Using iommufd requires two different kernel config: CONFIG_IOMMUFD and CONFIG_VFIO_DEVICE_CDEV https://docs.kernel.org/driver-api/vfio.html#vfio-device-cdev
It can be complex to identify what is missing when trying to use it. This series gives hints to user about it. Suggested on: https://lore.kernel.org/qemu-devel/[email protected]/ Tested using a cross compiled QEMU and a custom kernel + debian rootfs [1]. [1] https://github.com/p-b-o/qemu-linux-stack/tree/device_passthrough v2 -- - Move /dev/iommu to iommufd_backend_complete, so we can report the error instead of aborting. Pierrick Bouvier (2): backends/iommufd.c: report error when /dev/iommu is not available hw/vfio/iommufd.c: report hint to user when vfio-dev/vfio*/dev is missing backends/iommufd.c | 6 ++++++ hw/vfio/iommufd.c | 5 ++++- 2 files changed, 10 insertions(+), 1 deletion(-) -- 2.47.3
