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From:   Chong Cai <chongc@google.com>
Date:   Tue, 28 Mar 2023 13:43:37 -0700
Message-ID: <CALRH0ChZ7dtJ9ST-mbjVz7Q2jY9QQm6mor5137YyFtSX4td-bw@mail.gmail.com>
Subject: Re: [PATCH v1 0/3] TDX Guest Quote generation support
To:     Dionna Amalie Glaze <dionnaglaze@google.com>
Cc:     Erdem Aktas <erdemaktas@google.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        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 Tue, Mar 28, 2023 at 12:59=E2=80=AFPM Dionna Amalie Glaze
<dionnaglaze@google.com> wrote:
>
> +Chong Cai
>
> Adding a colleague per his request since he's not subscribed to the list =
yet.
>
> On Mon, Mar 27, 2023 at 10:36=E2=80=AFAM Erdem Aktas <erdemaktas@google.c=
om> wrote:
> >
> > 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 bas=
ed
> > 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.
>
> +1 to Erdem's point. A simple TDVMCALL interface could make it much
> easier for user cases that can not depend on virtio and vsock.
> Without the TDVMCALL, it will largely limit those user cases to adopt TDX=
.
> Thanks Sathyanarayanan for submitting this patch.
> --
> -Dionna Glaze, PhD (she/her)