Hi Nuno,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on asm-generic/master]
[also build test WARNING on tip/master linux/master linus/master v5.13-rc3 next-20210528]
[cannot apply to tip/x86/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Nuno-Das-Neves/Microsoft-Hypervisor-root-partition-ioctl-interface/20210529-064549
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git master
config: x86_64-randconfig-b001-20210528 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project bc6799f2f79f0ae87e9f1ebf9d25ba799fbd25a9)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/2761f56915a9f31c98287f68fd2b286b7ec16d41
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Nuno-Das-Neves/Microsoft-Hypervisor-root-partition-ioctl-interface/20210529-064549
        git checkout 2761f56915a9f31c98287f68fd2b286b7ec16d41
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from <built-in>:1:
   In file included from ./usr/include/linux/mshv.h:12:
>> ./usr/include/asm/hyperv-tlfs.h:751:14: warning: // comments are not allowed in this language [-Wcomment]
           __u8 cr8:4; // only set for exo partitions
                       ^
   1 warning generated.

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org