Re: [Qemu-devel] [PATCH 2/2] qemu: add linkspeed and duplex setting to virtio-net

[Yan Vugenfirer]

> On 14 Dec 2017, at 21:33, Jason Baron via Qemu-devel <qemu-devel@xxxxxxxxxx> wrote:
> 
> Although they can be currently set in linux via 'ethtool -s', this requires
> guest changes, and thus it would be nice to extend this functionality such
> that it can be configured automatically from the host (as other network
> do).
> 
> Linkspeed and duplex settings can be set as:
> '-device virtio-net,speed=10000,duplex=full'
> 
> where speed is [-1...INT_MAX], and duplex is ["half"|"full"].
> 
> Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>
> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
> Cc: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> hw/net/virtio-net.c                         | 29 +++++++++++++++++++++++++++++
> include/hw/virtio/virtio-net.h              |  3 +++
> include/standard-headers/linux/virtio_net.h |  4 ++++
> 3 files changed, 36 insertions(+)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 38674b0..d63e790 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -40,6 +40,12 @@
> #define VIRTIO_NET_RX_QUEUE_MIN_SIZE VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE
> #define VIRTIO_NET_TX_QUEUE_MIN_SIZE VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE
> 
> +/* duplex and speed defines */
> +#define DUPLEX_UNKNOWN          0xff
> +#define DUPLEX_HALF             0x00
> +#define DUPLEX_FULL             0x01
> +#define SPEED_UNKNOWN           -1
> +
> /*
>  * Calculate the number of bytes up to and including the given 'field' of
>  * 'container'.
> @@ -61,6 +67,8 @@ static VirtIOFeature feature_sizes[] = {
>      .end = endof(struct virtio_net_config, max_virtqueue_pairs)},
>     {.flags = 1 << VIRTIO_NET_F_MTU,
>      .end = endof(struct virtio_net_config, mtu)},
> +    {.flags = 1 << VIRTIO_NET_F_SPEED_DUPLEX,
> +     .end = endof(struct virtio_net_config, duplex)},
>     {}
> };
> 
> @@ -88,6 +96,8 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
>     virtio_stw_p(vdev, &netcfg.status, n->status);
>     virtio_stw_p(vdev, &netcfg.max_virtqueue_pairs, n->max_queues);
>     virtio_stw_p(vdev, &netcfg.mtu, n->net_conf.mtu);
> +    virtio_stl_p(vdev, &netcfg.speed, n->net_conf.speed);
> +    netcfg.duplex = n->net_conf.duplex;
>     memcpy(netcfg.mac, n->mac, ETH_ALEN);
>     memcpy(config, &netcfg, n->config_size);
> }
> @@ -1941,6 +1951,23 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
>         n->host_features |= (0x1 << VIRTIO_NET_F_MTU);
>     }
> 
> +    n->host_features |= (0x1 << VIRTIO_NET_F_SPEED_DUPLEX);
> +    if (n->net_conf.duplex_str) {
> +        if (strncmp(n->net_conf.duplex_str, "half", 5) == 0) {
> +            n->net_conf.duplex = DUPLEX_HALF;
> +        } else if (strncmp(n->net_conf.duplex_str, "full", 5) == 0) {
> +            n->net_conf.duplex = DUPLEX_FULL;
> +        } else {
> +            error_setg(errp, "'duplex' must be 'half' or 'full'");
> +        }
> +    } else {
> +        n->net_conf.duplex = DUPLEX_UNKNOWN;
> +    }
> +    if (n->net_conf.speed < SPEED_UNKNOWN) {
> +            error_setg(errp, "'speed' must be between -1 (SPEED_UNKOWN) and "
> +                       "INT_MAX");
> +    }
> +
>     virtio_net_set_config_size(n, n->host_features);
>     virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size);
> 
> @@ -2160,6 +2187,8 @@ static Property virtio_net_properties[] = {
>     DEFINE_PROP_UINT16("host_mtu", VirtIONet, net_conf.mtu, 0),
>     DEFINE_PROP_BOOL("x-mtu-bypass-backend", VirtIONet, mtu_bypass_backend,
>                      true),
> +    DEFINE_PROP_INT32("speed", VirtIONet, net_conf.speed, SPEED_UNKNOWN),

>From Windows guest perspective I prefer to have some reasonable default (10G for example). 

Thanks,
Yan.

> +    DEFINE_PROP_STRING("duplex", VirtIONet, net_conf.duplex_str),
>     DEFINE_PROP_END_OF_LIST(),
> };
> 
> diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
> index b81b6a4..af74a94 100644
> --- a/include/hw/virtio/virtio-net.h
> +++ b/include/hw/virtio/virtio-net.h
> @@ -38,6 +38,9 @@ typedef struct virtio_net_conf
>     uint16_t rx_queue_size;
>     uint16_t tx_queue_size;
>     uint16_t mtu;
> +    int32_t speed;
> +    char *duplex_str;
> +    uint8_t duplex;
> } virtio_net_conf;
> 
> /* Maximum packet size we can receive from tap device: header + 64k */
> diff --git a/include/standard-headers/linux/virtio_net.h b/include/standard-headers/linux/virtio_net.h
> index 30ff249..0ff1447 100644
> --- a/include/standard-headers/linux/virtio_net.h
> +++ b/include/standard-headers/linux/virtio_net.h
> @@ -36,6 +36,7 @@
> #define VIRTIO_NET_F_GUEST_CSUM	1	/* Guest handles pkts w/ partial csum */
> #define VIRTIO_NET_F_CTRL_GUEST_OFFLOADS 2 /* Dynamic offload configuration. */
> #define VIRTIO_NET_F_MTU	3	/* Initial MTU advice */
> +#define VIRTIO_NET_F_SPEED_DUPLEX 4	/* Host set linkspeed and duplex */
> #define VIRTIO_NET_F_MAC	5	/* Host has given MAC address. */
> #define VIRTIO_NET_F_GUEST_TSO4	7	/* Guest can handle TSOv4 in. */
> #define VIRTIO_NET_F_GUEST_TSO6	8	/* Guest can handle TSOv6 in. */
> @@ -76,6 +77,9 @@ struct virtio_net_config {
> 	uint16_t max_virtqueue_pairs;
> 	/* Default maximum transmit unit advice */
> 	uint16_t mtu;
> +	/* Host exported linkspeed and duplex */
> +	uint32_t speed;
> +	uint8_t duplex;
> } QEMU_PACKED;
> 
> /*
> -- 
> 2.6.1
> 
>