From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDC5FC432C0 for ; Thu, 28 Nov 2019 13:06:08 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8FCF22176D for ; Thu, 28 Nov 2019 13:06:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TtUaBPmb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8FCF22176D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48926 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaJUl-00039X-LC for qemu-devel@archiver.kernel.org; Thu, 28 Nov 2019 08:06:07 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:39658) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaJEz-0001Lh-8J for qemu-devel@nongnu.org; Thu, 28 Nov 2019 07:49:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iaJEu-0007XB-Mu for qemu-devel@nongnu.org; Thu, 28 Nov 2019 07:49:46 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:44972 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iaJEt-0007Lg-4J for qemu-devel@nongnu.org; Thu, 28 Nov 2019 07:49:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574945377; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UWbEwNE5dX/q4JlmKwilYeuVLjux593GL+hLmoBhNAw=; b=TtUaBPmb4svF2R8ww3qyRT/cck/QXV5YNvOHLNdsT9AXlbxbu9UoLXGEnXY4JMuD07dzN4 TGr4xeTI2N5GVMlK4nGFSIoOgETKP1WUbf/olUDPVFypJrtaJrq0CQVK7h23i+QPmCyy4X cl0dbtJ2zXeST6s5uTS0+C4sCkHj7lo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-340-kbC3U64HPNeBtW8iiogvvg-1; Thu, 28 Nov 2019 07:49:36 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C1178107ACC7; Thu, 28 Nov 2019 12:49:35 +0000 (UTC) Received: from gondolin (ovpn-116-200.ams2.redhat.com [10.36.116.200]) by smtp.corp.redhat.com (Postfix) with ESMTP id DF84560BE1; Thu, 28 Nov 2019 12:49:34 +0000 (UTC) Date: Thu, 28 Nov 2019 13:49:32 +0100 From: Cornelia Huck To: "Daniel P. =?UTF-8?B?QmVycmFuZ8Op?=" Subject: Re: [PATCH RFC] qga: fence guest-set-time if hwclock not available Message-ID: <20191128134932.5ef30a30.cohuck@redhat.com> In-Reply-To: <20191128124532.GF248361@redhat.com> References: <20191128123658.28351-1-cohuck@redhat.com> <20191128124532.GF248361@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: kbC3U64HPNeBtW8iiogvvg-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michael Roth , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 28 Nov 2019 12:45:32 +0000 Daniel P. Berrang=C3=A9 wrote: > On Thu, Nov 28, 2019 at 01:36:58PM +0100, Cornelia Huck wrote: > > The Posix implementation of guest-set-time invokes hwclock to > > set/retrieve the time to/from the hardware clock. If hwclock > > is not available, the user is currently informed that "hwclock > > failed to set hardware clock to system time", which is quite > > misleading. This may happen e.g. on s390x, which has a different > > timekeeping concept anyway. > >=20 > > Let's check for the availability of the hwclock command and > > return QERR_UNSUPPORTED for guest-set-time if it is not available. > >=20 > > Signed-off-by: Cornelia Huck > > --- > >=20 > > Not sure if that is the correct approach, but the current error > > message is really quite confusing. =20 >=20 > I guess the alternative is to just #ifndef __s390x__ the whole > impl of the qmp_guest_set_time method, but I don't have a > strong opinion on which is best. This hardcodes this as a s390x specialty, though, and I'm not sure that assumption is and will stay correct. >=20 > >=20 > > Gave it a quick test with an s390x and an x86_64 guest; invoking > > 'virsh domtime ' now fails with 'not currently supported' > > on s390x and continues to work as before on x86_64. > >=20 > > --- > > qga/commands-posix.c | 20 +++++++++++++++++++- > > 1 file changed, 19 insertions(+), 1 deletion(-) > >=20 > > diff --git a/qga/commands-posix.c b/qga/commands-posix.c > > index 1c1a165daed8..bd298a38b716 100644 > > --- a/qga/commands-posix.c > > +++ b/qga/commands-posix.c > > @@ -149,6 +149,13 @@ int64_t qmp_guest_get_time(Error **errp) > > return tq.tv_sec * 1000000000LL + tq.tv_usec * 1000; > > } > > =20 > > +static int check_hwclock_available(const char *path) > > +{ > > + struct stat st; > > + > > + return (stat(path, &st) < 0) ? 0 : 1; > > +} > > + > > void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp) > > { > > int ret; > > @@ -156,6 +163,17 @@ void qmp_guest_set_time(bool has_time, int64_t tim= e_ns, Error **errp) > > pid_t pid; > > Error *local_err =3D NULL; > > struct timeval tv; > > + const char *hwclock_path =3D "/sbin/hwclock"; > > + static int hwclock_available =3D -1; > > + > > + if (hwclock_available < 0) { > > + hwclock_available =3D check_hwclock_available(hwclock_path); = =20 >=20 > Could do this inline with: >=20 > hwclock_available =3D (access(hwclock_available, X_OK) =3D=3D 0); >=20 > getting a slightly better result as this check for it being > executable as well as existing. Yes, that looks better. Can do if we agree on this approach. >=20 > > + } > > + > > + if (!hwclock_available) { > > + error_setg(errp, QERR_UNSUPPORTED); > > + return; > > + } > > =20 > > /* If user has passed a time, validate and set it. */ > > if (has_time) { > > @@ -195,7 +213,7 @@ void qmp_guest_set_time(bool has_time, int64_t time= _ns, Error **errp) > > =20 > > /* Use '/sbin/hwclock -w' to set RTC from the system time, > > * or '/sbin/hwclock -s' to set the system time from RTC. */ > > - execle("/sbin/hwclock", "hwclock", has_time ? "-w" : "-s", > > + execle(hwclock_path, "hwclock", has_time ? "-w" : "-s", > > NULL, environ); > > _exit(EXIT_FAILURE); > > } else if (pid < 0) { > > --=20 > > 2.21.0 > >=20 > > =20 >=20 > Regards, > Daniel