Re: [PATCH 03/27] gpu: nova-core: set MCTP transport header version to 1

On 8/20/26 2:38 AM, Zhi Wang wrote:
> On Tue, 18 Aug 2026 20:51:56 -0700
> John Hubbard <[email protected]> wrote:
> 
> One nit: might be better to update the doc as well.

Yes. Agreed. I'll send individual replies to the patch feedback
as usual, but let me first mention that I've applied all of your 
and Timur's feedback, 100%, to a -v2 branch already.

It's passing tests cleanly, so as soon as I make a few more passes
through it I'll post that. Likely tomorrow.

thanks,
John Hubbard

> 
> Reviewed-by: Zhi Wang <[email protected]>
> 
> diff --git a/Documentation/gpu/nova/core/fsp.rst
> b/Documentation/gpu/nova/core/fsp.rst index 52d618d22bb8..60c647181da0
> 100644 --- a/Documentation/gpu/nova/core/fsp.rst
> +++ b/Documentation/gpu/nova/core/fsp.rst
> @@ -106,6 +106,8 @@ All FSP messages share a common header format
> consisting of two 32-bit words:
>  - Bit 30: EOM (End of Message)
>  - Bits 29:28: Packet sequence number
>  - Bits 23:16: Source Endpoint ID
> +- Bits 15:8: Destination Endpoint ID
> +- Bits 3:0: MCTP header version (1)
>  
>  **NVDM header** (NVIDIA Vendor Defined Message):
>  
> 
> 
>> FSP requires MCTP transport header version 1. Nova-core leaves version
>> bits 3:0 at zero, so every CoT and PRC request carries an invalid
>> transport header.
>>
>> Define the version and destination endpoint ID fields. Set the version
>> to 1 for single-packet requests, and leave the unused destination
>> endpoint ID at zero.
>>
>> Assisted-by: Cursor:claude-opus-5
>> Signed-off-by: John Hubbard <[email protected]>
>> ---
>>  drivers/gpu/nova-core/mctp.rs | 14 ++++++++++++--
>>  1 file changed, 12 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/nova-core/mctp.rs
>> b/drivers/gpu/nova-core/mctp.rs index 90c642c91a72..03546213da28
>> 100644 --- a/drivers/gpu/nova-core/mctp.rs
>> +++ b/drivers/gpu/nova-core/mctp.rs
>> @@ -42,13 +42,23 @@ pub(crate) struct MctpHeader(u32) {
>>          29:28 seq;
>>          /// Source endpoint ID.
>>          23:16 seid;
>> +        /// Destination endpoint ID.
>> +        15:8 deid;
>> +        /// MCTP header version.
>> +        3:0 version;
>>      }
>>  }
>>  
>>  impl MctpHeader {
>> -    /// Builds a single-packet MCTP header (`SOM=1`, `EOM=1`,
>> `SEQ=0`, `SEID=0`).
>> +    /// MCTP specification version 1.0.
>> +    const VERSION: u32 = 1;
>> +
>> +    /// Builds a single-packet MCTP header (`SOM=1`, `EOM=1`,
>> `SEQ=0`, `SEID=0`, `VERSION=1`). pub(crate) fn single_packet() ->
>> Self {
>> -        Self::zeroed().with_som(true).with_eom(true)
>> +        Self::zeroed()
>> +            .with_const_version::<{ Self::VERSION }>()
>> +            .with_som(true)
>> +            .with_eom(true)
>>      }
>>  
>>      /// Returns whether this is a complete single-packet message
>> (`SOM=1` and `EOM=1`).
>