[PATCH v2 2/7] OvmfPkg: introduce PciCapPciSegmentLib

[Laszlo Ersek <lersek@redhat.com>]

Add a library class, and a BASE lib instance, that are layered on top of
PciCapLib, and allow clients to plug a PciSegmentLib backend into
PciCapLib, for config space access.

(Side note:

The "MaxDomain" parameter is provided because, in practice, platforms
exist where a PCI Express device may show up on a root bridge such that
the root bridge doesn't support access to extended config space. Earlier
the same issue was handled for MdeModulePkg/PciHostBridgeDxe in commit
014b472053ae3. However, that solution does not apply to the PciSegmentLib
class, because:

(1) The config space accessor functions of the PciSegmentLib class, such
    as PciSegmentReadBuffer(), have no way of informing the caller whether
    access to extended config space actually succeeds.

    (For example, in the UefiPciSegmentLibPciRootBridgeIo instace, which
    could in theory benefit from commit 014b472053ae3, the
    EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Pci.Read() status code is explicitly
    ignored, because there's no way for the lib instance to propagate it
    to the PciSegmentLib caller. If the
    EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Pci.Read() call fails, then
    DxePciSegmentLibPciRootBridgeIoReadWorker() returns Data with
    indeterminate value.)

(2) There is no *general* way for any firmware platform to provide, or
    use, a PciSegmentLib instance in which access to extended config space
    always succeeds.

In brief, on a platform where config space may be limited to 256 bytes,
access to extended config space through PciSegmentLib may invoke undefined
behavior; therefore PciCapPciSegmentLib must give platforms a way to
prevent such access.)

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---

Notes:
    v2:
    - move library from MdePkg to OvmfPkg, for initial introduction

 OvmfPkg/OvmfPkg.dec                                                 |   5 +
 OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.inf |  35 +++
 OvmfPkg/Include/Library/PciCapPciSegmentLib.h                       |  82 +++++++
 OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.h   |  47 ++++
 OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.c   | 226 ++++++++++++++++++++
 5 files changed, 395 insertions(+)

diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 74818a2e2a19..fbec1cfe4a8e 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -35,6 +35,11 @@ [LibraryClasses]
   #                  config space.
   PciCapLib|Include/Library/PciCapLib.h
 
+  ##  @libraryclass  Layered on top of PciCapLib, allows clients to plug a
+  #                  PciSegmentLib backend into PciCapLib, for config space
+  #                  access.
+  PciCapPciSegmentLib|Include/Library/PciCapPciSegmentLib.h
+
   ##  @libraryclass  Access QEMU's firmware configuration interface
   #
   QemuFwCfgLib|Include/Library/QemuFwCfgLib.h
diff --git a/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.inf b/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.inf
new file mode 100644
index 000000000000..e3cf5de49b15
--- /dev/null
+++ b/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.inf
@@ -0,0 +1,35 @@
+## @file
+# Plug a PciSegmentLib backend into PciCapLib, for config space access.
+#
+# Copyright (C) 2018, Red Hat, Inc.
+#
+# This program and the accompanying materials are licensed and made available
+# under the terms and conditions of the BSD License which accompanies this
+# distribution.  The full text of the license may be found at
+# http://opensource.org/licenses/bsd-license.php
+#
+# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+# WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+##
+
+[Defines]
+  INF_VERSION    = 1.27
+  BASE_NAME      = BasePciCapPciSegmentLib
+  FILE_GUID      = ED011855-AA31-43B9-ACC0-BF45A05C5985
+  MODULE_TYPE    = BASE
+  VERSION_STRING = 1.0
+  LIBRARY_CLASS  = PciCapPciSegmentLib
+
+[Sources]
+  BasePciCapPciSegmentLib.h
+  BasePciCapPciSegmentLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  MemoryAllocationLib
+  PciSegmentLib
diff --git a/OvmfPkg/Include/Library/PciCapPciSegmentLib.h b/OvmfPkg/Include/Library/PciCapPciSegmentLib.h
new file mode 100644
index 000000000000..6b6930288d16
--- /dev/null
+++ b/OvmfPkg/Include/Library/PciCapPciSegmentLib.h
@@ -0,0 +1,82 @@
+/** @file
+  Library class layered on top of PciCapLib that allows clients to plug a
+  PciSegmentLib backend into PciCapLib, for config space access.
+
+  Copyright (C) 2018, Red Hat, Inc.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#ifndef __PCI_CAP_PCI_SEGMENT_LIB_H__
+#define __PCI_CAP_PCI_SEGMENT_LIB_H__
+
+#include <Library/PciCapLib.h>
+
+
+/**
+  Create a PCI_CAP_DEV object from the PCI Segment:Bus:Device.Function
+  quadruplet. The config space accessors are based upon PciSegmentLib.
+
+  @param[in] MaxDomain   If MaxDomain is PciCapExtended, then
+                         PciDevice->ReadConfig() and PciDevice->WriteConfig()
+                         will delegate extended config space accesses too to
+                         PciSegmentReadBuffer() and PciSegmentWriteBuffer(),
+                         respectively. Otherwise, PciDevice->ReadConfig() and
+                         PciDevice->WriteConfig() will reject accesses to
+                         extended config space with RETURN_UNSUPPORTED, without
+                         calling PciSegmentReadBuffer() or
+                         PciSegmentWriteBuffer(). By setting MaxDomain to
+                         PciCapNormal, the platform can prevent undefined
+                         PciSegmentLib behavior when the PCI root bridge under
+                         the PCI device at Segment:Bus:Device.Function doesn't
+                         support extended config space.
+
+  @param[in] Segment     16-bit wide segment number.
+
+  @param[in] Bus         8-bit wide bus number.
+
+  @param[in] Device      5-bit wide device number.
+
+  @param[in] Function    3-bit wide function number.
+
+  @param[out] PciDevice  The PCI_CAP_DEV object constructed as described above.
+                         PciDevice can be passed to the PciCapLib APIs.
+
+  @retval RETURN_SUCCESS            PciDevice has been constructed and output.
+
+  @retval RETURN_INVALID_PARAMETER  Device or Function does not fit in the
+                                    permitted number of bits.
+
+  @retval RETURN_OUT_OF_RESOURCES   Memory allocation failed.
+**/
+RETURN_STATUS
+EFIAPI
+PciCapPciSegmentDeviceInit (
+  IN  PCI_CAP_DOMAIN MaxDomain,
+  IN  UINT16         Segment,
+  IN  UINT8          Bus,
+  IN  UINT8          Device,
+  IN  UINT8          Function,
+  OUT PCI_CAP_DEV    **PciDevice
+  );
+
+
+/**
+  Free the resources used by PciDevice.
+
+  @param[in] PciDevice  The PCI_CAP_DEV object to free, originally produced by
+                        PciCapPciSegmentDeviceInit().
+**/
+VOID
+EFIAPI
+PciCapPciSegmentDeviceUninit (
+  IN PCI_CAP_DEV *PciDevice
+  );
+
+#endif // __PCI_CAP_PCI_SEGMENT_LIB_H__
diff --git a/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.h b/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.h
new file mode 100644
index 000000000000..3ce15fe0fb57
--- /dev/null
+++ b/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.h
@@ -0,0 +1,47 @@
+/** @file
+  Plug a PciSegmentLib backend into PciCapLib, for config space access --
+  internal macro and type definitions.
+
+  Copyright (C) 2018, Red Hat, Inc.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#ifndef __BASE_PCI_CAP_PCI_SEGMENT_LIB_H__
+#define __BASE_PCI_CAP_PCI_SEGMENT_LIB_H__
+
+#include <Library/DebugLib.h>
+
+#include <Library/PciCapPciSegmentLib.h>
+
+#define SEGMENT_DEV_SIG SIGNATURE_64 ('P', 'C', 'P', 'S', 'G', 'M', 'N', 'T')
+
+typedef struct {
+  //
+  // Signature identifying the derived class.
+  //
+  UINT64 Signature;
+  //
+  // Members added by the derived class, specific to the use of PciSegmentLib.
+  //
+  PCI_CAP_DOMAIN MaxDomain;
+  UINT16         SegmentNr;
+  UINT8          BusNr;
+  UINT8          DeviceNr;
+  UINT8          FunctionNr;
+  //
+  // Base class.
+  //
+  PCI_CAP_DEV BaseDevice;
+} SEGMENT_DEV;
+
+#define SEGMENT_DEV_FROM_PCI_CAP_DEV(PciDevice) \
+  CR (PciDevice, SEGMENT_DEV, BaseDevice, SEGMENT_DEV_SIG)
+
+#endif // __BASE_PCI_CAP_PCI_SEGMENT_LIB_H__
diff --git a/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.c b/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.c
new file mode 100644
index 000000000000..57eb6b625b56
--- /dev/null
+++ b/OvmfPkg/Library/BasePciCapPciSegmentLib/BasePciCapPciSegmentLib.c
@@ -0,0 +1,226 @@
+/** @file
+  Plug a PciSegmentLib backend into PciCapLib, for config space access.
+
+  Copyright (C) 2018, Red Hat, Inc.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include <IndustryStandard/Pci23.h>
+
+#include <Library/BaseLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/PciSegmentLib.h>
+
+#include "BasePciCapPciSegmentLib.h"
+
+
+/**
+  Read the config space of a given PCI device (both normal and extended).
+
+  SegmentDevReadConfig() performs as few config space accesses as possible
+  (without attempting 64-bit wide accesses).
+
+  @param[in] PciDevice           Implementation-specific unique representation
+                                 of the PCI device in the PCI hierarchy.
+
+  @param[in] SourceOffset        Source offset in the config space of the PCI
+                                 device to start reading from.
+
+  @param[out] DestinationBuffer  Buffer to store the read data to.
+
+  @param[in] Size                The number of bytes to transfer.
+
+  @retval RETURN_SUCCESS      Size bytes have been transferred from config
+                              space to DestinationBuffer.
+
+  @retval RETURN_UNSUPPORTED  Accessing Size bytes from SourceOffset exceeds
+                              the config space limit of the PCI device.
+                              Although PCI_CAP_DEV_READ_CONFIG allows reading
+                              fewer than Size bytes in this case,
+                              SegmentDevReadConfig() will read none.
+**/
+STATIC
+RETURN_STATUS
+EFIAPI
+SegmentDevReadConfig (
+  IN  PCI_CAP_DEV *PciDevice,
+  IN  UINT16      SourceOffset,
+  OUT VOID        *DestinationBuffer,
+  IN  UINT16      Size
+  )
+{
+  SEGMENT_DEV *SegmentDev;
+  UINT16      ConfigSpaceSize;
+  UINT64      SourceAddress;
+
+  SegmentDev = SEGMENT_DEV_FROM_PCI_CAP_DEV (PciDevice);
+  ConfigSpaceSize = (SegmentDev->MaxDomain == PciCapNormal ?
+                     PCI_MAX_CONFIG_OFFSET : PCI_EXP_MAX_CONFIG_OFFSET);
+  //
+  // Note that all UINT16 variables below are promoted to INT32, and the
+  // addition and the comparison is carried out in INT32.
+  //
+  if (SourceOffset + Size > ConfigSpaceSize) {
+    return RETURN_UNSUPPORTED;
+  }
+  SourceAddress = PCI_SEGMENT_LIB_ADDRESS (SegmentDev->SegmentNr,
+                    SegmentDev->BusNr, SegmentDev->DeviceNr,
+                    SegmentDev->FunctionNr, SourceOffset);
+  PciSegmentReadBuffer (SourceAddress, Size, DestinationBuffer);
+  return RETURN_SUCCESS;
+}
+
+
+/**
+  Write the config space of a given PCI device (both normal and extended).
+
+  SegmentDevWriteConfig() performs as few config space accesses as possible
+  (without attempting 64-bit wide accesses).
+
+  @param[in] PciDevice          Implementation-specific unique representation
+                                of the PCI device in the PCI hierarchy.
+
+  @param[in] DestinationOffset  Destination offset in the config space of the
+                                PCI device to start writing at.
+
+  @param[in] SourceBuffer       Buffer to read the data to be stored from.
+
+  @param[in] Size               The number of bytes to transfer.
+
+  @retval RETURN_SUCCESS      Size bytes have been transferred from
+                              SourceBuffer to config space.
+
+  @retval RETURN_UNSUPPORTED  Accessing Size bytes at DestinationOffset exceeds
+                              the config space limit of the PCI device.
+                              Although PCI_CAP_DEV_WRITE_CONFIG allows writing
+                              fewer than Size bytes in this case,
+                              SegmentDevWriteConfig() will write none.
+**/
+STATIC
+RETURN_STATUS
+EFIAPI
+SegmentDevWriteConfig (
+  IN PCI_CAP_DEV *PciDevice,
+  IN UINT16      DestinationOffset,
+  IN VOID        *SourceBuffer,
+  IN UINT16      Size
+  )
+{
+  SEGMENT_DEV *SegmentDev;
+  UINT16      ConfigSpaceSize;
+  UINT64      DestinationAddress;
+
+  SegmentDev = SEGMENT_DEV_FROM_PCI_CAP_DEV (PciDevice);
+  ConfigSpaceSize = (SegmentDev->MaxDomain == PciCapNormal ?
+                     PCI_MAX_CONFIG_OFFSET : PCI_EXP_MAX_CONFIG_OFFSET);
+  //
+  // Note that all UINT16 variables below are promoted to INT32, and the
+  // addition and the comparison is carried out in INT32.
+  //
+  if (DestinationOffset + Size > ConfigSpaceSize) {
+    return RETURN_UNSUPPORTED;
+  }
+  DestinationAddress = PCI_SEGMENT_LIB_ADDRESS (SegmentDev->SegmentNr,
+                         SegmentDev->BusNr, SegmentDev->DeviceNr,
+                         SegmentDev->FunctionNr, DestinationOffset);
+  PciSegmentWriteBuffer (DestinationAddress, Size, SourceBuffer);
+  return RETURN_SUCCESS;
+}
+
+
+/**
+  Create a PCI_CAP_DEV object from the PCI Segment:Bus:Device.Function
+  quadruplet. The config space accessors are based upon PciSegmentLib.
+
+  @param[in] MaxDomain   If MaxDomain is PciCapExtended, then
+                         PciDevice->ReadConfig() and PciDevice->WriteConfig()
+                         will delegate extended config space accesses too to
+                         PciSegmentReadBuffer() and PciSegmentWriteBuffer(),
+                         respectively. Otherwise, PciDevice->ReadConfig() and
+                         PciDevice->WriteConfig() will reject accesses to
+                         extended config space with RETURN_UNSUPPORTED, without
+                         calling PciSegmentReadBuffer() or
+                         PciSegmentWriteBuffer(). By setting MaxDomain to
+                         PciCapNormal, the platform can prevent undefined
+                         PciSegmentLib behavior when the PCI root bridge under
+                         the PCI device at Segment:Bus:Device.Function doesn't
+                         support extended config space.
+
+  @param[in] Segment     16-bit wide segment number.
+
+  @param[in] Bus         8-bit wide bus number.
+
+  @param[in] Device      5-bit wide device number.
+
+  @param[in] Function    3-bit wide function number.
+
+  @param[out] PciDevice  The PCI_CAP_DEV object constructed as described above.
+                         PciDevice can be passed to the PciCapLib APIs.
+
+  @retval RETURN_SUCCESS            PciDevice has been constructed and output.
+
+  @retval RETURN_INVALID_PARAMETER  Device or Function does not fit in the
+                                    permitted number of bits.
+
+  @retval RETURN_OUT_OF_RESOURCES   Memory allocation failed.
+**/
+RETURN_STATUS
+EFIAPI
+PciCapPciSegmentDeviceInit (
+  IN  PCI_CAP_DOMAIN MaxDomain,
+  IN  UINT16         Segment,
+  IN  UINT8          Bus,
+  IN  UINT8          Device,
+  IN  UINT8          Function,
+  OUT PCI_CAP_DEV    **PciDevice
+  )
+{
+  SEGMENT_DEV *SegmentDev;
+
+  if (Device > PCI_MAX_DEVICE || Function > PCI_MAX_FUNC) {
+    return RETURN_INVALID_PARAMETER;
+  }
+
+  SegmentDev = AllocatePool (sizeof *SegmentDev);
+  if (SegmentDev == NULL) {
+    return RETURN_OUT_OF_RESOURCES;
+  }
+
+  SegmentDev->Signature              = SEGMENT_DEV_SIG;
+  SegmentDev->MaxDomain              = MaxDomain;
+  SegmentDev->SegmentNr              = Segment;
+  SegmentDev->BusNr                  = Bus;
+  SegmentDev->DeviceNr               = Device;
+  SegmentDev->FunctionNr             = Function;
+  SegmentDev->BaseDevice.ReadConfig  = SegmentDevReadConfig;
+  SegmentDev->BaseDevice.WriteConfig = SegmentDevWriteConfig;
+
+  *PciDevice = &SegmentDev->BaseDevice;
+  return RETURN_SUCCESS;
+}
+
+
+/**
+  Free the resources used by PciDevice.
+
+  @param[in] PciDevice  The PCI_CAP_DEV object to free, originally produced by
+                        PciCapPciSegmentDeviceInit().
+**/
+VOID
+EFIAPI
+PciCapPciSegmentDeviceUninit (
+  IN PCI_CAP_DEV *PciDevice
+  )
+{
+  SEGMENT_DEV *SegmentDev;
+
+  SegmentDev = SEGMENT_DEV_FROM_PCI_CAP_DEV (PciDevice);
+  FreePool (SegmentDev);
+}
-- 
2.14.1.3.gb7cf6e02401b