Re: [Qemu-devel] [PATCH V2 04/11] virtio-ccw: introduce ccw specific queue limit

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Thu, 26 Feb 2015 15:04:39 +0800
Jason Wang <jasowang@redhat.com> wrote:

> Instead of depending on marco, using a bus specific limit.
> 
> Cc: Alexander Graf <agraf@suse.de>
> Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Cc: Richard Henderson <rth@twiddle.net>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  hw/s390x/s390-virtio-ccw.c |  7 +++++--
>  hw/s390x/virtio-ccw.c      | 13 +++++++------
>  include/hw/virtio/virtio.h |  1 +
>  3 files changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 71bafe0..6aeb815 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -43,6 +43,7 @@ void io_subsystem_reset(void)
> 
>  static int virtio_ccw_hcall_notify(const uint64_t *args)
>  {
> +    VirtIODevice *vdev;
>      uint64_t subch_id = args[0];
>      uint64_t queue = args[1];
>      SubchDev *sch;
> @@ -55,10 +56,12 @@ static int virtio_ccw_hcall_notify(const uint64_t *args)
>      if (!sch || !css_subch_visible(sch)) {
>          return -EINVAL;
>      }
> -    if (queue >= VIRTIO_PCI_QUEUE_MAX) {
> +
> +    vdev = virtio_ccw_get_vdev(sch);
> +    if (queue >= virtio_get_queue_max(vdev)) {

But we already know we have a virtio_ccw device, right? So why not just
check against VIRTIO_CCW_QUEUE_MAX?

>          return -EINVAL;
>      }
> -    virtio_queue_notify(virtio_ccw_get_vdev(sch), queue);
> +    virtio_queue_notify(vdev, queue);
>      return 0;
> 
>  }

(...)

> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index 9fe0d92..04ad532 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -93,6 +93,7 @@ typedef struct VirtQueueElement
>  } VirtQueueElement;
> 
>  #define VIRTIO_PCI_QUEUE_MAX 64
> +#define VIRTIO_CCW_QUEUE_MAX 64

Does generic code need to know about the ccw limit?

> 
>  #define VIRTIO_NO_VECTOR 0xffff
>