device, then skip the rest\r
+        // of this PCI device\r
+        //\r
+        if (Function == 0 && !IS_PCI_MULTI_FUNC (&Pci)) {\r
+          break;\r
+        }\r
+      }\r
+    }\r
+\r
+    //\r
+    // If at least one PCI device was found on the primary bus of this PCI\r
+    // root bridge, then the PCI root bridge exists.\r
+    //\r
+    if (NumberOfDevices > 0) {\r
+      RootBridges = ReallocatePool (\r
+        (*NumberOfRootBridges) * sizeof (PCI_ROOT_BRIDGE),\r
+        (*NumberOfRootBridges + 1) * sizeof (PCI_ROOT_BRIDGE),\r
+        RootBridges\r
+      );\r
+      ASSERT (RootBridges != NULL);\r
+      PciHostBridgeUtilityInitRootBridge (\r
+        Attributes, Attributes, 0,\r
+        FALSE, PcdGet16 (PcdOvmfHostBridgePciDevId) != INTEL_Q35_MCH_DEVICE_ID,\r
+        (UINT8) PrimaryBus, (UINT8) SubBus,\r
+        &Io, &Mem, &MemAbove4G, &mNonExistAperture, &mNonExistAperture,\r
+        &RootBridges[*NumberOfRootBridges]\r
+      );\r
+      RootBridges[*NumberOfRootBridges].ResourceAssigned = TRUE;\r
+      //\r
+      // Increment the index for the next PCI Root Bridge\r
+      //\r
+      (*NumberOfRootBridges)++;\r
+    }\r
+  }\r
+\r
+  return RootBridges;\r
+}\r