Re: [PATCH v6 4/9] x86/nmi: Assign and register NMI-source vectors

[Sohil Mehta]

On 6/3/2025 9:34 AM, Xin Li wrote:
> On 5/13/2025 1:37 PM, Sohil Mehta wrote:
>> Prior to NMI-source support, the vector information was ignored by the
>> hardware while delivering NMIs. With NMI-source, the architecture
>> currently supports a 16-bit source bitmap to identify the source of the
>> NMI. Upon receiving an NMI, this bitmap is delivered as part of the FRED
>> event delivery mechanism to the kernel.
>>
>> Assign a vector space of 0-15 that is specific to NMI-source and
>> independent of the IDT vector space of 0-255. Being a bitmap, the
>> NMI-source vectors do not have any inherent priority associated with
>> them. The order of executing the NMI handlers is up to the kernel.
> 
> I'm thinking should we mention that the bitmap could be extended more
> than 16 bits in future?  Or we just don't emphasize 16-bit or 0~15?
> 

That was mainly to justify the value of NMIS_VECTORS_MAX defined in this
patch. I will include a sentence to mention that the bitmap size could
be extended in the future.

We could even set NMIS_VECTORS_MAX to 64 right now to make this
future-proof. Though in practice, I don't see it happening any time soon.

Sohil