Re: [PATCH] vfio: selftests: only build tests on arm64 and x86_64

[David Matlack <dmatlack@google.com>]

On 2026-01-30 04:02 PM, Ted Logan wrote:
> Only build vfio self-tests on arm64 and x86_64; these are the only
> architectures where the vfio self-tests are run. Addresses compiler
> warnings for format and conversions on i386.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202601211830.aBEjmEFD-lkp@intel.com/
> Signed-off-by: Ted Logan <tedlogan@fb.com>
> ---
> Do not build vfio self-tests for 32-bit architectures, where they're
> untested and unmaintained. Only build these tests for arm64 and x86_64,
> where they're regularly tested.
> 
> Compiler warning fixed by patch:
> 
>    In file included from tools/testing/selftests/vfio/lib/include/libvfio.h:6:
>    tools/testing/selftests/vfio/lib/include/libvfio/iommu.h:49:2: warning: format specifies type 'unsigned long' but the argument has type 'u64' (aka 'unsigned long long') [-Wformat]
>       49 |         VFIO_ASSERT_EQ(__iommu_unmap(iommu, region, NULL), 0);
>          |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    tools/testing/selftests/vfio/lib/include/libvfio/assert.h:32:37: note: expanded from macro 'VFIO_ASSERT_EQ'
>       32 | #define VFIO_ASSERT_EQ(_a, _b, ...) VFIO_ASSERT_OP(_a, _b, ==, ##__VA_ARGS__)
>          |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    tools/testing/selftests/vfio/lib/include/libvfio/assert.h:27:22: note: expanded from macro 'VFIO_ASSERT_OP'
>       26 |         fprintf(stderr, "  Observed: %#lx %s %#lx\n",                           \
>          |                                              ~~~~
>       27 |                         (u64)__lhs, #_op, (u64)__rhs);                          \
>          |                                           ^~~~~~~~~~
> ---
>  tools/testing/selftests/vfio/Makefile | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/tools/testing/selftests/vfio/Makefile b/tools/testing/selftests/vfio/Makefile
> index ead27892ab65..eeb63ea2b4da 100644
> --- a/tools/testing/selftests/vfio/Makefile
> +++ b/tools/testing/selftests/vfio/Makefile
> @@ -1,3 +1,10 @@
> +ARCH ?= $(shell uname -m 2>/dev/null || echo not)

What's the reason for the stderr redirection and "echo not"?

> +
> +ifeq (,$(filter $(ARCH),arm64 x86_64))
> +nothing:
> +.PHONY: all clean run_tests install
> +.SILENT:

I think you can just add the following line so that this is a valid
empty selftest Makefile on unsupported architectures, without having to
define all those targets:

  include ../lib.mk

Also I would recommend spacing things out a little so that the
unsupported architecture handling is more "off to the side".

e.g.

diff --git a/tools/testing/selftests/vfio/Makefile b/tools/testing/selftests/vfio/Makefile
index ead27892ab65..9386f75b590d 100644
--- a/tools/testing/selftests/vfio/Makefile
+++ b/tools/testing/selftests/vfio/Makefile
@@ -1,3 +1,10 @@
+ARCH ?= $(shell uname -m)
+
+ifeq (,$(filter $(ARCH),arm64 x86_64))
+# Do nothing on unsupported architectures.
+include ../lib.mk
+else
+
 CFLAGS = $(KHDR_INCLUDES)
 TEST_GEN_PROGS += vfio_dma_mapping_test
 TEST_GEN_PROGS += vfio_dma_mapping_mmio_test
@@ -28,3 +35,5 @@ TEST_DEP_FILES = $(patsubst %.o, %.d, $(TEST_GEN_PROGS_O) $(LIBVFIO_O))
 -include $(TEST_DEP_FILES)

 EXTRA_CLEAN += $(TEST_GEN_PROGS_O) $(TEST_DEP_FILES)
+
+endif


> +else
>  CFLAGS = $(KHDR_INCLUDES)
>  TEST_GEN_PROGS += vfio_dma_mapping_test
>  TEST_GEN_PROGS += vfio_dma_mapping_mmio_test
> @@ -28,3 +35,4 @@ TEST_DEP_FILES = $(patsubst %.o, %.d, $(TEST_GEN_PROGS_O) $(LIBVFIO_O))
>  -include $(TEST_DEP_FILES)
>  
>  EXTRA_CLEAN += $(TEST_GEN_PROGS_O) $(TEST_DEP_FILES)
> +endif
> 
> ---
> base-commit: c3cbc276c2a33b04fc78a86cdb2ddce094cb3614
> change-id: 20260130-vfio-selftest-only-64bit-422518bdeba7
> 
> Best regards,
> -- 
> Ted Logan <tedlogan@fb.com>
>