Re: [Qemu-devel] [PATCH 3/3] target-arm: Comments to mark location of pending work for 56 bit addresses

[Tom Hanson]

On 09/29/2016 07:27 PM, Peter Maydell wrote:
...
>> This work was not done at this time since the changes could not be tested
>> with current CPU models.  Comments have been added to flag the locations
>> where this will need to be fixed once a model is available.
> 
> This is *not* why we haven't done this work. We haven't done it
> because the maximum virtual address size permitted by the
> architecture is less than 56 bits, and so this is a "can't happen"
> situation.

But, in an earlier discussion which we had about the desire to use QEMU to test 
potential new ARM-based architectures with large address spaces I suggested 
that these changes be made now.  You said that the changes shouldn't be made 
because:
    where there is no supported guest CPU that could use
    that code, the code shouldn't be there because it's untested
    and untestable
Isn't that the same thing I said above?

>> 3 comments added in same file to identify cases in a switch.
> 
> This should be a separate patch, because it is unrelated to the
> tagged address stuff.

As part of that same conversation you suggested adding these comments rather 
than making the changes:
    If we can assert, or failing that have a comment in the place
    that would be modified anyway for 56 bit addresses then that
    ought to catch the future case I think.