From: "Laszlo Ersek" <lersek@redhat.com>
To: "Xu, Min M" <min.m.xu@intel.com>,
Brijesh Singh <brijesh.singh@amd.com>,
"devel@edk2.groups.io" <devel@edk2.groups.io>
Cc: James Bottomley <jejb@linux.ibm.com>,
"Yao, Jiewen" <jiewen.yao@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
"Justen, Jordan L" <jordan.l.justen@intel.com>,
Ard Biesheuvel <ardb+tianocore@kernel.org>
Subject: Re: [RFC PATCH 01/19] OvmfPkg: Reserve the Secrets and Cpuid page for the SEV-SNP guest
Date: Wed, 7 Apr 2021 15:24:37 +0200 [thread overview]
Message-ID: <69ebd115-e071-827b-be64-0ecaf27ca8bb@redhat.com> (raw)
In-Reply-To: <47bf3b5a-dde6-0807-ee54-704870326ef9@redhat.com>
On 04/07/21 15:22, Laszlo Ersek wrote:
> On 04/07/21 02:21, Xu, Min M wrote:
>
>> Intel TDX also has metadata which is consumed by QEMU. We put the metadata
>> in a single file (TdxMetadata.asm) and put it at the end of ResetVectorVtf0.
>> Then a pointer is placed in a known location in ResetVector.nasm. In this way
>> QEMU can easily read the Metadata by the pointer.
>> ------------------------------------------------------------------
>> ALIGN 8
>> ;
>> ; TDX Virtual Firmware injects metadata in VTF0.
>> ; The address of the metadata is injected in this location (0xffffffe8)
>> ;
>> DD (OVMF_IMAGE_SIZE_IN_KB * 1024 - (fourGigabytes - TdxMetadataGuid - 16))
>> ;
>> ; The VTF signature
>> ;
>> ; VTF-0 means that the VTF (Volume Top File) code does not require
>> ; any fixups.
>> ;
>> vtfSignature:
>> DB 'V', 'T', 'F', 0
>> ------------------------------------------------------------------
>>
>> The space in ResetVector is very precious and we all want a known location so that QEMU
>> can find the metadata easily. Putting the metadata in a single file give the developers
>> more flexible (They can put anything they want). So I think a pointer (point to a metadata
>> file) in a known location maybe a better solution.
>
> Assuming a QEMU version has been released that looks for the chain of
> GUID-ed structs already, then I think such a change would break
> compatibility with that QEMU version.
>
> If we definitely need a separate spot to include more information in the
> flash, for QEMU's parsing, then please introduce a new GUIDed structure,
> which contains nothing but a pointer to that spot.
Ah, upon re-reading James's earlier message which he just referenced,
namely at
https://listman.redhat.com/archives/edk2-devel-archive/2020-November/msg01063.html
it's clear that James had already proposed this:
> That's not to say we can't have a larger table ... we definitely can,
> but it can't be where it is now. we'd have to do something different
> like make the table guid describe where the actual table is located
> (as a 32 bit offset and length) so as not to break up the 16 bit jump
> code.
Thanks
Laszlo
next prev parent reply other threads:[~2021-04-07 13:24 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-24 15:31 [RFC PATCH 00/19] Add AMD Secure Nested Paging (SEV-SNP) support brijesh.singh
2021-03-24 15:31 ` [RFC PATCH 01/19] OvmfPkg: Reserve the Secrets and Cpuid page for the SEV-SNP guest Brijesh Singh
2021-04-06 8:11 ` Min Xu
2021-04-06 12:16 ` Laszlo Ersek
2021-04-07 0:21 ` Min Xu
2021-04-07 0:44 ` James Bottomley
2021-04-07 15:02 ` Laszlo Ersek
2021-04-07 15:12 ` James Bottomley
2021-04-08 6:24 ` [edk2-devel] " Min Xu
2021-04-08 13:31 ` Lendacky, Thomas
2021-04-09 12:29 ` Laszlo Ersek
2021-04-09 13:32 ` Laszlo Ersek
2021-04-09 13:44 ` Yao, Jiewen
2021-04-09 14:11 ` separate OVMF binary for TDX? [was: OvmfPkg: Reserve the Secrets and Cpuid page for the SEV-SNP guest] Laszlo Ersek
2021-04-12 8:35 ` Dr. David Alan Gilbert
2021-04-12 11:54 ` [edk2-devel] " Yao, Jiewen
2021-04-12 14:33 ` James Bottomley
2021-04-14 23:34 ` erdemaktas
2021-04-15 7:59 ` Paolo Bonzini
2021-04-15 19:42 ` Erdem Aktas
2021-04-21 0:38 ` Yao, Jiewen
2021-04-21 10:44 ` Laszlo Ersek
2021-04-21 17:07 ` Erdem Aktas
2021-04-22 14:20 ` Laszlo Ersek
2021-04-07 13:22 ` [RFC PATCH 01/19] OvmfPkg: Reserve the Secrets and Cpuid page for the SEV-SNP guest Laszlo Ersek
2021-04-07 13:24 ` Laszlo Ersek [this message]
2021-04-08 0:45 ` Min Xu
2021-04-07 0:31 ` James Bottomley
2021-04-12 14:52 ` Brijesh Singh
2021-04-13 9:49 ` Laszlo Ersek
2021-04-13 11:29 ` Brijesh Singh
2021-04-13 13:13 ` Laszlo Ersek
2021-04-19 21:42 ` Brijesh Singh
2021-04-20 8:14 ` Laszlo Ersek
2021-03-24 15:31 ` [RFC PATCH 02/19] OvmfPkg: validate the data pages used in the SEC phase Brijesh Singh
2021-03-24 15:31 ` [RFC PATCH 03/19] MdePkg: Expand the SEV MSR to include the SNP definition Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 04/19] OvmfPkg/MemEncryptSevLib: add MemEncryptSevSnpEnabled() Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 05/19] MdePkg: Define the GHCB GPA structure Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 06/19] UefiCpuPkg/MpLib: add support to register GHCB GPA when SEV-SNP is enabled Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 07/19] OvmfPkg: Add a library to support registering GHCB GPA Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 08/19] OvmfPkg: register GHCB gpa for the SEV-SNP guest Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 09/19] MdePkg: Add AsmPvalidate() support Brijesh Singh
2021-03-25 2:49 ` 回复: [edk2-devel] " gaoliming
2021-03-25 10:54 ` Brijesh Singh
2021-03-26 20:02 ` Andrew Fish
2021-03-24 15:32 ` [RFC PATCH 10/19] OvmfPkg: Define the Page State Change VMGEXIT structures Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 11/19] OvmfPkg/ResetVector: Invalidate the GHCB page Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 12/19] OvmfPkg/MemEncryptSevLib: Add support to validate system RAM Brijesh Singh
2021-04-01 6:37 ` Yao, Jiewen
2021-04-01 13:07 ` Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 13/19] OvmfPkg/SecMain: Validate the data/code pages used for the PEI phase Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 14/19] OvmfPkg/MemEncryptSevLib: Add support to validate RAM in " Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 15/19] OvmfPkg/PlatformPei: Validate the system RAM when SNP is active Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 16/19] OvmfPkg/MemEncryptSevLib: Add support to validate > 4GB memory in PEI phase Brijesh Singh
2021-04-01 6:43 ` Yao, Jiewen
2021-03-24 15:32 ` [RFC PATCH 17/19] OvmfPkg/VmgExitLib: Allow PMBASE register access in Dxe phase Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 18/19] OvmfPkg/MemEncryptSevLib: Validate the memory during set or clear enc attribute Brijesh Singh
2021-03-24 20:07 ` Brijesh Singh
2021-03-24 15:32 ` [RFC PATCH 19/19] OvmfPkg/MemEncryptSevLib: Skip page state change for non RAM region Brijesh Singh
2021-03-24 19:14 ` [edk2-devel] [RFC PATCH 00/19] Add AMD Secure Nested Paging (SEV-SNP) support Laszlo Ersek
2021-04-08 9:58 ` Laszlo Ersek
2021-04-08 11:59 ` Brijesh Singh
2021-04-09 12:24 ` Laszlo Ersek
2021-04-09 22:43 ` Brijesh Singh
2021-04-12 16:23 ` Laszlo Ersek
2021-04-12 20:14 ` Brijesh Singh
2021-04-13 13:00 ` Laszlo Ersek
2021-04-14 11:18 ` Brijesh Singh
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