Re: [PATCH] PCI: endpoint: pci-epf-test: Roll back BAR mapping when subrange setup fails

Christian Bruel
2026-03-18T08:35:23Z

>>>
>>> I think "modify TEST_F to SKIP if ENOSPC",
>>> since it will solve the problem for all platforms that have few
>>> inbound iATUs.
>>
>> That sounds like the right direction, though I think we would first
>> need a way
>> to propagate -ENOSPC back to the host side, instead of just collapsing
>> all
>> EP-side setup failures into STATUS_BAR_SUBRANGE_SETUP_FAIL, which
>> pci_endpoint_test currently maps to -EIO.
>>
>
> I think the epf test function can return several bits in the status
> mask, in addition of STATUS_BAR_SUBRANGE_SETUP_FAIL. e.g
> STATUS_BAR_SUBRANGE_SETUP_SKIP, or STATUS_BAR_SUBRANGE_SETUP_NOSPC.
> I prefer the former since we want to pass the cause, not the action and
> let the skip decision to the host
>

Rethinking this, having a pci_epc_feature to limit the maximum number of
simultaneously allocatable BARs might be a useful addition to the EPC
driver. The epc driver would need to keep track of the allocated BARs
and check it before calling set_bar() for skipping or not.

Do you think this added (minor) complexity is worth it compared to
simply returning ENOSPC in the status?

thank you,

Christian