Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758874Ab2JKQdz (ORCPT ); Thu, 11 Oct 2012 12:33:55 -0400 Received: from ch1ehsobe002.messaging.microsoft.com ([216.32.181.182]:17859 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758142Ab2JKQdv convert rfc822-to-8bit (ORCPT ); Thu, 11 Oct 2012 12:33:51 -0400 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: -4 X-BigFish: VS-4(zzbb2dI98dI9371I1432Izz1202h1d1ah1d2ahzzz2dh2a8h668h839h944hd2bhf0ah107ah1288h12a5h12a9h12bdh137ah139eh13b6h1441h1155h) Date: Thu, 11 Oct 2012 11:33:31 -0500 From: Scott Wood Subject: Re: linux-next: manual merge of the kvm-ppc tree with the powerpc-merge tree To: Alexander Graf CC: Tabi Timur-B04825 , Stephen Rothwell , "linux-kernel@vger.kernel.org" , David Howells , "linux-next@vger.kernel.org" , Paul Mackerras , "linuxppc-dev@lists.ozlabs.org" References: <1349970603.6903.2@snotra> In-Reply-To: (from agraf@suse.de on Thu Oct 11 10:56:51 2012) X-Mailer: Balsa 2.4.11 Message-ID: <1349973211.6903.3@snotra> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; delsp=Yes; format=Flowed Content-Disposition: inline Content-Transfer-Encoding: 8BIT X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2126 Lines: 54 On 10/11/2012 10:56:51 AM, Alexander Graf wrote: > > On 11.10.2012, at 17:50, Scott Wood wrote: > > > On 10/11/2012 08:04:58 AM, Alexander Graf wrote: > >> On 11.10.2012, at 05:32, Tabi Timur-B04825 wrote: > >> > On Wed, Oct 10, 2012 at 9:47 PM, Stephen Rothwell > wrote: > >> > > >> >> Commit 549d62d889b4 ("KVM: PPC: use definitions in epapr header > >> >> for hcalls") from the kvm-ppc tree added an include of > asm/epapr_hcall.h > >> >> to the user visible part of asm/kvm_para.h so asm/epapr_hcall.h > became a > >> >> user visible header file. > >> > > >> > Any real user-space code that tries to call any of the functions > in > >> > epapr_hcall.h will cause an exception. > > > > Actually it'll cause a linker error, as of the "Don't use hardcoded > opcode for ePAPR hcall invocation" patch. > > > >> > Claiming that kernel header files that KVM needs are suddenly > >> > user-space header files doesn't make much sense to me, but I > guess > >> > it's not my decision. > >> This is about kvm_host.h, which is the part that is exported to > user space. It usually contains constants and structs that are > required for the API. > > > > s/kvm_host/kvm_para/ > > > > I'm not sure anything in kvm_para.h or epapr_hcalls.h would be of > use to userspace, but it would be of use to the guest OS, so it's > still not kernel-internal. > > > > The variable externs should be #ifdef __KERNEL__ as David points > out. The asm stuff could still be useful in a guest OS if the guest > provides epapr_hypercall_start. > > I don't think we should worry about guest kernel code potentially > having use for this. Let's make the user space headers be great for > user space usage, not for guest code usage :). Well, that asm stuff started out as a guest header (from Freescale's Topaz hypervisor), not a Linux header. :-) -Scott -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/