BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275
The OvmfPkgX86 build reserves memory regions in MEMFD. The memory regions get accessed in the SEC phase. AMD SEV-SNP require that the guest's private memory be accepted or validated before access. Introduce a Guided metadata structure that describes the reserved memory regions. The VMM can locate the metadata structure by iterating through the reset vector guid and process the areas based on the platform specific requirements. Cc: Michael Roth <[email protected]> Cc: James Bottomley <[email protected]> Cc: Min Xu <[email protected]> Cc: Jiewen Yao <[email protected]> Cc: Tom Lendacky <[email protected]> Cc: Jordan Justen <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: Erdem Aktas <[email protected]> Cc: Gerd Hoffmann <[email protected]> Acked-by: Gerd Hoffmann <[email protected]> Signed-off-by: Brijesh Singh <[email protected]> --- OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm | 14 ++++++++ OvmfPkg/ResetVector/ResetVector.nasmb | 1 + OvmfPkg/ResetVector/X64/OvmfSevMetadata.asm | 34 ++++++++++++++++++++ 3 files changed, 49 insertions(+) create mode 100644 OvmfPkg/ResetVector/X64/OvmfSevMetadata.asm diff --git a/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm b/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm index dee2e3f9de31..12f2cedd6767 100644 --- a/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm +++ b/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm @@ -64,6 +64,20 @@ tdxMetadataOffsetStart: DB 0x86, 0x5e, 0x46, 0x85, 0xa7, 0xbf, 0x8e, 0xc2 tdxMetadataOffsetEnd: +; +; SEV metadata descriptor +; +; Provide the start offset of the metadata blob within the OVMF binary. + +; GUID : dc886566-984a-4798-A75e-5585a7bf67cc +; +OvmfSevMetadataOffsetStart: + DD (fourGigabytes - OvmfSevMetadataGuid) + DW OvmfSevMetadataOffsetEnd - OvmfSevMetadataOffsetStart + DB 0x66, 0x65, 0x88, 0xdc, 0x4a, 0x98, 0x98, 0x47 + DB 0xA7, 0x5e, 0x55, 0x85, 0xa7, 0xbf, 0x67, 0xcc +OvmfSevMetadataOffsetEnd: + %endif ; SEV Hash Table Block diff --git a/OvmfPkg/ResetVector/ResetVector.nasmb b/OvmfPkg/ResetVector/ResetVector.nasmb index 87effedb9c60..d847794feadb 100644 --- a/OvmfPkg/ResetVector/ResetVector.nasmb +++ b/OvmfPkg/ResetVector/ResetVector.nasmb @@ -109,6 +109,7 @@ %include "Ia32/AmdSev.asm" %include "Ia32/PageTables64.asm" %include "Ia32/IntelTdx.asm" +%include "X64/OvmfSevMetadata.asm" %endif %include "Ia16/Real16ToFlat32.asm" diff --git a/OvmfPkg/ResetVector/X64/OvmfSevMetadata.asm b/OvmfPkg/ResetVector/X64/OvmfSevMetadata.asm new file mode 100644 index 000000000000..9d8c3e8194a4 --- /dev/null +++ b/OvmfPkg/ResetVector/X64/OvmfSevMetadata.asm @@ -0,0 +1,34 @@ +;----------------------------------------------------------------------------- +; @file +; OVMF metadata for the AMD SEV confidential computing guests +; +; Copyright (c) 2021, AMD Inc. All rights reserved.<BR> +; +; SPDX-License-Identifier: BSD-2-Clause-Patent +;----------------------------------------------------------------------------- + +BITS 64 + +%define OVMF_SEV_METADATA_VERSION 1 + +; The section must be accepted or validated by the VMM before the boot +%define OVMF_SECTION_TYPE_SNP_SEC_MEM 0x1 + +ALIGN 16 + +TIMES (15 - ((OvmfSevGuidedStructureEnd - OvmfSevGuidedStructureStart + 15) % 16)) DB 0 + +OvmfSevGuidedStructureStart: +; +; OvmfSev metadata descriptor +; +OvmfSevMetadataGuid: + +_DescriptorSev: + DB 'A','S','E','V' ; Signature + DD OvmfSevGuidedStructureEnd - _DescriptorSev ; Length + DD OVMF_SEV_METADATA_VERSION ; Version + DD (OvmfSevGuidedStructureEnd - _DescriptorSev - 16) / 12 ; Number of sections + +OvmfSevGuidedStructureEnd: + ALIGN 16 -- 2.25.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#83585): https://edk2.groups.io/g/devel/message/83585 Mute This Topic: https://groups.io/mt/86969133/21656 Group Owner: [email protected] Unsubscribe: https://edk2.groups.io/g/devel/unsub [[email protected]] -=-=-=-=-=-=-=-=-=-=-=-
