Re: [Qemu-devel] [PATCH 09/15] hw/mips/malta: Replace 'empty_slot' by 'unimplemented_device'

[Peter Maydell]

On 2 October 2018 at 20:40, Philippe Mathieu-Daudé <address@hidden> wrote:
> On 10/2/18 3:23 PM, Peter Maydell wrote:
>> Not sure about this one. unimplemented_device means "there should
>> be something here, but QEMU's model is incomplete", and if the user
>> asks for 'unimp' warnings via the -d option then all accesses will
>> generate logging. In this MIPS board, we're modelling the hardware's
>> actual behaviour, and we shouldn't generate debug messages that
>> imply that QEMU has unimplemented functionality here.
>>
>> If we were writing a model of the Malta board from scratch we'd
>> probably do it by having the GT-64120A be modelled as a device
>> which was a container object that instantiated all its various
>> bits and pieces and mapped them into a MemoryRegion that spanned
>> the whole 1GB size of that part of the address space. We could
>> then give that MR a background region with the "RAZ/WI" behaviour
>> the hardware requires.
>
> Is 'git revert c7c3c9f8' a good example of your explanation?

That commit is OK, because the previous version was also
logging accesses as being unimplemented.

thanks
-- PMM