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But why exactly do you have pci bridges in your groups? That isn't entirely normal? > Since f0ea207ed781 ("iommu/arm-smmu-v3: Introduce struct > arm_smmu_vmaster"), group-wide translated-domain attachment therefore > fails when the first bridge is visited: > > pcieport 0009:00:00.0: > missing vDEVICE association for translated nested domain: > cfg=5 ret=-2 > > vfio-pci 0009:03:00.0: > VFIO_DEVICE_ATTACH_IOMMUFD_PT attach failed for pt_id 19: -ENOENT > > The same configuration worked with Linux 6.14. Hmm, but without a viommu we shouldn't have this vmaster stuff activating in the first place, I thought? + if (new_domain->type == IOMMU_DOMAIN_NESTED) { + ret = arm_smmu_attach_prepare_vmaster( + state, to_smmu_nested_domain(new_domain)); That should only be happening if the VMM is setting up vIOMMU. And vIOMMU wasn't supported in 6.14, so if it "worked" the VMM was doing something quite different - not seeing this as a regression If viommu should support multi-device groups, I'm not sure. I want to know why you even have multi-device groups in the first place because that is not normal at all. Jason