Re: [Qemu-devel] [PATCH V3 10/14] virtio: introduce virtio_queue_get_index()

[Jason Wang <jasowang@redhat.com>]

On Thu, Mar 5, 2015 at 2:12 PM, Fam Zheng <famz@redhat.com> wrote:
> On Thu, 03/05 13:48, Jason Wang wrote:
>>  This patch introduces a helper that can get the queue index of a
>>  VirtQueue. This is useful when traversing the list of VirtQueues.
>>  
>>  Cc: Anthony Liguori <aliguori@amazon.com>
>>  Cc: Michael S. Tsirkin <mst@redhat.com>
>>  Signed-off-by: Jason Wang <jasowang@redhat.com>
>>  ---
>>   hw/virtio/virtio.c         | 5 +++++
>>   include/hw/virtio/virtio.h | 1 +
>>   2 files changed, 6 insertions(+)
>>  
>>  diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
>>  index 5e6b879..bd32518 100644
>>  --- a/hw/virtio/virtio.c
>>  +++ b/hw/virtio/virtio.c
>>  @@ -725,6 +725,11 @@ hwaddr virtio_queue_get_addr(VirtIODevice 
>> *vdev, int n)
>>       return vdev->vq[n].pa;
>>   }
>>   
>>  +int virtio_queue_get_index(VirtIODevice *vdev, VirtQueue *vq)
>>  +{
>>  +    return vq - vdev->vq;
> 
> Probably assert the return value is within [0, 
> virtio_get_queue_max(vdev))?
> 
> Fam

Not sure this is necessary. If we add one such here, we probably needs 
to add more elsewhere.