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

["Andreas Färber" <afaerber@suse.de>]

Am 29.01.2013 16:41, schrieb Juan Quintela:
> * Portio port to new memory regions?
>   Andreas, could you fill?

MemoryRegion's .old_portio mechanism requires workarounds for VGA on
ppc, affecting among others the sPAPR PCI host bridge:
http://git.qemu.org/?p=qemu.git;a=commit;h=a3cfa18eb075c7ef78358ca1956fe7b01caa1724

Patches were posted and merged removing all .old_portio users but one:
hw/ioport.c:portio_list_add_1(), used by portio_list_add()

hw/isa-bus.c:    portio_list_add(piolist, isabus->address_space_io, start);
hw/qxl.c:    portio_list_add(qxl_vga_port_list,
pci_address_space_io(dev), 0x3b0);
hw/vga.c:        portio_list_add(vga_port_list, address_space_io, 0x3b0);
hw/vga.c:        portio_list_add(vbe_port_list, address_space_io, 0x1ce);

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.

Regards,
Andreas

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