Re: [PATCH v3 7/8] gpu: nova-core: add NVKV typed decoding

["Alexandre Courbot" <acourbot@nvidia.com>]

On Thu Oct 15, 2026 at 9:49 PM JST, Eliot Courtney wrote:
> On Wed Oct 7, 2026 at 3:30 PM JST, Alexandre Courbot wrote:
>> On Mon Sep 28, 2026 at 5:42 PM JST, Eliot Courtney wrote:
>>> Similar to the typed encoding layer, add some decoding type machinery.
>>> Add a simple macro `nvkv_decode!` which implements `Schema` for a struct
>>> by composing visit calls to each member. Add some common `Schema` kinds,
>>> such as `Array` which collects an array value into a fixed maximum size
>>> array, and `Required` which fails a decode if the value is not sent.
>>>
>>> Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
>>> ---
>>>  drivers/gpu/nova-core/gsp/nvkv.rs        |  11 +-
>>>  drivers/gpu/nova-core/gsp/nvkv/decode.rs | 622 ++++++++++++++++++++++++++++++-
>>>  2 files changed, 628 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/gpu/nova-core/gsp/nvkv.rs b/drivers/gpu/nova-core/gsp/nvkv.rs
>>> index 7ac3a459a98b..5791df07a7fa 100644
>>> --- a/drivers/gpu/nova-core/gsp/nvkv.rs
>>> +++ b/drivers/gpu/nova-core/gsp/nvkv.rs
>>> @@ -9,7 +9,7 @@
>>>  //! function calls will map to some struct - for example, f(GPU_NAME_STRING_KEY, 0, b"some gpu")
>>>  //! naturally maps to storing a &str with the GPU name.
>>>  
>>> -#![expect(unused_imports)]
>>> +#![cfg_attr(not(CONFIG_KUNIT), expect(unused_imports))]
>>>  #![cfg_attr(not(CONFIG_KUNIT), expect(unused_macros))]
>>>  
>>>  use core::{
>>> @@ -23,7 +23,8 @@
>>>  use kernel::{
>>>      alloc::{
>>>          allocator::KVmalloc,
>>> -        Allocator, //
>>> +        Allocator,
>>> +        ArrayVec, //
>>>      },
>>>      bitfield,
>>>      num::Bounded,
>>> @@ -148,6 +149,12 @@ fn default() -> Self {
>>>      }
>>>  }
>>>  
>>> +/// A schema field for an array value under the NVKV key `KEY_ID`.
>>> +#[repr(transparent)]
>>> +pub(crate) struct Array<T: Default + Copy, const N: usize, const KEY_ID: KeyId> {
>>> +    vec: ArrayVec<T, N>,
>>> +}
>>
>> I still don't see why this needs to be declared in this module when no
>> encoder element ever uses it, and the module reexports everything from
>> `decode` anyway. Can this be moved next to the other schema kinds?
>
> This will be used soon [1] for encoding. The convention I have been
> using is if a type is used for both encoding and decoding, I put it in
> nvkv.rs (since it doesn't fit obviously in either - the
> encoding/decoding related impls can go in there though). If we put
> IndexedKey in nvkv.rs as pub crate since we'll use it soon, it's
> consistent to keep Array here as well. WDYT?

Sure, if encoding is to use it then let's put it in its eventual
destination from the start.