RE: [PATCH v3 4/6] iommu: Regulate EINVAL in ->attach_dev callback functions

[Tian, Kevin]

> From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Sent: Thursday, September 15, 2022 3:59 PM
>
> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
> index c5e7e8b020a5..4cadbd744b7f 100644
> --- a/drivers/iommu/intel/pasid.c
> +++ b/drivers/iommu/intel/pasid.c
> @@ -101,8 +101,10 @@ int intel_pasid_alloc_table(struct device *dev)
> 
>  	might_sleep();
>  	info = dev_iommu_priv_get(dev);
> -	if (WARN_ON(!info || !dev_is_pci(dev) || info->pasid_table))
> -		return -EINVAL;
> +	if (WARN_ON(!info || !dev_is_pci(dev)))
> +		return -ENODEV;
> +	if (WARN_ON(info->pasid_table))
> +		return -EBUSY;

-EEXIST. It's not a busy condition which might change sometime after.

btw below -EVINAL in viommu should be converted to -ENODEV too
since it's a check purely on device side:

viommu_domain_finalise()
        viommu_page_size = 1UL << __ffs(viommu->pgsize_bitmap);
        if (viommu_page_size > PAGE_SIZE) {
                dev_err(vdev->dev,
                        "granule 0x%lx larger than system page size 0x%lx\n",
                        viommu_page_size, PAGE_SIZE);
                return -EINVAL;
        }