From: Tom Lendacky <thomas.lendacky@amd.com>
To: Ard Biesheuvel <ardb@kernel.org>,
devel@edk2.groups.io, kraxel@redhat.com
Cc: jiewen.yao@intel.com,
Dionna Amalie Glaze <dionnaglaze@google.com>,
Mikko Ylinen <mikko.ylinen@linux.intel.com>,
James Bottomley <jejb@linux.ibm.com>,
Michael Roth <michael.roth@amd.com>,
qinkun Bao <qinkun@google.com>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
"Aktas, Erdem" <erdemaktas@google.com>,
Peter Gonda <pgonda@google.com>,
"Johnson, Simon P" <simon.p.johnson@intel.com>,
"Xiang, Qinglan" <qinglan.xiang@intel.com>
Subject: Re: [edk2-devel] [RFC PATCH] OvmfPkg/SecurityPkg: Add build option for coexistance of vTPM and RTMR.
Date: Thu, 11 Apr 2024 09:07:37 -0500 [thread overview]
Message-ID: <226ff307-991d-693a-1bca-837931d08604@amd.com> (raw)
In-Reply-To: <CAMj1kXFDCThQhvVvDknV9GDzG2HWLPR4LC94CHhuckGE41Nvvw@mail.gmail.com>
On 4/11/24 05:33, Ard Biesheuvel wrote:
> On Thu, 11 Apr 2024 at 12:29, Gerd Hoffmann <kraxel@redhat.com> wrote:
>>
>> On Thu, Apr 11, 2024 at 09:56:48AM +0000, Yao, Jiewen wrote:
>>> Please allow me to clarify what you are proposing:
>>> Do you mean in vTPM case, we extend both, but we only need TCG event log, NOT CC event log?
>>
>> Elsewhere in this thread it was mentioned that writing both vTPM and
>> RTMR events to the event log is problematic because the event log format
>> has no field to specify whenever a given event was measured to vTPM or
>> RTMR.
>>
>> If the firmware can make sure all events are measured to both vTPM and
>> RTMR the need to trace them separately goes away.
>>
>> So, yes, in case a vTPM is present the firmware would:
>> (a) expose EFI_TCG2_PROTOCOL, measure to both vTPM + RTMR
>> (b) not expose EFI_CC_MEASUREMENT_PROTOCOL
>> (c) log measurements to TCG event log
>>
>
> A TDX attestation would require the PCR to RTMR mapping used by the
> firmware in order to reconstruct the RTMR values from the TCG event
> log, but that seems feasible to me.
>
> In any case, I think it should be the guest firmware's job to abstract
> away the difference.
Agreed, this approach seems to be the best way forward.
Thanks,
Tom
next prev parent reply other threads:[~2024-04-11 14:07 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-21 16:59 [RFC PATCH] OvmfPkg/SecurityPkg: Add build option for coexistance of vTPM and RTMR qinkun Bao
2024-03-21 17:46 ` Dionna Amalie Glaze
2024-03-22 2:39 ` Yao, Jiewen
2024-03-22 8:52 ` Gerd Hoffmann
2024-03-22 14:56 ` Dionna Amalie Glaze
2024-03-22 17:28 ` Qinkun Bao
2024-03-25 13:07 ` Mikko Ylinen
2024-03-25 15:28 ` Dionna Amalie Glaze
2024-04-11 1:20 ` Yao, Jiewen
2024-04-11 6:23 ` Qinkun Bao
2024-04-11 6:52 ` [edk2-devel] " Ard Biesheuvel
2024-04-11 8:07 ` Gerd Hoffmann
2024-04-11 9:56 ` Yao, Jiewen
2024-04-11 10:29 ` kraxel
2024-04-11 10:33 ` Ard Biesheuvel
2024-04-11 14:07 ` Tom Lendacky [this message]
2024-04-11 17:10 ` Xiang, Qinglan
2024-04-13 9:36 ` Qinkun Bao
2024-04-15 14:42 ` Ard Biesheuvel
[not found] ` <17C329C4A6D0CD18.8175@lists.confidentialcomputing.io>
[not found] ` <CAOjUGWcNedJ7iNjGCKL6qZeZo3aSt_8U5BN=9JUN2f2vjD+O4w@mail.gmail.com>
[not found] ` <CA+2DEOoc1Ckn2S-=57HiRsAd0W4YGRWVQQG-gOBR3Fc8nfX+Nw@mail.gmail.com>
2024-04-09 19:16 ` Fwd: [External] Re: [linux-collab] [CCC][tac] " Qinkun Bao
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