From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1425388AbeCBOVd (ORCPT ); Fri, 2 Mar 2018 09:21:33 -0500 Received: from mx2.suse.de ([195.135.220.15]:57583 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1425309AbeCBOVc (ORCPT ); Fri, 2 Mar 2018 09:21:32 -0500 Subject: Re: [Xen-devel] [PATCH] xen: use hvc console for dom0 To: Julien Grall , Stefano Stabellini Cc: nd@arm.com, Andrii Anisov , linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, boris.ostrovsky@oracle.com, jbeulich@suse.com References: <20180226110822.13787-1-jgross@suse.com> <0d8bdda5-faef-41da-344a-644b5c3d6006@epam.com> <58e94cc9-9b09-d6b7-3122-fb4c83e97926@suse.com> <19afb9f9-a845-e627-8f78-d1fdb349c6bd@arm.com> From: Juergen Gross Message-ID: <73110605-e3b9-92d2-cc78-56ff8d13b9ea@suse.com> Date: Fri, 2 Mar 2018 15:21:30 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <19afb9f9-a845-e627-8f78-d1fdb349c6bd@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/02/18 21:09, Julien Grall wrote: > Hi, > > On 27/02/2018 20:03, Stefano Stabellini wrote: >> On Tue, 27 Feb 2018, Julien Grall wrote: >>> Hi, >>> >>> On 26/02/18 12:32, Juergen Gross wrote: >>>> On 26/02/18 13:06, Andrii Anisov wrote: >>>>> Hello Juergen, >>>>> >>>>> >>>>> On 26.02.18 13:08, Juergen Gross wrote: >>>>>> Today the hvc console is added as a preferred console for pv domUs >>>>>> only. As this requires a boot parameter for getting dom0 messages per >>>>>> default add it for dom0, too. >>>>>> >>>>>> Signed-off-by: Juergen Gross >>>>>> --- >>>>>>     arch/x86/xen/enlighten_pv.c | 4 +++- >>>>>>     1 file changed, 3 insertions(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/arch/x86/xen/enlighten_pv.c >>>>>> b/arch/x86/xen/enlighten_pv.c >>>>> Is this something x86 specific? Could it be a generic approach? >>>> >>>> In case ARM wants something similar I guess the test for >>>> xen_initial_domain() should be dropped in xen_early_init(). >>> I am pretty sure we discussed to remove !xen_initial_domain() for Arm >>> in the >>> past. But I don't remember why the patch was not sent to remove it. >>> >>> Anyway, I guess this should be fine to have hvc as a preferred >>> console for the >>> initial domain as well. >> >> Usually, Dom0 has access to several physical UARTs and/or VGA, making >> this patch less obviously desirable. I think that for Dom0 the best >> behavior would be to add "hvc0" as first console rather than last >> console, so that if the user specified something else, this call won't >> interfere with it. > > Well, that's exactly the goal of add_preferred_console. It will use hvc0 > unless specified otherwise by the user on the command line. I suggest someone who can test it should post a patch for ARM. Juergen