I found it very difficult to cross-build kvmtool for all arches because for some architectures I couldn't get libfdt to install: either dtc wasn't compiling (x86 machine, Arch Linux, missing yaml.h include when building for arm and powerpc), or libfdt was not being found by Makefile after installing it (x86 machine, Debian 11, building for powerpc). It was possible to compile only libfdt and teach Makefile where to look for it, which is what I ended up doing, but in my opinion, that's not an ideal user experience. This is my attempt at making compilation easier by pulling in the libfdt library and having kvmtool compile it when an architecture requires it. All the user needs to do now is to find a suitable cross-compiler toolchain with glibc included [1]*. The static version of libfdt is linked against the final binary, regardless if kvmtool is built as a static or dynamic binary. This only happens for those arches that require libfdt (arm, arm64, riscv, powerpc); libfdt is not built for MIPS and x86. This has been measured to increase the size of the binary by 110KB, or 5.3% (details in patch #1). I am pretty happy with how libfdt has been integrated with the kvmtool build system. The only niggle is that the libfdt_clean target echoes the commands to remove the build artifacts: $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- clean Makefile:368: Skipping optional libraries: bfd zlib aio CLEAN (libfdt) rm -f libfdt/*.o libfdt/libfdt.a rm -f libfdt/libfdt.so.1 CLEAN but I believe that's impossible to change without modifying the libfdt Makefile, which I don't want to do to keep it as easy as possible to update libfdt. Redid the measurements about how libfdt affects the build time when building from a clean directory (incremental builds do not rebuild libfdt): - On a rockpro64, on the little core (Cortex-A53), running $ time taskset -c 0 make with libfdt it takes 90.838s (measured for one build, very similar to the previous measurements); without libfdt it takes 84.263s (measured as above). That's a 6.575s absolute increase, or a 7.803% relative increase. - On the same rockpro64, on the big core (Cortex-A72), running $ time taskset -c 5 make with libfdt takes 45.178s (one build, very similar to the measurements for v1); without libfdt it takes 41.919s (measured as above). That's a 3.260s absolute increase, or a 7.777% relative increase. I believe that the ease of use more than justifies the increased compilation time. *only for x86 hosts. Testing ======= On x86 host, compiled for x86, MIPS, arm, arm64, powerpc, riscv. Booted an x86 VM. On arm64 host, compiled for arm64 and arm. I tried to cross-compile for other targets, but I couldn't find a cross-compiler toolchain for arm64 hosts that included a libc implementation. The arm cross-compiler was downloaded from the developer.arm.com [2]. Ran kvm-unit-tests for arm64 and arm (on the arm64 version of kvmtool), and also booted a kernel. Changelog ========= Changes since v1: - Always link kvmtool against the static version of libfdt. The dynamic lkvm binary was rather embarrassingly for me still using the system library (Andre). [1] https://toolchains.bootlin.com/ [2] https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/downloads Alexandru Elisei (2): Add libfdt library INSTALL: Remove all mentions of libfdt INSTALL | 27 +- Makefile | 39 +- libfdt/.gitignore | 1 + libfdt/Makefile.libfdt | 18 + libfdt/TODO | 3 + libfdt/fdt.c | 335 ++++++ libfdt/fdt.h | 66 ++ libfdt/fdt_addresses.c | 101 ++ libfdt/fdt_check.c | 93 ++ libfdt/fdt_empty_tree.c | 38 + libfdt/fdt_overlay.c | 867 +++++++++++++++ libfdt/fdt_ro.c | 859 +++++++++++++++ libfdt/fdt_rw.c | 500 +++++++++ libfdt/fdt_strerror.c | 60 ++ libfdt/fdt_sw.c | 384 +++++++ libfdt/fdt_wip.c | 94 ++ libfdt/libfdt.h | 2147 ++++++++++++++++++++++++++++++++++++++ libfdt/libfdt_env.h | 96 ++ libfdt/libfdt_internal.h | 192 ++++ libfdt/meson.build | 55 + libfdt/version.lds | 83 ++ 21 files changed, 6018 insertions(+), 40 deletions(-) create mode 100644 libfdt/.gitignore create mode 100644 libfdt/Makefile.libfdt create mode 100644 libfdt/TODO create mode 100644 libfdt/fdt.c create mode 100644 libfdt/fdt.h create mode 100644 libfdt/fdt_addresses.c create mode 100644 libfdt/fdt_check.c create mode 100644 libfdt/fdt_empty_tree.c create mode 100644 libfdt/fdt_overlay.c create mode 100644 libfdt/fdt_ro.c create mode 100644 libfdt/fdt_rw.c create mode 100644 libfdt/fdt_strerror.c create mode 100644 libfdt/fdt_sw.c create mode 100644 libfdt/fdt_wip.c create mode 100644 libfdt/libfdt.h create mode 100644 libfdt/libfdt_env.h create mode 100644 libfdt/libfdt_internal.h create mode 100644 libfdt/meson.build create mode 100644 libfdt/version.lds -- 2.36.1 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
