Subject: Re: [PATCH v4 3/3] qemu: add linkspeed and duplex settings to virtio-net

From: "Michael S. Tsirkin" <[email-masked]>
Date: Thu, 8 Feb 2018 18:39:55 +0200

On Fri, Jan 05, 2018 at 05:44:55PM -0500, Jason Baron wrote:
> Although linkspeed and duplex can be set in a linux guest via 'ethtool -s',
> this requires custom ethtool commands for virtio-net by default.
> 
> 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'.
> 
> 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 <[email-masked]>
> Cc: "Michael S. Tsirkin" <[email-masked]>
> Cc: Jason Wang <[email-masked]>
> Cc: [email-masked]
> ---
>  hw/net/virtio-net.c                         | 32 +++++++++++++++++++++++++++++
>  include/hw/virtio/virtio-net.h              |  3 +++
>  include/standard-headers/linux/virtio_net.h | 13 ++++++++++++
>  3 files changed, 48 insertions(+)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 54823af..cd63659 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 */
> +#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'.

Please import ethtool.h with these macros from linux using scripts/update-linux-headers.sh
machinery.

> @@ -61,6 +67,8 @@ static VirtIOFeature feature_sizes[] = {
>       .end = endof(struct virtio_net_config, max_virtqueue_pairs)},
>      {.flags = 1ULL << VIRTIO_NET_F_MTU,
>       .end = endof(struct virtio_net_config, mtu)},
> +    {.flags = 1ULL << VIRTIO_NET_F_SPEED_DUPLEX,
> +     .end = endof(struct virtio_net_config, duplex)},
>      {}
>  };
>  
> @@ -89,6 +97,8 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
>      virtio_stw_p(vdev, &netcfg.max_virtqueue_pairs, n->max_queues);
>      virtio_stw_p(vdev, &netcfg.mtu, n->net_conf.mtu);
>      memcpy(netcfg.mac, n->mac, ETH_ALEN);
> +    virtio_stl_p(vdev, &netcfg.speed, n->net_conf.speed);
> +    netcfg.duplex = n->net_conf.duplex;
>      memcpy(config, &netcfg, n->config_size);
>  }
>  
> @@ -1941,6 +1951,26 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
>          n->host_features |= (1ULL << VIRTIO_NET_F_MTU);
>      }
>  
> +    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'");
> +        }
> +        n->host_features |= (1ULL << VIRTIO_NET_F_SPEED_DUPLEX);
> +    } 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");
> +    } else if (n->net_conf.speed >= 0) {
> +        n->host_features |= (1ULL << VIRTIO_NET_F_SPEED_DUPLEX);
> +    }
> +
>      virtio_net_set_config_size(n, n->host_features);
>      virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size);
>  
> @@ -2161,6 +2191,8 @@ 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),
> +    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 e7634c9..02484dc 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..17c8531 100644
> --- a/include/standard-headers/linux/virtio_net.h
> +++ b/include/standard-headers/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 {
>  	uint16_t max_virtqueue_pairs;
>  	/* Default maximum transmit unit advice */
>  	uint16_t mtu;
> +	/*
> +	 * speed, in units of 1Mb. All values 0 to INT_MAX are legal.
> +	 * Any other value stands for unknown.
> +	 */
> +	uint32_t speed;
> +	/*
> +	 * 0x00 - half duplex
> +	 * 0x01 - full duplex
> +	 * Any other value stands for unknown.
> +	 */
> +	uint8_t duplex;
>  } QEMU_PACKED;
>  
>  /*

This should be done as a separate patch by running the abovementioned
update script.

> diff --git a/pixman b/pixman
> new file mode 160000
> index 0000000..87eea99
> --- /dev/null
> +++ b/pixman
> @@ -0,0 +1 @@
> +Subproject commit 87eea99e443b389c978cf37efc52788bf03a0ee0

I don't think we need this part.

> -- 
> 2.6.1