Re: [PATCH net-next v5 2/5] ethtool: netlink: add ETHTOOL_MSG_MSE_GET and wire up PHY MSE access

[Jakub Kicinski <kuba@kernel.org>]

On Mon,  8 Sep 2025 14:46:07 +0200 Oleksij Rempel wrote:
> diff --git a/Documentation/netlink/specs/ethtool.yaml b/Documentation/netlink/specs/ethtool.yaml
> index 969477f50d84..d69dd3fb534b 100644
> --- a/Documentation/netlink/specs/ethtool.yaml
> +++ b/Documentation/netlink/specs/ethtool.yaml
> @@ -1899,6 +1899,79 @@ attribute-sets:
>          type: uint
>          enum: pse-event
>          doc: List of events reported by the PSE controller
> +  -
> +    name: mse-config
> +    attr-cnt-name: --ethtool-a-mse-config-cnt
> +    attributes:
> +      -
> +        name: unspec
> +        type: unused
> +        value: 0

Are you actually using this somewhere?
It's good to not use attr ID 0 in case we encounter an uninitialized
attr, but there's no need to define a name for it, usually.
Just skip the entry 0 if you don't need then name.

> +      -
> +        name: max-average-mse
> +        type: u32
> +      -
> +        name: max-peak-mse
> +        type: u32
> +      -
> +        name: refresh-rate-ps
> +        type: u64
> +      -
> +        name: num-symbols
> +        type: u64

type: uint for all these?

> +      -
> +        name: supported-caps
> +        type: nest
> +        nested-attributes: bitset
> +      -
> +        name: pad
> +        type: pad

you shouldn't need it if you use uint

> +  -
> +    name: mse-snapshot
> +    attr-cnt-name: --ethtool-a-mse-snapshot-cnt
> +    attributes:
> +      -
> +        name: unspec
> +        type: unused
> +        value: 0
> +      -
> +        name: channel
> +        type: u32
> +        enum: phy-mse-channel
> +      -
> +        name: average-mse
> +        type: u32
> +      -
> +        name: peak-mse
> +        type: u32
> +      -
> +        name: worst-peak-mse
> +        type: u32
> +  -
> +    name: mse
> +    attr-cnt-name: --ethtool-a-mse-cnt
> +    attributes:
> +      -
> +        name: unspec
> +        type: unused
> +        value: 0
> +      -
> +        name: header
> +        type: nest
> +        nested-attributes: header
> +      -
> +        name: channel
> +        type: u32

Please annotate attrs which carry enums and flags with

	enum: $name

> +        enum: phy-mse-channel
> +      -
> +        name: config
> +        type: nest
> +        nested-attributes: mse-config

config sounds like something we'd be able to change
Looks like this is more of a capability struct?

> +      -
> +        name: snapshot
> +        type: nest
> +        multi-attr: true
> +        nested-attributes: mse-snapshot

This multi-attr feels un-netlinky to me.
You define an enum for IDs which are then carried inside
snapshot.channel. In netlink IDs should be used as attribute types.
Why not add an entry here for all snapshot types?