Re: [PATCH v1] tests/qtest/migration: Fix A-B file build

[Peter Xu <peterx@redhat.com>]

On Wed, Apr 29, 2026 at 08:10:25PM -0300, Fabiano Rosas wrote:
> The generation of the guest workloads for migration-test is all
> broken:
> 
> 1) We moved code around and forgot to update the includes from the guest
> workloads at qtest/migration/<ARCH>/.
> 
> 2) Since this code doesn't build by default due to the need for cross
> compilation, we also broke the s390x code entirely by removing the
> libc implementation from sclp.c.
> 
> 3) The build adds a blank line at the end of the header files due to
> how the sed command used to remove extra variable declarations is
> written.
> 
> 4) Must be too long since we last built this thing that powerpc
> compilers would output BE by default. Nowadays we need -mbig-endian to
> force it.
> 
> 5) Format of comments needs fixing to please checkpatch.
> 
> Fix everything. Most changes are trivial, except for s390x where I had
> to reimplement some of the routines from sclp.c. Compiling that object
> file in doesn't work because of its various includes that this
> standalone code can't provide.
> 
> Testing this change (assuming x86 host):
> $ cd build
> $ pushd tests/qtest/migration
> $ make clean
> $ make i386
> $ make CROSS_PREFIX=your-favorite-cross-compiler- s390x
> $ make CROSS_PREFIX=your-favorite-cross-compiler- aarch64
> $ make CROSS_PREFIX=your-favorite-cross-compiler- ppc64
> $ popd
> $ make -j$(nproc) # must build the tests again
> $ QTEST_QEMU_BINARY=./qemu-system-<ARCH> migration-test
> 
> Fixes: 9f4278837d ("pc-bios/s390-ccw: Use the libc from SLOF and remove sclp prints")
> Fixes: e1803dabdc ("tests/qtest/migration: Move common test code")
> Signed-off-by: Fabiano Rosas <farosas@suse.de>

Since things are essentially broken, I queued this one directly.  However I
don't have any knowledge to review the s390 changes, please s390x
developers do so and if things need change we can do follow ups.

I did test all these and they work.  One thing to mention below,

> ---
>  tests/qtest/migration/Makefile             |  11 +-
>  tests/qtest/migration/aarch64/Makefile     |   4 +-
>  tests/qtest/migration/aarch64/a-b-kernel.S |   2 +-
>  tests/qtest/migration/aarch64/a-b-kernel.h |   7 +-
>  tests/qtest/migration/bootfile.h           |  11 +
>  tests/qtest/migration/i386/Makefile        |   4 +-
>  tests/qtest/migration/i386/a-b-bootblock.S |   2 +-
>  tests/qtest/migration/i386/a-b-bootblock.h |   8 +-
>  tests/qtest/migration/ppc64/Makefile       |   6 +-
>  tests/qtest/migration/ppc64/a-b-kernel.S   |   2 +-
>  tests/qtest/migration/ppc64/a-b-kernel.h   |   8 +-
>  tests/qtest/migration/s390x/Makefile       |   8 +-
>  tests/qtest/migration/s390x/a-b-bios.c     |  66 ++-
>  tests/qtest/migration/s390x/a-b-bios.h     | 609 +++++++++++++--------

I somehow generated different a-b-bios.h for s390x after cross-make.  But I
verified both versions of s390x_elf[] work here.

My gut feeling is it is a compiler difference causing different code
generated, even if there's no real functional difference.

My "your-favorite-cross-compiler-" dumps this:

$ s390x-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/usr/bin/s390x-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/s390x-linux-gnu/15/lto-wrapper
Target: s390x-linux-gnu
Configured with: ../gcc-15.2.1-20250808/configure --bindir=/usr/bin --build=x86_64-redhat-linux-gnu --datadir=/usr/share --disable-decimal-float --disable-dependency-tracking --disable-gold --disable-libgcj --disable-libgomp --disable-libmpx --disable-libquadmath --disable-libssp --disable-libunwind-exceptions --disable-shared --disable-silent-rules --disable-sjlj-exceptions --disable-threads --with-ld=/usr/bin/s390x-linux-gnu-ld --enable-__cxa_atexit --enable-checking=release --enable-gnu-unique-object --enable-initfini-array --enable-languages=c,c++ --enable-linker-build-id --enable-lto --enable-nls --enable-obsolete --enable-plugin --enable-targets=all --exec-prefix=/usr --host=x86_64-redhat-linux-gnu --includedir=/usr/include --infodir=/usr/share/info --libexecdir=/usr/libexec --localstatedir=/var --mandir=/usr/share/man --prefix=/usr --program-prefix=s390x-linux-gnu- --sbindir=/usr/bin --sharedstatedir=/var/lib --sysconfdir=/etc --target=s390x-linux-gnu --with-bugurl=http://bugzilla.redhat.com/bugzilla/ --with-gcc-major-version-only --with-isl --with-newlib --with-plugin-ld=/usr/bin/s390x-linux-gnu-ld --with-sysroot=/usr/s390x-linux-gnu/sys-root --with-system-libunwind --with-system-zlib --without-headers --with-arch=zEC12 --with-tune=z13 --enable-decimal-float --with-long-double-128 --enable-gnu-indirect-function --with-linker-hash-style=gnu
Thread model: single
Supported LTO compression algorithms: zlib zstd
gcc version 15.2.1 20250808 (Red Hat Cross 15.2.1-1) (GCC) 

-- 
Peter Xu