Re: [Qemu-devel] [PATCH v4 3/5] s390x: Add I/O adapter registration.

[Alexander Graf <agraf@suse.de>]

On 09.04.14 16:24, Cornelia Huck wrote:
> On Wed, 09 Apr 2014 16:05:00 +0200
> Alexander Graf <agraf@suse.de> wrote:
>
>> On 09.04.14 13:34, Cornelia Huck wrote:
>>> Register an I/O adapter interrupt source for when virtio-ccw devices start
>>> using adapter interrupts.
>>>
>>> Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
>>> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
>>> ---
>>>    hw/intc/s390_flic.c   |   59 +++++++++++++++++++++++++++++++++++++++++++++++++
>>>    hw/s390x/css.c        |   51 ++++++++++++++++++++++++++++++++++++++++++
>>>    hw/s390x/css.h        |    4 ++++
>>>    hw/s390x/virtio-ccw.c |    4 ++++
>>>    hw/s390x/virtio-ccw.h |    1 +
>>>    target-s390x/cpu.h    |   33 +++++++++++++++++++++++++++
>>>    6 files changed, 152 insertions(+)
>>>
>>> diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
>>> index 2bf0af8..1193682 100644
>>> --- a/hw/s390x/virtio-ccw.c
>>> +++ b/hw/s390x/virtio-ccw.c
>>> @@ -522,6 +522,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
>>>                    dev->thinint_isc = thinint->isc;
>>>                    dev->ind_bit = thinint->ind_bit;
>>>                    cpu_physical_memory_unmap(thinint, hw_len, 0, hw_len);
>>> +                ret = css_register_io_adapter(CSS_IO_ADAPTER_VIRTIO,
>>> +                                              dev->thinint_isc, true, false,
>>> +                                              &dev->adapter_id);
>> In all other machines the machine file is the one creating the link
>> between a device and the interrupt controller. Can we do something
>> similar for s390?
> Hm. This would imply we'd need to add a virtio I/O adapter for each isc
> (0-7) at startup, regardless whether the guest enables adapter
> interrupts on any of those iscs. Moreover, we'd need to do the same for
> each type (on each isc) if we add more types of I/O adapters later
> (should we want to support one of the other adapter-interrupt using
> devices). I'd prefer to add an I/O adapter only when needed.

I'm not sure I can follow you here. Instead of registering the interrupt 
vector on the fly, you would still register it on the fly, but after the 
virtio-ccw device got created, no?


Alex