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Message-ID: <f40fe89d9b978d525ed5d56b0679d1c20b10864b.camel@intel.com>
Subject: Re: [PATCH v3 4/4] platform/x86: intel_tdx_attest: Add TDX Guest
 attestation interface driver
From:   Kai Huang <kai.huang@intel.com>
To:     Dave Hansen <dave.hansen@intel.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,
        Hans de Goede <hdegoede@redhat.com>,
        Mark Gross <mgross@linux.intel.com>
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>, linux-kernel@vger.kernel.org,
        platform-driver-x86@vger.kernel.org
Date:   Wed, 20 Apr 2022 10:21:55 +1200
In-Reply-To: <975b5050-2108-9ace-cc71-46f17db0a731@intel.com>
References: <20220415220109.282834-1-sathyanarayanan.kuppuswamy@linux.intel.com>
         <20220415220109.282834-5-sathyanarayanan.kuppuswamy@linux.intel.com>
         <bd83067542a3519ee4c91f9d50e9bd4fac27e4bb.camel@intel.com>
         <975b5050-2108-9ace-cc71-46f17db0a731@intel.com>
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On Tue, 2022-04-19 at 07:13 -0700, Dave Hansen wrote:
> On 4/19/22 00:47, Kai Huang wrote:
> > > From security's perspective, attestation is an essential part of TDX.  That
> > being said, w/o attestation support in TD guest, I guess nobody will seriously
> > use TD guest.
> 
> Are you saying you can't think of a single threat model where there's a
> benefit to running a TDX guest without attestation?  Will TDX only be
> used in environments where secrets are provisioned to guests on the
> basis of attestation?
> 
> > 

I don't think anyone should provision secret to a TD before it get attested that
it is a genuine TD that he/she expected.  If someone does that, he/she takes the
risk of losing the secret.  Of course if someone just want to try a TD then w/o
attestation is totally fine.

-- 
Thanks,
-Kai