From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:53591) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hCKld-0008LM-Fw for qemu-devel@nongnu.org; Fri, 05 Apr 2019 05:04:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hCKjt-0003BT-MZ for qemu-devel@nongnu.org; Fri, 05 Apr 2019 05:02:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60544) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hCKjt-0003AY-3d for qemu-devel@nongnu.org; Fri, 05 Apr 2019 05:02:21 -0400 Date: Fri, 5 Apr 2019 10:02:12 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Message-ID: <20190405090212.GF6105@redhat.com> Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20190404185730.GA22512@ls3530.dellerweb.de> <068f4832-7e0b-8850-ffa0-fcf1ecd50295@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <068f4832-7e0b-8850-ffa0-fcf1ecd50295@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] configure: Automatically fall back to TCI on non-release architectures List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Cc: Helge Deller , Peter Maydell , Michael Tokarev , Samuel Thibault , QEMU Developers , Aurelien Jarno On Fri, Apr 05, 2019 at 10:47:54AM +0200, Philippe Mathieu-Daud=C3=A9 wro= te: > Hi Helge, >=20 > On 4/5/19 9:56 AM, Helge Deller wrote: > > On 05.04.19 03:34, Peter Maydell wrote: > >> On Fri, 5 Apr 2019 at 01:59, Helge Deller wrote: > >>> If a non-release architecture is found, and it's known that there i= s no > >>> native TCG support for that CPU, automatically fall back to the TCI > >>> implementation instead of requesting the user to run configure agai= n > >>> with the --enable-tcg-interpreter option. > >>> > >>> This change simplifies building qemu in automatic build environment= s > >>> (like in my case the debian buildds) because one does not need to > >>> special case on the architectures. > >> > >> I don't think we should do this. TCI is unmaintained, has several > >> known flaws, > >=20 > > Just out of interest: Is there a list with those flaws somewhere? >=20 > The last big discussion is in this thread: > https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg06528.html Do the various crashes that you illustrate in that cover letter still exist today ? If so, 2 years of continued brokenness with no fixes would reinforce the the view that it is time to remove TCI from the codebase. Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| |: https://libvirt.org -o- https://fstop138.berrange.c= om :| |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :| 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=-2.3 required=3.0 tests=FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 784B4C4360F for ; Fri, 5 Apr 2019 09:05:52 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 47F2821738 for ; Fri, 5 Apr 2019 09:05:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 47F2821738 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 ([127.0.0.1]:38386 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hCKnH-000133-FL for qemu-devel@archiver.kernel.org; Fri, 05 Apr 2019 05:05:51 -0400 Received: from eggs.gnu.org ([209.51.188.92]:53591) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hCKld-0008LM-Fw for qemu-devel@nongnu.org; Fri, 05 Apr 2019 05:04:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hCKjt-0003BT-MZ for qemu-devel@nongnu.org; Fri, 05 Apr 2019 05:02:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60544) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hCKjt-0003AY-3d for qemu-devel@nongnu.org; Fri, 05 Apr 2019 05:02:21 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 2AD6530018C2; Fri, 5 Apr 2019 09:02:20 +0000 (UTC) Received: from redhat.com (ovpn-112-43.ams2.redhat.com [10.36.112.43]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 81A39611D9; Fri, 5 Apr 2019 09:02:15 +0000 (UTC) Date: Fri, 5 Apr 2019 10:02:12 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Message-ID: <20190405090212.GF6105@redhat.com> References: <20190404185730.GA22512@ls3530.dellerweb.de> <068f4832-7e0b-8850-ffa0-fcf1ecd50295@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <068f4832-7e0b-8850-ffa0-fcf1ecd50295@redhat.com> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Fri, 05 Apr 2019 09:02:20 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH] configure: Automatically fall back to TCI on non-release architectures X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Peter Maydell , Helge Deller , Michael Tokarev , QEMU Developers , Samuel Thibault , Aurelien Jarno Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190405090212.L2RBuNeZcMRGYP1p_pMn3XY-Q9--14COr7yq-hm9ze4@z> On Fri, Apr 05, 2019 at 10:47:54AM +0200, Philippe Mathieu-Daud=C3=A9 wro= te: > Hi Helge, >=20 > On 4/5/19 9:56 AM, Helge Deller wrote: > > On 05.04.19 03:34, Peter Maydell wrote: > >> On Fri, 5 Apr 2019 at 01:59, Helge Deller wrote: > >>> If a non-release architecture is found, and it's known that there i= s no > >>> native TCG support for that CPU, automatically fall back to the TCI > >>> implementation instead of requesting the user to run configure agai= n > >>> with the --enable-tcg-interpreter option. > >>> > >>> This change simplifies building qemu in automatic build environment= s > >>> (like in my case the debian buildds) because one does not need to > >>> special case on the architectures. > >> > >> I don't think we should do this. TCI is unmaintained, has several > >> known flaws, > >=20 > > Just out of interest: Is there a list with those flaws somewhere? >=20 > The last big discussion is in this thread: > https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg06528.html Do the various crashes that you illustrate in that cover letter still exist today ? If so, 2 years of continued brokenness with no fixes would reinforce the the view that it is time to remove TCI from the codebase. Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| |: https://libvirt.org -o- https://fstop138.berrange.c= om :| |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :|