[v3] iommufd: give hints to user about kernel support

[PATCH v3 0/2] iommufd: give hints to user about kernel support

Pierrick Bouvier posted 2 patches 2 days, 15 hours ago

Diff against v1 v2
Download series mbox

Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20260319205942.367705-1-pierrick.bouvier@linaro.org

Maintainers: Yi Liu <yi.l.liu@intel.com>, Eric Auger <eric.auger@redhat.com>, Zhenzhong Duan <zhenzhong.duan@intel.com>, Alex Williamson <alex@shazbot.org>, "Cédric Le Goater" <clg@redhat.com>

backends/iommufd.c | 3 +++
hw/vfio/iommufd.c  | 5 ++++-
2 files changed, 7 insertions(+), 1 deletion(-)

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[PATCH v3 0/2] iommufd: give hints to user about kernel support

Posted by Pierrick Bouvier 2 days, 15 hours ago

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/0cc139d6-9289-44a0-9122-d701426dae0c@linaro.org/

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

v3
--

- more accurate check for /dev/iommu presence in iommufd_backend_complete

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 | 3 +++
 hw/vfio/iommufd.c  | 5 ++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

-- 
2.47.3