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Date:   Thu, 21 Jul 2022 17:27:08 -0700
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Subject: Re: [PATCH v8 5/5] x86/tdx: Add Quote generation support
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To:     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
Cc:     "H . Peter Anvin" <hpa@zytor.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Kai Huang <kai.huang@intel.com>,
        Wander Lairson Costa <wander@redhat.com>,
        Isaku Yamahata <isaku.yamahata@gmail.com>,
        marcelo.cerri@canonical.com, tim.gardner@canonical.com,
        khalid.elmously@canonical.com, philip.cox@canonical.com,
        linux-kernel@vger.kernel.org
References: <20220609025220.2615197-1-sathyanarayanan.kuppuswamy@linux.intel.com>
 <20220609025220.2615197-6-sathyanarayanan.kuppuswamy@linux.intel.com>
From:   Dave Hansen <dave.hansen@intel.com>
In-Reply-To: <20220609025220.2615197-6-sathyanarayanan.kuppuswamy@linux.intel.com>
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On 6/8/22 19:52, Kuppuswamy Sathyanarayanan wrote:
> In TDX guest, the second stage in attestation process is to send the
> TDREPORT to QE/QGS to generate the TD Quote. For platforms that does
> not support communication channels like vsock or TCP/IP, implement
> support to get TD Quote using hypercall. GetQuote hypercall can be used
> by the TD guest to request VMM facilitate the Quote generation via
> QE/QGS. More details about GetQuote hypercall can be found in TDX
> Guest-Host Communication Interface (GHCI) for Intel TDX 1.0, section
> titled "TDG.VP.VMCALL<GetQuote>.

So, the quote portion of this is basically a bidirectional blob sender.
 It's to send a blob between guest userspace to host userspace.

Do we *REALLY* need specific driver functionality for this?  For
instance, is there no existing virtio device that can send blobs back
and forth?