RE: [PATCH v4 6/7] iommu/vt-d: Add support for static identity domain

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Friday, August 9, 2024 1:55 PM
> 
> +static int context_setup_pass_through(struct device *dev, u8 bus, u8 devfn)
> +{
> +	struct device_domain_info *info = dev_iommu_priv_get(dev);
> +	struct intel_iommu *iommu = info->iommu;
> +	struct context_entry *context;
> +
> +	spin_lock(&iommu->lock);
> +	context = iommu_context_addr(iommu, bus, devfn, 1);
> +	if (!context) {
> +		spin_unlock(&iommu->lock);
> +		return -ENOMEM;
> +	}
> +
> +	if (context_present(context) && !context_copied(iommu, bus, devfn))
> {
> +		spin_unlock(&iommu->lock);
> +		return 0;
> +	}

Is it a valid case to setup passthrough on a present entry?