From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756597Ab2IQObQ (ORCPT ); Mon, 17 Sep 2012 10:31:16 -0400 Received: from smtp.eu.citrix.com ([62.200.22.115]:27899 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756416Ab2IQObP (ORCPT ); Mon, 17 Sep 2012 10:31:15 -0400 X-IronPort-AV: E=Sophos;i="4.80,435,1344211200"; d="scan'208";a="14583396" Date: Mon, 17 Sep 2012 15:30:28 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Stefano Stabellini CC: Sergei Shtylyov , "arnd@arndb.de" , "xen-devel@lists.xensource.com" , "linaro-dev@lists.linaro.org" , Ian Campbell , "konrad.wilk@oracle.com" , "catalin.marinas@arm.com" , "Tim (Xen.org)" , "linux-kernel@vger.kernel.org" , "linux@arm.linux.org.uk" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v4 12/24] xen/arm: introduce CONFIG_XEN on ARM In-Reply-To: Message-ID: References: <1347621207-11294-12-git-send-email-stefano.stabellini@eu.citrix.com> <505374E2.5080308@mvista.com> <50571289.3040509@mvista.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 17 Sep 2012, Stefano Stabellini wrote: > On Mon, 17 Sep 2012, Sergei Shtylyov wrote: > > Hello. > > > > On 17-09-2012 14:57, Stefano Stabellini wrote: > > > > >>> Changes in v2: > > > > >>> - mark Xen guest support on ARM as EXPERIMENTAL. > > > > >>> Signed-off-by: Stefano Stabellini > > >>> Acked-by: Konrad Rzeszutek Wilk > > >>> --- > > >>> arch/arm/Kconfig | 10 ++++++++++ > > >>> 1 files changed, 10 insertions(+), 0 deletions(-) > > > > >>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > > >>> index 2f88d8d..e92518d 100644 > > >>> --- a/arch/arm/Kconfig > > >>> +++ b/arch/arm/Kconfig > > >>> @@ -1897,6 +1897,16 @@ config DEPRECATED_PARAM_STRUCT > > >>> This was deprecated in 2001 and announced to live on for 5 years. > > >>> Some old boot loaders still use this way. > > >>> > > >>> +config XEN_DOM0 > > >>> + def_bool y > > >>> + > > >>> +config XEN > > >>> + bool "Xen guest support on ARM (EXPERIMENTAL)" > > >>> + depends on EXPERIMENTAL && ARM && OF > > >>> + select XEN_DOM0 > > > > >> What's the point of selecting it if it's always "y"? > > > > > That's because on X86 is not always "y": there are things under > > > drivers/xen that compile on both platforms and depend on XEN_DOM0. > > > > But we're not on x86. On ARM this select is pointless. > > We need some common code (under drivers/xen) that compiles only if > XEN_DOM0 is selected, so it is not pointless after all. > > XEN_DOM0 is not the only symbol that is conditionally compiled on one > architectuire and always "y" on another... > Wait a sec, I have just realized that written this way XEN_DOM0 is always "y", even if XEN is not! The right way of doing this is: config XEN_DOM0 def_bool y depends on XEN config XEN bool "Xen guest support on ARM (EXPERIMENTAL)" depends on EXPERIMENTAL && ARM && OF help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. I am not sure if this is what you meant, but thanks for making me realize this mistake anyway! :)