Re: [Qemu-devel] [PATCH 0/9] Add platform bus

[Peter Maydell]

On 23 July 2013 15:26, Anthony Liguori <address@hidden> wrote:
> Peter Maydell <address@hidden> writes:
>
>> On 23 July 2013 13:34, Paolo Bonzini <address@hidden> wrote:
>>> Il 23/07/2013 14:22, Peter Maydell ha scritto:
>>>> On 23 July 2013 13:19, Paolo Bonzini <address@hidden> wrote:
>> Yes, we should have easy support for defining a pluggable
>> bus as a collection of pins.
>>
>>> In fact, the main thing I dislike about Alex's patch is adding a new bus
>>> instead of making sysbus devices "just work" as pluggable devices.
>>
>> Agreed, more or less. Actually I'd rather sysbus devices
>> went away -- the requirement for interrupt and GPIO and
>> memory regions to all be defined as single arrays (so you
>> have to know what interrupt line 3 happens to be, and
>> that memory region 1 is the registers, and so on) is
>> pretty unfriendly. We should be able to define all these
>> as named connections.
>
> The concrete next steps here are well known.
>
> 1) Make MemoryRegion's QOM objects and add them as children to the
>    devices that own them.
>
> 2) Make qemu_irq a QOM object.
>
> Then you could use -device to plumb up all of these things without
> SysBus being involved.
>
> But the above is a lot of work for a use-case that while interesting
> academically so far hasn't proven to be all that important.

Yeah, I've generally been happy to limp along with the current
sysbus stuff; I'm just saying that if we want to be able to
create arbitrary MMIO devices on the command line (which is what
this patchset seems to be trying to achieve) we should do it
in the way you suggest above.

-- PMM