On Fri, Feb 06, 2026 at 01:34:23PM +0000, Bertrand Marquis wrote: > > > > On 6 Feb 2026, at 14:29, Roger Pau Monné <[email protected]> wrote: > > > > On Fri, Feb 06, 2026 at 11:38:02AM +0100, Jan Beulich wrote: > >> On 06.02.2026 09:17, Bertrand Marquis wrote: > >>> Xen does not provide a Darwin build configuration for selecting > >>> GNU tool definitions. On macOS, the tools we use are either GNU > >>> compatible or we only rely on features supported by Mac OS, so > >>> using the GNU tool definitions is appropriate. > >>> > >>> Add config/Darwin.mk to include StdGNU.mk and force > >>> XEN_COMPILE_ARCH=Darwin, ensuring Darwin builds always follow > >>> the cross-compile path as we depend on the Linux ABI so compiling > >>> on Mac OS is always a cross compilation case. > >>> > >>> An example of how to build the hypervisor for arm64 on Mac OS > >>> (tools cannot be build for now) using a compiler from brew: > >>> - brew install aarch64-elf-gcc > >>> - cd xen > >>> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=gcc
I've just noticed: it's a bit misleading to use HOSTCC=gcc here, as (under a normal OSX system) gcc is a plain wrapped around clang: % gcc -v Apple clang version 17.0.0 (clang-1700.6.3.2) Target: arm64-apple-darwin24.6.0 Thread model: posix You might as well use HOSTCC=clang and make it explicit the host compiler is clang and not gcc. > >>> > >>> Signed-off-by: Bertrand Marquis <[email protected]> > >>> --- > >>> Changes since v2: > >>> - Subject was "xen: Add macOS hypervisor build configuration" > >>> - Update Darwin.mk comments to more accurate versions (Jan) > >>> - Remove the build-on-macos help as we have no dependency on anything > >>> coming from brew anymore and the toolchain can be retrieved by lots of > >>> other solutions than brew on mac os. Switch to a simple doc in the > >>> commit message instead > >> > >> Did you see Roger's notice on Matrix about objcopy? > > > > I think Bertrand considers objcopy to be part of the toolchain, hence > > "retrieving a toolchain" is meant to include objcopy (either the GNU, > > LLVM or elftoolchain one) > > Sorry i only saw your message in matrix. > > I checked and i installed both gcc and binutils in homebrew. > > So i think the commit message needs modifying to stay: > > brew install aarch64-elf-gcc aarch64-elf-binutils > > to be fully complete. Yes, I didn't notice that in the commit message you explicitly mentioned the brew install dependencies. There's also bison and flex needed for Kconfig, but AFAICT those are part of command line tools. I think python is also part of the command line tools, and not sure it's required for arm64, as it's required for x86 to generate the cpuid headers (but I don't know if arm64 has anything equivalent). > > > >>> --- /dev/null > >>> +++ b/config/Darwin.mk > >>> @@ -0,0 +1,7 @@ > >>> +# Use GNU tool definitions as the tools we are using are either GNU > >>> compatible > >>> +# or we only use features which are supported on Mac OS. > >>> +include $(XEN_ROOT)/config/StdGNU.mk > >>> + > >>> +# Xen uses Linux'es ABI so we are cross compiling on Mac OS. > >>> +# Force COMPILE_ARCH to a fake value to make sure it is always the case. > >>> +XEN_COMPILE_ARCH = Darwin > >> > >> I first wondered why you say "fake", seeing the file is named Darwin.mk. > >> But > >> in Config.mk's cross-compile check the build host OS doesn't even matter. > >> So > >> yes, it needs faking here for the time being. > > > > Hm, setting it to "Darwin" seems weird to me. I understand the > > purpose of this is to force the user to set XEN_TARGET_ARCH > > explicitly. I however wouldn't see it as fully uncorrect to not set > > this. It will then execute `uname -m` and get `arm64` back for Apple > > silicon macs (which is kind of OK?). Other I suggest we use a non-OSX > > specific value here, so that if required we could distinguish this > > case where the user is expected to provide XEN_COMPILE_ARCH. > > > > Maybe XEN_COMPILE_ARCH = { unknown | undefined }? > > I am ok to change this with either but maybe unsupported could be > a third choice? No strong opinion for either naming, as long as we don't explicitly use "Darwin". Thanks, Roger.
