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Cc:     baolu.lu@linux.intel.com, Joerg Roedel <joro@8bytes.org>,
        David Woodhouse <dwmw2@infradead.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 4/5] iommu/vt-d: Convert intel iommu driver to the
 iommu ops
To:     Tom Murphy <murphyt7@tcd.ie>, iommu@lists.linux-foundation.org
References: <20200903201839.7327-1-murphyt7@tcd.ie>
 <20200903201839.7327-5-murphyt7@tcd.ie>
From:   Lu Baolu <baolu.lu@linux.intel.com>
Message-ID: <7b0c0f62-2efa-8183-0cbc-6028feb8ec93@linux.intel.com>
Date:   Wed, 9 Sep 2020 09:59:11 +0800
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On 9/4/20 4:18 AM, Tom Murphy wrote:
> +static int intel_iommu_needs_bounce_buffer(struct device *d)
> +{
> +	return !intel_no_bounce && dev_is_pci(d) && to_pci_dev(d)->untrusted;
> +}
> +
> +
>   static void intel_iommu_probe_finalize(struct device *dev)
>   {
> -	struct iommu_domain *domain;
> +	dma_addr_t base = IOVA_START_PFN << VTD_PAGE_SHIFT;
> +	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> +	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
>   
> -	domain = iommu_get_domain_for_dev(dev);
> -	if (device_needs_bounce(dev))
> -		set_dma_ops(dev, &bounce_dma_ops);
> -	else if (domain && domain->type == IOMMU_DOMAIN_DMA)
> -		set_dma_ops(dev, &intel_dma_ops);
> +	if (intel_iommu_needs_bounce_buffer(dev) ||

For untrusted devices, the DMA type of domain is enforced. There's no
need to check again here.

Best regards,
baolu

> +			(domain && domain->type == IOMMU_DOMAIN_DMA))
> +		iommu_setup_dma_ops(dev, base,
> +				__DOMAIN_MAX_ADDR(dmar_domain->gaw) - base);
>   	else
>   		set_dma_ops(dev, NULL);
>   }
>