RE: [PATCH v2 2/6] iommu/vt-d: Remove scalable mode context entry setup from attach_dev

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Tuesday, December 5, 2023 9:22 AM
>
>  static int domain_context_mapping_one(struct dmar_domain *domain,
>  				      struct intel_iommu *iommu,
> -				      struct pasid_table *table,
>  				      u8 bus, u8 devfn)

since this is called in legacy now it's clearer to add a legacy_ prefix
to this and other related functions.

> 
> -	/* PASID table is mandatory for a PCI device in scalable mode. */
> -	if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) {
> -		/* Setup the PASID entry for requests without PASID: */
> -		if (hw_pass_through && domain_type_is_si(domain))
> -			ret = intel_pasid_setup_pass_through(iommu,
> -					dev, IOMMU_NO_PASID);
> -		else if (domain->use_first_level)
> -			ret = domain_setup_first_level(iommu, domain, dev,
> -					IOMMU_NO_PASID);
> -		else
> -			ret = intel_pasid_setup_second_level(iommu,
> domain,
> -					dev, IOMMU_NO_PASID);
> -		if (ret) {
> -			dev_err(dev, "Setup RID2PASID failed\n");
> -			device_block_translation(dev);
> -			return ret;
> -		}
> -	}
> +	if (dev_is_real_dma_subdevice(dev))
> +		return 0;

is it a functional change? old code doesn't early exit for such device.