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Date:   Tue, 10 May 2022 04:30:38 +0300
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     Kai Huang <kai.huang@intel.com>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Sathyanarayanan Kuppuswamy 
        <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,
        "H . Peter Anvin" <hpa@zytor.com>, Tony Luck <tony.luck@intel.com>,
        Andi Kleen <ak@linux.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
Subject: Re: [PATCH v5 3/3] x86/tdx: Add Quote generation support
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On Tue, May 10, 2022 at 11:54:12AM +1200, Kai Huang wrote:
> On Mon, 2022-05-09 at 15:09 +0300, Kirill A. Shutemov wrote:
> > On Mon, May 09, 2022 at 03:37:22PM +1200, Kai Huang wrote:
> > > On Sat, 2022-05-07 at 03:42 +0300, Kirill A. Shutemov wrote:
> > > > On Fri, May 06, 2022 at 12:11:03PM +1200, Kai Huang wrote:
> > > > > Kirill, what's your opinion?
> > > > 
> > > > I said before that I think DMA API is the right tool here.
> > > > 
> > > > Speculation about future of DMA in TDX is irrelevant here. If semantics
> > > > change we will need to re-evaluate all users. VirtIO uses DMA API and it
> > > > is conceptually the same use-case: communicate with the host.
> > > 
> > > Virtio is designed for device driver to use, so it's fine to use DMA API. And
> > > real DMA can happen to the virtio DMA buffers.  Attestation doesn't have such
> > > assumption.
> > 
> > Whether attestation driver uses struct device is implementation detail.
> > I don't see what is you point.
> 
> No real DMA is involved in attestation.

As with VirtIO. So what?

-- 
 Kirill A. Shutemov