Messages in this thread | | | Date | Thu, 8 Jul 2021 11:28:05 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] iommu/amd: Enable swiotlb if any device supports iommu v2 and uses identity mapping |
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On Thu, Jul 08, 2021 at 03:42:32PM +0800, Kai-Heng Feng wrote: > @@ -344,6 +344,9 @@ static int iommu_init_device(struct device *dev) > > iommu = amd_iommu_rlookup_table[dev_data->devid]; > dev_data->iommu_v2 = iommu->is_iommu_v2; > + > + if (dev_data->iommu_v2) > + swiotlb = 1;
This looks like the big hammer, as it will affect all other systems where the AMD GPUs are in their own group.
What is needed here is an explicit check whether a non-iommu-v2 device is direct-mapped because it shares a group with the GPU, and only enable swiotlb in this case.
Thanks,
Joerg
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