[PATCH v5 3/5] Ovmf/HardwareInfoLib: Add Dxe lib to dynamically parse heterogenous data

["Ojeda Leon, Nicolas" <ncoleon@amazon.com>]

Following the Hardware Info library, create the DxeHardwareInfoLib
which implements the whole API capable of parsing heterogeneous hardware
information. The list-like API grants callers a flexible and common
pattern to retrieve the data. Moreover, the initial source is a BLOB
which generalizes the host-to-guest transmission mechanism.

The Hardware Info library main objective is to provide a way to
describe non-discoverable hardware so that the host can share the
available resources with the guest in Ovmf platforms. This change
features and embraces the main idea behind the library by providing
an API that parses a BLOB into a linked list to retrieve hardware
data from any source. Additionally, list-like APIs are provided so
that the hardware info list can be traversed conveniently.
Similarly, the capability is provided to filter results by specific
hardware types. However, heterogeneous elements can be added to the
list, increasing the flexibility. This way, a single source, for
example a fw-cfg file, can be used to describe several instances of
multiple types of hardware.

This part of the Hardware Info library makes use of dynamic memory
and is intended for stages in which memory services are available.
A motivation example is the PciHostBridgeLib. This library, part
of the PCI driver populates the list of PCI root bridges during DXE
stage for future steps to discover the resources under them. The
hardware info library can be used to obtain the detailed description
of available host bridges, for instance in the form of a fw-cfg file,
and parse that information into a dynmaic list that allows, first to
verify consistency of the data, and second discover the resources
availabe for each root bridge.

Cc: Alexander Graf <graf@amazon.de>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Nicolas Ojeda Leon <ncoleon@amazon.com>
---
 .../HardwareInfoLib/DxeHardwareInfoLib.inf    |  43 +++
 .../Library/HardwareInfoLib/HardwareInfoDxe.c | 255 ++++++++++++++++++
 OvmfPkg/OvmfPkgX64.dsc                        |   1 +
 3 files changed, 299 insertions(+)
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/DxeHardwareInfoLib.inf
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/HardwareInfoDxe.c

diff --git a/OvmfPkg/Library/HardwareInfoLib/DxeHardwareInfoLib.inf b/OvmfPkg/Library/HardwareInfoLib/DxeHardwareInfoLib.inf
new file mode 100644
index 0000000000..0a93d24b8a
--- /dev/null
+++ b/OvmfPkg/Library/HardwareInfoLib/DxeHardwareInfoLib.inf
@@ -0,0 +1,43 @@
+## @file
+#  Hardware information library to describe non-discoverable hardware resources
+#
+#  Copyright 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+#  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                    = 0x00010005
+  BASE_NAME                      = DxeHardwareInfoLib
+  FILE_GUID                      = F60B206A-5C56-11EC-AEAC-67CB080BCFF2
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = DxeHardwareInfoLib
+
+#
+# The following information is for reference only and not required by the build
+# tools.
+#
+#  VALID_ARCHITECTURES           = X64
+#
+
+[Sources]
+  HardwareInfoDxe.c
+  HardwareInfoPciHostBridgeLib.c
+  QemuFwCfgHardwareInfoLib.c
+
+[Packages]
+  MdeModulePkg/MdeModulePkg.dec
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  BaseMemoryLib
+  DebugLib
+  MemoryAllocationLib
diff --git a/OvmfPkg/Library/HardwareInfoLib/HardwareInfoDxe.c b/OvmfPkg/Library/HardwareInfoLib/HardwareInfoDxe.c
new file mode 100644
index 0000000000..4f0b51c942
--- /dev/null
+++ b/OvmfPkg/Library/HardwareInfoLib/HardwareInfoDxe.c
@@ -0,0 +1,255 @@
+/*/@file
+  Hardware info parsing functions.
+  Binary data is expected as a consecutive series of header - object pairs.
+  Complete library providing list-like interface to dynamically manipulate
+  hardware info objects and parsing from a generic blob.
+
+  Copyright 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+  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 <string.h>
+#include <Uefi/UefiBaseType.h>
+#include <Uefi/UefiSpec.h>
+#include <Library/DebugLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/BaseLib.h>
+#include <Library/UefiLib.h>
+
+#include <Library/HardwareInfoLib.h>
+
+EFI_STATUS
+CreateHardwareInfoList (
+  IN  UINT8               *Blob,
+  IN  UINTN               BlobSize,
+  IN  HARDWARE_INFO_TYPE  TypeFilter,
+  OUT LIST_ENTRY          *ListHead
+  )
+{
+  UINT8          *Index;
+  HARDWARE_INFO  *HwComponent;
+
+  if ((Blob == NULL) || (BlobSize <= 0) ||
+      (ListHead == NULL))
+  {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  Index = Blob;
+  while (Index < (Blob + BlobSize)) {
+    HwComponent = AllocateZeroPool (sizeof (HARDWARE_INFO));
+
+    if (HwComponent == NULL) {
+      goto FailedAllocate;
+    }
+
+    HwComponent->Header.Type.Uint64 = *((UINT64 *)Index);
+    Index                          += sizeof (HwComponent->Header.Type);
+    HwComponent->Header.Size        = *((UINT64 *)(Index));
+    Index                          += sizeof (HwComponent->Header.Size);
+
+    //
+    // Check if optional TypeFilter is set, skip if the current
+    // object is of a different type and release the partially
+    // allocated object
+    //
+    if ((TypeFilter != HardwareInfoTypeUndefined) &&
+        (HwComponent->Header.Type.Value != TypeFilter))
+    {
+      FreePool (HwComponent);
+      Index += HwComponent->Header.Size;
+      continue;
+    }
+
+    HwComponent->Data.Raw = AllocateZeroPool (HwComponent->Header.Size);
+    if (HwComponent->Data.Raw == NULL) {
+      goto FreeResources;
+    }
+
+    CopyMem (HwComponent->Data.Raw, Index, HwComponent->Header.Size);
+    Index += HwComponent->Header.Size;
+
+    InsertTailList (ListHead, &HwComponent->Link);
+  }
+
+  return EFI_SUCCESS;
+
+FreeResources:
+  //
+  // Clean the resources allocated in the incomplete cycle
+  //
+  FreePool (HwComponent);
+
+FailedAllocate:
+  DEBUG ((
+    EFI_D_ERROR,
+    "%a: Failed to allocate memory for hardware info\n",
+    __FUNCTION__
+    ));
+
+  return EFI_OUT_OF_RESOURCES;
+}
+
+VOID
+FreeHardwareInfoList (
+  IN OUT  LIST_ENTRY  *ListHead
+  )
+{
+  LIST_ENTRY     *CurrentLink;
+  HARDWARE_INFO  *HwComponent;
+
+  if (IsListEmpty (ListHead)) {
+    return;
+  }
+
+  CurrentLink = ListHead->ForwardLink;
+  while (CurrentLink != NULL && CurrentLink != ListHead) {
+    HwComponent = HARDWARE_INFO_FROM_LINK (CurrentLink);
+
+    //
+    // Remove item from list before invalidating the pointers
+    //
+    CurrentLink = RemoveEntryList (CurrentLink);
+
+    FreePool (HwComponent->Data.Raw);
+    FreePool (HwComponent);
+  }
+}
+
+/**
+  Validates if the specified Node has a valid data size and is of
+  specified type.
+  The data size can be less or equal to the provided type size to be
+  regarded as valid and thus accessible with the typed pointer.
+
+  For future compatibility the size is allowed to be smaller so that
+  different versions interpret fields differently and, particularly,
+  have smaller data structures. However, it cannot be larger than the
+  type size to avoid accessing memory out of bounds.
+
+  @param[in]  Node      Hardware Info node to be validated
+  @param[in]  TypeSize  Size (in bytes) of the data type intended to be
+                        used to dereference the data.
+  @retval TRUE  Node is valid and can be accessed
+  @retval FALSE Node is not valid
+/*/
+STATIC
+BOOLEAN
+IsHardwareInfoNodeValidByType (
+  IN  LIST_ENTRY          *ListHead,
+  IN  LIST_ENTRY          *Link,
+  IN  HARDWARE_INFO_TYPE  Type,
+  IN  UINTN               TypeSize
+  )
+{
+  HARDWARE_INFO  *HwComponent;
+
+  if (IsNull (ListHead, Link)) {
+    return FALSE;
+  }
+
+  HwComponent = HARDWARE_INFO_FROM_LINK (Link);
+
+  //
+  // Verify if the node type is the specified one and the size of
+  // the data allocated to the node is greater than the size of
+  // the type intended to dereference it in order to avoid access
+  // to memory out of bondaries.
+  //
+  if ((HwComponent->Header.Type.Value == Type) &&
+      (HwComponent->Header.Size >= TypeSize))
+  {
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+UINTN
+GetHardwareInfoCountByType (
+  IN  LIST_ENTRY          *ListHead,
+  IN  HARDWARE_INFO_TYPE  Type,
+  IN  UINTN               TypeSize
+  )
+{
+  UINTN       Count;
+  LIST_ENTRY  *Link;
+
+  Count = 0;
+  for (Link = GetFirstHardwareInfoByType (ListHead, Type, TypeSize);
+       !IsNull (ListHead, Link);
+       Link = GetNextHardwareInfoByType (ListHead, Link, Type, TypeSize))
+  {
+    if (IsHardwareInfoNodeValidByType (ListHead, Link, Type, TypeSize)) {
+      Count++;
+    }
+  }
+
+  return Count;
+}
+
+LIST_ENTRY *
+GetFirstHardwareInfoByType (
+  IN  LIST_ENTRY          *ListHead,
+  IN  HARDWARE_INFO_TYPE  Type,
+  IN  UINTN               TypeSize
+  )
+{
+  LIST_ENTRY  *Link;
+
+  if (IsListEmpty (ListHead)) {
+    return ListHead;
+  }
+
+  Link = GetFirstNode (ListHead);
+
+  if (IsHardwareInfoNodeValidByType (ListHead, Link, Type, TypeSize)) {
+    return Link;
+  }
+
+  return GetNextHardwareInfoByType (ListHead, Link, Type, TypeSize);
+}
+
+LIST_ENTRY *
+GetNextHardwareInfoByType (
+  IN  LIST_ENTRY          *ListHead,
+  IN  LIST_ENTRY          *Node,
+  IN  HARDWARE_INFO_TYPE  Type,
+  IN  UINTN               TypeSize
+  )
+{
+  LIST_ENTRY  *Link;
+
+  Link = GetNextNode (ListHead, Node);
+
+  while (!IsNull (ListHead, Link)) {
+    if (IsHardwareInfoNodeValidByType (ListHead, Link, Type, TypeSize)) {
+      //
+      // Found a node of specified type and with valid size. Break and
+      // return the found node.
+      //
+      break;
+    }
+
+    Link = GetNextNode (ListHead, Link);
+  }
+
+  return Link;
+}
+
+BOOLEAN
+EndOfHardwareInfoList (
+  IN  LIST_ENTRY  *ListHead,
+  IN  LIST_ENTRY  *Node
+  )
+{
+  return IsNull (ListHead, Node);
+}
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 1904b1bc63..8d1203b6f5 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -190,6 +190,7 @@
   MemEncryptSevLib|OvmfPkg/Library/BaseMemEncryptSevLib/DxeMemEncryptSevLib.inf
   MemEncryptTdxLib|OvmfPkg/Library/BaseMemEncryptTdxLib/BaseMemEncryptTdxLib.inf
   PeiHardwareInfoLib|OvmfPkg/Library/HardwareInfoLib/PeiHardwareInfoLib.inf
+  DxeHardwareInfoLib|OvmfPkg/Library/HardwareInfoLib/DxeHardwareInfoLib.inf
 
 !if $(SMM_REQUIRE) == FALSE
   LockBoxLib|OvmfPkg/Library/LockBoxLib/LockBoxBaseLib.inf
-- 
2.32.0




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