> 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
>>>
>>> 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.
>
>>> --- /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?
Cheers
Bertrand
>
> Thanks, Roger.
