Re: [PATCH v2 5/8] gpu: nova-core: add NVKV decoder

On Thu Sep 10, 2026 at 4:47 PM JST, Alexandre Courbot wrote:

On Thu Aug 27, 2026 at 11:12 PM JST, Eliot Courtney wrote:
<...>

quoted

+    /// Decodes every pair into `schema` and returns the result of [`Schema::finish`].
+    pub(crate) fn decode<'s, S: Schema>(
+        &self,
+        schema: &'s mut S,
+    ) -> Result<impl Init<S::Target, Error> + 's> {
+        let mut cursor = Cursor::new(self.data);
+        while !cursor.is_empty() {
+            let op: Op = cursor.take_u64()?.into();
+
+            let key = op.key().into();
+            let index = op.index();
+            let op_value: u32 = op.value().into();
+            match op.opcode()? {
+                Opcode::Imm32 => {
+                    self.visit(schema, key, index, DecoderValue::Scalar32(op_value))?;
+                }
+                Opcode::Seq32 => {
+                    let values = cursor.take_u32s(num::u32_as_usize(op_value))?;
+                    for (i, &value) in values.iter().enumerate() {
+                        let key = Self::seq_key(key, i)?;
+                        self.visit(schema, key, index, DecoderValue::Scalar32(value))?;
+                    }
+                }
+                Opcode::Seq64 => {
+                    let values = cursor.take_u64s(num::u32_as_usize(op_value))?;
+                    for (i, &value) in values.iter().enumerate() {
+                        let key = Self::seq_key(key, i)?;
+                        self.visit(schema, key, index, DecoderValue::Scalar64(value))?;
+                    }
+                }

Another thing that could be worth clarifying: are `Seq32`/`Seq64` with a
count of `0` valid? Right now they won't trigger a visit or an error,
i.e. they will be silently ignored. Whereas arrays of size 0 do trigger
a visit (which sounds logical). I'm not saying this is a problem, just
wondering if the behavior is consistent with what NVKV specifies in such
cases.

Yes, it's valid to have a sequence of length zero according to the C
implementation [1]. The semantics are that a sequence of length 0 is
equivalent to nothing sent.

[1]: https://github.com/NVIDIA/open-gpu-kernel-modules/blob/615.71.09/src/nvidia/src/libraries/nvkv/nvkv.c#L62-L119