On 6/3/2025 9:34 AM, Xin Li wrote:

On 5/13/2025 1:37 PM, Sohil Mehta wrote:

quoted

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