Messages in this thread | | | Date | Tue, 27 Feb 2024 15:53:05 +0000 | Subject | Re: [PATCH v4 5/5] iommu/dma: Force swiotlb_max_mapping_size on an untrusted device | From | Robin Murphy <> |
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On 27/02/2024 3:40 pm, Christoph Hellwig wrote: > On Wed, Feb 21, 2024 at 11:35:04AM +0000, Will Deacon wrote: >> +static size_t iommu_dma_max_mapping_size(struct device *dev) >> +{ >> + if (is_swiotlb_active(dev) && dev_is_untrusted(dev)) >> + return swiotlb_max_mapping_size(dev); > > Curious: do we really need both checks here? If swiotlb is active > for a device (for whatever reason), aren't we then always bound > by the max size? If not please add a comment explaining it. >
Oh, good point - if we have an untrusted device but SWIOTLB isn't initialised for whatever reason, then it doesn't matter what max_mapping_size returns because iommu_dma_map_page() is going to bail out regardless.
Thanks, Robin.
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