Hi Michal, I was building Marc's kvm development kernel outside of the sources (make O=), and I got the following build error: arch/arm64/kvm/../../../arch/arm/kvm/mmio.c: fatal error: opening dependency file arch/arm64/kvm/../../../arch/arm/kvm/.mmio.o.d: No such file or directory The cause was that kbuild did not create the output directory arch/arm64/kvm/../../../arch/arm/kvm, and so gcc failed. Here is what was in his makefile: obj-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o) I changed this to build a composite and kbuild then created the output directories: obj-$(CONFIG_KVM_ARM_HOST) += kvm.o kvm-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o) I guess kbuild used some other rules and saw the dependency on the output directory. So, my questions are: Is it expected that the original rule should fail? Is my fix the correct way? Can I use some other way to get those output directories created? Just FYI, the original source is here: https://git.kernel.org/cgit/linux/kernel/git/maz/arm-platforms.git/tree/arch/arm64/kvm/Makefile?h=kvm-arm64/kvm-for-next Thanks for your help. -Geoff -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html