[edk2-devel] [PATCH V7 1/1] OvmfPkg: Enable TDX in ResetVector

[Brijesh Singh via groups.io]

On 9/24/21 6:17 AM, Gerd Hoffmann via groups.io wrote:
> On Fri, Sep 24, 2021 at 05:38:21AM -0500, Brijesh Singh wrote:
>> On 9/24/21 5:11 AM, Yao, Jiewen wrote:
>>> You are right. My statement for page table is wrong. Both TDX and SEV need them.
>>>
>>> That is NOT our original design. But I can understand why it is changed today.
>>>
>>> I compare https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Ftianocore%2Fedk2-staging%2Fblob%2FTDVF%2FOvmfPkg%2FResetVector%2FX64%2FTdxMetadata.asm&data=04%7C01%7Cbrijesh.singh%40amd.com%7C7c131e7f76de43f01ae808d97f4cfb01%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637680790883761087%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=1nG6d2htqsRuvsnzlFTsGazh1f57WzAGG6pxn6sj90w%3D&reserved=0 and https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FAMDESE%2Fovmf%2Fblob%2Fsnp-v8%2FOvmfPkg%2FResetVector%2FX64%2FOvmfMetadata.asm&data=04%7C01%7Cbrijesh.singh%40amd.com%7C7c131e7f76de43f01ae808d97f4cfb01%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637680790883761087%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=TNcIqgCGnXn3Hl7QTrbePcuWmjtAH9DWUs9c6SENywY%3D&reserved=0.
>>>
>>> There are 8 entries in TDX, and 10 entries in SEV.
>>> 2 of them are same, page table and TEMP RAM.
>>> 6 entries are TDX unique. 8 entries are SEV unique.
>> In the SEV patches you are seeing more sections because I tried to keep
>> it in sync with the MEMFD [1] so that its much more readable.
> We could add just a single range for stack + heap + pagetables  (+more?)
> and comments saying which MEMFD areas are covered by that range, to keep
> the table small.

Sure, that is not an issue at all. As a matter of fact I had only one
section in my original SNP_BOOT_BLOCK GUID to cover the MEMFD region ;)
I think we can live with just 2 to 3 sections common to cover a large
amount of MEMFD, and still keep the code readable.

Section 1: Page table + lockBox + GuidedExtractHandler (0x0 - 0x8000)

Section 2: WorkArea + Ghcbbackup + TempRam (0xb000 - 0x20000)

The region 0x8000 - 0xa000 can be platform specific.

> take care,
>   Gerd
>
>
>
> 
>
>


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