Re: [Qemu-devel] [PATCH] virtio-net: Remove RX_EXTRA feature

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Jun 12, 2009 at 01:17:04PM -0600, Alex Williamson wrote:
> No need to use a feature bit to identify the RX modes.  The guest
> will get an error back if the backend doesn't support these controls.
> 
> Signed-off-by: Alex Williamson <alex.williamson@hp.com>

What's the motivation here - are we running out of feature bits already?
Using feature bits for everything makes the interface more consistent
and IMO easier to use.


> ---
> 
>  hw/virtio-net.c |    3 +--
>  hw/virtio-net.h |    8 ++++----
>  2 files changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> index d584287..fd5753a 100644
> --- a/hw/virtio-net.c
> +++ b/hw/virtio-net.c
> @@ -122,8 +122,7 @@ static uint32_t virtio_net_get_features(VirtIODevice *vdev)
>                          (1 << VIRTIO_NET_F_STATUS) |
>                          (1 << VIRTIO_NET_F_CTRL_VQ) |
>                          (1 << VIRTIO_NET_F_CTRL_RX) |
> -                        (1 << VIRTIO_NET_F_CTRL_VLAN) |
> -                        (1 << VIRTIO_NET_F_CTRL_RX_EXTRA);
> +                        (1 << VIRTIO_NET_F_CTRL_VLAN);
>  
>      return features;
>  }
> diff --git a/hw/virtio-net.h b/hw/virtio-net.h
> index 2085181..9bc4210 100644
> --- a/hw/virtio-net.h
> +++ b/hw/virtio-net.h
> @@ -43,7 +43,6 @@
>  #define VIRTIO_NET_F_CTRL_VQ    17      /* Control channel available */
>  #define VIRTIO_NET_F_CTRL_RX    18      /* Control channel RX mode support */
>  #define VIRTIO_NET_F_CTRL_VLAN  19      /* Control channel VLAN filtering */
> -#define VIRTIO_NET_F_CTRL_RX_EXTRA 20   /* Extra RX mode control support */
>  
>  #define VIRTIO_NET_S_LINK_UP    1       /* Link is up */
>  
> @@ -106,9 +105,10 @@ typedef uint8_t virtio_net_ctrl_ack;
>  /*
>   * Control the RX mode, ie. promisucous, allmulti, etc...
>   * All commands require an "out" sg entry containing a 1 byte
> - * state value, zero = disable, non-zero = enable.  Commands
> - * 0 and 1 are supported with the VIRTIO_NET_F_CTRL_RX feature.
> - * Commands 2-5 are added with VIRTIO_NET_F_CTRL_RX_EXTRA.
> + * state value, zero = disable, non-zero = enable.  This group
> + * of commands are available with the VIRTIO_NET_F_CTRL_RX
> + * feature.  Individual commands may return VIRTIO_NET_ERR if
> + * unsupported by the host.
>   */
>  #define VIRTIO_NET_CTRL_RX_MODE    0
>   #define VIRTIO_NET_CTRL_RX_MODE_PROMISC      0
> 
>