Re: [PATCH RFC 01/20] ctlv: Add the schema language and generator

[Jiri Pirko]

Wed, Oct 21, 2026 at 12:31:32AM +0200, jic23@xxxxxxxxxx wrote:
>On Thu, 15 Oct 2026 16:50:34 +0200
>Jiri Pirko <jiri@xxxxxxxxxxx> wrote:
>
>> From: Jiri Pirko <jiri@xxxxxxxxxx>
>> 
>> Define the YAML schema and append-only family registry. Add ctlvgen to
>> validate specifications and emit kernel and UAPI outputs.
>> 
>> Assisted-by: Cursor: GPT-5.6 Sol
>> Assisted-by: Cursor: Claude Opus 5.5
>> Signed-off-by: Jiri Pirko <jiri@xxxxxxxxxx>
>
>Obviously you asked for broad structural review and this isn't that. I'm terrible
>at reading code for just the big picture but feel free to ignore the small stuff
>in this reply.
>
>My python being even worse than my yaml I'll only say that
>part looked plausible to me!
>
>> diff --git a/Documentation/ctlv/ctlv-schema.yaml b/Documentation/ctlv/ctlv-schema.yaml
>> new file mode 100644
>> index 000000000000..38fd56e6627c
>> --- /dev/null
>> +++ b/Documentation/ctlv/ctlv-schema.yaml
>> @@ -0,0 +1,359 @@
>> +# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://kernel.org/schemas/ctlv/ctlv-schema.yaml#
>> +$schema: https://json-schema.org/draft-07/schema
>> +
>> +# The syntax gate for a CTLV family specification: permitted keys, their shapes
>> +# and the closed sets of keywords. Anything needing more than one declaration at
>> +# a time is checked by tools/ctlv/ctlvgen/lib/semantics.py.
>> +
>> +$defs:
>> +  name:
>> +    description: Kebab-case identifier. A dot is reserved for selectors.
>> +    type: string
>> +    pattern: ^[a-z0-9]+(-[a-z0-9]+)*$
>> +
>> +  family-name:
>> +    description: Name carried by family discovery.
>> +    allOf:
>> +      - $ref: '#/$defs/name'
>> +      - maxLength: 63
>> +
>> +  selector:
>> +    description: |
>
>Really trivial but nice to drop | where it doesn't make sense to
>force line break preservation like here. 

Okay

>
>> +      A named attr set, a whole attr group, or one exact attr as
>> +      "group.attr". There are no tuple selectors and no cross-family
>> +      qualification.
>> +    type: string
>> +    pattern: ^[a-z0-9]+(-[a-z0-9]+)*(\.[a-z0-9]+(-[a-z0-9]+)*)?$
>> +
>> +  selectors:
>> +    oneOf:
>> +      - $ref: '#/$defs/selector'
>> +      - type: array
>> +        minItems: 1
>> +        items:
>> +          $ref: '#/$defs/selector'
>
>My yaml is terrible (and all learnt form reviewing DT bindings which are
>undoubtedly perfect :) but random LLM agrees with me that you can simplify
>this as it's a local definition.  I think doing so makes life a little
>easier for reader by indicating it is thing defined a few lines up.
>
>            $ref: 'selector'
>
>I don't care that much though.

Okay

>
>> +
>> +  uint:
>> +    type: integer
>> +    minimum: 0
>> +    maximum: 4294967295
>> +
>> +  integer-bound:
>> +    type: integer
>> +    minimum: -9223372036854775808
>> +    maximum: 18446744073709551615
>> +
>> +  max-occurrences:
>> +    description: |
>> +      A finite positive count, or unlimited, which is reachable only from
>> +      query replies.
>> +    oneOf:
>> +      - type: integer
>> +        minimum: 1
>> +        maximum: 4294967295
>> +      - const: unlimited
>> +
>> +  unit:
>> +    description: CTLV-owned unit, matching enum ctlv_unit.
>> +    enum: [ seconds, hertz, bytes, celsius ]
>
>These are used in here?  I'm sure some are but guessing not
>all of them yet.

Nope. I just want these to be part of the initial schema as it is not
omitted by later family implementation by accident. Easy to pick up by
AI assistents I believe.


>
>
>> +  attr:
>> +    description: |
>> +      One attr declaration. Exactly one primary form out of type, enum,
>> +      flags, attrs and blob must be present. optional-attrs and recursive
>> +      may only accompany attrs.
>
>Maybe worth the yaml gynastics needed to enforce this rather than
>just putting it in the description?  An LLM fed me something when
>I sanity checked how bad it would be and it's only somewhat nasty...
>
>Bunch of:
> oneOf:
>      - required: [ type ]
>        not: { anyOf: [ { required: [ enum ] }, { required: [ flags ] }, { required: [ attrs ] }, 	{ required: [ blob ] } ] }
>
>lines, though I thought there was a more compact way to do it.

Okay, will try.


>
>
>> +    type: object
>> +    required: [ name ]
>> +    additionalProperties: false
>> +    properties:
>> +      name:
>> +        $ref: '#/$defs/name'
>> +      type:
>> +        description: |
>> +          Primitive payload. Integers are always 64-bit, and a bool is one
>> +          byte holding zero or one.
>> +        enum: [ uint, sint, bool, string, binary ]
>> +      enum:
>> +        description: Name of an enum definition; implies an unsigned payload.
>> +        $ref: '#/$defs/name'
>> +      flags:
>> +        description: Name of a flags definition; implies an unsigned payload.
>> +        $ref: '#/$defs/name'
>> +      attrs:
>> +        description: Nested payload, given as selectors.
>> +        $ref: '#/$defs/selectors'
>> +      optional-attrs:
>> +        description: Further nested payload whose placements are optional.
>> +        $ref: '#/$defs/selectors'
>> +      recursive:
>> +        description: |
>> +          The nested payload is one attr set that may contain this attr
>> +          again, describing a structure of any depth. Only a query reply can
>> +          hold one, since such a nest has no maximum length.
>> +        const: true
>> +      blob:
>> +        $ref: '#/$defs/blob'
>> +      min:
>> +        description: Inclusive minimum of an integer payload.
>> +        $ref: '#/$defs/integer-bound'
>> +      max:
>> +        description: Inclusive maximum of an integer payload.
>> +        $ref: '#/$defs/integer-bound'
>> +      length:
>> +        description: Exact payload length of a binary attr.
>> +        $ref: '#/$defs/uint'
>> +      min-length:
>> +        description: |
>> +          Minimum payload length, excluding the terminator of a string.
>> +        $ref: '#/$defs/uint'
>> +      max-length:
>> +        description: |
>> +          Maximum payload length, excluding the terminator of a string.
>> +        $ref: '#/$defs/uint'
>> +      unit:
>> +        $ref: '#/$defs/unit'
>> +      scale:
>> +        description: Decimal exponent applied to the payload.
>> +        type: integer
>> +        minimum: -128
>> +        maximum: 127
>> +      max-occurrences:
>> +        $ref: '#/$defs/max-occurrences'
>> +