Re: [PATCH 2/2] vdpa: Add support to update speed/duplex in vDPA/mlx5_vnet

[Carlos Bilbao <cbilbao@digitalocean.com>]

Hello,

On 8/29/24 9:31 PM, Jason Wang wrote:
> On Fri, Aug 30, 2024 at 5:08 AM Dragos Tatulea <dtatulea@nvidia.com> wrote:
>> (resending as I accidentally replied only to Carlos)
>>
>> On 29.08.24 18:16, Carlos Bilbao wrote:
>>> From: Carlos Bilbao <cbilbao@digitalocean.com>
>>>
>>> Include support to update the vDPA configuration fields of speed and
>>> duplex (as needed by VHOST_VDPA_SET_CONFIG). This includes function
>>> mlx5_vdpa_set_config() as well as changes in vdpa.c to fill the initial
>>> values to UNKNOWN. Also add a warning message for when
>>> mlx5_vdpa_get_config() receives offset and length out of bounds.
>>>
>>> Signed-off-by: Carlos Bilbao <cbilbao@digitalocean.com>
>>> ---
>>>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 34 ++++++++++++++++++++++++++++++-
>>>  drivers/vdpa/vdpa.c               | 27 ++++++++++++++++++++++++
>>>  include/uapi/linux/vdpa.h         |  2 ++
>>>  3 files changed, 62 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> index c47009a8b472..a44bb2072eec 100644
>>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> @@ -3221,12 +3221,44 @@ static void mlx5_vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,
>>>
>>>       if (offset + len <= sizeof(struct virtio_net_config))
>>>               memcpy(buf, (u8 *)&ndev->config + offset, len);
>>> +     else
>>> +             mlx5_vdpa_warn(mvdev, "Offset and length out of bounds\n");
>>>  }
>>>
>>>  static void mlx5_vdpa_set_config(struct vdpa_device *vdev, unsigned int offset, const void *buf,
>>>                                unsigned int len)
>>>  {
>>> -     /* not supported */
>>> +     struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
>>> +     struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
>>> +
>>> +     if (offset + len > sizeof(struct virtio_net_config)) {
>>> +             mlx5_vdpa_warn(mvdev, "Offset and length out of bounds\n");
>>> +             return;
>>> +     }
>>> +
>>> +     /*
>>> +      * Note that this will update the speed/duplex configuration fields
>>> +      * but the hardware support to actually perform this change does
>>> +      * not exist yet.
>>> +      */
>>> +     switch (offset) {
>>> +     case offsetof(struct virtio_net_config, speed):
>>> +             if (len == sizeof(((struct virtio_net_config *) 0)->speed))
>>> +                     memcpy(&ndev->config.speed, buf, len);
>>> +             else
>>> +                     mlx5_vdpa_warn(mvdev, "Invalid length for speed.\n");
>>> +             break;
>>> +
>>> +     case offsetof(struct virtio_net_config, duplex):
>>> +             if (len == sizeof(((struct virtio_net_config *)0)->duplex))
>>> +                     memcpy(&ndev->config.duplex, buf, len);
>>> +             else
>>> +                     mlx5_vdpa_warn(mvdev, "Invalid length for duplex.\n");
>>> +             break;
>>> +
>>> +     default:
>>> +             mlx5_vdpa_warn(mvdev, "Configuration field not supported.\n");
>> This will trigger noise in dmesg because there is a MAC configuration here.
>>> +     }
>> I would prefer that the .set_config remains a stub TBH. Setting the fields here is
>> misleading: the user might deduce that the configuration worked when they read the
>> values and see that they were updated.
> Yes, and actually, those fields are read-only according to the spec:
>
> """
> The network device has the following device configuration layout. All
> of the device configuration fields are read-only for the driver.
> """
>
> Thanks


Should I go ahead and remove the ioctl then?


>
>> Thanks,
>> dragos
>>>  }
>>>
>>>  static u32 mlx5_vdpa_get_generation(struct vdpa_device *vdev)
>>> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
>>> index 4dbd2e55a288..b920e4405f6d 100644
>>> --- a/drivers/vdpa/vdpa.c
>>> +++ b/drivers/vdpa/vdpa.c
>>> @@ -15,6 +15,7 @@
>>>  #include <net/genetlink.h>
>>>  #include <linux/mod_devicetable.h>
>>>  #include <linux/virtio_ids.h>
>>> +#include <uapi/linux/ethtool.h>
>>>
>>>  static LIST_HEAD(mdev_head);
>>>  /* A global mutex that protects vdpa management device and device level operations. */
>>> @@ -919,6 +920,22 @@ static int vdpa_dev_net_status_config_fill(struct sk_buff *msg, u64 features,
>>>       return nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16);
>>>  }
>>>
>>> +static int vdpa_dev_net_speed_config_fill(struct sk_buff *msg, u64 features,
>>> +                                     struct virtio_net_config *config)
>>> +{
>>> +     __le32 speed = cpu_to_le32(SPEED_UNKNOWN);
>>> +
>>> +     return nla_put(msg, VDPA_ATTR_DEV_NET_CFG_SPEED, sizeof(speed), &speed);
>>> +}
>>> +
>>> +static int vdpa_dev_net_duplex_config_fill(struct sk_buff *msg, u64 features,
>>> +                                     struct virtio_net_config *config)
>>> +{
>>> +     u8 duplex = DUPLEX_UNKNOWN;
>>> +
>>> +     return nla_put(msg, VDPA_ATTR_DEV_NET_CFG_DUPLEX, sizeof(duplex), &duplex);
>>> +}
>>> +
>>>  static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
>>>  {
>>>       struct virtio_net_config config = {};
>>> @@ -940,6 +957,16 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
>>>
>>>       if (vdpa_dev_net_status_config_fill(msg, features_device, &config))
>>>               return -EMSGSIZE;
>>> +     /*
>>> +      * mlx5_vdpa vDPA devicess currently do not support the
>>> +      * VIRTIO_NET_F_SPEED_DUPLEX feature, which reports speed and
>>> +      * duplex; hence these are set to UNKNOWN for now.
>>> +      */
>>> +     if (vdpa_dev_net_speed_config_fill(msg, features_device, &config))
>>> +             return -EMSGSIZE;
>>> +
>>> +     if (vdpa_dev_net_duplex_config_fill(msg, features_device, &config))
>>> +             return -EMSGSIZE;
>>>
>>>       return vdpa_dev_net_mq_config_fill(msg, features_device, &config);
>>>  }
>>> diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
>>> index 842bf1201ac4..1c64ee0dd7b1 100644
>>> --- a/include/uapi/linux/vdpa.h
>>> +++ b/include/uapi/linux/vdpa.h
>>> @@ -43,6 +43,8 @@ enum vdpa_attr {
>>>       VDPA_ATTR_DEV_NET_STATUS,               /* u8 */
>>>       VDPA_ATTR_DEV_NET_CFG_MAX_VQP,          /* u16 */
>>>       VDPA_ATTR_DEV_NET_CFG_MTU,              /* u16 */
>>> +     VDPA_ATTR_DEV_NET_CFG_SPEED,            /* u32 */
>>> +     VDPA_ATTR_DEV_NET_CFG_DUPLEX,           /* u8 */
>>>
>>>       VDPA_ATTR_DEV_NEGOTIATED_FEATURES,      /* u64 */
>>>       VDPA_ATTR_DEV_MGMTDEV_MAX_VQS,          /* u32 */


Thanks, Carlos