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=-8.3 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,URIBL_BLOCKED, 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 3D630C432C0 for ; Thu, 28 Nov 2019 15:30:14 +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 076E421787 for ; Thu, 28 Nov 2019 15:30:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="DEmV5kO1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 076E421787 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]:50048 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaLkD-0007aE-79 for qemu-devel@archiver.kernel.org; Thu, 28 Nov 2019 10:30:13 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:54869) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaKzH-0000f8-Gk for qemu-devel@nongnu.org; Thu, 28 Nov 2019 09:41:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iaKzF-0002am-FA for qemu-devel@nongnu.org; Thu, 28 Nov 2019 09:41:43 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:56226 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iaKzD-0002YC-DB for qemu-devel@nongnu.org; Thu, 28 Nov 2019 09:41:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574952097; h=from:from:reply-to: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=1al+xMBUfe+lICix5Ut5ftQ/McBHfOm5pQqkihlKVpY=; b=DEmV5kO1Fa+Z3g0xe7F5fvHHRzCGAmLsGb8zHgE6J6Dl6vmNLPOoPq0dUmY+cR7T1BATBd qecr58H9envsfCQati7YKwcF+P48lqFvnwXjj7D2+IE8ziTRKALdo5rNnsCfHJBsK5RUNG BCZs39jRhPQGLo7mugFXwalYb45a9n0= 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-19-sd1dqDbiNZ-rxIhJfVN5YA-1; Thu, 28 Nov 2019 09:41:33 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 600201005514; Thu, 28 Nov 2019 14:41:32 +0000 (UTC) Received: from redhat.com (unknown [10.42.16.105]) by smtp.corp.redhat.com (Postfix) with ESMTPS id ADD35608B9; Thu, 28 Nov 2019 14:41:31 +0000 (UTC) Date: Thu, 28 Nov 2019 14:41:29 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Cornelia Huck Subject: Re: [PATCH RFC] qga: fence guest-set-time if hwclock not available Message-ID: <20191128144129.GL248361@redhat.com> References: <20191128123658.28351-1-cohuck@redhat.com> <20191128124532.GF248361@redhat.com> <20191128134932.5ef30a30.cohuck@redhat.com> MIME-Version: 1.0 In-Reply-To: <20191128134932.5ef30a30.cohuck@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: sd1dqDbiNZ-rxIhJfVN5YA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Michael Roth , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Nov 28, 2019 at 01:49:32PM +0100, Cornelia Huck wrote: > On Thu, 28 Nov 2019 12:45:32 +0000 > Daniel P. Berrang=C3=A9 wrote: >=20 > > 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. >=20 > This hardcodes this as a s390x specialty, though, and I'm not sure that > assumption is and will stay correct. >=20 > >=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 t= ime_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. >=20 > Yes, that looks better. Can do if we agree on this approach. I'm fine with this Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberrange= :| |: https://libvirt.org -o- https://fstop138.berrange.com= :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange= :|