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From:   Erdem Aktas <erdemaktas@google.com>
Date:   Mon, 27 Mar 2023 10:36:17 -0700
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Subject: Re: [PATCH v1 0/3] TDX Guest Quote generation support
To:     Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        Shuah Khan <shuah@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        "H . Peter Anvin" <hpa@zytor.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Wander Lairson Costa <wander@redhat.com>,
        Guorui Yu <GuoRui.Yu@linux.alibaba.com>,
        Du Fan <fan.du@intel.com>, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org
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On Sat, Mar 25, 2023 at 11:20=E2=80=AFPM Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com> wrote:
>
> Hi All,
>
> In TDX guest, the attestation process is used to verify the TDX guest
> trustworthiness to other entities before provisioning secrets to the
> guest.
>
> The TDX guest attestation process consists of two steps:
>
> 1. TDREPORT generation
> 2. Quote generation.
>
> The First step (TDREPORT generation) involves getting the TDX guest
> measurement data in the format of TDREPORT which is further used to
> validate the authenticity of the TDX guest. The second step involves
> sending the TDREPORT to a Quoting Enclave (QE) server to generate a
> remotely verifiable Quote. TDREPORT by design can only be verified on
> the local platform. To support remote verification of the TDREPORT,
> TDX leverages Intel SGX Quoting Enclave to verify the TDREPORT
> locally and convert it to a remotely verifiable Quote. Although
> attestation software can use communication methods like TCP/IP or
> vsock to send the TDREPORT to QE, not all platforms support these
> communication models. So TDX GHCI specification [1] defines a method
> for Quote generation via hypercalls. Please check the discussion from
> Google [2] and Alibaba [3] which clarifies the need for hypercall based
Thanks Sathyanarayanan for submitting patches again.

I just wanted to reiterate what I said before that having a clean
TDVMCALL based interface to get TDX Quote without any virtio/vsock
dependency  is critical for us to support many use cases.