[PATCH v3 0/4] Introduce vfio_dma_mapping_perf_test

[Aaron Lewis <aaronlewis@google.com>]

Add a new VFIO selftest, vfio_dma_mapping_perf_test, to provide a
configurable tool for measuring DMA mapping and unmapping latencies.

This selftest introduces command-line parameters to provide a convenient
way to tune the test for specific situations. For example, it can be used
to observe the lengthy unmap times of the Type 1 IOMMU on large memory
regions, or to compare DMA mapping performance between the Type 1 IOMMU
and IOMMUFD. These scenarios can now be easily configured and run via the
command line.

Changes in v3:
 - Replaced raw printf() calls with ksft_print_msg()
 - Updated the TIME macro to preserve errno
 - Added 'fd' and 'fd_offset' to struct dma_region
 - Simplified teardown_memfd() by removing redundant error checks
 - Replaced the command-line argument passthrough (-a "...") approach with
   first-class support in kselftest_harness.h
 - Added collision validation in optstring_append_custom() to prevent custom
   options from overlapping with built-in harness options.
 - Switched test_enabled() to match exact option characters rather than
   tolower(opt), ensuring custom options that differ only by case (such as
   'R') do not mistakenly match built-in single-case options like '-r'.

Aaron Lewis (4):
  vfio: selftests: Assert the region was unmapped in iommu_unmap()
  vfio: selftests: Introduce vfio_dma_mapping_perf_test
  vfio: selftests: Add memfd test to vfio_dma_mapping_perf_test
  vfio: selftests: Allow a size for vfio_dma_mapping_perf_test

 tools/testing/selftests/kselftest_harness.h   |  86 +++++-
 tools/testing/selftests/vfio/Makefile         |   1 +
 .../selftests/vfio/lib/include/libvfio.h      |  31 +++
 .../vfio/lib/include/libvfio/iommu.h          |  14 +-
 tools/testing/selftests/vfio/lib/iommu.c      |  24 ++
 .../vfio/vfio_dma_mapping_perf_test.c         | 263 ++++++++++++++++++
 .../selftests/vfio/vfio_dma_mapping_test.c    |  11 +-
 7 files changed, 406 insertions(+), 24 deletions(-)
 create mode 100644 tools/testing/selftests/vfio/vfio_dma_mapping_perf_test.c

-- 
2.55.0.1003.g10538fe699-goog