On Fri, 2024-02-16 at 14:26 -0800, Kuppuswamy Sathyanarayanan wrote: > It looks like for an ARI capable device the limit is 256. Why not add > that > check as well? " With ARI, the 16-bit field is interpreted as two fields instead of three: an 8-bit Bus Number and an 8-bit Function Number - the Device Number field is eliminated. This new interpretation enables an ARI Device to support up to 256 Functions [0..255] instead of 8 Functions [0..7]." the above statement on PCIe Spec highlights that since the Function Number field in an ARI-enabled device is 8 bits, it inherently supports numbering from 0 to 255. Thus, there's no need for additional checks to limit the function number to this range; the 8-bit size of the field naturally imposes this limit. This efficient use of the available address space aligns with the goals of ARI to enhance device functionality within the PCIe specification. Kind regards, Bean
