From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36374) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZONGR-0006KG-AX for qemu-devel@nongnu.org; Sun, 09 Aug 2015 05:51:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZONGM-0007Rm-FD for qemu-devel@nongnu.org; Sun, 09 Aug 2015 05:51:35 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:34273) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZONGM-0007RF-8h for qemu-devel@nongnu.org; Sun, 09 Aug 2015 05:51:30 -0400 Received: by wicne3 with SMTP id ne3so103818312wic.1 for ; Sun, 09 Aug 2015 02:51:29 -0700 (PDT) References: <1438966995-5913-1-git-send-email-a.rigo@virtualopensystems.com> <1438966995-5913-6-git-send-email-a.rigo@virtualopensystems.com> <20150808124401.GA18166@aurel32.net> <871tfcnann.fsf@linaro.org> <20150809084020.GA5883@aurel32.net> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <20150809084020.GA5883@aurel32.net> Date: Sun, 09 Aug 2015 10:51:27 +0100 Message-ID: <87zj20lrhc.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [RFC v4 5/9] configure: Enable/disable new qemu_{ld, st} excl insns List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Aurelien Jarno Cc: mttcg@listserver.greensocs.com, claudio.fontana@huawei.com, Alvise Rigo , qemu-devel@nongnu.org, pbonzini@redhat.com, jani.kokkonen@huawei.com, tech@virtualopensystems.com Aurelien Jarno writes: > On 2015-08-09 09:11, Alex Bennée wrote: >> >> Aurelien Jarno writes: >> >> > On 2015-08-07 19:03, Alvise Rigo wrote: >> >> Introduce the new --enable-tcg-ldst-excl configure option to enable the >> >> LL/SC operations only for those backends that support them. >> >> >> >> Suggested-by: Jani Kokkonen >> >> Suggested-by: Claudio Fontana >> >> Signed-off-by: Alvise Rigo >> >> --- >> >> configure | 21 +++++++++++++++++++++ >> >> 1 file changed, 21 insertions(+) >> > >> > We have seen that for this kind of patch, it's better to add support in >> > all backends, otherwise it takes ages to get all the backends converted. >> > I think you should involve the backend maintainers. I can try to provide >> > the corresponding patches for mips and ia64. >> >> We discussed this on the last MTTCG call and agree. However we will need >> help from the other TCG maintainers for the backends. The changes should >> be fairly mechanical though. >> >> However in the spirit of keeping trees building in the meantime should >> we change this from a configure option to just a static option for each >> given backend as it is converted? > > I am not even sure we need a static option. I guess providing we are > doing that early enough in the 2.5 cycle, we can just add the new ops > and start using them. Of course we should put the backends maintainers > in the loop so they can fix that quickly and don't get a surprise weeks > afters. > > That said, please see my other email, I am not sure we actually need to > modify backends, I think we can implement these new "ops" through > tcg-runtime. We still need to ensure "normal" ld/st operations trip the exclusive bit though. > > Aurelien -- Alex Bennée