[PATCH v5] xen: Add Darwin.mk

[PATCH v5] xen: Add Darwin.mk

[Bertrand Marquis]

Xen does not provide a Darwin build configuration useable on Mac OS.
It is possible to build Xen Hypervisor (tools are not supported) with a
toolchain able to produce ELF binaries (GCC or others).

Add config/Darwin.mk to include StdGNU.mk and force
XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
the cross-compile path so compiling on Mac OS is always handled as a
cross compilation case.

Only compiling the hypervisor has been tested !

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 aarch64-elf-binutils
- make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang

Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Change-Id: Iba91634afbaab58767bb8744b4b722ce5732a6dd
---
Changes since v4:
- Subect was "xen: Add Darwin.mk for GNU toolchains" but remove the GNU
  toolchains part as this could also work with Clang
- remove 'cd xen' from commit message
- simplify comment in Darwin.mk and rework commit message.

Changes since v3:
- set XEN_COMPILE_ARCH to unknown instead of Darwin
- list binutils as a dependency to install in brew in commit message

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
---
 config/Darwin.mk | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 config/Darwin.mk

diff --git a/config/Darwin.mk b/config/Darwin.mk
new file mode 100644
index 000000000000..b1fc9ca859b0
--- /dev/null
+++ b/config/Darwin.mk
@@ -0,0 +1,6 @@
+# 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
+
+# Cross compile on Mac OS, only hypervisor build has been tested, no tools
+XEN_COMPILE_ARCH = unknow
-- 
2.52.0

Re: [PATCH v5] xen: Add Darwin.mk

[Jan Beulich]

On 09.02.2026 11:46, Bertrand Marquis wrote:
> Xen does not provide a Darwin build configuration useable on Mac OS.
> It is possible to build Xen Hypervisor (tools are not supported) with a
> toolchain able to produce ELF binaries (GCC or others).
> 
> Add config/Darwin.mk to include StdGNU.mk and force
> XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
> the cross-compile path so compiling on Mac OS is always handled as a
> cross compilation case.
> 
> Only compiling the hypervisor has been tested !
> 
> 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 aarch64-elf-binutils
> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang
> 
> Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>

Acked-by: Jan Beulich <jbeulich@suse.com>

> Change-Id: Iba91634afbaab58767bb8744b4b722ce5732a6dd

This wants removing, I suppose.

> --- /dev/null
> +++ b/config/Darwin.mk
> @@ -0,0 +1,6 @@
> +# 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
> +
> +# Cross compile on Mac OS, only hypervisor build has been tested, no tools
> +XEN_COMPILE_ARCH = unknow

There was an 'n' lost, as the reason for forcing cross-compilation also
isn't stated. I'll take the liberty to add both back in.

Jan

Re: [PATCH v5] xen: Add Darwin.mk

[Bertrand Marquis]

> On 9 Feb 2026, at 14:01, Jan Beulich <jbeulich@suse.com> wrote:
> 
> On 09.02.2026 11:46, Bertrand Marquis wrote:
>> Xen does not provide a Darwin build configuration useable on Mac OS.
>> It is possible to build Xen Hypervisor (tools are not supported) with a
>> toolchain able to produce ELF binaries (GCC or others).
>> 
>> Add config/Darwin.mk to include StdGNU.mk and force
>> XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
>> the cross-compile path so compiling on Mac OS is always handled as a
>> cross compilation case.
>> 
>> Only compiling the hypervisor has been tested !
>> 
>> 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 aarch64-elf-binutils
>> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang
>> 
>> Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
> 
> Acked-by: Jan Beulich <jbeulich@suse.com>
> 
>> Change-Id: Iba91634afbaab58767bb8744b4b722ce5732a6dd
> 
> This wants removing, I suppose.

oh yes sorry for that

> 
>> --- /dev/null
>> +++ b/config/Darwin.mk
>> @@ -0,0 +1,6 @@
>> +# 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
>> +
>> +# Cross compile on Mac OS, only hypervisor build has been tested, no tools
>> +XEN_COMPILE_ARCH = unknow
> 
> There was an 'n' lost, as the reason for forcing cross-compilation also
> isn't stated. I'll take the liberty to add both back in.

ok with me.

Cheers
Bertrand

> 
> Jan

Re: [PATCH v5] xen: Add Darwin.mk

[Roger Pau Monné]

On Mon, Feb 09, 2026 at 11:46:44AM +0100, Bertrand Marquis wrote:
> Xen does not provide a Darwin build configuration useable on Mac OS.
> It is possible to build Xen Hypervisor (tools are not supported) with a
> toolchain able to produce ELF binaries (GCC or others).
> 
> Add config/Darwin.mk to include StdGNU.mk and force
> XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
> the cross-compile path so compiling on Mac OS is always handled as a
> cross compilation case.
> 
> Only compiling the hypervisor has been tested !
> 
> 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 aarch64-elf-binutils
> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang

This needs 'xen' target passed.

> 
> Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>

Acked-by: Roger Pau Monné <roger.pau@citrix.com>

Thanks, Roger.

Re: [PATCH v5] xen: Add Darwin.mk

[Bertrand Marquis]

Hi Roger

> On 9 Feb 2026, at 14:26, Roger Pau Monné <roger.pau@citrix.com> wrote:
> 
> On Mon, Feb 09, 2026 at 11:46:44AM +0100, Bertrand Marquis wrote:
>> Xen does not provide a Darwin build configuration useable on Mac OS.
>> It is possible to build Xen Hypervisor (tools are not supported) with a
>> toolchain able to produce ELF binaries (GCC or others).
>> 
>> Add config/Darwin.mk to include StdGNU.mk and force
>> XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
>> the cross-compile path so compiling on Mac OS is always handled as a
>> cross compilation case.
>> 
>> Only compiling the hypervisor has been tested !
>> 
>> 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 aarch64-elf-binutils
>> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang
> 
> This needs 'xen' target passed.

Without any target, xen is built by default so i kept the simplest possible command
But I am ok with adding xen

> 
>> 
>> Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
> 
> Acked-by: Roger Pau Monné <roger.pau@citrix.com>

Thanks

Bertrand

> 
> Thanks, Roger.

Re: [PATCH v5] xen: Add Darwin.mk

[Roger Pau Monné]

On Mon, Feb 09, 2026 at 01:33:13PM +0000, Bertrand Marquis wrote:
> Hi Roger
> 
> > On 9 Feb 2026, at 14:26, Roger Pau Monné <roger.pau@citrix.com> wrote:
> > 
> > On Mon, Feb 09, 2026 at 11:46:44AM +0100, Bertrand Marquis wrote:
> >> Xen does not provide a Darwin build configuration useable on Mac OS.
> >> It is possible to build Xen Hypervisor (tools are not supported) with a
> >> toolchain able to produce ELF binaries (GCC or others).
> >> 
> >> Add config/Darwin.mk to include StdGNU.mk and force
> >> XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
> >> the cross-compile path so compiling on Mac OS is always handled as a
> >> cross compilation case.
> >> 
> >> Only compiling the hypervisor has been tested !
> >> 
> >> 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 aarch64-elf-binutils
> >> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang
> > 
> > This needs 'xen' target passed.
> 
> Without any target, xen is built by default so i kept the simplest possible command
> But I am ok with adding xen

With the `cd xen` omitted, won't that also attempt to build the tools
then?

Thanks, Roger.

Re: [PATCH v5] xen: Add Darwin.mk

[Bertrand Marquis]

> On 9 Feb 2026, at 14:39, Roger Pau Monné <roger.pau@citrix.com> wrote:
> 
> On Mon, Feb 09, 2026 at 01:33:13PM +0000, Bertrand Marquis wrote:
>> Hi Roger
>> 
>>> On 9 Feb 2026, at 14:26, Roger Pau Monné <roger.pau@citrix.com> wrote:
>>> 
>>> On Mon, Feb 09, 2026 at 11:46:44AM +0100, Bertrand Marquis wrote:
>>>> Xen does not provide a Darwin build configuration useable on Mac OS.
>>>> It is possible to build Xen Hypervisor (tools are not supported) with a
>>>> toolchain able to produce ELF binaries (GCC or others).
>>>> 
>>>> Add config/Darwin.mk to include StdGNU.mk and force
>>>> XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
>>>> the cross-compile path so compiling on Mac OS is always handled as a
>>>> cross compilation case.
>>>> 
>>>> Only compiling the hypervisor has been tested !
>>>> 
>>>> 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 aarch64-elf-binutils
>>>> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang
>>> 
>>> This needs 'xen' target passed.
>> 
>> Without any target, xen is built by default so i kept the simplest possible command
>> But I am ok with adding xen
> 
> With the `cd xen` omitted, won't that also attempt to build the tools
> then?

This is supposed to be called in the xen sub-directory not in the main directory.

Now i get why you wanted the xen (and hence why there was the cd xen before)

Maybe having -C xen would be a better idea, building from main Makefile could
bring other side effects i guess.

Cheers
Bertrand


> 
> Thanks, Roger.

Re: [PATCH v5] xen: Add Darwin.mk

[Jan Beulich]

On 09.02.2026 14:42, Bertrand Marquis wrote:
>> On 9 Feb 2026, at 14:39, Roger Pau Monné <roger.pau@citrix.com> wrote:
>> On Mon, Feb 09, 2026 at 01:33:13PM +0000, Bertrand Marquis wrote:
>>>> On 9 Feb 2026, at 14:26, Roger Pau Monné <roger.pau@citrix.com> wrote:
>>>> On Mon, Feb 09, 2026 at 11:46:44AM +0100, Bertrand Marquis wrote:
>>>>> Xen does not provide a Darwin build configuration useable on Mac OS.
>>>>> It is possible to build Xen Hypervisor (tools are not supported) with a
>>>>> toolchain able to produce ELF binaries (GCC or others).
>>>>>
>>>>> Add config/Darwin.mk to include StdGNU.mk and force
>>>>> XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
>>>>> the cross-compile path so compiling on Mac OS is always handled as a
>>>>> cross compilation case.
>>>>>
>>>>> Only compiling the hypervisor has been tested !
>>>>>
>>>>> 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 aarch64-elf-binutils
>>>>> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang
>>>>
>>>> This needs 'xen' target passed.
>>>
>>> Without any target, xen is built by default so i kept the simplest possible command
>>> But I am ok with adding xen
>>
>> With the `cd xen` omitted, won't that also attempt to build the tools
>> then?
> 
> This is supposed to be called in the xen sub-directory not in the main directory.
> 
> Now i get why you wanted the xen (and hence why there was the cd xen before)
> 
> Maybe having -C xen would be a better idea, building from main Makefile could
> bring other side effects i guess.

Happy to add "-C xen" while committing, if that's what we now have settled
upon?

Jan

Re: [PATCH v5] xen: Add Darwin.mk

[Bertrand Marquis]

Hi Jan,

> On 9 Feb 2026, at 15:13, Jan Beulich <jbeulich@suse.com> wrote:
> 
> On 09.02.2026 14:42, Bertrand Marquis wrote:
>>> On 9 Feb 2026, at 14:39, Roger Pau Monné <roger.pau@citrix.com> wrote:
>>> On Mon, Feb 09, 2026 at 01:33:13PM +0000, Bertrand Marquis wrote:
>>>>> On 9 Feb 2026, at 14:26, Roger Pau Monné <roger.pau@citrix.com> wrote:
>>>>> On Mon, Feb 09, 2026 at 11:46:44AM +0100, Bertrand Marquis wrote:
>>>>>> Xen does not provide a Darwin build configuration useable on Mac OS.
>>>>>> It is possible to build Xen Hypervisor (tools are not supported) with a
>>>>>> toolchain able to produce ELF binaries (GCC or others).
>>>>>> 
>>>>>> Add config/Darwin.mk to include StdGNU.mk and force
>>>>>> XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
>>>>>> the cross-compile path so compiling on Mac OS is always handled as a
>>>>>> cross compilation case.
>>>>>> 
>>>>>> Only compiling the hypervisor has been tested !
>>>>>> 
>>>>>> 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 aarch64-elf-binutils
>>>>>> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang
>>>>> 
>>>>> This needs 'xen' target passed.
>>>> 
>>>> Without any target, xen is built by default so i kept the simplest possible command
>>>> But I am ok with adding xen
>>> 
>>> With the `cd xen` omitted, won't that also attempt to build the tools
>>> then?
>> 
>> This is supposed to be called in the xen sub-directory not in the main directory.
>> 
>> Now i get why you wanted the xen (and hence why there was the cd xen before)
>> 
>> Maybe having -C xen would be a better idea, building from main Makefile could
>> bring other side effects i guess.
> 
> Happy to add "-C xen" while committing, if that's what we now have settled
> upon?

Yes I think this will make it clearer and obvious that we only operate in the hypervisor
sub-directory.

Thanks
Bertrand

> 
> Jan

Re: [PATCH v5] xen: Add Darwin.mk

[Roger Pau Monné]

On Mon, Feb 09, 2026 at 01:42:05PM +0000, Bertrand Marquis wrote:
> 
> 
> > On 9 Feb 2026, at 14:39, Roger Pau Monné <roger.pau@citrix.com> wrote:
> > 
> > On Mon, Feb 09, 2026 at 01:33:13PM +0000, Bertrand Marquis wrote:
> >> Hi Roger
> >> 
> >>> On 9 Feb 2026, at 14:26, Roger Pau Monné <roger.pau@citrix.com> wrote:
> >>> 
> >>> On Mon, Feb 09, 2026 at 11:46:44AM +0100, Bertrand Marquis wrote:
> >>>> Xen does not provide a Darwin build configuration useable on Mac OS.
> >>>> It is possible to build Xen Hypervisor (tools are not supported) with a
> >>>> toolchain able to produce ELF binaries (GCC or others).
> >>>> 
> >>>> Add config/Darwin.mk to include StdGNU.mk and force
> >>>> XEN_COMPILE_ARCH=unknown, ensuring Darwin builds always follow
> >>>> the cross-compile path so compiling on Mac OS is always handled as a
> >>>> cross compilation case.
> >>>> 
> >>>> Only compiling the hypervisor has been tested !
> >>>> 
> >>>> 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 aarch64-elf-binutils
> >>>> - make XEN_TARGET_ARCH=arm64 CROSS_COMPILE=aarch64-elf- HOSTCC=clang
> >>> 
> >>> This needs 'xen' target passed.
> >> 
> >> Without any target, xen is built by default so i kept the simplest possible command
> >> But I am ok with adding xen
> > 
> > With the `cd xen` omitted, won't that also attempt to build the tools
> > then?
> 
> This is supposed to be called in the xen sub-directory not in the main directory.
> 
> Now i get why you wanted the xen (and hence why there was the cd xen before)
> 
> Maybe having -C xen would be a better idea, building from main Makefile could
> bring other side effects i guess.

I don't have a strong opinion, both -C xen or xen seem to work for me.

Thanks, Roger.

Re: [PATCH v5] xen: Add Darwin.mk

[Jan Beulich]

On 09.02.2026 11:46, Bertrand Marquis wrote:
> --- /dev/null
> +++ b/config/Darwin.mk
> @@ -0,0 +1,6 @@
> +# 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
> +
> +# Cross compile on Mac OS, only hypervisor build has been tested, no tools
> +XEN_COMPILE_ARCH = unknow

While editing in the ABI aspect, it occurred to me to check what Apple has
to say regarding their ABI. For both aarch64 and x86-64 they say they use
the standard ABI with some modifications. We may want to evaluate whether
those modifications are actually compatible with what we need.

Talking of x86-64: Has building on an x86 Mac been tested as well?
Especially if that doesn't work, it may want mentioning.

Jan

Re: [PATCH v5] xen: Add Darwin.mk

[Bertrand Marquis]

Hi Jan,

> On 10 Feb 2026, at 11:46, Jan Beulich <jbeulich@suse.com> wrote:
> 
> On 09.02.2026 11:46, Bertrand Marquis wrote:
>> --- /dev/null
>> +++ b/config/Darwin.mk
>> @@ -0,0 +1,6 @@
>> +# 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
>> +
>> +# Cross compile on Mac OS, only hypervisor build has been tested, no tools
>> +XEN_COMPILE_ARCH = unknow
> 
> While editing in the ABI aspect, it occurred to me to check what Apple has
> to say regarding their ABI. For both aarch64 and x86-64 they say they use
> the standard ABI with some modifications. We may want to evaluate whether
> those modifications are actually compatible with what we need.
> 
> Talking of x86-64: Has building on an x86 Mac been tested as well?

No i did not tested that (and i have no x86 mac i can use to do so).

> Especially if that doesn't work, it may want mentioning.

We might have to say that it was only tested on arm mac.

I would expect that it works on x86 mac but i cannot sign on that.

Cheers
Bertrand

> 
> Jan

Re: [PATCH v5] xen: Add Darwin.mk

[Roger Pau Monné]

On Tue, Feb 10, 2026 at 11:46:44AM +0100, Jan Beulich wrote:
> On 09.02.2026 11:46, Bertrand Marquis wrote:
> > --- /dev/null
> > +++ b/config/Darwin.mk
> > @@ -0,0 +1,6 @@
> > +# 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
> > +
> > +# Cross compile on Mac OS, only hypervisor build has been tested, no tools
> > +XEN_COMPILE_ARCH = unknow
> 
> While editing in the ABI aspect, it occurred to me to check what Apple has
> to say regarding their ABI. For both aarch64 and x86-64 they say they use
> the standard ABI with some modifications. We may want to evaluate whether
> those modifications are actually compatible with what we need.
> 
> Talking of x86-64: Has building on an x86 Mac been tested as well?
> Especially if that doesn't work, it may want mentioning.

I no longer have access to an x86 Mac, those are about to disappear.

FWIW, I build x86 on Mac using the Docker containers, just as the CI
does.  OSX Docker allows running x86 containers on arm64 using the
"Rosetta 2" binary translation layer.

I've attempted doing a cross-build from an arm64 Mac using the x86-elf
toolchain, but got the following error:

% make XEN_TARGET_ARCH=x86_64 CROSS_COMPILE=x86_64-elf- HOSTCC=gcc -C xen V=1
[...]
/Library/Developer/CommandLineTools/usr/bin/make -f ./Rules.mk obj=common need-builtin=1
  x86_64-elf-gcc -MMD -MP -MF common/.bitmap.o.d -m64 -DBUILD_ID -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes -Wno-unused-but-set-variable -Wno-unused-local-typedefs   -O1 -fno-omit-frame-pointer -nostdinc -fno-builtin -fno-common -fzero-init-padding-bits=all -Werror -Wredundant-decls -Wwrite-strings -Wno-pointer-arith -Wdeclaration-after-statement -Wuninitialized -Wvla -Wflex-array-member-not-at-end -Winit-self -pipe -D__XEN__ -include ./include/xen/config.h -Wa,--strip-local-absolute -ffunction-sections -fdata-sections -g -malign-data=abi -mindirect-branch=thunk-extern -mindirect-branch-register -fno-jump-tables -mfunction-return=thunk-extern -Wa,-mx86-used-note=no  -fno-stack-protector -I./include -I./arch/x86/include -I./arch/x86/include/generated -DXEN_IMG_OFFSET=0x200000 -msoft-float -fno-pie -fno-exceptions -fno-asynchronous-unwind-tables -Wnested-externs -DHAVE_AS_QUOTED_SYM -DHAVE_AS_MOVDIR -DHAVE_AS_ENQCMD -DHAVE_AS_NOPS_DIRECTIVE -mno-red-zone -fpic -mno-mmx -mno-sse -mskip-rax-setup -fcf-protection=branch -mmanual-endbr -fno-jump-tables -mmemcpy-strategy=unrolled_loop:16:noalign,libcall:-1:noalign -mmemset-strategy=unrolled_loop:16:noalign,libcall:-1:noalign -Wa,-I./include -Wa,-I./include '-D__OBJECT_LABEL__=common/bitmap.o' -mpreferred-stack-boundary=3   -c common/bitmap.c -o common/.bitmap.o.tmp -MQ common/bitmap.o
./arch/x86/include/asm/bitops.h: Assembler messages:
./arch/x86/include/asm/bitops.h:511: Error: found '
', expected: ')'
./arch/x86/include/asm/bitops.h:511: Error: found '
', expected: ')'
./arch/x86/include/asm/bitops.h:511: Error: found '
', expected: ')'
./arch/x86/include/asm/bitops.h:511: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:20: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:20: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
./arch/x86/include/asm/nospec.h:20: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:20: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
./arch/x86/include/asm/nospec.h:28: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:28: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
./arch/x86/include/asm/nospec.h:28: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:28: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
./arch/x86/include/asm/nospec.h:28: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:28: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
./arch/x86/include/asm/nospec.h:20: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:20: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
./arch/x86/include/asm/nospec.h:20: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:20: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
./arch/x86/include/asm/nospec.h:28: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:28: Error: found '
', expected: ')'
./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range

I haven't investigated further.  Seems like some issue with
alternative and the uses of CPUID defines.  We probably want to
mention in the commit message that only arm64 builds have been tested
so far.

Thanks, Roger.

Re: [PATCH v5] xen: Add Darwin.mk

[Bertrand Marquis]

Hi Roger,

> On 10 Feb 2026, at 12:41, Roger Pau Monné <roger.pau@citrix.com> wrote:
> 
> On Tue, Feb 10, 2026 at 11:46:44AM +0100, Jan Beulich wrote:
>> On 09.02.2026 11:46, Bertrand Marquis wrote:
>>> --- /dev/null
>>> +++ b/config/Darwin.mk
>>> @@ -0,0 +1,6 @@
>>> +# 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
>>> +
>>> +# Cross compile on Mac OS, only hypervisor build has been tested, no tools
>>> +XEN_COMPILE_ARCH = unknow
>> 
>> While editing in the ABI aspect, it occurred to me to check what Apple has
>> to say regarding their ABI. For both aarch64 and x86-64 they say they use
>> the standard ABI with some modifications. We may want to evaluate whether
>> those modifications are actually compatible with what we need.
>> 
>> Talking of x86-64: Has building on an x86 Mac been tested as well?
>> Especially if that doesn't work, it may want mentioning.
> 
> I no longer have access to an x86 Mac, those are about to disappear.
> 
> FWIW, I build x86 on Mac using the Docker containers, just as the CI
> does.  OSX Docker allows running x86 containers on arm64 using the
> "Rosetta 2" binary translation layer.
> 
> I've attempted doing a cross-build from an arm64 Mac using the x86-elf
> toolchain, but got the following error:
> 
> % make XEN_TARGET_ARCH=x86_64 CROSS_COMPILE=x86_64-elf- HOSTCC=gcc -C xen V=1
> [...]
> /Library/Developer/CommandLineTools/usr/bin/make -f ./Rules.mk obj=common need-builtin=1
>  x86_64-elf-gcc -MMD -MP -MF common/.bitmap.o.d -m64 -DBUILD_ID -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes -Wno-unused-but-set-variable -Wno-unused-local-typedefs   -O1 -fno-omit-frame-pointer -nostdinc -fno-builtin -fno-common -fzero-init-padding-bits=all -Werror -Wredundant-decls -Wwrite-strings -Wno-pointer-arith -Wdeclaration-after-statement -Wuninitialized -Wvla -Wflex-array-member-not-at-end -Winit-self -pipe -D__XEN__ -include ./include/xen/config.h -Wa,--strip-local-absolute -ffunction-sections -fdata-sections -g -malign-data=abi -mindirect-branch=thunk-extern -mindirect-branch-register -fno-jump-tables -mfunction-return=thunk-extern -Wa,-mx86-used-note=no  -fno-stack-protector -I./include -I./arch/x86/include -I./arch/x86/include/generated -DXEN_IMG_OFFSET=0x200000 -msoft-float -fno-pie -fno-exceptions -fno-asynchronous-unwind-tables -Wnested-externs -DHAVE_AS_QUOTED_SYM -DHAVE_AS_MOVDIR -DHAVE_AS_ENQCMD -DHAVE_AS_NOPS_DIRECTIVE -mno-red-zone -fpic -mno-mmx -mno-sse -mskip-rax-setup -fcf-protection=branch -mmanual-endbr -fno-jump-tables -mmemcpy-strategy=unrolled_loop:16:noalign,libcall:-1:noalign -mmemset-strategy=unrolled_loop:16:noalign,libcall:-1:noalign -Wa,-I./include -Wa,-I./include '-D__OBJECT_LABEL__=common/bitmap.o' -mpreferred-stack-boundary=3   -c common/bitmap.c -o common/.bitmap.o.tmp -MQ common/bitmap.o
> ./arch/x86/include/asm/bitops.h: Assembler messages:
> ./arch/x86/include/asm/bitops.h:511: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/bitops.h:511: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/bitops.h:511: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/bitops.h:511: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:20: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:20: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
> ./arch/x86/include/asm/nospec.h:20: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:20: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
> ./arch/x86/include/asm/nospec.h:28: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:28: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
> ./arch/x86/include/asm/nospec.h:28: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:28: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
> ./arch/x86/include/asm/nospec.h:28: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:28: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
> ./arch/x86/include/asm/nospec.h:20: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:20: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
> ./arch/x86/include/asm/nospec.h:20: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:20: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
> ./arch/x86/include/asm/nospec.h:28: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:28: Error: found '
> ', expected: ')'
> ./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
> 
> I haven't investigated further.  Seems like some issue with
> alternative and the uses of CPUID defines.  We probably want to
> mention in the commit message that only arm64 builds have been tested
> so far.

I just tried the same and could reproduce that.

This is apparently not related to mac os but to binutils (2.45.1 on my side)

After some digging i found out that this can be triggered with a simple assembler test where
.if (2/32) 
triggers the same error, while
.if 2/32
is fine (ie parenthesis are the source of the issue).

So the same error would probably occur with the same binutils version in linux i guess (unless it
brew specific version or patches which are creating that).

I did not dig further than that but we should keep that in mind in case this comes back in other
scenarios.

Cheers
Bertrand

> 
> Thanks, Roger.

Re: [PATCH v5] xen: Add Darwin.mk

[Jan Beulich]

On 10.02.2026 13:56, Bertrand Marquis wrote:
> Hi Roger,
> 
>> On 10 Feb 2026, at 12:41, Roger Pau Monné <roger.pau@citrix.com> wrote:
>>
>> On Tue, Feb 10, 2026 at 11:46:44AM +0100, Jan Beulich wrote:
>>> On 09.02.2026 11:46, Bertrand Marquis wrote:
>>>> --- /dev/null
>>>> +++ b/config/Darwin.mk
>>>> @@ -0,0 +1,6 @@
>>>> +# 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
>>>> +
>>>> +# Cross compile on Mac OS, only hypervisor build has been tested, no tools
>>>> +XEN_COMPILE_ARCH = unknow
>>>
>>> While editing in the ABI aspect, it occurred to me to check what Apple has
>>> to say regarding their ABI. For both aarch64 and x86-64 they say they use
>>> the standard ABI with some modifications. We may want to evaluate whether
>>> those modifications are actually compatible with what we need.
>>>
>>> Talking of x86-64: Has building on an x86 Mac been tested as well?
>>> Especially if that doesn't work, it may want mentioning.
>>
>> I no longer have access to an x86 Mac, those are about to disappear.
>>
>> FWIW, I build x86 on Mac using the Docker containers, just as the CI
>> does.  OSX Docker allows running x86 containers on arm64 using the
>> "Rosetta 2" binary translation layer.
>>
>> I've attempted doing a cross-build from an arm64 Mac using the x86-elf
>> toolchain, but got the following error:

If it's really x86-elf (not x86-linux), then likely ...

>> % make XEN_TARGET_ARCH=x86_64 CROSS_COMPILE=x86_64-elf- HOSTCC=gcc -C xen V=1
>> [...]
>> /Library/Developer/CommandLineTools/usr/bin/make -f ./Rules.mk obj=common need-builtin=1
>>  x86_64-elf-gcc -MMD -MP -MF common/.bitmap.o.d -m64 -DBUILD_ID -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes -Wno-unused-but-set-variable -Wno-unused-local-typedefs   -O1 -fno-omit-frame-pointer -nostdinc -fno-builtin -fno-common -fzero-init-padding-bits=all -Werror -Wredundant-decls -Wwrite-strings -Wno-pointer-arith -Wdeclaration-after-statement -Wuninitialized -Wvla -Wflex-array-member-not-at-end -Winit-self -pipe -D__XEN__ -include ./include/xen/config.h -Wa,--strip-local-absolute -ffunction-sections -fdata-sections -g -malign-data=abi -mindirect-branch=thunk-extern -mindirect-branch-register -fno-jump-tables -mfunction-return=thunk-extern -Wa,-mx86-used-note=no  -fno-stack-protector -I./include -I./arch/x86/include -I./arch/x86/include/generated -DXEN_IMG_OFFSET=0x200000 -msoft-float -fno-pie -fno-exceptions -fno-asynchronous-unwind-tables -Wnested-externs -DHAVE_AS_QUOTED_SYM -DHAVE_AS_MOVDIR -DHAVE_AS_ENQCMD -DHAVE_AS_NOPS_DIRECTIVE -mno-red-zone -fpic -mno-mmx -mno-sse -mskip-rax-setup -fcf-protection=branch -mmanual-endbr -fno-jump-tables -mmemcpy-strategy=unrolled_loop:16:noalign,libcall:-1:noalign -mmemset-strategy=unrolled_loop:16:noalign,libcall:-1:noalign -Wa,-I./include -Wa,-I./include '-D__OBJECT_LABEL__=common/bitmap.o' -mpreferred-stack-boundary=3   -c common/bitmap.c -o common/.bitmap.o.tmp -MQ common/bitmap.o
>> ./arch/x86/include/asm/bitops.h: Assembler messages:
>> ./arch/x86/include/asm/bitops.h:511: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/bitops.h:511: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/bitops.h:511: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/bitops.h:511: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:20: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:20: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
>> ./arch/x86/include/asm/nospec.h:20: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:20: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
>> ./arch/x86/include/asm/nospec.h:28: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:28: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
>> ./arch/x86/include/asm/nospec.h:28: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:28: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
>> ./arch/x86/include/asm/nospec.h:28: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:28: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
>> ./arch/x86/include/asm/nospec.h:20: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:20: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
>> ./arch/x86/include/asm/nospec.h:20: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:20: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:21: Error: alternative feature outside of featureset range
>> ./arch/x86/include/asm/nospec.h:28: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:28: Error: found '
>> ', expected: ')'
>> ./arch/x86/include/asm/nospec.h:29: Error: alternative feature outside of featureset range
>>
>> I haven't investigated further.  Seems like some issue with
>> alternative and the uses of CPUID defines.  We probably want to
>> mention in the commit message that only arm64 builds have been tested
>> so far.
> 
> I just tried the same and could reproduce that.
> 
> This is apparently not related to mac os but to binutils (2.45.1 on my side)
> 
> After some digging i found out that this can be triggered with a simple assembler test where
> .if (2/32) 
> triggers the same error, while
> .if 2/32
> is fine (ie parenthesis are the source of the issue).

... the wrong conclusion is being drawn here. It's not the parenthesis then,
but the fact that '/' is a comment character there. Requires adding --divide
to the command line options to have the character re-obtain its meaning as
division operator. (GNU, Linux, FreeBSD, NetBSD, Haiku, and Dragonfly are
the targets where '/' isn't a comment character by default, at present. Yes,
this is pretty confusing.)

Jan