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> > + return ops->blocked_domain; > > How is MSI allocation handled for T=0 devices? The ITS calls > iommu_dma_prepare_msi(), which appears to return -EOPNOTSUPP > for the blocked domain. Is that intentional? For a TDISP capable devince MSI is always issued using T=0, meaning it does not go through the SMMU. It should be wired to defeat iommu_dma_prepare_msi() and use an identity IOVA as though there is no iommu present.. AFAIK this is true for all devices all arches today. Jason