Re: [PATCH v4 11/15] iommu/arm-smmu-v3: Discard partial PRI faults on PRIQ overflow

From: Jonathan Cameron

Date: Thu Sep 10 2026 - 20:25:30 EST


> On PRIQ overflow, partial requests stored via report_partial_fault() whose
> LAST-page entry was lost stay in iopf_param->partial. Drop them by calling
> iopf_queue_discard_partial(), matching intel-iommu's handling.
>
> Do it only after the queue is fully drained, since the visible entries all
> precede the loss point: a group whose LAST-page entry is still in the queue
> gets assembled before the discard, rather than losing its stored partials
> to it.
>
> Nothing can arrive in between, as an active overflow inhibits new entries
> from being written to the PRI queue until a final CONS write acknowledges
> it (IHI0070 8.1).
>
> Suggested-by: Harsha Vardhan V <harsha.v@xxxxxxxxxxxxxxxx>
> Assisted-by: Claude:claude-sonnet-5
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>

Reviewed-by: Jonathan Cameron <jonathan.cameron@xxxxxxxxxxxxxxxx>

--
Jonathan Cameron <jonathan.cameron@xxxxxxxxxxxxxxxx>