Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031495AbXHMRfk (ORCPT ); Mon, 13 Aug 2007 13:35:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S973748AbXHMRb7 (ORCPT ); Mon, 13 Aug 2007 13:31:59 -0400 Received: from nf-out-0910.google.com ([64.233.182.184]:47480 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S973738AbXHMRb4 (ORCPT ); Mon, 13 Aug 2007 13:31:56 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=rqyeuoF8xXQw4qmPfdTK2GSN5ZmLvJcM6K6kcyElMQiVQ2hNi+mNvks9d/GDVeCR1vMxumSOHTF4ACJ0gbximEL1ncn4hzlXF9CqxWX6HGvfS1SkBU1Mnu6HdESTOjK7XHAOEMs1tXSqaoxRwPl7ticE6+/bYV8W37jKNJ+a3Xo= Message-ID: Date: Mon, 13 Aug 2007 23:01:53 +0530 From: "Satyam Sharma" To: "Avi Kivity" Subject: Re: kvm warning Cc: "Andrew Morton" , "Ingo Molnar" , kvm-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, tony.luck@intel.com In-Reply-To: <46BA4D12.8090301@qumranet.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20070808151446.9a4eebda.akpm@linux-foundation.org> <20070808221956.GA16238@elte.hu> <46BA4827.3080907@qumranet.com> <20070808155901.bcb249d9.akpm@linux-foundation.org> <46BA4D12.8090301@qumranet.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2328 Lines: 56 On 8/9/07, Avi Kivity wrote: > Andrew Morton wrote: > > On Thu, 09 Aug 2007 01:48:07 +0300 > > Avi Kivity wrote: > > > >> Ingo Molnar wrote: > >> > >>> * Andrew Morton wrote: > >>> > >>>> ia64 allmodconfig says > >>>> > >>>> drivers/kvm/Kconfig:14:warning: 'select' used by config symbol 'KVM' > >>>> refers to undefined symbol 'PREEMPT_NOTIFIERS' > >>>> > >>> hm, why doesnt ia64 pick up kernel/Kconfig.preempt, like all the other > >>> arches? Due to that ia64 also misses out on voluntary preempt and on > >>> preempt-bkl. > >>> > >> Even more hm, how does ia64 manage to enable kvm? It 'depends on X86' > >> at this moment. > > > > beats me. CONFIG_KVM doesn't get set. But it seems that kconfig wants > > to do error-checking on that item anyway. > > I could do a 'select PREEMPT_NOTIFIERS if X86' but it seems silly. I'd > call it a Kconfig bug. I remember this issue well [1] ... it's a Kconfig deficiency indeed. Basically kconfig options for generic stuff cannot use "select" for symbols that are defined only for specific archs (here ia64 synthetically created this situation by failing to source "kernel/Kconfig.preempt" in its arch/ia64/Kconfig). Leads to no real build problems, but causes these bogus warnings to be printed on other archs (that don't have that symbol visible to them). Possible solutions could be to (1) source "kernel/Kconfig.preempt" from arch/ia64/Kconfig, or (2) Use "default y if KVM" for PREEMPT_NOTIFIERS (but this would be kludgy, horrible and tasteless). I'm not sure if "select PREEMPT_NOTIFIERS if X86" would cut it to get rid of the bogus warnings, though. Solution (1) above sounds preferable, unless there are mysterious reasons why ia64 wants to avoid Kconfig.preempt (adding Tony Luck to Cc:). Satyam [1] Last time this happened was with something called ATARI_KBD_CORE. I submitted a patch that unfortunately degenerated into a flamewar :-) The bogus warnings remained (causing more traffic) for a month or so, before an alternate solution got finally merged. - 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/