linux-kernel - Re: [PATCH 3/3] x86/sev: add a SVSM vTPM platform device

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <sf5zezwsokmz7lkl7fdl5z5q6lipeqd5d4sws2hpi6pznyvdap@tjfv5p5uty7y>
Date: Thu, 23 Jan 2025 11:09:53 +0100
From: Stefano Garzarella <sgarzare@...hat.com>
To: Jarkko Sakkinen <jarkko@...nel.org>
Cc: Dionna Amalie Glaze <dionnaglaze@...gle.com>, 
	Jarkko Sakkinen <jarkko.sakkinen@....fi>, Jason Gunthorpe <jgg@...pe.ca>, 
	James Bottomley <james.bottomley@...senpartnership.com>, linux-coco@...ts.linux.dev, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, Peter Huewe <peterhuewe@....de>, 
	"H. Peter Anvin" <hpa@...or.com>, linux-integrity@...r.kernel.org, x86@...nel.org, 
	Joerg Roedel <jroedel@...e.de>, linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>, 
	Thomas Gleixner <tglx@...utronix.de>, Claudio Carvalho <cclaudio@...ux.ibm.com>, 
	Dov Murik <dovmurik@...ux.ibm.com>, Tom Lendacky <thomas.lendacky@....com>
Subject: Re: [PATCH 3/3] x86/sev: add a SVSM vTPM platform device

On Thu, Jan 23, 2025 at 11:50:40AM +0200, Jarkko Sakkinen wrote:
>On Wed Jan 22, 2025 at 11:29 PM EET, Dionna Amalie Glaze wrote:
>> I can appreciate this viewpoint. It even surfaced Microsoft's fTPM
>> paper to me, which solves some interesting problems we need to solve
>> in SVSM too. So thanks for that.
>>
>> Just to clarify, you're not asking for SVSM to implement the TIS-MMIO
>> interface instead, but rather to use the fTPM stack, which could make
>> SVSM calls a TEE device operation?
>
>I don't really know what I'm asking because this is barely even a
>PoC, and I state it like this knowingly.
>
>You should make the argument, and the case for the solution. Then
>it is my turn to comment on that scheme.

I'll check if I can use fTPM, in the meantime I had started to simplify
this series, avoiding the double stack and exposing some APIs from SEV
to probe the vTPM and to send the commands. The final driver in
drivers/char/tpm would be quite simple.

But I'll try to see if reusing fTPM is a feasible way, I like the idea.

>
>That said, I would not give high odds for acceptance of a duplicate
>TPM stack succeeding.

Got it ;-)

Thanks to everyone for the helpful feedbacks!

I've been a bit messy these days and I'm in FOSDEM next week, so I hope
not to take too long for the v2.

Stefano