From: Marc-André Lureau <>

This module measures and log the boot environment. It also produces
the Tcg2 protocol, which allows for example to read the log from OS.

The linux kernel doesn't yet read the EFI_TCG2_EVENT_LOG_FORMAT_TCG_2,
which is required for crypto-agile log. In fact, only upcoming 4.16
adds support EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2:

[    0.000000] efi: EFI v2.70 by EDK II
[    0.000000] efi:  SMBIOS=0x3fa1f000  ACPI=0x3fbb6000  ACPI 2.0=0x3fbb6014  
MEMATTR=0x3e7d4318  TPMEventLog=0x3db21018

$ python tpm parse_log binary_bios_measurements

[CHIPSEC] Version 1.3.5.dev2
[CHIPSEC] API mode: using OS native API (not using CHIPSEC kernel module)
[CHIPSEC] Executing command 'tpm' with args ['parse_log', 

PCR: 0  type: EV_S_CRTM_VERSION                 size: 0x2       digest: 
        + version:
PCR: 0  type: EV_EFI_PLATFORM_FIRMWARE_BLOB     size: 0x10      digest: 
        + base: 0x820000        length: 0xe0000
PCR: 0  type: EV_EFI_PLATFORM_FIRMWARE_BLOB     size: 0x10      digest: 
        + base: 0x900000        length: 0xa00000
PCR: 7  type: EV_EFI_VARIABLE_DRIVER_CONFIG     size: 0x35      digest: 
PCR: 7  type: EV_EFI_VARIABLE_DRIVER_CONFIG     size: 0x24      digest: 
PCR: 7  type: EV_EFI_VARIABLE_DRIVER_CONFIG     size: 0x26      digest: 
PCR: 7  type: EV_EFI_VARIABLE_DRIVER_CONFIG     size: 0x24      digest: 
PCR: 7  type: EV_EFI_VARIABLE_DRIVER_CONFIG     size: 0x26      digest: 
PCR: 7  type: EV_SEPARATOR                      size: 0x4       digest: 
PCR: 1  type: EV_EFI_VARIABLE_BOOT              size: 0x3e      digest: 
PCR: 1  type: EV_EFI_VARIABLE_BOOT              size: 0x6e      digest: 
PCR: 1  type: EV_EFI_VARIABLE_BOOT              size: 0x80      digest: 
PCR: 1  type: EV_EFI_VARIABLE_BOOT              size: 0x84      digest: 
PCR: 1  type: EV_EFI_VARIABLE_BOOT              size: 0x9a      digest: 
PCR: 1  type: EV_EFI_VARIABLE_BOOT              size: 0xbd      digest: 
PCR: 1  type: EV_EFI_VARIABLE_BOOT              size: 0x88      digest: 
PCR: 4  type: EV_EFI_ACTION                     size: 0x28      digest: 
PCR: 0  type: EV_SEPARATOR                      size: 0x4       digest: 
PCR: 1  type: EV_SEPARATOR                      size: 0x4       digest: 
PCR: 2  type: EV_SEPARATOR                      size: 0x4       digest: 
PCR: 3  type: EV_SEPARATOR                      size: 0x4       digest: 
PCR: 4  type: EV_SEPARATOR                      size: 0x4       digest: 
PCR: 5  type: EV_SEPARATOR                      size: 0x4       digest: 

$ tpm2_pcrlist
sha1 :
  0  : 35bd1786b6909daad610d7598b1d620352d33b8a
  1  : ec0511e860206e0af13c31da2f9e943fb6ca353d
  2  : b2a83b0ebf2f8374299a5b2bdfc31ea955ad7236
  3  : b2a83b0ebf2f8374299a5b2bdfc31ea955ad7236
  4  : 45a323382bd933f08e7f0e256bc8249e4095b1ec
  5  : d16d7e629fd8d08ca256f9ad3a3a1587c9e6cc1b
  6  : b2a83b0ebf2f8374299a5b2bdfc31ea955ad7236
  7  : 518bd167271fbb64589c61e43d8c0165861431d8
  8  : 0000000000000000000000000000000000000000
  9  : 0000000000000000000000000000000000000000
  10 : 0000000000000000000000000000000000000000
  11 : 0000000000000000000000000000000000000000
  12 : 0000000000000000000000000000000000000000
  13 : 0000000000000000000000000000000000000000
  14 : 0000000000000000000000000000000000000000
  15 : 0000000000000000000000000000000000000000
  16 : 0000000000000000000000000000000000000000
  17 : ffffffffffffffffffffffffffffffffffffffff
  18 : ffffffffffffffffffffffffffffffffffffffff
  19 : ffffffffffffffffffffffffffffffffffffffff
  20 : ffffffffffffffffffffffffffffffffffffffff
  21 : ffffffffffffffffffffffffffffffffffffffff
  22 : ffffffffffffffffffffffffffffffffffffffff
  23 : 0000000000000000000000000000000000000000
sha256 :
  0  : 9ae903dbae3357ac00d223660bac19ea5c021499a56201104332ab966631ce2c
  1  : acc611d90245cf04e77b0ca94901f90e7fa54770f0426f53c3049b532243d1b8
  2  : 3d458cfe55cc03ea1f443f1562beec8df51c75e14a9fcf9a7234a13f198e7969
  3  : 3d458cfe55cc03ea1f443f1562beec8df51c75e14a9fcf9a7234a13f198e7969
  4  : 7a94ffe8a7729a566d3d3c577fcb4b6b1e671f31540375f80eae6382ab785e35
  5  : a5ceb755d043f32431d63e39f5161464620a3437280494b5850dc1b47cc074e0
  6  : 3d458cfe55cc03ea1f443f1562beec8df51c75e14a9fcf9a7234a13f198e7969
  7  : 65caf8dd1e0ea7a6347b635d2b379c93b9a1351edc2afc3ecda700e534eb3068
  8  : 0000000000000000000000000000000000000000000000000000000000000000
  9  : 0000000000000000000000000000000000000000000000000000000000000000
  10 : 0000000000000000000000000000000000000000000000000000000000000000
  11 : 0000000000000000000000000000000000000000000000000000000000000000
  12 : 0000000000000000000000000000000000000000000000000000000000000000
  13 : 0000000000000000000000000000000000000000000000000000000000000000
  14 : 0000000000000000000000000000000000000000000000000000000000000000
  15 : 0000000000000000000000000000000000000000000000000000000000000000
  16 : 0000000000000000000000000000000000000000000000000000000000000000
  17 : ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
  18 : ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
  19 : ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
  20 : ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
  21 : ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
  22 : ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
  23 : 0000000000000000000000000000000000000000000000000000000000000000
sha384 :

The PhysicalPresenceLib is required, it sets some variables, but the
firmware doesn't act on it yet.

Laszlo Ersek explained on the list why Tpm2DeviceLib has to be
resolved differently for DXE_DRIVER modules in general and for
"Tcg2Dxe.inf" specifically:

  * We have a library class called Tpm2DeviceLib -- this is basically the
  set of APIs declared in "SecurityPkg/Include/Library/Tpm2DeviceLib.h".
  Its leading comment says "This library abstract how to access TPM2
  hardware device".

  There are two *sets* of APIs in "Tpm2DeviceLib.h":

  (a) functions that deal with the TPM2 device:
      - Tpm2RequestUseTpm(),
      - Tpm2SubmitCommand()

      This set of APIs is supposed to be used by clients that *consume*
      the TPM2 device abstraction.

  (b) the function Tpm2RegisterTpm2DeviceLib(), which is supposed to be
      used by *providers* of various TPM2 device abstractions.

  * Then, we have two implementations (instances) of the Tpm2DeviceLib class:
  (1) SecurityPkg/Library/Tpm2DeviceLibTcg2/Tpm2DeviceLibTcg2.inf
  (2) SecurityPkg/Library/Tpm2DeviceLibRouter/Tpm2DeviceLibRouterDxe.inf

  (1) The first library instance ("Tpm2DeviceLibTcg2.inf") implements the
  APIs listed under (a), and it does not implement (b) -- see
  EFI_UNSUPPORTED. In other words, this lib instance is strictly meant for
  drivers that *consume* the TPM2 device abstraction. And, the (a) group
  of APIs is implemented by forwarding the requests to the TCG2 protocol.

  The idea here is that all the drivers that consume the TPM2 abstraction
  do not have to be statically linked with a large TPM2 device library
  instance; instead they are only linked (statically) with this "thin"
  library instance, and all the actual work is delegated to whichever
  driver that provides the singleton TCG2 protocol.

  (2) The second library instance ("Tpm2DeviceLibRouterDxe.inf") is meant
  for the driver that offers (produces) the TCG2 protocol. This lib
  instance implements both (a) and (b) API groups.

  * Here's how things fit together:

  (i) The "SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2InstanceLibDTpm.inf"
  library instance (which has no lib class) is linked into "Tcg2Dxe.inf"
  via NULL class resolution. This simply means that before the
  "Tcg2Dxe.inf" entry point function is entered, the constructor function
  of "Tpm2InstanceLibDTpm.inf" will be called.

  (ii) This Tpm2InstanceLibDTpmConstructor() function calls API (b), and
  registers its own actual TPM2 command implementation with the
  "Tpm2DeviceLibRouter" library instance (also linked into the Tcg2Dxe
  driver). This provides the back-end for the API set (a).

         TCG2 protocol provider (Tcg2Dxe.inf driver) launches
    NULL class: Tpm2InstanceLibDTpm instance construction
    Tpm2DeviceLib class: Tpm2DeviceLibRouter instance
           backend registration for API set (a)

  (iii) The Tcg2Dxe driver exposes the TCG2 protocol.

  (iv) A TPM2 consumer calls API set (a) via lib instance (1). Such calls
  land in Tcg2Dxe, via the protocol.

  (v) Tcg2Dxe serves the protocol request by forwarding it to API set (a)
  from lib instance (2).

  (vi) Those functions call the "backend" functions registered by
  Tpm2DeviceLibDTpm in step (ii).

       TPM 2 consumer driver
  Tpm2DeviceLib class: Tpm2DeviceLibTcg2 instance
         TCG2 protocol interface
  TCG2 protocol provider: Tcg2Dxe.inf driver
  Tpm2DeviceLib class: Tpm2DeviceLibRouter instance
     NULL class: Tpm2InstanceLibDTpm instance
        (via earlier registration)
       TPM2 chip (actual hardware)

  * So that is the "router" pattern in edk2. Namely,

  - Consumers of an abstraction use a thin library instance.

  - The thin library instance calls a firmware-global (singleton) service,
    i.e. a PPI (in the PEI phase) or protocol (in the DXE phase).

  - The PEIM providing the PPI, or the DXE driver providing the protocol,
    don't themselves implement the actual service either. Instead they
    offer a "registration" service too, and they only connect the incoming
    "consumer" calls to the earlier registered back-end(s).

  - The "registration service", for back-ends to use, may take various

    It can be exposed globally to the rest of the firmware, as
    another member function of the PPI / protocol structure. Then backends
    can be provided by separate PEIMs / DXE drivers.

    Or else, the registration service can be exposed as just another
    library API. In this case, the backends are provided as NULL class
    library instances, and a platform  DSC file links them into the PEIM /
    DXE driver via NULL class resolutions. The backend lib instances call
    the registration service in their own respective constructor

Cc: Laszlo Ersek <>
Cc: Stefan Berger <>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Marc-André Lureau <>
 OvmfPkg/OvmfPkgX64.dsc | 16 ++++++++++++++++
 OvmfPkg/OvmfPkgX64.fdf |  4 ++++
 2 files changed, 20 insertions(+)

diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 3fa1a31f4c37..7753852144fb 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -211,6 +211,8 @@ [LibraryClasses]
 !if $(TPM2_ENABLE) == TRUE
@@ -362,6 +364,10 @@ [LibraryClasses.common.DXE_DRIVER]
+!if $(TPM2_ENABLE)
+  Tpm2DeviceLib|SecurityPkg/Library/Tpm2DeviceLibTcg2/Tpm2DeviceLibTcg2.inf
@@ -642,6 +648,16 @@ [Components]
+!if $(TPM2_ENABLE) == TRUE
+  SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.inf {
+    <LibraryClasses>
+      NULL|SecurityPkg/Library/Tpm2DeviceLibDTpm/Tpm2InstanceLibDTpm.inf
+      NULL|SecurityPkg/Library/HashInstanceLibSha1/HashInstanceLibSha1.inf
+      NULL|SecurityPkg/Library/HashInstanceLibSha256/HashInstanceLibSha256.inf
+  }
   MdeModulePkg/Universal/SecurityStubDxe/SecurityStubDxe.inf {
diff --git a/OvmfPkg/OvmfPkgX64.fdf b/OvmfPkg/OvmfPkgX64.fdf
index c0173e7adf5f..1a46104fc63d 100644
--- a/OvmfPkg/OvmfPkgX64.fdf
+++ b/OvmfPkg/OvmfPkgX64.fdf
@@ -392,6 +392,10 @@ [FV.DXEFV]
 INF  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
+!if $(TPM2_ENABLE) == TRUE
+INF  SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.inf

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