reproduce (this is a W=1 build):
        # https://github.com/sean-jc/linux/commit/c64fb3423cc30049e385769287c3d3d5475a4ac6
        git remote add sean-jc https://github.com/sean-jc/linux
        git fetch --no-tags sean-jc x86/pmu_fixed_ctr_ctrl_helper
        git checkout c64fb3423cc30049e385769287c3d3d5475a4ac6
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash arch/x86/kvm/