From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [RFC PATCH 0/2] ARM: KVM: Moving GIC/timer out of arch/arm Date: Sun, 12 May 2013 12:03:59 +0300 Message-ID: <20130512090359.GE10830@redhat.com> References: <1367589773-5609-1-git-send-email-marc.zyngier@arm.com> <5183DDD5.6000202@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Anup Patel , linux-arm-kernel , "kvmarm@lists.cs.columbia.edu" , "kvm@vger.kernel.org" , Christoffer Dall , Catalin Marinas To: Marc Zyngier Return-path: Received: from mx1.redhat.com ([209.132.183.28]:32411 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751958Ab3ELJEs (ORCPT ); Sun, 12 May 2013 05:04:48 -0400 Content-Disposition: inline In-Reply-To: <5183DDD5.6000202@arm.com> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, May 03, 2013 at 04:55:01PM +0100, Marc Zyngier wrote: > On 03/05/13 16:31, Anup Patel wrote: > > On Fri, May 3, 2013 at 7:32 PM, Marc Zyngier wrote: > >> As KVM/arm64 is looming on the horizon, it makes sense to move some > >> of the common code to a single location in order to reduce duplication. > >> > >> The code could live anywhere. Actually, most of KVM is already built > >> with a bunch of ugly ../../.. hacks in the various Makefiles, so we're > >> not exactly talking about style here. But maybe it is time to start > >> moving into a less ugly direction. > >> > >> The include files must be in a "public" location, as they are accessed > >> from non-KVM files (arch/arm/kernel/asm-offsets.c). > >> > >> For this purpose, introduce two new locations: > >> - virt/kvm/arm/ : x86 and ia64 already share the ioapic code in > >> virt/kvm, so this could be seen as a (very ugly) precedent. > >> - include/kvm/ : there is already an include/xen, and while the > >> intent is slightly different, this seems as good a location as > >> any > >> > >> Once the code has been moved, it becomes easy to build it in a > >> less hackish way, which makes the code easily reusable by KVM/arm64. > >> > >> Marc Zyngier (2): > >> ARM: KVM: move GIC/timer code to a common location > >> ARM: KVM: standalone Makefile for vgic and timers > >> > >> Makefile | 2 +- > >> arch/arm/include/asm/kvm_host.h | 4 ++-- > >> arch/arm/kvm/Makefile | 5 ++--- > >> {arch/arm/include/asm => include/kvm}/kvm_arch_timer.h | 0 > >> {arch/arm/include/asm => include/kvm}/kvm_vgic.h | 0 > >> virt/Makefile | 1 + > >> virt/kvm/Makefile | 1 + > >> virt/kvm/arm/Makefile | 2 ++ > >> {arch/arm/kvm => virt/kvm/arm}/arch_timer.c | 4 ++-- > >> {arch/arm/kvm => virt/kvm/arm}/vgic.c | 0 > >> 10 files changed, 11 insertions(+), 8 deletions(-) > >> rename {arch/arm/include/asm => include/kvm}/kvm_arch_timer.h (100%) > >> rename {arch/arm/include/asm => include/kvm}/kvm_vgic.h (100%) > >> create mode 100644 virt/Makefile > >> create mode 100644 virt/kvm/Makefile > >> create mode 100644 virt/kvm/arm/Makefile > >> rename {arch/arm/kvm => virt/kvm/arm}/arch_timer.c (99%) > >> rename {arch/arm/kvm => virt/kvm/arm}/vgic.c (100%) > >> > >> -- > >> 1.8.2.1 > >> > >> > >> > >> _______________________________________________ > >> kvmarm mailing list > >> kvmarm@lists.cs.columbia.edu > >> https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm > > > > The source files arch/arm/kvm/arm.c and arch/arm/kvm/mmu.c are also > > shared between KVM ARM and KVM ARM64. > > > > Can we move these files in virt/arm ? > > I suggest we start by finding out if there is an agreement on the > location, method and overall usefulness of this particular patch. > > Moving core ARM code around is quite different from sharing what is > basically device emulation stuff. > Yes, so the question in this regard: are there any plans to eventually merge arch/arm and arch/arm64 like it happened with arch/i386 and arch/x86_64? Is it even feasible? Looking at the dark days of i386/x86_64 split there were a lot of ../../i386/ and -Iarch/i386/kernel in arch/x86_64. Isn't there some code, outside of kvm, that can be shared between arm/arm64? How will it be shared? -- Gleb.