Hi Liu,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on hch-configfs/for-next]
[cannot apply to joro-iommu/next awilliam-vfio/next linus/master v5.15-rc1 next-20210917]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Liu-Yi-L/Introduce-dev-iommu-for-userspace-I-O-address-space-management/20210919-144631
base:   git://git.infradead.org/users/hch/configfs.git for-next
config: ia64-buildonly-randconfig-r001-20210919 (attached as .config)
compiler: ia64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/611f151814f65b3087eeeb3f9115f42c647746c2
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Liu-Yi-L/Introduce-dev-iommu-for-userspace-I-O-address-space-management/20210919-144631
        git checkout 611f151814f65b3087eeeb3f9115f42c647746c2
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=ia64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   ia64-linux-ld: drivers/iommu/iommufd/iommufd.o: in function `iommu_device_add_cap_chain.constprop.0':
   iommufd.c:(.text+0x1d2): undefined reference to `vfio_device_add_iova_cap'
   ia64-linux-ld: drivers/iommu/iommufd/iommufd.o: in function `ioas_put_locked':
>> iommufd.c:(.text+0x792): undefined reference to `vfio_iommu_type1_release'
>> ia64-linux-ld: iommufd.c:(.text+0x872): undefined reference to `vfio_iommu_type1_release'
   ia64-linux-ld: drivers/iommu/iommufd/iommufd.o: in function `iommufd_device_attach_ioasid':
>> iommufd.c:(.text+0x1682): undefined reference to `vfio_iommu_add_group'
   ia64-linux-ld: drivers/iommu/iommufd/iommufd.o: in function `iommufd_device_detach_ioasid':
>> iommufd.c:(.text+0x1bd2): undefined reference to `vfio_iommu_remove_group'
   ia64-linux-ld: drivers/iommu/iommufd/iommufd.o: in function `iommufd_process_dma_op':
>> iommufd.c:(.text+0x1f12): undefined reference to `vfio_iommu_type1_map_dma'
>> ia64-linux-ld: iommufd.c:(.text+0x1fb2): undefined reference to `vfio_iommu_type1_unmap_dma'
   ia64-linux-ld: drivers/iommu/iommufd/iommufd.o: in function `iommufd_ioasid_alloc':
>> iommufd.c:(.text+0x2752): undefined reference to `vfio_iommu_type1_open'

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for IOMMUFD
   Depends on IOMMU_SUPPORT
   Selected by
   - VFIO_PCI && VFIO && PCI && EVENTFD && MMU

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org