Re: [PATCH v8 3/4] iommu/arm-smmu-v3: Standardize ATS enablement failure reporting

[Jason Gunthorpe]

On Thu, Jun 04, 2026 at 06:21:15PM +0000, Pranjal Shrivastava wrote:
> Update arm_smmu_enable_ats() to wrap the pci_enable_ats() call in
> WARN_ON(). Since probe-time checks now preclude configuration errors
> any failure during hardware enablement is considered a kernel bug.
> 
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Signed-off-by: Pranjal Shrivastava <praan@xxxxxxxxxx>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

> +	 /*
> +	  * Since pci_prepare_ats() has already verified the HW capability
> +	  * and programmed the STE, pci_enable_ats() should not fail here.
> +	  */
> +	if (WARN_ON(pci_enable_ats(pdev, stu)))
>  		dev_err(master->dev, "Failed to enable ATS (STU %zu)\n", stu);
>  }

I would fold the dev_err string into the WARN though

Jason