On Thu, Jan 04, 2018 at 12:16:44AM -0500, Jason Baron wrote:
> The ability to set speed and duplex for virtio_net is useful in various
> scenarios as described here:
>
> 16032be virtio_net: add ethtool support for set and get of settings
>
> However, it would be nice to be able to set this from the hypervisor,
> such that virtio_net doesn't require custom guest ethtool commands.
>
> Introduce a new feature flag, VIRTIO_NET_F_SPEED_DUPLEX, which allows
> the hypervisor to export a linkspeed and duplex setting. The user can
> subsequently overwrite it later if desired via: 'ethtool -s'.
>
> Note that VIRTIO_NET_F_SPEED_DUPLEX is defined as bit 63, the intention
> is that device feature bits are to grow down from bit 63, since the
> transports are starting from bit 24 and growing up.
>
> Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>
> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
> Cc: Jason Wang <jasowang@xxxxxxxxxx>
> Cc: virtio-dev@xxxxxxxxxxxxxxxxxxxx
> ---
> drivers/net/virtio_net.c | 19 ++++++++++++++++++-
> include/uapi/linux/virtio_net.h | 13 +++++++++++++
> 2 files changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 6fb7b65..0b2d314 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2146,6 +2146,22 @@ static void virtnet_config_changed_work(struct work_struct *work)
>
> vi->status = v;
>
> + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_SPEED_DUPLEX)) {
> + u32 speed;
> + u8 duplex;
> +
> + speed = virtio_cread32(vi->vdev,
> + offsetof(struct virtio_net_config,
> + speed));
> + if (ethtool_validate_speed(speed))
> + vi->speed = speed;
> + duplex = virtio_cread8(vi->vdev,
> + offsetof(struct virtio_net_config,
> + duplex));
> + if (ethtool_validate_duplex(duplex))
> + vi->duplex = duplex;
> + }
> +
> if (vi->status & VIRTIO_NET_S_LINK_UP) {
> netif_carrier_on(vi->dev);
> netif_tx_wake_all_queues(vi->dev);
> @@ -2796,7 +2812,8 @@ static struct virtio_device_id id_table[] = {
> VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN, \
> VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, \
> VIRTIO_NET_F_CTRL_MAC_ADDR, \
> - VIRTIO_NET_F_MTU, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS
> + VIRTIO_NET_F_MTU, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, \
> + VIRTIO_NET_F_SPEED_DUPLEX
>
> static unsigned int features[] = {
> VIRTNET_FEATURES,
Still missing the update from virtnet_config_changed_work, and I think
it's important to reflex host changes within guest when the
feature bit has been acked.
> diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
> index fc353b5..5de6ed3 100644
> --- a/include/uapi/linux/virtio_net.h
> +++ b/include/uapi/linux/virtio_net.h
> @@ -57,6 +57,8 @@
> * Steering */
> #define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */
>
> +#define VIRTIO_NET_F_SPEED_DUPLEX 63 /* Device set linkspeed and duplex */
> +
> #ifndef VIRTIO_NET_NO_LEGACY
> #define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */
> #endif /* VIRTIO_NET_NO_LEGACY */
> @@ -76,6 +78,17 @@ struct virtio_net_config {
> __u16 max_virtqueue_pairs;
> /* Default maximum transmit unit advice */
> __u16 mtu;
> + /*
> + * speed, in units of 1Mb. All values 0 to INT_MAX are legal.
> + * Any other value stands for unknown.
> + */
> + __u32 speed;
> + /*
> + * 0x00 - half duplex
> + * 0x01 - full duplex
> + * Any other value stands for unknown.
> + */
> + __u8 duplex;
> } __attribute__((packed));
>
> /*
> --
> 2.6.1
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