Re: [PATCH v3 11/33] gpu: nova-core: add GMC transport receive path

[Timur Tabi]

On Thu, 2026-09-17 at 18:06 -0700, John Hubbard wrote:
> 
> +/// The check of [`QueueElementHeader::validate`] that a queue element header fails.
> +#[derive(Debug, Clone, Copy)]
> +pub(crate) enum QueueElementHeaderError {
> +    /// The first word is not `"MCTP"`.
> +    BadMagic,
> +    /// The MCTP header carries a version other than the one that this driver uses.
> +    BadMctpVersion,
> +    /// The NVDM header names a vendor other than NVIDIA, or a message type other than
> +    /// vendor-defined.
> +    BadNvdmVendor,
> +    /// The element length is shorter than the queue element header and the message together,
> or
> +    /// above the maximum element size.
> +    BadLength,
>  }

Can you add a comment somewhere explaining why we're adding a new error type, instead of just
using the standard error codes?

> -    /// Validates this header against the expected NVIDIA NVDM format and type.
> -    pub(crate) fn validate(self, expected_type: NvdmType) -> bool {
> +    pub(crate) fn has_nvidia_vendor(self) -> bool {
>          u8::from(self.msg_type()) == MSG_TYPE_VENDOR_PCI
>              && u16::from(self.vendor_id()) == Vendor::NVIDIA.as_raw()
> +    }

When would we ever receive a non-Nvidia message?  Normally this check is done if we're receiving
messages from an external source.