This series allows the memory_region_register_iommu_notifier() to fail. As of now, when a MAP notifier is attempted to be registered along with SMMUv3 or AMD IOMMU, we exit in the IOMMU MR notify_flag_changed() callback.
In case of VFIO assigned device hotplug, this could be handled more nicely directly within the VFIO code, simply rejecting the hotplug without exiting. This is what the series achieves by handling the memory_region_register_iommu_notifier() returned value and Error object. To propagate errors collected during vfio_listener_region_add() we now store the error handle inside the VFIO container instead of a returned value. The message now is: (QEMU) device_add id=hot0 driver=vfio-pci host=0000:89:00.0 bus=pcie.1 {"error": {"class": "GenericError", "desc": "vfio 0000:89:00.0: failed to setup container for group 2: memory listener initialization failed: Region smmuv3-iommu-memory-region-0-6: device 01.00.0 requires iommu MAP notifier which is not currently supported"}} Best Regards Eric This series can be found at: https://github.com/eauger/qemu/tree/v4.1.0_register_iommu_notifier_fail_v3 History: v2 -> v3: - also pass an Error handle (suggested by Peter) - VFIO container error becomes and Error handle v1 -> v2: - Intel IOMMU now handles the problem differently with machine init done notifier and machine hotplug allowed hook. - use assert(!ret) - message rewording in SMMUv3 Follow-up of "VFIO/SMMUv3: Fail on VFIO/HW nested paging detection" https://patchew.org/QEMU/20190829090141.21821-1-eric.au...@redhat.com/ Eric Auger (2): vfio: Turn the container error into an Error handle memory: allow memory_region_register_iommu_notifier() to fail exec.c | 10 ++++-- hw/arm/smmuv3.c | 18 +++++----- hw/i386/amd_iommu.c | 17 +++++---- hw/i386/intel_iommu.c | 8 +++-- hw/ppc/spapr_iommu.c | 8 +++-- hw/vfio/common.c | 67 +++++++++++++++++++++-------------- hw/vfio/spapr.c | 4 ++- hw/virtio/vhost.c | 9 +++-- include/exec/memory.h | 21 ++++++++--- include/hw/vfio/vfio-common.h | 2 +- memory.c | 31 ++++++++++------ 11 files changed, 126 insertions(+), 69 deletions(-) -- 2.20.1