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

[Ted Logan <tedlogan@fb.com>]

On Mon, Feb 02, 2026 at 11:33:21PM +0000, David Matlack wrote:
> 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"?

I got that from tools/testing/selftests/arm64/Makefile but it's probably
not all that useful. I guess the idea is to allow for the possibility
that uname could fail, but I don't really know if that's really useful.

> 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".

Thanks for the suggestion, I'll post an updated patch shortly.

- Ted