OvmfPkg: QemuFwCfgLib: implement for SEC

The QemuFwCfgSecLib library instance
- is stateless,
- has no library constructor,
- is available to SEC client code,
- must be queried with QemuFwCfgIsAvailable() before use,
- is restricted to SEC in order to limit the explicit querying
  requirement. (There is no current user.)

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15046 6f19259b-4bc3-4df7-8a09-765794883524

5 files changed, 138 insertions, 0 deletions

diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c
new file mode 100644
index 0000000000..88c32ce89a
--- /dev/null
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSec.c
@@ -0,0 +1,81 @@
+/** @file

+

+  Stateless fw_cfg library implementation.

+

+  Clients must call QemuFwCfgIsAvailable() first.

+

+  Copyright (C) 2013, Red Hat, Inc.

+  Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>

+

+  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/DebugLib.h>

+#include <Library/QemuFwCfgLib.h>

+

+

+/**

+  Returns a boolean indicating if the firmware configuration interface

+  is available or not.

+

+  This function may change fw_cfg state.

+

+  @retval    TRUE   The interface is available

+  @retval    FALSE  The interface is not available

+

+**/

+BOOLEAN

+EFIAPI

+QemuFwCfgIsAvailable (

+  VOID

+  )

+{

+  UINT32 Signature;

+  UINT32 Revision;

+

+  QemuFwCfgSelectItem (QemuFwCfgItemSignature);

+  Signature = QemuFwCfgRead32 ();

+  DEBUG ((EFI_D_INFO, "FW CFG Signature: 0x%x\n", Signature));

+  QemuFwCfgSelectItem (QemuFwCfgItemInterfaceVersion);

+  Revision = QemuFwCfgRead32 ();

+  DEBUG ((EFI_D_INFO, "FW CFG Revision: 0x%x\n", Revision));

+  if ((Signature != SIGNATURE_32 ('Q', 'E', 'M', 'U')) ||

+      (Revision < 1)

+     ) {

+    DEBUG ((EFI_D_INFO, "QemuFwCfg interface not supported.\n"));

+    return FALSE;

+  }

+

+  DEBUG ((EFI_D_INFO, "QemuFwCfg interface is supported.\n"));

+  return TRUE;

+}

+

+

+/**

+  Returns a boolean indicating if the firmware configuration interface is

+  available for library-internal purposes.

+

+  This function never changes fw_cfg state.

+

+  @retval    TRUE   The interface is available internally.

+  @retval    FALSE  The interface is not available internally.

+**/

+BOOLEAN

+EFIAPI

+InternalQemuFwCfgIsAvailable (

+  VOID

+  )

+{

+  //

+  // We always return TRUE, because the consumer of this library ought to have

+  // called QemuFwCfgIsAvailable before making other calls which would hit this

+  // path.

+  //

+  return TRUE;

+}

diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf
new file mode 100644
index 0000000000..71beacbaf9
--- /dev/null
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf
@@ -0,0 +1,54 @@
+## @file

+#

+#  Stateless fw_cfg library that must be queried before use.

+#

+#  Copyright (C) 2013, Red Hat, Inc.

+#  Copyright (c) 2008 - 2012, Intel Corporation. All rights reserved.<BR>

+#

+#  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                      = QemuFwCfgSecLib

+  FILE_GUID                      = 60a910e5-7443-413d-9a30-97e57497cd1b

+  MODULE_TYPE                    = BASE

+  VERSION_STRING                 = 1.0

+  LIBRARY_CLASS                  = QemuFwCfgLib|SEC

+

+#

+# The following information is for reference only and not required by the build tools.

+#

+#  VALID_ARCHITECTURES           = IA32 X64

+#

+

+[Sources]

+  QemuFwCfgLib.c

+  QemuFwCfgSec.c

+

+[Sources.IA32]

+  Ia32/IoLibExAsm.asm

+  Ia32/IoLibExAsm.S

+

+[Sources.X64]

+  X64/IoLibExAsm.asm

+  X64/IoLibExAsm.S

+

+[Packages]

+  MdePkg/MdePkg.dec

+  OvmfPkg/OvmfPkg.dec

+

+[LibraryClasses]

+  BaseLib

+  BaseMemoryLib

+  DebugLib

+  IoLib

+  MemoryAllocationLib

+

diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
index 2e13e0ed5d..c7c90fb3dc 100644
--- a/OvmfPkg/OvmfPkgIa32.dsc
+++ b/OvmfPkg/OvmfPkgIa32.dsc
@@ -127,6 +127,7 @@
 !endif

 

 [LibraryClasses.common.SEC]

+  QemuFwCfgLib|OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf

 !ifdef $(DEBUG_ON_SERIAL_PORT)

   DebugLib|MdePkg/Library/BaseDebugLibSerialPort/BaseDebugLibSerialPort.inf

 !else

diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
index 64404a6647..b8c569a149 100644
--- a/OvmfPkg/OvmfPkgIa32X64.dsc
+++ b/OvmfPkg/OvmfPkgIa32X64.dsc
@@ -132,6 +132,7 @@
 !endif

 

 [LibraryClasses.common.SEC]

+  QemuFwCfgLib|OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf

 !ifdef $(DEBUG_ON_SERIAL_PORT)

   DebugLib|MdePkg/Library/BaseDebugLibSerialPort/BaseDebugLibSerialPort.inf

 !else

diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 467260717e..7b1fa52174 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -132,6 +132,7 @@
 !endif

 

 [LibraryClasses.common.SEC]

+  QemuFwCfgLib|OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgSecLib.inf

 !ifdef $(DEBUG_ON_SERIAL_PORT)

   DebugLib|MdePkg/Library/BaseDebugLibSerialPort/BaseDebugLibSerialPort.inf

 !else