Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751961AbbLIP1S (ORCPT ); Wed, 9 Dec 2015 10:27:18 -0500 Received: from prv-mh.provo.novell.com ([137.65.248.74]:39676 "EHLO prv-mh.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751352AbbLIP1R convert rfc822-to-8bit (ORCPT ); Wed, 9 Dec 2015 10:27:17 -0500 Message-Id: <5668566202000078000BDB6E@prv-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.2.0 Date: Wed, 09 Dec 2015 08:27:14 -0700 From: "Jan Beulich" To: "Sander Eikelenboom" , "Boris Ostrovsky" Cc: "David Vrabel" , , , , , , , , Subject: Re: [Xen-devel] [PATCH] x86: Xen PV guests don't have the rtc_cmos platform device References: <1449671569-4540-1-git-send-email-boris.ostrovsky@oracle.com> <56684BD402000078000BDB00@prv-mh.provo.novell.com> <745827c24ef5e59808d725d5777b5698@eikelenboom.it> <56684595.4040402@oracle.com> In-Reply-To: <56684595.4040402@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1427 Lines: 43 >>> On 09.12.15 at 16:15, wrote: > On 12/09/2015 10:00 AM, Sander Eikelenboom wrote: >> On 2015-12-09 15:42, Jan Beulich wrote: >>>>>> On 09.12.15 at 15:32, wrote: >>>> --- a/arch/x86/kernel/rtc.c >>>> +++ b/arch/x86/kernel/rtc.c >>>> @@ -200,6 +200,9 @@ static __init int add_rtc_cmos(void) >>>> } >>>> #endif >>>> >>>> + if (paravirt_enabled()) >>>> + return -ENODEV; >>> >>> What about Xen Dom0? >>> >>> Jan >> >> Checked that in my testing and that still worked: >> [ 16.733837] rtc_cmos 00:02: RTC can wake from S4 >> [ 16.734030] rtc_cmos 00:02: rtc core: registered rtc_cmos as rtc0 >> [ 16.734087] rtc_cmos 00:02: alarms up to one month, y3k, 114 bytes >> nvram >> [ 17.760329] rtc_cmos 00:02: setting system clock to 2015-12-09 >> 08:43:48 UTC (1449650628) >> >> and /dev/rtc and /dev/rtc0 both exist. >> >> But i don't know the nitty gritty details about why ... > > > That's because it is discovered by ACPI earlier. I don't know though > whether we can always assume this will be the case. I don't think we should - Dom0 should (device-wise) behave just like a native kernel. Jan -- 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/