Re: [RFC PATCH 2/2] ARM: KVM: standalone Makefile for vgic and timers

From: Paolo Bonzini <pbonzini@redhat.com>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: cdall@cs.columbia.edu, catalin.marinas@arm.com,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Subject: Re: [RFC PATCH 2/2] ARM: KVM: standalone Makefile for vgic and timers
Date: Fri, 10 May 2013 11:39:32 +0200	[thread overview]
Message-ID: <518CC054.9070002@redhat.com> (raw)
In-Reply-To: <1367589773-5609-3-git-send-email-marc.zyngier@arm.com>

Il 03/05/2013 16:02, Marc Zyngier ha scritto:
> On the road to turn KVM/arm64 into something more sensible, change
> the way we compile the VGIC and arch_timer code by using local
> Makefiles instead of the very backward method we used before.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  Makefile              | 2 +-
>  arch/arm/kvm/Makefile | 2 --
>  virt/Makefile         | 1 +
>  virt/kvm/Makefile     | 1 +
>  virt/kvm/arm/Makefile | 2 ++
>  5 files changed, 5 insertions(+), 3 deletions(-)
>  create mode 100644 virt/Makefile
>  create mode 100644 virt/kvm/Makefile
>  create mode 100644 virt/kvm/arm/Makefile
> 
> diff --git a/Makefile b/Makefile
> index 6db672b..19d51df 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -732,7 +732,7 @@ export mod_sign_cmd
>  
>  
>  ifeq ($(KBUILD_EXTMOD),)
> -core-y		+= kernel/ mm/ fs/ ipc/ security/ crypto/ block/
> +core-y		+= kernel/ mm/ fs/ ipc/ security/ crypto/ block/ virt/
>  
>  vmlinux-dirs	:= $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \
>  		     $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
> diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
> index 110d6da..e0540fd 100644
> --- a/arch/arm/kvm/Makefile
> +++ b/arch/arm/kvm/Makefile
> @@ -20,5 +20,3 @@ kvm-arm-y = $(addprefix $(KVM)/, kvm_main.o coalesced_mmio.o)
>  obj-y += kvm-arm.o init.o interrupts.o
>  obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o
>  obj-y += coproc.o coproc_a15.o mmio.o psci.o perf.o
> -obj-$(CONFIG_KVM_ARM_VGIC) += $(addprefix $(KVM)/arm/, vgic.o)
> -obj-$(CONFIG_KVM_ARM_TIMER) += $(addprefix $(KVM)/arm/, arch_timer.o)
> diff --git a/virt/Makefile b/virt/Makefile
> new file mode 100644
> index 0000000..c3b9ad0
> --- /dev/null
> +++ b/virt/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_KVM)	+= kvm/
> diff --git a/virt/kvm/Makefile b/virt/kvm/Makefile
> new file mode 100644
> index 0000000..dc87943
> --- /dev/null
> +++ b/virt/kvm/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_KVM_ARM_HOST)	+= arm/
> diff --git a/virt/kvm/arm/Makefile b/virt/kvm/arm/Makefile
> new file mode 100644
> index 0000000..4df943b
> --- /dev/null
> +++ b/virt/kvm/arm/Makefile
> @@ -0,0 +1,2 @@
> +obj-$(CONFIG_KVM_ARM_VGIC) += vgic.o
> +obj-$(CONFIG_KVM_ARM_TIMER) += arch_timer.o
> 

I'm not sure it is a good idea to do this just for ARM, and I think the
patch would look quite different if you were to support x86 (because x86
builds KVM as a module).  So I would hold off this for now.

OTOH, it is a good idea to use the same idiom to access
../../../virt/kvm from the arch directories.  Can you change
x86/PPC/s390/ia64 as well to use $(KVM) instead of $(addprefix)?

Paolo