Re: [RFC PATCH 3/6] PCI/AER: Enable RCEC to report internal error for CXL root port

From: Li, Ming
Date: Sun Apr 21 2024 - 22:07:15 EST


On 4/18/2024 10:57 PM, Dan Williams wrote:
> Li, Ming wrote:
>> On 4/16/2024 10:46 PM, Terry Bowman wrote:
>>> The driver support is much simpler if RCEC does not handle VH protocol errors. Is there
>>> a reason to forward root port VH mode protocol errors to an RCEC rather than consume
>>> in the root port's AER driver and forward to CXL error handler?
>>>
>> I agree that is simpler if only root port handle VH protocol errors,
>> but I think that software has no chance to choose if VH protocol
>> errors reported to RCEC or root port, it depends on platform
>> implementation. So I think we should support both cases.
>
> The question is whether the CXL spec RDPAS behavior causes any problems
> for platforms that follow PCIe rather than CXL reporting flows for
> root-port errors. I.e. does it cause problems if Linux starts scanning
> root ports on RCEC notifications?
>
> I do think the lookup needs to change to be based on CXL host-bridge
> detection and not CXL-type-3 endpoint detection, but otherwise it looks
> like CXL spec wants to invalidate PCIe spec expectations.

Hi Dan, if my understanding is correct, the CXL host-bridge detection you mentioned is that iterating all root ports under RCEC associated bus range for RCEC reported VH protocol errors case, and the CXL-type-3 detection is that iterating all CXL-type-3 endpoint under RCEC associated bus range. is it right?