Re: [PATCH 2/2 V2] virtio-spec: dynamic network offloads configuration

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

On Thu, Mar 28, 2013 at 12:01:00PM +0200, Dmitry Fleytman wrote:
> From: Dmitry Fleytman <dfleytma@redhat.com>
> 
> Virtio-net driver currently negotiates network offloads
> on startup via features mechanism and have no ability to
> change offloads state later.
> This patch introduced a new control command that allows
> to configure device network offloads state dynamically.
> The patch also introduces a new feature flag
> VIRTIO_NET_F_CTRL_GUEST_OFFLD.

Maybe rename it VIRTIO_NET_F_CTRL_GUEST_OFFLOADS to match
the command name.

Otherwise OK.

> 
> Signed-off-by: Dmitry Fleytman <dfleytma@redhat.com>
> ---
>  virtio-spec.lyx | 143 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 143 insertions(+)
> 
> diff --git a/virtio-spec.lyx b/virtio-spec.lyx
> index 3d2f485..cdc4320 100644
> --- a/virtio-spec.lyx
> +++ b/virtio-spec.lyx
> @@ -60,6 +60,7 @@
>  \author -1930653948 "Amos Kong" 
>  \author -608949062 "Rusty Russell,,," 
>  \author -385801441 "Cornelia Huck" cornelia.huck@de.ibm.com
> +\author 460276516 "Dmitry Fleytman" dfleytma@redhat.com
>  \author 1112500848 "Rusty Russell" rusty@rustcorp.com.au
>  \author 1531152142 "Paolo Bonzini,,," 
>  \author 1717892615 "Alexey Zaytsev,,," 
> @@ -4261,6 +4262,20 @@ VIRTIO_NET_F_GUEST_CSUM
>  \end_inset
>  
>  (1) Guest handles packets with partial checksum
> +\change_inserted 460276516 1363712169
> +
> +\end_layout
> +
> +\begin_layout Description
> +
> +\change_inserted 460276516 1363712334
> +VIRTIO_NET_F_CTRL_GUEST_OFFLD
> +\begin_inset space ~
> +\end_inset
> +
> +(2) Control channel offloads reconfiguration support.
> +\change_unchanged
> +
>  \end_layout
>  
>  \begin_layout Description
> @@ -5675,6 +5690,134 @@ virtqueue_pairs = 1
>   
>  \end_layout
>  
> +\begin_layout Subsection*
> +
> +\change_inserted 460276516 1363765850
> +Offloads State Configuration
> +\end_layout
> +
> +\begin_layout Standard
> +
> +\change_inserted 460276516 1363765861
> +If the VIRTIO_NET_F_CTRL_GUEST_OFFLD feature is negotiated, the driver can
> + send control commands for dynamic offloads state configuration.
> +\end_layout
> +
> +\begin_layout Subsubsection*
> +
> +\change_inserted 460276516 1363765928
> +Setting offloads state
> +\end_layout
> +
> +\begin_layout Standard
> +
> +\change_inserted 460276516 1363713225
> +\begin_inset listings
> +inline false
> +status open
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363765996
> +
> +u32 offloads;
> +\end_layout
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363765997
> +
> +\end_layout
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363766044
> +
> +#define VIRTIO_NET_OFFLOAD_GUEST_CSUM       1
> +\end_layout
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363766051
> +
> +#define VIRTIO_NET_OFFLOAD_GUEST_TSO4       2
> +\end_layout
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363766055
> +
> +#define VIRTIO_NET_OFFLOAD_GUEST_TSO6       4
> +\end_layout
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363766064
> +
> +#define VIRTIO_NET_OFFLOAD_GUEST_ECN        8
> +\end_layout
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363766035
> +
> +#define VIRTIO_NET_OFFLOAD_GUEST_UFO       16
> +\end_layout
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363766031
> +
> +\end_layout
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363765865
> +
> +#define VIRTIO_NET_CTRL_GUEST_OFFLOADS       5
> +\end_layout
> +
> +\begin_layout Plain Layout
> +
> +\change_inserted 460276516 1363765867
> +
> + #define VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET          0
> +\end_layout
> +
> +\end_inset
> +
> +
> +\end_layout
> +
> +\begin_layout Standard
> +
> +\change_inserted 460276516 1363766082
> +The class VIRTIO_NET_CTRL_GUEST_OFFLOADS has one command: VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET
> + applies the new offloads configuration.
> +\end_layout
> +
> +\begin_layout Standard
> +
> +\change_inserted 460276516 1363766435
> +u32 value passed as command data is a bitmask, bits set define offloads
> + to be enabled, bits cleared - offloads to be disabled.
> +\end_layout
> +
> +\begin_layout Standard
> +
> +\change_inserted 460276516 1363766757
> +There is a corresponding device feature for each offload.
> + Upon feature negotiation corresponding offload gets enabled to preserve
> + backward compartibility.
> +\end_layout
> +
> +\begin_layout Standard
> +
> +\change_inserted 460276516 1363766720
> +Corresponding feature must be negotiated at startup in order to allow dynamic
> + change of specific offload state.
> +\end_layout
> +
>  \begin_layout Chapter*
>  Appendix D: Block Device
>  \end_layout
> -- 
> 1.8.1.4