Re: [Qemu-devel] KVM call minutes 2013-01-29 - Port I/O

[Peter Maydell]

On 30 January 2013 11:39, Andreas Färber <address@hidden> wrote:
> Proposal by hpoussin was to move _list_add() code to ISADevice:
> http://lists.gnu.org/archive/html/qemu-devel/2013-01/msg00508.html
>
> Concerns:
> * PCI devices (VGA, QXL) register I/O ports as well
>   => above patches add dependency on ISABus to machines
>      -> "<benh> no mac ever had one"
>   => PCIDevice shouldn't use ISA API with NULL ISADevice
> * Lack of avi: Who decides about memory API these days?
>
> armbru and agraf concluded that moving this into ISA is wrong.
>
> => I will drop the remaining ioport patches from above series.
>
> Suggestions on how to proceed with tackling the issue are welcome.

How does this stuff work on real hardware? I would have
expected that a PCI device registering the fact it has
IO ports would have to do so via the PCI controller it
is plugged into...

My naive don't-know-much-about-portio suggestion is that this
should work the same way as memory regions: each device
provides portio regions, and the controller for the bus
(ISA or PCI) exposes those to the next layer up, and
something at board level maps it all into the right places.

-- PMM