Re: [RFC Patch v1 0/3] Fix using wrong GPF DVSEC location issue

[Li Ming]

On 3/21/2025 11:59 AM, Davidlohr Bueso wrote:
> On Thu, 20 Mar 2025, Davidlohr Bueso wrote:
>
>> On Wed, 19 Mar 2025, Li Ming wrote:
>>
>>> But I am not sure if all dports under a same port will have same
>>> configuration space layout, if yes, that will not be a problem. If I am
>>> wrong, please let me know, thanks.
>>
>> Yes, when caching the dvsec was suggested, it was my assumption that the
>> config space would be the same.
>
> Ultimately I don't know what the expectation is here, but your updates
> do allow more flexibility from vendors, I guess(?). It's a bit late
> in the cycle, unfortunately, so if these are to go in for v6.15, they
> would be considered a fix imo, otherwise perhaps they are wanted for
> v6.16 or not at all (patch 3 does look useful regardless)?

My understanding is that the expectation of the patchset is to avoid using a wrong GPF DVSEC in case of dports under a same port have different config space layout. And I think the change is more closely to the description of CXL spec.

If the case(dports under a same port have different config space layout) would not happen, maybe add a comment in cxl_gpf_port_setup() is another option.

Yes, if patch 1 & 2 are considered to be merged, they are worth a fix tag. And patch 3 is an obvious cleanup change.

>
> Based on some of the topologies listed in qemu, I did some testing (and
> this was also why the same dvsec config layout) and see things working as
> expected.

Thanks for testing.


Ming

[snip]