Re: [PATCH v3 13/13] iommu/arm-smmu-v3: Enable PRI for PCI device in arm_smmu_probe_device()

[sashiko-bot@kernel.org]

> Now PRI requests can be correctly handled. Enable the PCI cap when probing
> a PCI device. Also flush the priq in arm_smmu_attach_release().
> 
> Drain the priq for any PRI-enabled master following the same rationale as
> the eventq drain: a stale page request must be answered while it can still
> resolve to the old attach handle, even when the old attachment did not set
> up IOPF, or else the threaded handler could route it to the next domain.
> 
> Note that PRI is enabled at the probe time, while ATS gets toggled by the
> attach/detach routines, so a master could have PRI enabled when its ATS is
> disabled. PCIe (Base 6.3, Table 10-14) sets no ATS precondition on the PRI
> Enable bit. Its only ordering rule is that the interface must have gotten
> successfully Stopped prior to an enabling, which pci_enable_pri() already
> checks using PCI_PRI_STATUS_STOPPED. Also, a PRI-enabled device would not
> issue a page request until it starts to use ATS.
> [ ... ]
> up for them; keeping PRI enabled would let a PRI request arrive on an alias
> StreamID and get a PRI_RESP_DENY issued against streams[0] by the driver's
> error-response path.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>

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

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