During normal boot, when EFI_DXE_SMM_READY_TO_LOCK_PROTOCOL is installed by platform BDS, the SMM IPL locks SMRAM (TSEG) through EFI_SMM_ACCESS2_PROTOCOL.Lock(). See SmmIplReadyToLockEventNotify() in "MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c". During S3 resume, S3Resume2Pei locks SMRAM (TSEG) through PEI_SMM_ACCESS_PPI.Lock(), before executing the boot script. See S3ResumeExecuteBootScript() in "UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c". Those are precisely the places where the SMRAM at the default SMBASE should be locked too. Add such an action to SmramAccessLock(). Notes: - The SMRAM at the default SMBASE doesn't support the "closed and unlocked" state (and so it can't be closed without locking it, and it cannot be opened after closing it). - The SMRAM at the default SMBASE isn't (and shouldn't) be exposed with another EFI_SMRAM_DESCRIPTOR in the GetCapabilities() members of EFI_SMM_ACCESS2_PROTOCOL / PEI_SMM_ACCESS_PPI. That's because the SMRAM in question is not "general purpose"; it's only QEMU's solution to protect the initial SMI handler from the OS, when a VCPU is hot-plugged. Consequently, the state of the SMRAM at the default SMBASE is not reflected in the "OpenState" / "LockState" fields of the protocol and PPI. - An alternative to extending SmramAccessLock() would be to register an EFI_DXE_SMM_READY_TO_LOCK_PROTOCOL notify in SmmAccess2Dxe (for locking at normal boot), and an EDKII_S3_SMM_INIT_DONE_GUID PPI notify in SmmAccessPei (for locking at S3 resume). Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Jordan Justen <jordan.l.justen@intel.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1512 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com> Message-Id: <20200129214412.2361-10-lersek@redhat.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
57 lines
1.3 KiB
INI
57 lines
1.3 KiB
INI
## @file
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# A DXE_DRIVER providing SMRAM access by producing EFI_SMM_ACCESS2_PROTOCOL.
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#
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# Q35 TSEG is expected to have been verified and set up by the SmmAccessPei
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# driver.
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#
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# Copyright (C) 2013, 2015, Red Hat, Inc.
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#
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# SPDX-License-Identifier: BSD-2-Clause-Patent
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#
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##
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[Defines]
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INF_VERSION = 0x00010005
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BASE_NAME = SmmAccess2Dxe
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FILE_GUID = AC95AD3D-4366-44BF-9A62-E4B29D7A2206
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MODULE_TYPE = DXE_DRIVER
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VERSION_STRING = 1.0
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PI_SPECIFICATION_VERSION = 0x00010400
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ENTRY_POINT = SmmAccess2DxeEntryPoint
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#
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# The following information is for reference only and not required by the build tools.
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#
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# VALID_ARCHITECTURES = IA32 X64
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#
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[Sources]
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SmmAccess2Dxe.c
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SmramInternal.c
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SmramInternal.h
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[Packages]
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MdeModulePkg/MdeModulePkg.dec
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MdePkg/MdePkg.dec
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OvmfPkg/OvmfPkg.dec
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[LibraryClasses]
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DebugLib
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PcdLib
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PciLib
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UefiBootServicesTableLib
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UefiDriverEntryPoint
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[Protocols]
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gEfiSmmAccess2ProtocolGuid ## PRODUCES
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[FeaturePcd]
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gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
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[Pcd]
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gUefiOvmfPkgTokenSpaceGuid.PcdQ35SmramAtDefaultSmbase
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gUefiOvmfPkgTokenSpaceGuid.PcdQ35TsegMbytes
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[Depex]
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TRUE
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