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From: "Gerd Hoffmann" <kraxel@redhat.com>
To: devel@edk2.groups.io, jiewen.yao@intel.com
Cc: "Xu, Min M" <min.m.xu@intel.com>,
	Brijesh Singh <brijesh.singh@amd.com>,
	James Bottomley <jejb@linux.ibm.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	"Justen, Jordan L" <jordan.l.justen@intel.com>,
	Ard Biesheuvel <ardb+tianocore@kernel.org>,
	Erdem Aktas <erdemaktas@google.com>,
	Michael Roth <Michael.Roth@amd.com>
Subject: Re: [edk2-devel] [PATCH v6 06/29] OvmfPkg/ResetVector: pre-validate the data pages used in SEC phase
Date: Thu, 16 Sep 2021 09:42:36 +0200	[thread overview]
Message-ID: <20210916074236.5bohsughhh7hpfnh@sirius.home.kraxel.org> (raw)
In-Reply-To: <PH0PR11MB488556C180E536A94FF68BB68CDA9@PH0PR11MB4885.namprd11.prod.outlook.com>

On Tue, Sep 14, 2021 at 03:49:31AM +0000, Yao, Jiewen wrote:
> I can explain why we prefer DQ instead of DD.
> 
> You are right that current TD entrypoint is 32bit. However, we cannot predict that is always TRUE for the future.

So a "save space in MEMFD" vs. "be future proof" tradeoff.

> Back to 16 bit machine, we have entrypoint at F000:FFF0. But in 32bit mode we removed 1M limitation and move entrypoint to below 4G.
> There is no limitation that we move 64bit entrypoint above 4G for 64bit machine.

Any plans to actually do that?

Defining an 64-bit entry point is a more than just using 64-bit
addresses.  For starters long mode requires paging being enabled.
So a set of initial page tables is needed, and you possibly need
to handle virtual vs. physical addresses.  You also need to find
a place above 4G where you can place the firmware without conflicts
with something else.

So I have my doubts that trying to make the struct future-proof
will actually work out in practice.  Or that we will actually
need that anytime soon.

take care,
  Gerd


  reply	other threads:[~2021-09-16  7:42 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-01 16:16 [PATCH v6 00/29] Add AMD Secure Nested Paging (SEV-SNP) support Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 01/29] OvmfPkg: reserve SNP secrets page Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 02/29] OvmfPkg: reserve CPUID page for SEV-SNP Brijesh Singh
2021-09-02  8:04   ` Gerd Hoffmann
2021-09-02 12:28     ` Brijesh Singh
2021-09-02 21:17       ` Brijesh Singh
2021-09-03  6:28         ` Gerd Hoffmann
2021-09-03 11:56           ` [edk2-devel] " Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 03/29] OvmfPkg/ResetVector: introduce SEV-SNP boot block GUID Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 04/29] OvmfPkg/ResetVector: invalidate the GHCB page Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 05/29] OvmfPkg/ResetVector: check the vmpl level Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 06/29] OvmfPkg/ResetVector: pre-validate the data pages used in SEC phase Brijesh Singh
2021-09-02  8:20   ` Gerd Hoffmann
2021-09-06  1:10     ` [edk2-devel] " Min Xu
2021-09-06 12:16       ` Gerd Hoffmann
2021-09-06 13:19         ` Min Xu
2021-09-07  7:07           ` Gerd Hoffmann
2021-09-07 13:27             ` Brijesh Singh
2021-09-08  6:36               ` Min Xu
2021-09-14  3:49             ` Yao, Jiewen
2021-09-16  7:42               ` Gerd Hoffmann [this message]
2021-09-01 16:16 ` [PATCH v6 07/29] OvmfPkg/ResetVector: use SEV-SNP-validated CPUID values Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 08/29] UefiCpuPkg: Define the SEV-SNP specific dynamic PCDs Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 09/29] OvmfPkg/MemEncryptSevLib: add MemEncryptSevSnpEnabled() Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 10/29] OvmfPkg/SecMain: move SEV specific routines in AmdSev.c Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 11/29] OvmfPkg/SecMain: register GHCB gpa for the SEV-SNP guest Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 12/29] OvmfPkg/VmgExitLib: use SEV-SNP-validated CPUID values Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 13/29] OvmfPkg/PlatformPei: register GHCB gpa for the SEV-SNP guest Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 14/29] OvmfPkg/AmdSevDxe: do not use extended PCI config space Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 15/29] OvmfPkg/MemEncryptSevLib: add support to validate system RAM Brijesh Singh
2021-09-02  9:50   ` Gerd Hoffmann
2021-09-02 13:34     ` Brijesh Singh
2021-09-03  7:04       ` Gerd Hoffmann
2021-09-01 16:16 ` [PATCH v6 16/29] OvmfPkg/BaseMemEncryptSevLib: skip the pre-validated " Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 17/29] OvmfPkg/MemEncryptSevLib: add support to validate > 4GB memory in PEI phase Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 18/29] OvmfPkg/SecMain: pre-validate the memory used for decompressing Fv Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 19/29] OvmfPkg/PlatformPei: validate the system RAM when SNP is active Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 20/29] OvmfPkg/PlatformPei: set the SEV-SNP enabled PCD Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 21/29] OvmfPkg/PlatformPei: set the Hypervisor Features PCD Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 22/29] MdePkg/GHCB: increase the GHCB protocol max version Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 23/29] UefiCpuPkg/MpLib: add support to register GHCB GPA when SEV-SNP is enabled Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 24/29] UefiCpuPkg/MpInitLib: use BSP to do extended topology check Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 25/29] OvmfPkg/MemEncryptSevLib: change the page state in the RMP table Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 26/29] OvmfPkg/MemEncryptSevLib: skip page state change for Mmio address Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 27/29] OvmfPkg/PlatformPei: mark cpuid and secrets memory reserved in EFI map Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 28/29] OvmfPkg/AmdSev: expose the SNP reserved pages through configuration table Brijesh Singh
2021-09-01 16:16 ` [PATCH v6 29/29] UefiCpuPkg/MpInitLib: Use SEV-SNP AP Creation NAE event to launch APs Brijesh Singh
2021-09-07  2:36 ` [PATCH v6 00/29] Add AMD Secure Nested Paging (SEV-SNP) support Yao, Jiewen
2021-09-08  2:29   ` Min Xu
2021-09-08  6:03     ` Yao, Jiewen
2021-09-08 19:45   ` Brijesh Singh
2021-09-09  0:31     ` Min Xu
2021-09-09 10:51       ` Brijesh Singh
2021-09-09 11:22         ` Gerd Hoffmann
2021-09-09 11:40           ` Brijesh Singh
2021-09-09 11:45             ` [edk2-devel] " Min Xu
2021-09-09 11:55         ` Yao, Jiewen
2021-09-12 22:55   ` Brijesh Singh
2021-09-13  0:33     ` Yao, Jiewen

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