(a) OvmfPkg first had to resolve the TpmMeasurementLib class -- for SECURE_BOOT_ENABLE only -- when the DxeImageVerificationLib instance became dependent on TpmMeasurementLib. For details, refer to commit 0d28d286bf4d ("OvmfPkg: resolve TpmMeasurementLib dependency introduced in r14687", 2013-09-21).
(b) At the time, only one instance of TpmMeasurementLib existed, namely DxeTpmMeasurementLib. This lib instance didn't do anything -- like it was desirable for OVMF --, because OVMF didn't include any Tcg / TrEE protocol implementations. (c) In commit 308521b13354 ("MdeModulePkg: Move TpmMeasurementLib LibraryClass from SecurityPkg", 2015-07-01), TpmMeasurementLibNull was introduced. (d) In commit 285542ebbb03 ("OvmfPkg: Link AuthVariableLib for following merged variable driver deploy", 2015-07-01), a TpmMeasurementLib resolution became necessary regardless of SECURE_BOOT_ENABLE. And so TpmMeasurementLib was resolved to TpmMeasurementLibNull in OVMF, but only in the non-SECURE_BOOT_ENABLE case. This step -- possibly, the larger series containing commit 285542ebbb03 -- missed an opportunity for simplification: given (b), the DxeTpmMeasurementLib instance should have been simply replaced with the TpmMeasurementLibNull instance, regardless of SECURE_BOOT_ENABLE. (e) In commit 1abfa4ce4835 ("Add TPM2 support defined in trusted computing group.", 2015-08-13), the TrEE dependency was replaced with a Tcg2 dependency in DxeTpmMeasurementLib. (f) Starting with commit 0c0a50d6b3ff ("OvmfPkg: include Tcg2Dxe module", 2018-03-09), OVMF would include a Tcg2 protocol implementation, thereby satisfying DxeTpmMeasurementLib's dependency. With TPM2_ENABLE, it would actually make sense to consume DxeTpmMeasurementLib -- however, DxeTpmMeasurementLib would never be used without SECURE_BOOT_ENABLE. Therefore, we have the following four scenarios: - TPM2_ENABLE + SECURE_BOOT_ENABLE: works as expected. - Neither enabled: works as expected. - Only TPM2_ENABLE: this build is currently incorrect, because Variable/RuntimeDxe consumes TpmMeasurementLib directly, but TpmMeasureAndLogData() will never reach the TPM because we link TpmMeasurementLibNull into the variable driver. This is a problem from the larger series containing (f). - Only SECURE_BOOT_ENABLE: this build works as expected, but it is wasteful -- given that the protocol database will never contain Tcg2 without TPM2_ENABLE, we should simply use TpmMeasurementLibNull. This is a problem from (d). Resolving TpmMeasurementLib to DxeTpmMeasurementLib as a function of *only* TPM2_ENABLE, we can fix / optimize the last two cases. v2: - Amend the title and description suggested by Laszlo - Move TpmMeasurementLib to the existed TPM2_ENABLE block Cc: Jordan Justen <jordan.l.jus...@intel.com> Cc: Laszlo Ersek <ler...@redhat.com> Cc: Marc-André Lureau <marcandre.lur...@redhat.com> Cc: Stefan Berger <stef...@linux.ibm.com> Signed-off-by: Gary Lin <g...@suse.com> --- OvmfPkg/OvmfPkgIa32.dsc | 4 ++-- OvmfPkg/OvmfPkgIa32X64.dsc | 4 ++-- OvmfPkg/OvmfPkgX64.dsc | 4 ++-- 3 files changed, 6 insertions(+), 6 deletions(-) diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc index 87716123997a..5bbf87540ab9 100644 --- a/OvmfPkg/OvmfPkgIa32.dsc +++ b/OvmfPkg/OvmfPkgIa32.dsc @@ -178,10 +178,8 @@ [LibraryClasses] !if $(SECURE_BOOT_ENABLE) == TRUE PlatformSecureLib|OvmfPkg/Library/PlatformSecureLib/PlatformSecureLib.inf - TpmMeasurementLib|SecurityPkg/Library/DxeTpmMeasurementLib/DxeTpmMeasurementLib.inf AuthVariableLib|SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf !else - TpmMeasurementLib|MdeModulePkg/Library/TpmMeasurementLibNull/TpmMeasurementLibNull.inf AuthVariableLib|MdeModulePkg/Library/AuthVariableLibNull/AuthVariableLibNull.inf !endif VarCheckLib|MdeModulePkg/Library/VarCheckLib/VarCheckLib.inf @@ -207,8 +205,10 @@ [LibraryClasses] Tpm2CommandLib|SecurityPkg/Library/Tpm2CommandLib/Tpm2CommandLib.inf Tcg2PhysicalPresenceLib|OvmfPkg/Library/Tcg2PhysicalPresenceLibQemu/DxeTcg2PhysicalPresenceLib.inf Tcg2PpVendorLib|SecurityPkg/Library/Tcg2PpVendorLibNull/Tcg2PpVendorLibNull.inf + TpmMeasurementLib|SecurityPkg/Library/DxeTpmMeasurementLib/DxeTpmMeasurementLib.inf !else Tcg2PhysicalPresenceLib|OvmfPkg/Library/Tcg2PhysicalPresenceLibNull/DxeTcg2PhysicalPresenceLib.inf + TpmMeasurementLib|MdeModulePkg/Library/TpmMeasurementLibNull/TpmMeasurementLibNull.inf !endif [LibraryClasses.common] diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc index ad20531ceb8b..5015e92b6eea 100644 --- a/OvmfPkg/OvmfPkgIa32X64.dsc +++ b/OvmfPkg/OvmfPkgIa32X64.dsc @@ -183,10 +183,8 @@ [LibraryClasses] !if $(SECURE_BOOT_ENABLE) == TRUE PlatformSecureLib|OvmfPkg/Library/PlatformSecureLib/PlatformSecureLib.inf - TpmMeasurementLib|SecurityPkg/Library/DxeTpmMeasurementLib/DxeTpmMeasurementLib.inf AuthVariableLib|SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf !else - TpmMeasurementLib|MdeModulePkg/Library/TpmMeasurementLibNull/TpmMeasurementLibNull.inf AuthVariableLib|MdeModulePkg/Library/AuthVariableLibNull/AuthVariableLibNull.inf !endif VarCheckLib|MdeModulePkg/Library/VarCheckLib/VarCheckLib.inf @@ -212,8 +210,10 @@ [LibraryClasses] Tpm2CommandLib|SecurityPkg/Library/Tpm2CommandLib/Tpm2CommandLib.inf Tcg2PhysicalPresenceLib|OvmfPkg/Library/Tcg2PhysicalPresenceLibQemu/DxeTcg2PhysicalPresenceLib.inf Tcg2PpVendorLib|SecurityPkg/Library/Tcg2PpVendorLibNull/Tcg2PpVendorLibNull.inf + TpmMeasurementLib|SecurityPkg/Library/DxeTpmMeasurementLib/DxeTpmMeasurementLib.inf !else Tcg2PhysicalPresenceLib|OvmfPkg/Library/Tcg2PhysicalPresenceLibNull/DxeTcg2PhysicalPresenceLib.inf + TpmMeasurementLib|MdeModulePkg/Library/TpmMeasurementLibNull/TpmMeasurementLibNull.inf !endif [LibraryClasses.common] diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc index 0542ac2235b4..dda8dac18441 100644 --- a/OvmfPkg/OvmfPkgX64.dsc +++ b/OvmfPkg/OvmfPkgX64.dsc @@ -183,10 +183,8 @@ [LibraryClasses] !if $(SECURE_BOOT_ENABLE) == TRUE PlatformSecureLib|OvmfPkg/Library/PlatformSecureLib/PlatformSecureLib.inf - TpmMeasurementLib|SecurityPkg/Library/DxeTpmMeasurementLib/DxeTpmMeasurementLib.inf AuthVariableLib|SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf !else - TpmMeasurementLib|MdeModulePkg/Library/TpmMeasurementLibNull/TpmMeasurementLibNull.inf AuthVariableLib|MdeModulePkg/Library/AuthVariableLibNull/AuthVariableLibNull.inf !endif VarCheckLib|MdeModulePkg/Library/VarCheckLib/VarCheckLib.inf @@ -212,8 +210,10 @@ [LibraryClasses] Tpm2CommandLib|SecurityPkg/Library/Tpm2CommandLib/Tpm2CommandLib.inf Tcg2PhysicalPresenceLib|OvmfPkg/Library/Tcg2PhysicalPresenceLibQemu/DxeTcg2PhysicalPresenceLib.inf Tcg2PpVendorLib|SecurityPkg/Library/Tcg2PpVendorLibNull/Tcg2PpVendorLibNull.inf + TpmMeasurementLib|SecurityPkg/Library/DxeTpmMeasurementLib/DxeTpmMeasurementLib.inf !else Tcg2PhysicalPresenceLib|OvmfPkg/Library/Tcg2PhysicalPresenceLibNull/DxeTcg2PhysicalPresenceLib.inf + TpmMeasurementLib|MdeModulePkg/Library/TpmMeasurementLibNull/TpmMeasurementLibNull.inf !endif [LibraryClasses.common] -- 2.22.0 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. 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