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

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Date: Mon, 22 Apr 2024 10:06:54 +0800
From: "Li, Ming" <ming4.li@...el.com>
To: Dan Williams <dan.j.williams@...el.com>, Terry Bowman
	<Terry.Bowman@....com>, <rrichter@....com>
CC: <linux-cxl@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 3/6] PCI/AER: Enable RCEC to report internal error for
 CXL root port

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?