Re: [PATCH v11 20/20] Documentation/x86: Add documentation for TDX host support

[Dave Hansen]

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.