Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932329Ab2JJQB5 (ORCPT ); Wed, 10 Oct 2012 12:01:57 -0400 Received: from smtp.ctxuk.citrix.com ([62.200.22.115]:27333 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752483Ab2JJQB4 (ORCPT ); Wed, 10 Oct 2012 12:01:56 -0400 X-IronPort-AV: E=Sophos;i="4.80,565,1344211200"; d="scan'208";a="15080299" Date: Wed, 10 Oct 2012 17:01:26 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Ian Campbell CC: Stefano Stabellini , Arnd Bergmann , Jeremy Fitzhardinge , "xen-devel@lists.xensource.com" , Konrad Rzeszutek Wilk , "linux-kernel@vger.kernel.org" , Russell King , "linux-arm-kernel@lists.infradead.org" Subject: Re: [Xen-devel] [PATCH 5/9] ARM: Xen: fix initial build problems: In-Reply-To: <1349880826.10070.41.camel@zakaz.uk.xensource.com> Message-ID: References: <1349796183-30648-1-git-send-email-arnd@arndb.de> <1349796183-30648-6-git-send-email-arnd@arndb.de> <201210091821.27818.arnd@arndb.de> <1349855687.6952.75.camel@dagon.hellion.org.uk> <1349880826.10070.41.camel@zakaz.uk.xensource.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 Content-Length: 2405 Lines: 50 On Wed, 10 Oct 2012, Ian Campbell wrote: > On Wed, 2012-10-10 at 15:47 +0100, Stefano Stabellini wrote: > > On Wed, 10 Oct 2012, Ian Campbell wrote: > > > On Tue, 2012-10-09 at 19:21 +0100, Arnd Bergmann wrote: > > > > On Tuesday 09 October 2012, Stefano Stabellini wrote: > > > > > > config XEN > > > > > > bool "Xen guest support on ARM (EXPERIMENTAL)" > > > > > > depends on EXPERIMENTAL && ARM && OF > > > > > > + depends on !CPU_V6 > > > > > > help > > > > > > Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. > > > > > > > > > > Considering that we rely on the virtualization extensions, this one can > > > > > be: > > > > > > > > > > depends on CPU_V7 > > > > > > > > > > The rest looks fine. I can submit a second patch to change !CPU_V6 into > > > > > CPU_V7 later, if you prefer. > > > > > > > > CPU_V6 and CPU_V7 are not exclusive, I saw the problem when building a > > > > combined kernel for both V6 and V7. The code also needs to depend on ARMv7 > > > > with virtualization extensions, but that is a different issue. We don't > > > > actually have a configuration symbol for that yet, as far as I can tell. > > > > > > I don't think the guest kernels (including dom0) need the extensions to > > > run under Xen, they are only need by Xen itself. The guests should just > > > see a relatively normal v7 processor. > > > > > > Stefano, does that sound right? > > > > Keep in mind that we are using HVC to issue hypercalls, and HVC has been > > introduced with the virtualization extensions, if I am not mistaken. > > I think we can ignore that in this context since it is only used by bits > which are already virtualisation aware -- i.e. you wouldn't want to add > it to the Kconfig as a dependency for Xen. Considering that ARM CPU_V* symbols are not mutually exclusive, if Linux had a CPU_V7_VIRTEXT symbol I don't see why we shouldn't add it to our list of dependencies. It is more accurate than CPU_V7 after all. But I don't think that it is necessary to introduce one now only for Xen, because like you said, we only need HVC and that is only used in virtualization aware code. -- 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/