[PATCH v7 5/8] net/gve: add support for MTU setting

[Guo, Junfeng]

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit at amd.com>
> Sent: Friday, October 21, 2022 17:50
> To: Guo, Junfeng <junfeng.guo at intel.com>; Zhang, Qi Z
> <qi.z.zhang at intel.com>; Wu, Jingjing <jingjing.wu at intel.com>; Xing,
> Beilei <beilei.xing at intel.com>
> Cc: dev at dpdk.org; Li, Xiaoyun <xiaoyun.li at intel.com>;
> awogbemila at google.com; Richardson, Bruce
> <bruce.richardson at intel.com>; hemant.agrawal at nxp.com;
> stephen at networkplumber.org; Xia, Chenbo <chenbo.xia at intel.com>;
> Zhang, Helin <helin.zhang at intel.com>
> Subject: Re: [PATCH v7 5/8] net/gve: add support for MTU setting
> 
> On 10/21/2022 10:19 AM, Junfeng Guo wrote:
> 
> >
> > Support dev_ops mtu_set.
> >
> > Signed-off-by: Xiaoyun Li <xiaoyun.li at intel.com>
> > Signed-off-by: Junfeng Guo <junfeng.guo at intel.com>
> 
> <...>
> 
> > +static int
> > +gve_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
> > +{
> > +       struct gve_priv *priv = dev->data->dev_private;
> > +       int err;
> > +
> > +       if (mtu < RTE_ETHER_MIN_MTU || mtu > priv->max_mtu) {
> > +               PMD_DRV_LOG(ERR, "MIN MTU is %u, MAX MTU is %u",
> > +                           RTE_ETHER_MIN_MTU, priv->max_mtu);
> > +               return -EINVAL;
> > +       }
> > +
> > +       /* mtu setting is forbidden if port is start */
> > +       if (dev->data->dev_started) {
> > +               PMD_DRV_LOG(ERR, "Port must be stopped before
> configuration");
> > +               return -EBUSY;
> > +       }
> > +
> > +       err = gve_adminq_set_mtu(priv, mtu);
> > +       if (err) {
> > +               PMD_DRV_LOG(ERR, "Failed to set mtu as %u err = %d", mtu,
> err);
> > +               return err;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> 
> [copy/paste from previous version]
> 
> configure() (gve_dev_configure()) also get 'mtu' as user config
> ('eth_conf->rxmode.mtu') which is ignored right now,
> 
> since there is 'gve_adminq_set_mtu()' command already what do you
> think
> to use it within 'gve_dev_configure()'?

There may be issues to set mtu with ('eth_conf->rxmode.mtu'). 
So better to keep this ignored at this stage.