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Date:   Fri, 16 Jun 2023 09:26:39 -0700
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Subject: Re: [PATCH v11 20/20] Documentation/x86: Add documentation for TDX
 host support
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To:     Nikolay Borisov <nik.borisov@suse.com>,
        Kai Huang <kai.huang@intel.com>, linux-kernel@vger.kernel.org,
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From:   Dave Hansen <dave.hansen@intel.com>
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On 6/16/23 02:02, Nikolay Borisov wrote:
>>
>> +TDX reports a list of "Convertible Memory Region" (CMR) to tell the
> 
> nit: It might be worth mentioning that those CMRs ultimately come from
> the BIOS.  Because it's never mentioned here and in the "Physical Memory
> Hotplug" it's directly mentioned that bios shouldn't support hot-removal
> of memory. So the bios is a central component in a sense.

The BIOS is weird on TDX systems.  It's central, sure, but it's also
untrusted.  The TDX module generally has a kind of "trust but verify"
approach to the BIOS.

I guess the BIOS is the one poking at the memory controllers and getting
the DIMMs fired up.  But I _do_ think it's OK to say that CMRs come from
the TDX module.  The important thing is that they're trusted.