[PATCH 1/5] OvmfPkg: introduce Q35TsegSizeLib (class header and sole lib instance)

[Laszlo Ersek <lersek@redhat.com>]

OvmfPkg contains three modules that work with the TSEG (SMRAM) size:
PlatformPei (PEIM), SmmAccessPei (PEIM), and SmmAccess2Dxe (DXE_DRIVER).
These modules open-code the interpretation of the ESMRAMC register's
TSEG_SZ bit-field. That is OK as long as we stick with the Q35 hardware
spec and nothing more, but it makes it difficult to benefit from an
upcoming QEMU feature, namely extended TSEG sizes.

Introduce the Q35TsegSizeLib class, and its sole lib instance, for
extracting / centralizing TSEG size querying and interpretation. This
library instance is self contained and does not consume dynamic PCDs (for
example, it doesn't consume PcdOvmfHostBridgePciDevId), because such PCDs
tend to be set in PlatformPei, but the dispatch order between PlatformPei
and SmmAccessPei is unspecified (both have TRUE for DEPEX).

In the next few patches we're going to rebase the three listed modules to
Q35TsegSizeLib. As introduced, the library instance only captures the
currently supported TSEG sizes.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 OvmfPkg/OvmfPkg.dec                               |   5 +
 OvmfPkg/OvmfPkgIa32.dsc                           |   1 +
 OvmfPkg/OvmfPkgIa32X64.dsc                        |   1 +
 OvmfPkg/OvmfPkgX64.dsc                            |   1 +
 OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.inf |  47 +++++
 OvmfPkg/Include/Library/Q35TsegSizeLib.h          |  74 ++++++++
 OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.c   | 186 ++++++++++++++++++++
 7 files changed, 315 insertions(+)

diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 5627be0bab0a..7b9220369b95 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -27,14 +27,19 @@ [LibraryClasses]
   #
   LoadLinuxLib|Include/Library/LoadLinuxLib.h
 
   ##  @libraryclass  Save and restore variables using a file
   #
   NvVarsFileLib|Include/Library/NvVarsFileLib.h
 
+  ##  @libraryclass  Utility library to query TSEG size-related quantities on
+  #                  Q35.
+  #
+  Q35TsegSizeLib|Include/Library/Q35TsegSizeLib.h
+
   ##  @libraryclass  Access QEMU's firmware configuration interface
   #
   QemuFwCfgLib|Include/Library/QemuFwCfgLib.h
 
   ##  @libraryclass  S3 support for QEMU fw_cfg
   #
   QemuFwCfgS3Lib|Include/Library/QemuFwCfgS3Lib.h
diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
index 0647f346257a..8917c2f7b085 100644
--- a/OvmfPkg/OvmfPkgIa32.dsc
+++ b/OvmfPkg/OvmfPkgIa32.dsc
@@ -129,14 +129,15 @@ [LibraryClasses]
   UefiLib|MdePkg/Library/UefiLib/UefiLib.inf
   UefiBootServicesTableLib|MdePkg/Library/UefiBootServicesTableLib/UefiBootServicesTableLib.inf
   UefiRuntimeServicesTableLib|MdePkg/Library/UefiRuntimeServicesTableLib/UefiRuntimeServicesTableLib.inf
   UefiDriverEntryPoint|MdePkg/Library/UefiDriverEntryPoint/UefiDriverEntryPoint.inf
   UefiApplicationEntryPoint|MdePkg/Library/UefiApplicationEntryPoint/UefiApplicationEntryPoint.inf
   DevicePathLib|MdePkg/Library/UefiDevicePathLibDevicePathProtocol/UefiDevicePathLibDevicePathProtocol.inf
   NvVarsFileLib|OvmfPkg/Library/NvVarsFileLib/NvVarsFileLib.inf
+  Q35TsegSizeLib|OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.inf
   FileHandleLib|MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.inf
   UefiCpuLib|UefiCpuPkg/Library/BaseUefiCpuLib/BaseUefiCpuLib.inf
   SecurityManagementLib|MdeModulePkg/Library/DxeSecurityManagementLib/DxeSecurityManagementLib.inf
   NetLib|MdeModulePkg/Library/DxeNetLib/DxeNetLib.inf
   IpIoLib|MdeModulePkg/Library/DxeIpIoLib/DxeIpIoLib.inf
   UdpIoLib|MdeModulePkg/Library/DxeUdpIoLib/DxeUdpIoLib.inf
   DpcLib|MdeModulePkg/Library/DxeDpcLib/DxeDpcLib.inf
diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
index 1182b1858a7d..56e9c5b790d7 100644
--- a/OvmfPkg/OvmfPkgIa32X64.dsc
+++ b/OvmfPkg/OvmfPkgIa32X64.dsc
@@ -134,14 +134,15 @@ [LibraryClasses]
   UefiLib|MdePkg/Library/UefiLib/UefiLib.inf
   UefiBootServicesTableLib|MdePkg/Library/UefiBootServicesTableLib/UefiBootServicesTableLib.inf
   UefiRuntimeServicesTableLib|MdePkg/Library/UefiRuntimeServicesTableLib/UefiRuntimeServicesTableLib.inf
   UefiDriverEntryPoint|MdePkg/Library/UefiDriverEntryPoint/UefiDriverEntryPoint.inf
   UefiApplicationEntryPoint|MdePkg/Library/UefiApplicationEntryPoint/UefiApplicationEntryPoint.inf
   DevicePathLib|MdePkg/Library/UefiDevicePathLibDevicePathProtocol/UefiDevicePathLibDevicePathProtocol.inf
   NvVarsFileLib|OvmfPkg/Library/NvVarsFileLib/NvVarsFileLib.inf
+  Q35TsegSizeLib|OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.inf
   FileHandleLib|MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.inf
   UefiCpuLib|UefiCpuPkg/Library/BaseUefiCpuLib/BaseUefiCpuLib.inf
   SecurityManagementLib|MdeModulePkg/Library/DxeSecurityManagementLib/DxeSecurityManagementLib.inf
   NetLib|MdeModulePkg/Library/DxeNetLib/DxeNetLib.inf
   IpIoLib|MdeModulePkg/Library/DxeIpIoLib/DxeIpIoLib.inf
   UdpIoLib|MdeModulePkg/Library/DxeUdpIoLib/DxeUdpIoLib.inf
   DpcLib|MdeModulePkg/Library/DxeDpcLib/DxeDpcLib.inf
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 636dfb1b5638..618b72bffa80 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -134,14 +134,15 @@ [LibraryClasses]
   UefiLib|MdePkg/Library/UefiLib/UefiLib.inf
   UefiBootServicesTableLib|MdePkg/Library/UefiBootServicesTableLib/UefiBootServicesTableLib.inf
   UefiRuntimeServicesTableLib|MdePkg/Library/UefiRuntimeServicesTableLib/UefiRuntimeServicesTableLib.inf
   UefiDriverEntryPoint|MdePkg/Library/UefiDriverEntryPoint/UefiDriverEntryPoint.inf
   UefiApplicationEntryPoint|MdePkg/Library/UefiApplicationEntryPoint/UefiApplicationEntryPoint.inf
   DevicePathLib|MdePkg/Library/UefiDevicePathLibDevicePathProtocol/UefiDevicePathLibDevicePathProtocol.inf
   NvVarsFileLib|OvmfPkg/Library/NvVarsFileLib/NvVarsFileLib.inf
+  Q35TsegSizeLib|OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.inf
   FileHandleLib|MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.inf
   UefiCpuLib|UefiCpuPkg/Library/BaseUefiCpuLib/BaseUefiCpuLib.inf
   SecurityManagementLib|MdeModulePkg/Library/DxeSecurityManagementLib/DxeSecurityManagementLib.inf
   NetLib|MdeModulePkg/Library/DxeNetLib/DxeNetLib.inf
   IpIoLib|MdeModulePkg/Library/DxeIpIoLib/DxeIpIoLib.inf
   UdpIoLib|MdeModulePkg/Library/DxeUdpIoLib/DxeUdpIoLib.inf
   DpcLib|MdeModulePkg/Library/DxeDpcLib/DxeDpcLib.inf
diff --git a/OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.inf b/OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.inf
new file mode 100644
index 000000000000..8f99e55b8c48
--- /dev/null
+++ b/OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.inf
@@ -0,0 +1,47 @@
+## @file
+# Utility library to query TSEG size-related quantities on Q35.
+#
+# Copyright (C) 2017, 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                    = 1.25
+  BASE_NAME                      = Q35TsegSizeLib
+  FILE_GUID                      = 6019578F-0078-46D4-86EE-06C486A304D2
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = Q35TsegSizeLib|PEIM DXE_DRIVER
+
+#
+# The following information is for reference only and not required by the build
+# tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64
+#
+
+[Sources]
+  Q35TsegSizeLib.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  PcdLib
+  PciLib
+
+[FeaturePcd]
+  gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
+
+[FixedPcd]
+  gUefiOvmfPkgTokenSpaceGuid.PcdQ35TsegMbytes
diff --git a/OvmfPkg/Include/Library/Q35TsegSizeLib.h b/OvmfPkg/Include/Library/Q35TsegSizeLib.h
new file mode 100644
index 000000000000..580ef6887931
--- /dev/null
+++ b/OvmfPkg/Include/Library/Q35TsegSizeLib.h
@@ -0,0 +1,74 @@
+/** @file
+  Utility library to query TSEG size-related quantities on Q35.
+
+  Copyright (C) 2017, 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 __Q35_TSEG_SIZE_LIB__
+#define __Q35_TSEG_SIZE_LIB__
+
+/**
+  Query the preferred size of TSEG, in megabytes.
+
+  The caller is responsible for calling this function only on the Q35 board. If
+  the function is called on another board, the function logs an informative
+  error message and does not return.
+
+  @return  The preferred size of TSEG, expressed in megabytes.
+**/
+UINT16
+EFIAPI
+Q35TsegSizeGetPreferredMbytes (
+  VOID
+  );
+
+/**
+  Query the ESMRAMC.TSEG_SZ bit-field value that corresponds to the preferred
+  TSEG size.
+
+  The caller is responsible for calling this function only on the Q35 board. If
+  the function is called on another board, the function logs an informative
+  error message and does not return.
+
+  @return  The ESMRAMC.TSEG_SZ bit-field value that corresponds to the
+           preferred TSEG size. The return value is a subset of
+           MCH_ESMRAMC_TSEG_MASK, defined in <IndustryStandard/Q35MchIch9.h>.
+**/
+UINT8
+EFIAPI
+Q35TsegSizeGetPreferredEsmramcTsegSzMask (
+  VOID
+  );
+
+/**
+  Extract the TSEG_SZ bit-field from the passed in ESMRAMC register value, and
+  return the number of megabytes that it represents.
+
+  The caller is responsible for calling this function only on the Q35 board. If
+  the function is called on another board, the function logs an informative
+  error message and does not return.
+
+  @param[in] EsmramcVal  The ESMRAMC register value to extract the TSEG_SZ
+                         bit-field from, using MCH_ESMRAMC_TSEG_MASK from
+                         <IndustryStandard/Q35MchIch9.h>. If the extracted
+                         bit-field cannot be mapped to a MB count, the function
+                         logs an error message and does not return.
+
+  @return  The number of megabytes that the extracted TSEG_SZ bit-field
+           represents.
+**/
+UINT16
+EFIAPI
+Q35TsegSizeConvertEsmramcValToMbytes (
+  IN UINT8 EsmramcVal
+  );
+
+#endif
diff --git a/OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.c b/OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.c
new file mode 100644
index 000000000000..db57a8b308de
--- /dev/null
+++ b/OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.c
@@ -0,0 +1,186 @@
+/** @file
+  Utility library to query TSEG size-related quantities on Q35.
+
+  Copyright (C) 2017, 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 <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/PcdLib.h>
+#include <Library/PciLib.h>
+#include <Library/Q35TsegSizeLib.h>
+#include <OvmfPlatforms.h>
+
+STATIC BOOLEAN mPreferencesInitialized;
+STATIC UINT8   mPreferredEsmramcTsegSzMask;
+
+/**
+  Fetch the preferences into static variables that are going to be used by the
+  public functions of this library instance.
+
+  The Q35 board requirement documented on those interfaces is commonly enforced
+  here.
+**/
+STATIC
+VOID
+Q35TsegSizeGetPreferences (
+  VOID
+  )
+{
+  UINT16 HostBridgeDevId;
+
+  if (mPreferencesInitialized) {
+    return;
+  }
+
+  //
+  // This function should only be reached if SMRAM support is required.
+  //
+  ASSERT (FeaturePcdGet (PcdSmmSmramRequire));
+
+  HostBridgeDevId = PciRead16 (OVMF_HOSTBRIDGE_DID);
+  if (HostBridgeDevId != INTEL_Q35_MCH_DEVICE_ID) {
+    DEBUG ((
+      DEBUG_ERROR,
+      "%a: %a: no TSEG (SMRAM) on host bridge DID=0x%04x; "
+      "only DID=0x%04x (Q35) is supported\n",
+      gEfiCallerBaseName,
+      __FUNCTION__,
+      HostBridgeDevId,
+      INTEL_Q35_MCH_DEVICE_ID
+      ));
+    ASSERT (FALSE);
+    CpuDeadLoop ();
+  }
+
+  mPreferencesInitialized = TRUE;
+
+  switch (FixedPcdGet8 (PcdQ35TsegMbytes)) {
+  case 1:
+    mPreferredEsmramcTsegSzMask = MCH_ESMRAMC_TSEG_1MB;
+    break;
+  case 2:
+    mPreferredEsmramcTsegSzMask = MCH_ESMRAMC_TSEG_2MB;
+    break;
+  case 8:
+    mPreferredEsmramcTsegSzMask = MCH_ESMRAMC_TSEG_8MB;
+    break;
+  default:
+    ASSERT (FALSE);
+  }
+}
+
+
+/**
+  Query the preferred size of TSEG, in megabytes.
+
+  The caller is responsible for calling this function only on the Q35 board. If
+  the function is called on another board, the function logs an informative
+  error message and does not return.
+
+  @return  The preferred size of TSEG, expressed in megabytes.
+**/
+UINT16
+EFIAPI
+Q35TsegSizeGetPreferredMbytes (
+  VOID
+  )
+{
+  //
+  // Query the ESMRAMC.TSEG_SZ preference and convert it to megabytes.
+  //
+  return Q35TsegSizeConvertEsmramcValToMbytes (
+           Q35TsegSizeGetPreferredEsmramcTsegSzMask ()
+           );
+}
+
+
+/**
+  Query the ESMRAMC.TSEG_SZ bit-field value that corresponds to the preferred
+  TSEG size.
+
+  The caller is responsible for calling this function only on the Q35 board. If
+  the function is called on another board, the function logs an informative
+  error message and does not return.
+
+  @return  The ESMRAMC.TSEG_SZ bit-field value that corresponds to the
+           preferred TSEG size. The return value is a subset of
+           MCH_ESMRAMC_TSEG_MASK, defined in <IndustryStandard/Q35MchIch9.h>.
+**/
+UINT8
+EFIAPI
+Q35TsegSizeGetPreferredEsmramcTsegSzMask (
+  VOID
+  )
+{
+  Q35TsegSizeGetPreferences ();
+  return mPreferredEsmramcTsegSzMask;
+}
+
+
+/**
+  Extract the TSEG_SZ bit-field from the passed in ESMRAMC register value, and
+  return the number of megabytes that it represents.
+
+  The caller is responsible for calling this function only on the Q35 board. If
+  the function is called on another board, the function logs an informative
+  error message and does not return.
+
+  @param[in] EsmramcVal  The ESMRAMC register value to extract the TSEG_SZ
+                         bit-field from, using MCH_ESMRAMC_TSEG_MASK from
+                         <IndustryStandard/Q35MchIch9.h>. If the extracted
+                         bit-field cannot be mapped to a MB count, the function
+                         logs an error message and does not return.
+
+  @return  The number of megabytes that the extracted TSEG_SZ bit-field
+           represents.
+**/
+UINT16
+EFIAPI
+Q35TsegSizeConvertEsmramcValToMbytes (
+  IN UINT8 EsmramcVal
+  )
+{
+  UINT8  TsegSizeBits;
+  UINT16 Mbytes;
+
+  Q35TsegSizeGetPreferences ();
+
+  TsegSizeBits = EsmramcVal & MCH_ESMRAMC_TSEG_MASK;
+  switch (TsegSizeBits) {
+  case MCH_ESMRAMC_TSEG_1MB:
+    Mbytes = 1;
+    break;
+  case MCH_ESMRAMC_TSEG_2MB:
+    Mbytes = 2;
+    break;
+  case MCH_ESMRAMC_TSEG_8MB:
+    Mbytes = 8;
+    break;
+  default:
+    DEBUG ((
+      DEBUG_ERROR,
+      "%a: %a: unknown TsegSizeBits=0x%02x\n",
+      gEfiCallerBaseName,
+      __FUNCTION__,
+      TsegSizeBits
+      ));
+    ASSERT (FALSE);
+    CpuDeadLoop ();
+
+    //
+    // Keep compilers happy.
+    //
+    Mbytes = 0;
+  }
+
+  return Mbytes;
+}
-- 
2.9.3