24e4ad7554
When SEV is enabled, the MMIO memory range must be mapped as unencrypted (i.e C-bit cleared). We need to clear the C-bit for MMIO GCD entries in order to cover the ranges that were added during the PEI phase (through memory resource descriptor HOBs). Additionally, the NonExistent ranges are processed in order to cover, in advance, MMIO ranges added later in the DXE phase by various device drivers, via the appropriate DXE memory space services. The approach is not transparent for later addition of system memory ranges to the GCD memory space map. (Such ranges should be encrypted.) OVMF does not do such a thing at the moment, so this approach should be OK. The driver is being added to the APRIORI DXE file so that, we clear the C-bit from MMIO regions before any driver accesses it. Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Leo Duran <leo.duran@amd.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Suggested-by: Jiewen Yao <jiewen.yao@intel.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Acked-by: Jordan Justen <jordan.l.justen@intel.com>
44 lines
1.2 KiB
INI
44 lines
1.2 KiB
INI
#/** @file
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#
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# Driver clears the encryption attribute from MMIO regions when SEV is enabled
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#
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# Copyright (c) 2017, AMD Inc. All rights reserved.<BR>
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#
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# This program and the accompanying materials
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# are licensed and made available under the terms and conditions of the BSD
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# License which accompanies this distribution. The full text of the license may
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# be found at http://opensource.org/licenses/bsd-license.php
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#
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# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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#
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#**/
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[Defines]
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INF_VERSION = 1.25
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BASE_NAME = AmdSevDxe
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FILE_GUID = 2ec9da37-ee35-4de9-86c5-6d9a81dc38a7
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MODULE_TYPE = DXE_DRIVER
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VERSION_STRING = 1.0
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ENTRY_POINT = AmdSevDxeEntryPoint
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[Sources]
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AmdSevDxe.c
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[Packages]
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MdePkg/MdePkg.dec
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MdeModulePkg/MdeModulePkg.dec
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OvmfPkg/OvmfPkg.dec
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[LibraryClasses]
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BaseLib
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UefiLib
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UefiDriverEntryPoint
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UefiBootServicesTableLib
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DxeServicesTableLib
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DebugLib
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MemEncryptSevLib
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[Depex]
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TRUE
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