b97dc4b92b
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3108 To ensure that we always use a validated encryption mask for an SEV-ES guest, create a new interface in the MemEncryptSevLib library to return the encryption mask. This can be used in place of the multiple locations where CPUID is used to retrieve the value (which would require validation again) and allows the validated mask to be returned. The PEI phase will use the value from the SEV-ES work area. Since the SEV-ES work area isn't valid in the DXE phase, the DXE phase will use the PcdPteMemoryEncryptionAddressOrMask PCD which is set during PEI. Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com> Cc: Rebecca Cran <rebecca@bsdio.com> Cc: Peter Grehan <grehan@freebsd.org> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Julien Grall <julien@xen.org> Cc: Brijesh Singh <brijesh.singh@amd.com> Acked-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Message-Id: <e12044dc01b21e6fc2e9535760ddf3a38a142a71.1610045305.git.thomas.lendacky@amd.com>
64 lines
1.9 KiB
C
64 lines
1.9 KiB
C
/** @file
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Secure Encrypted Virtualization (SEV) library helper function
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Copyright (c) 2017 - 2020, AMD Incorporated. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Library/BaseLib.h>
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#include <Library/DebugLib.h>
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#include <Library/MemEncryptSevLib.h>
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#include <Library/PcdLib.h>
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#include <Register/QemuSmramSaveStateMap.h>
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#include <Register/SmramSaveStateMap.h>
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#include <Uefi/UefiBaseType.h>
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/**
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Locate the page range that covers the initial (pre-SMBASE-relocation) SMRAM
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Save State Map.
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@param[out] BaseAddress The base address of the lowest-address page that
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covers the initial SMRAM Save State Map.
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@param[out] NumberOfPages The number of pages in the page range that covers
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the initial SMRAM Save State Map.
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@retval RETURN_SUCCESS BaseAddress and NumberOfPages have been set on
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output.
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@retval RETURN_UNSUPPORTED SMM is unavailable.
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**/
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RETURN_STATUS
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EFIAPI
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MemEncryptSevLocateInitialSmramSaveStateMapPages (
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OUT UINTN *BaseAddress,
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OUT UINTN *NumberOfPages
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)
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{
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UINTN MapStart;
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UINTN MapEnd;
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UINTN MapPagesStart; // MapStart rounded down to page boundary
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UINTN MapPagesEnd; // MapEnd rounded up to page boundary
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UINTN MapPagesSize; // difference between MapPagesStart and MapPagesEnd
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if (!FeaturePcdGet (PcdSmmSmramRequire)) {
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return RETURN_UNSUPPORTED;
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}
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MapStart = SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET;
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MapEnd = MapStart + sizeof (QEMU_SMRAM_SAVE_STATE_MAP);
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MapPagesStart = MapStart & ~(UINTN)EFI_PAGE_MASK;
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MapPagesEnd = ALIGN_VALUE (MapEnd, EFI_PAGE_SIZE);
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MapPagesSize = MapPagesEnd - MapPagesStart;
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ASSERT ((MapPagesSize & EFI_PAGE_MASK) == 0);
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*BaseAddress = MapPagesStart;
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*NumberOfPages = MapPagesSize >> EFI_PAGE_SHIFT;
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return RETURN_SUCCESS;
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}
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