Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162643Ab3DETgL (ORCPT ); Fri, 5 Apr 2013 15:36:11 -0400 Received: from mail-qc0-f182.google.com ([209.85.216.182]:59678 "EHLO mail-qc0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162615Ab3DETgK (ORCPT ); Fri, 5 Apr 2013 15:36:10 -0400 Date: Fri, 5 Apr 2013 15:36:06 -0400 (EDT) From: Nicolas Pitre To: Stefano Stabellini cc: "xen-devel@lists.xensource.com" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "will.deacon@arm.com" , "arnd@arndb.de" , "rob.herring@calxeda.com" Subject: Re: [PATCH v6 4/4] xen/arm: introduce xen_early_init, use PSCI on xen In-Reply-To: Message-ID: References: <1365167495-18508-4-git-send-email-stefano.stabellini@eu.citrix.com> User-Agent: Alpine 2.03 (LFD 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: 1424 Lines: 44 On Fri, 5 Apr 2013, Stefano Stabellini wrote: > This is what happens: > > - No Xen > Xen is not running on the platform and a Xen hypervisor node is not > available on device tree. > Everything keeps working seamlessly, this patch doesn't change anything. > > - we are running on Xen > Xen is running on the platform, we are running as a guest on Xen and an > hypervisor node is available on device tree. > Let's also assume that there aren't any "arm,cci" compatible nodes on > device tree because Xen wouldn't export this kind of information to any > guests right now. Therefore PSCI should be used to boot secondary cpus. > Because the versatile express machine sets smp_init to > vexpress_smp_init_ops, vexpress_smp_init_ops will be called. > vexpress_smp_init_ops sets smp_ops to vexpress_smp_ops, that *break* > Xen. OK I see. > With this patch, xen_smp_init will be called instead of > vexpress_smp_init_ops, and smp_ops will be set to psci_smp_ops, > therefore *unbreaking* Xen. However that breaks MCPM. > In fact what makes this patch really necessary is smp_init together with > the MCPM series. Yes. > Do you agree with me? On the Xen issue, yes. Nicolas -- 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/