MTU change is currently only allowed when device is stopped.
Current code in master branch already sets MTU in shared data correctly when
starting the device:
static int
vmxnet3_setup_driver_shared(struct rte_eth_dev *dev)
{
struct rte_eth_conf port_conf = dev->data->dev_conf;
struct vmxnet3_hw *hw = dev->data->dev_private;
uint32_t mtu = dev->data->mtu;
...
devRead->misc.mtu = rte_le_to_cpu_32(mtu);
...
}
However current code in master branch does not implement a mtu_set() function
so MTU in the dev->data is never changed from default of 1500:
int
rte_eth_dev_set_mtu(uint16_t port_id, uint16_t mtu)
{
int ret;
struct rte_eth_dev_info dev_info;
struct rte_eth_dev *dev;
RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
dev = &rte_eth_devices[port_id];
RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->mtu_set, -ENOTSUP);
/*
* Check if the device supports dev_infos_get, if it does not
* skip min_mtu/max_mtu validation here as this requires values
* that are populated within the call to rte_eth_dev_info_get()
* which relies on dev->dev_ops->dev_infos_get.
*/
if (*dev->dev_ops->dev_infos_get != NULL) {
rte_eth_dev_info_get(port_id, &dev_info);
if (mtu < dev_info.min_mtu || mtu > dev_info.max_mtu)
return -EINVAL;
}
ret = (*dev->dev_ops->mtu_set)(dev, mtu);
if (!ret)
dev->data->mtu = mtu;
return eth_err(port_id, ret);
}
The vmxnet3 driver just needs to implement mtu_set() so that
rte_eth_dev_set_mtu() allows changing the MTU and puts the value in
dev->data->mtu .
-----Original Message-----
From: Stephen Hemminger <step...@networkplumber.org>
Sent: Tuesday, August 20, 2019 6:43 PM
To: Myers, Charles <charles.my...@spirent.com>
Cc: Yong Wang <yongw...@vmware.com>; dev@dpdk.org
Subject: Re: [PATCH v3] net/vmxnet3: Added mtu_set() function to allow setting
MTU.
On Wed, 21 Aug 2019 02:16:58 +0000
"Myers, Charles" <charles.my...@spirent.com> wrote:
>
> static int
> +vmxnet3_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu) {
> + if (dev->data->dev_started) {
> + PMD_DRV_LOG(ERR, "Port %d must be stopped to configure MTU",
> + dev->data->port_id);
> + return -EBUSY;
> + }
> +
> + return 0;
> +}
> +
Don't you need to reset the rx ring to change mtu on the fly?
At a minimum you need to communicate this value to host through the shared
driver page.
