From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34339) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bCwAR-0005OU-2I for qemu-devel@nongnu.org; Tue, 14 Jun 2016 17:46:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bCwAN-0002FQ-4r for qemu-devel@nongnu.org; Tue, 14 Jun 2016 17:46:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53527) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bCwAM-0002FK-St for qemu-devel@nongnu.org; Tue, 14 Jun 2016 17:46:35 -0400 Date: Tue, 14 Jun 2016 18:46:32 -0300 From: Eduardo Habkost Message-ID: <20160614214632.GD18662@thinpad.lan.raisama.net> References: <1465937948-548-1-git-send-email-ehabkost@redhat.com> <1465937948-548-11-git-send-email-ehabkost@redhat.com> <1990888058.22417362.1465939000140.JavaMail.zimbra@redhat.com> <20160614213103.GB18662@thinpad.lan.raisama.net> <722462862.22421584.1465940322027.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <722462862.22421584.1465940322027.JavaMail.zimbra@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PULL 10/10] target-i386: Print obsolete warnings if +-features are used List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Peter Maydell , Andreas =?iso-8859-1?Q?F=E4rber?= , qemu-devel@nongnu.org, Richard Henderson , Igor Mammedov On Tue, Jun 14, 2016 at 05:38:42PM -0400, Paolo Bonzini wrote: >=20 >=20 > ----- Original Message ----- > > From: "Eduardo Habkost" > > To: "Paolo Bonzini" > > Cc: "Peter Maydell" , "Andreas F=E4rber" , qemu-devel@nongnu.org, "Richard > > Henderson" , "Igor Mammedov" > > Sent: Tuesday, June 14, 2016 11:31:03 PM > > Subject: Re: [PULL 10/10] target-i386: Print obsolete warnings if +-f= eatures are used > >=20 > > On Tue, Jun 14, 2016 at 05:16:40PM -0400, Paolo Bonzini wrote: > > > ----- Original Message ----- > > > > From: "Eduardo Habkost" > > > > To: "Peter Maydell" > > > > Cc: "Andreas F=E4rber" , qemu-devel@nongnu.org,= "Richard > > > > Henderson" , "Paolo > > > > Bonzini" , "Igor Mammedov" > > > > Sent: Tuesday, June 14, 2016 10:59:08 PM > > > > Subject: [PULL 10/10] target-i386: Print obsolete warnings if +-f= eatures > > > > are used > > > >=20 > > > > From: Igor Mammedov > > > >=20 > > > > Signed-off-by: Igor Mammedov > > > > [ehabkost: Changed to use error_report()] > > > > Signed-off-by: Eduardo Habkost > > > > --- > > > > target-i386/cpu.c | 6 ++++++ > > > > 1 file changed, 6 insertions(+) > > > >=20 > > > > diff --git a/target-i386/cpu.c b/target-i386/cpu.c > > > > index 3665fec..baa3783 100644 > > > > --- a/target-i386/cpu.c > > > > +++ b/target-i386/cpu.c > > > > @@ -1980,9 +1980,15 @@ static void x86_cpu_parse_featurestr(CPUSt= ate *cs, > > > > char *features, > > > > /* Compatibility syntax: */ > > > > if (featurestr[0] =3D=3D '+') { > > > > add_flagname_to_bitmaps(featurestr + 1, plus_feature= s, > > > > &local_err); > > > > + error_report( > > > > + "'+%s' is obsolete and will be removed in future= , use > > > > '%s=3Don'", > > > > + featurestr + 1, featurestr + 1); > > > > continue; > > > > } else if (featurestr[0] =3D=3D '-') { > > > > add_flagname_to_bitmaps(featurestr + 1, minus_featur= es, > > > > &local_err); > > > > + error_report( > > > > + "'-%s' is obsolete and will be removed in future= , use > > > > '%s=3Doff'", > > > > + featurestr + 1, featurestr + 1); > > > > continue; > > > > } > > >=20 > > > I still disagree with this change. > >=20 > > I've just removed the patch from the x86-pull-request tag, while > > we sort this out. > >=20 > > Do you suggest supporting the "[+-]feature" syntax forever? >=20 > I suggest supporting it, but removing the awful interaction with "featu= re=3Don/off" > as soon as possible. This shouldn't block this pull request, of course= . I plan to fix the awful ordering semantics. First with a warning for 1 or 2 releases (only when the weird semantics is really triggered), then +feature/-feature could be directly translated to feature=3Don/feature=3Doff. >=20 > I just believe it's not practical to remove the feature. For example > kvm-unit-tests can be used with new kernel and old QEMU, so I don't thi= nk > it will move away from [+-]feature very soon. >=20 > Regarding libvirt, is "feature=3Don/off" introspectable? That would al= so be > a problem for libvirt to support both old and new QEMU. Good point. Removing the feature would require dozens of extra compatibility code to libvirt and kvm-unit-tests just to save 6 lines of code in QEMU. You convinced me. --=20 Eduardo