RE: [PATCH Part2 v6 05/49] x86/sev: Add RMP entry lookup helpers

[Kalra, Ashish]

[AMD Official Use Only - General]

As I mentioned before, in the future we will have architectural support to read RMP table entries, we will first check for
availability of this feature and use it always if it is supported and enabled, and only fallback to doing raw RMP table access
if this architectural support is not available.

Thanks,
Ashish

-----Original Message-----
From: Borislav Petkov <bp@xxxxxxxxx> 
Sent: Friday, July 22, 2022 2:38 PM
To: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Kalra, Ashish <Ashish.Kalra@xxxxxxx>; Dave Hansen <dave.hansen@xxxxxxxxx>; x86@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; linux-coco@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; linux-crypto@xxxxxxxxxxxxxxx; tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; jroedel@xxxxxxx; Lendacky, Thomas <Thomas.Lendacky@xxxxxxx>; hpa@xxxxxxxxx; ardb@xxxxxxxxxx; pbonzini@xxxxxxxxxx; vkuznets@xxxxxxxxxx; jmattson@xxxxxxxxxx; luto@xxxxxxxxxx; dave.hansen@xxxxxxxxxxxxxxx; slp@xxxxxxxxxx; pgonda@xxxxxxxxxx; peterz@xxxxxxxxxxxxx; srinivas.pandruvada@xxxxxxxxxxxxxxx; rientjes@xxxxxxxxxx; dovmurik@xxxxxxxxxxxxx; tobin@xxxxxxx; Roth, Michael <Michael.Roth@xxxxxxx>; vbabka@xxxxxxx; kirill@xxxxxxxxxxxxx; ak@xxxxxxxxxxxxxxx; tony.luck@xxxxxxxxx; marcorr@xxxxxxxxxx; sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx; alpergun@xxxxxxxxxx; dgilbert@xxxxxxxxxx; jarkko@xxxxxxxxxx
Subject: Re: [PATCH Part2 v6 05/49] x86/sev: Add RMP entry lookup helpers

Btw,

what could work is to spec only a *version* field somewhere in the HW or FW which says which version the RMP header has.

Then, OS would check that field and if it doesn't support that certain version, it'll bail.

I'd need to talk to folks first, though, what the whole story is behind not spec-ing the RMP format...

--
Regards/Gruss,
    Boris.

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