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From: "Gerd Hoffmann" <kraxel@redhat.com>
To: "Yao, Jiewen" <jiewen.yao@intel.com>
Cc: "Xu, Min M" <min.m.xu@intel.com>,
	"devel@edk2.groups.io" <devel@edk2.groups.io>,
	"brijesh.singh@amd.com" <brijesh.singh@amd.com>,
	Ard Biesheuvel <ardb+tianocore@kernel.org>,
	"Justen, Jordan L" <jordan.l.justen@intel.com>,
	Erdem Aktas <erdemaktas@google.com>,
	James Bottomley <jejb@linux.ibm.com>,
	Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [edk2-devel] [PATCH V7 1/1] OvmfPkg: Enable TDX in ResetVector
Date: Fri, 24 Sep 2021 06:54:16 +0200	[thread overview]
Message-ID: <20210924045416.3vb7qxcetgtdggbs@sirius.home.kraxel.org> (raw)
In-Reply-To: <PH0PR11MB4885D523395C08266148DEFD8CA39@PH0PR11MB4885.namprd11.prod.outlook.com>

On Thu, Sep 23, 2021 at 01:38:52PM +0000, Yao, Jiewen wrote:
> Good point, Min.
> 
> If https://github.com/AMDESE/ovmf/blob/snp-v8/OvmfPkg/ResetVector/X64/OvmfMetadata.asm is the proposal, then I have more comment:
> 
> Type: OVMF_SECTION_TYPE_CODE, OVMF_SECTION_TYPE_VARS are NOT used for SEV. I am not sure why they are there.

tdx needs them (for measurement).  It's not a tdx-specific concept,
possibly sev-snp wants use that too in the future.

> Type: OVMF_SECTION_TYPE_CPUID should be SEV specific. TDX does not need CPUID page.

A cpuid page can be used without sev too.

> Type: OVMF_SECTION_TYPE_SEC_MEM also seems for SEV. TDX does not need this special memory, such as Page table. It is already covered by code.

These are "needs pre-validation / pre-acceptance" regions.
TDX surely needs that too.

> Type: OVMF_SECTION_TYPE_SNP_SECRETS / OVMF_SECTION_TYPE_SNP_SEC_MEM is SEV specific.

Yes.

> The SEV table is totally different with TDX metadata table.

I can't see a fundamental difference.  In both cases the VMM needs
to know the firmware memory layout for (a) attestation, and (b)
pre-validating/pre-acceptance of memory, and (c) some
hardware-specific ranges such as snp secrets page.

> I really cannot see the benefit to merge into one table.

Keep reset vector small?
Have common parser structs and code?

take care,
  Gerd


  parent reply	other threads:[~2021-09-24  4:54 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-21  9:05 [PATCH V7 0/1] Add Intel TDX support in OvmfPkg/ResetVector Min Xu
2021-09-21  9:05 ` [PATCH V7 1/1] OvmfPkg: Enable TDX in ResetVector Min Xu
2021-09-22  7:49   ` Gerd Hoffmann
2021-09-23  0:38     ` Min Xu
2021-09-23  8:48       ` Gerd Hoffmann
2021-09-23 11:39         ` Yao, Jiewen
2021-09-23 12:54           ` Brijesh Singh
2021-09-23 13:18             ` Yao, Jiewen
2021-09-23 13:19             ` [edk2-devel] " Min Xu
2021-09-23 13:38               ` Yao, Jiewen
2021-09-23 14:03                 ` Brijesh Singh
2021-09-23 14:15                   ` Min Xu
2021-09-23 14:19                     ` Yao, Jiewen
2021-09-24  5:37                       ` Gerd Hoffmann
2021-09-24  7:36                         ` Yao, Jiewen
2021-09-24  9:24                           ` Gerd Hoffmann
2021-09-24  9:55                             ` Yao, Jiewen
2021-09-24  5:28                     ` Gerd Hoffmann
2021-09-24  6:55                       ` Min Xu
2021-09-24 10:07                         ` Gerd Hoffmann
2021-09-24 10:33                           ` Yao, Jiewen
2021-09-24 14:02                             ` Gerd Hoffmann
2021-09-24 16:40                               ` Yao, Jiewen
2021-09-27  8:05                                 ` Gerd Hoffmann
2021-09-27 10:05                                   ` Yao, Jiewen
2021-09-27 14:59                                     ` Gerd Hoffmann
2021-09-28  0:21                                       ` Yao, Jiewen
2021-09-24  7:32                       ` Yao, Jiewen
2021-09-24  9:15                         ` Gerd Hoffmann
2021-09-24  4:54                 ` Gerd Hoffmann [this message]
2021-09-24  7:39                   ` Yao, Jiewen
2021-09-24  9:34                     ` Gerd Hoffmann
2021-09-24 10:11                       ` Yao, Jiewen
2021-09-24 10:38                         ` Brijesh Singh
2021-09-24 11:17                           ` Gerd Hoffmann
2021-09-24 11:29                             ` Brijesh Singh
2021-09-24 10:14                     ` Brijesh Singh
2021-09-24 10:58   ` Brijesh Singh
2021-09-25  0:03     ` Min Xu
2021-09-25  3:21       ` Brijesh Singh
2021-09-25 23:17         ` [edk2-devel] " Min Xu
2021-09-25 23:30           ` Yao, Jiewen
2021-09-27  8:44           ` Gerd Hoffmann

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