Re: Virtualization difficulty -- phandles

[Cyril Novikov <cnovikov-wte42BQEg7M@public.gmane.org>]

On 7/14/2017 3:58 AM, Mark Rutland wrote:

>> Would it be possible to add metadata properties to the binary FDT
>> format, which would identify other property cells that are in fact
>> phandles? It could be a per-node property or a single root node
>> property, up to you guys. DTC would then automatically generate the
>> metadata property along with the phandle property when compiling the
>> DTS.
> 
> Unfortunately, even ignoring the above, this metadata isn't likely to be
> reliable, as after compilation, other agents (e.g. the bootloader) may
> modify the FDT, without updating the metadata that they are not aware
> of.

Well, it depends on the design of said metadata. For example, imagine a 
node property named ".dependencies", which simply lists all phandles 
referenced by other properties in the same node. I would be very 
surprised if the bootloader does something that breaks that. It would 
require a major intervention into the FDT.

Even if they do, like I said in my reply to David, we don't strive to 
achieve a full automation, so it's probably tolerable. Oh well, we've 
missed some dependencies. It's still better than what we have now.

--
Cyril