Hi, On 12/21/19 11:03 PM, Tom Murphy wrote:
@@ -5618,9 +5583,13 @@ static int intel_iommu_add_device(struct device *dev) struct iommu_domain *domain; struct intel_iommu *iommu; struct iommu_group *group; + u64 dma_mask = *dev->dma_mask; u8 bus, devfn; int ret;+ if (dev->coherent_dma_mask && dev->coherent_dma_mask < dma_mask)+ dma_mask = dev->coherent_dma_mask; + iommu = device_to_iommu(dev, &bus, &devfn); if (!iommu) return -ENODEV; @@ -5640,7 +5609,12 @@ static int intel_iommu_add_device(struct device *dev) domain = iommu_get_domain_for_dev(dev); dmar_domain = to_dmar_domain(domain); if (domain->type == IOMMU_DOMAIN_DMA) { - if (device_def_domain_type(dev) == IOMMU_DOMAIN_IDENTITY) { + /* + * We check dma_mask >= dma_get_required_mask(dev) because + * 32 bit DMA falls back to non-identity mapping. + */ + if (device_def_domain_type(dev) == IOMMU_DOMAIN_IDENTITY && + dma_mask >= dma_get_required_mask(dev)) { ret = iommu_request_dm_for_dev(dev); if (ret) { dmar_remove_one_dev_info(dev);
dev->dma_mask is set to 32bit by default. During loading driver, it sets the real dma_mask with dma_set_mask() according to the real capability. Here you will always see 32bit dma_mask for each device. Best regards, baolu _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
