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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 9732CC2BD09 for ; Thu, 5 Dec 2019 14:29:13 +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 663A724651 for ; Thu, 5 Dec 2019 14:29:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Y/mb4+bJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 663A724651 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]:55380 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ics80-0005xY-IX for qemu-devel@archiver.kernel.org; Thu, 05 Dec 2019 09:29:12 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:38205) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ics17-0006ku-M8 for qemu-devel@nongnu.org; Thu, 05 Dec 2019 09:22:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ics15-0007az-6r for qemu-devel@nongnu.org; Thu, 05 Dec 2019 09:22:05 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:48089) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ics12-0007Z8-V8 for qemu-devel@nongnu.org; Thu, 05 Dec 2019 09:22:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575555719; 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=6Vr0Gig3Nbjr/9Im+n7OJHPEbRRkSiW7mNmtuEC70fo=; b=Y/mb4+bJxkPNpT7BJ69rmOQ6EdlegafD9rsiz6gtifRPAL8bjmyVEAzh2DupbWBBzvFiTe 4VOgjiVgytB+3JJs2njDl9dtTosCsDFEOyZERXdOQfHzwV/8itrkh5cT2Uz7vfNARSQ3oX O4HVTQWTzhQ1ZNrAdz1cqJshmF+otbE= 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-2-6s-N3LCCPSOmN3yqtK1ETQ-1; Thu, 05 Dec 2019 09:21:58 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7C54F1005514; Thu, 5 Dec 2019 14:21:57 +0000 (UTC) Received: from [10.43.2.30] (unknown [10.43.2.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 14D135C1B5; Thu, 5 Dec 2019 14:21:53 +0000 (UTC) Subject: Re: [PATCH v3] qga: fence guest-set-time if hwclock not available To: Cornelia Huck , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= References: <20191205115350.18713-1-cohuck@redhat.com> <5aaa7f3a-e3d1-0057-5fe2-07dea4864bc7@redhat.com> <20191205141212.6cb05ac7.cohuck@redhat.com> From: Michal Privoznik Message-ID: <189346a8-62f1-02d1-00e4-23d2485646cd@redhat.com> Date: Thu, 5 Dec 2019 15:21:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20191205141212.6cb05ac7.cohuck@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-MC-Unique: 6s-N3LCCPSOmN3yqtK1ETQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8; format=flowed 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: Laszlo Ersek , =?UTF-8?Q?Daniel_P_=2e_Berrang=c3=a9?= , Michael Roth , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 12/5/19 2:12 PM, Cornelia Huck wrote: > On Thu, 5 Dec 2019 14:05:19 +0100 > Philippe Mathieu-Daud=C3=A9 wrote: >=20 >> Hi Cornelia, >> >> On 12/5/19 12:53 PM, 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. >>> >>> Let's check for the availability of the hwclock command and >>> return QERR_UNSUPPORTED for guest-set-time if it is not available. >>> >>> Reviewed-by: Laszlo Ersek >>> Reviewed-by: Daniel P. Berrang=C3=A9 >>> Reviewed-by: Michael Roth >>> Signed-off-by: Cornelia Huck >>> --- >>> >>> v2->v3: >>> - added 'static' keyword to hwclock_path >>> >>> Not sure what tree this is going through; if there's no better place, >>> I can also take this through the s390 tree. >> >> s390 or trivial trees seems appropriate. >> >>> >>> --- >>> qga/commands-posix.c | 13 ++++++++++++- >>> 1 file changed, 12 insertions(+), 1 deletion(-) >>> >>> diff --git a/qga/commands-posix.c b/qga/commands-posix.c >>> index 1c1a165daed8..0be301a4ea77 100644 >>> --- a/qga/commands-posix.c >>> +++ b/qga/commands-posix.c >>> @@ -156,6 +156,17 @@ 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; >>> + static const char hwclock_path[] =3D "/sbin/hwclock"; >>> + static int hwclock_available =3D -1; >>> + >>> + if (hwclock_available < 0) { >>> + hwclock_available =3D (access(hwclock_path, X_OK) =3D=3D 0); >>> + } >>> + >>> + if (!hwclock_available) { >>> + error_setg(errp, QERR_UNSUPPORTED); >> >> In include/qapi/qmp/qerror.h we have: >> >> /* >> * These macros will go away, please don't use in new code, and do not >> * add new ones! >> */ >=20 > Sigh, it is really hard to keep track here :( I just copied from other > callers in this file... >=20 >> >> Maybe we can replace it by "this feature is not supported on this >> architecture"? (or without 'on this architecture'). >=20 > This is not really architecture specific, you'd get this on any setup > that does not have /sbin/hwclock. >=20 > Q: Is libvirt doing anything with such an error message from QEMU? Do > we have the freedom to say e.g "guest-set-time is not supported" or so? > Or is it beneficial to print the same error message for any unsupported > feature? No. Libvirt threats error messages as an opaque data. In a few cases we=20 check for the class of the error and for instance issue a different=20 command if class was CommandNotFound. You are free to change error=20 messages as you wish. Note that this is not true for HMP - there libvirt does some parsing to=20 figure out the source of error. For instance: https://libvirt.org/git/?p=3Dlibvirt.git;a=3Dblob;f=3Dsrc/qemu/qemu_monitor= _text.c;h=3D9054682d608b13347880f36cacd0e023151322e6;hb=3DHEAD#l36 Michal