Re: [PATCH v4 09/18] PCI: Add ACS egress control vector accessor

> From: Leon Romanovsky <[email protected]>
> 
> Whether ACS P2P Egress Control routes, redirects, or blocks a peer-to-peer
> request depends on the Egress Control Vector bit for the target port, not
> on the enable bit alone (PCIe r7.0, sec 6.12.3).
> 
> Provide a helper to read that bit for a peer Root or Switch Downstream
> Port. Report an unreadable or uncovered vector as an error rather than as
> a clear bit, so callers do not mistake it for permission to route
> directly.
> 
> Each bit corresponds to a Port Number within one Switch or Root Complex
> (sec 7.7.12.4), so both ports have to number their ports in the same
> place. Downstream Ports of one Switch share its internal bus, and Root
> Ports of one Root Complex share a root bus, so require a shared bus and
> reject anything else. A target numbered elsewhere has no bit in this
> vector and would select an unrelated one.
> 
> Tested-by: Tushar Dave <[email protected]>
> Reviewed-by: Logan Gunthorpe <[email protected]>
> Signed-off-by: Leon Romanovsky <[email protected]>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=9