Re: [Qemu-devel] [PATCH v2 15/15] arm/xlnx-zynqmp: put APUs and RPUs in separate GDB groups

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 04/10/2018 23:53, Eduardo Habkost wrote:
> On Thu, Oct 04, 2018 at 09:01:09PM +0100, Peter Maydell wrote:
>> On 4 October 2018 at 20:52, Eduardo Habkost <ehabkost@redhat.com> wrote:
>>> Changing the object hierarchy based on GDB groups doesn't seem
>>> right, but I don't think it would be a big deal if we have the
>>> board code explicitly telling the GDB code how to group the CPUs.
>>>
>>> If you really want to do it implicitly, would it work if you
>>> simply group the CPUs based on object_get_canonical_path()?
>>>
>>> If a more explicit GDB grouping API is acceptable, what about
>>> just adding a INTERFACE_GDB_GROUP interface name to (existing)
>>> container objects that we expect to become GDB groups?
>>>
>>> I'm not sure which way is better. I'm a bit worried that making
>>> things too implicit could easily break (e.g. if somebody changes
>>> the CPU QOM hierarchy in the future for unrelated reasons).
>>
>> I don't want things implicit. I just don't want the explicitness
>> to be "this is all about GDB", because it isn't. I want us
>> to explicitly say "these 4 CPUs are in one cluster" (or
>> whatever term we use), because that affects more than merely GDB.
> 
> We already have a way to say "these 4 CPUs are in one cluster",
> don't we?  That's the QOM hierarchy.
> 
> My question is if "the CPUs are in one cluster" should implicitly
> mean "the CPUs are in one GDB group".
> 

What about having the container implement INTERFACE_CPU_CLUSTER?

Or even cleaner, add a TYPE_CPU_CLUSTER which is just a container for
TYPE_CPU[*]?