From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60219) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fYAeX-0001ej-Jh for qemu-devel@nongnu.org; Wed, 27 Jun 2018 09:38:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fYAeS-0007WR-QH for qemu-devel@nongnu.org; Wed, 27 Jun 2018 09:38:33 -0400 Received: from mail-qk0-x243.google.com ([2607:f8b0:400d:c09::243]:42020) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fYAeS-0007Vm-Lm for qemu-devel@nongnu.org; Wed, 27 Jun 2018 09:38:28 -0400 Received: by mail-qk0-x243.google.com with SMTP id u62-v6so1014379qkf.9 for ; Wed, 27 Jun 2018 06:38:28 -0700 (PDT) Sender: =?UTF-8?Q?Philippe_Mathieu=2DDaud=C3=A9?= References: <20180625131253.11218-1-kraxel@redhat.com> <20180625131253.11218-2-kraxel@redhat.com> <6ad67e44-b002-1cd7-cfd1-2d98ebde1a7e@redhat.com> <20180627065126.mwzdxshr3njzok7n@sirius.home.kraxel.org> <0df8a05c-43fc-6e85-b13c-d3f5c4691964@redhat.com> <87fu18ach6.fsf_-_@dusky.pond.sub.org> <20180627110923.GG30628@redhat.com> <87d0wcwfdv.fsf@linaro.org> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Message-ID: Date: Wed, 27 Jun 2018 10:38:24 -0300 MIME-Version: 1.0 In-Reply-To: <87d0wcwfdv.fsf@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] Drop support for 32bit hosts in qemu? (was: [PULL 1/6] audio/hda: create millisecond timers that handle IO) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?Q?Alex_Benn=c3=a9e?= Cc: "=?UTF-8?Q?Daniel_P._Berrang=c3=a9?=" , Martin Schrodt , Thomas Huth , qemu-devel@nongnu.org, Markus Armbruster , Gerd Hoffmann , Max Reitz On 06/27/2018 10:03 AM, Alex Bennée wrote: > > Daniel P. Berrangé writes: > >> On Wed, Jun 27, 2018 at 09:57:09AM +0200, Markus Armbruster wrote: >>> Thomas Huth writes: >>> >>>> On 27.06.2018 08:51, Gerd Hoffmann wrote: >>> [...] >>>>> Drop support for 32bit hosts in qemu? >>>> >>>> I guess the only way to answer that question reliably is to send a patch >>>> to mark 32-bit hosts as deprecated... >>>> >>>> Anyway, you still have got to fix that problem with -m32 now somehow >>>> since we certainly can not drop 32-bit immediately. >>> >>> We certainly can if we want to. >>> >>> Our formal deprecation policy codifies our compromise between the need >>> to evolve QEMU and the need of its users for stable external interfaces. >>> >>> "Compiles on host X" is also a need, but it's a different one. >>> Evidence: "Supported build platforms" has its own appendix, separate >>> from "Deprecated features". It's mum on 32-bit hosts. >> >> It is silent on host architecture coverage in general in fact. It was >> only really focusing on operating systems and so any arch coverage is >> at best inferred from what those OS target. Fedora covers 32-bit & 64-bit >> arches for example, so you could take that to imply we need to support >> both in QEMU. >> >> It is fuzzier though because while Peter has good OS coverage for his >> merge testing, I don't think he has full host arch coverage for everything >> that downstreams expect QEMU to build on ? > > We do however have cross build infrastructure for all tcg/foo backends. > They are run by the shippable CI framework (which is how I noticed): > > https://app.shippable.com/github/qemu/qemu/runs?branchName=master FWIW we can also build ppc32 again (with the apt-fake kludge although). > > Once we have the changes made to the wiki I'd like to use: > > https://wiki.qemu.org/Template:CIStatus > > In a few choice places on the wiki, including the front page, for better > visibility. > >>> I'm not saying we *should* drop 32-bit hosts immediately. Only that the >>> feature deprecation policy does not apply. >>> >>> Is QEMU still useful on 32-bit hosts? Honest question! >> >> That answer varies depending on what you're using QEMU for I think. It >> could be that people see tools like qemu-img/qemu-nbd as useful even >> if they don't use system emulators. And of course userspace emulators >> are enough distinct use case. >> >> IMHO as long as distros are shipping 32-bit support, it is reasonable >> to assume there will be people who find QEMU useful to some degree. >> >> Personally I don't have any need for 32-bit hosts, but clearly some >> people do since otherwise distros would have killed their 32-bit >> arches already. > > I know of at least one kernel developer who uses qemu-system-aarch64 on > their 32 bit ARM Chromebook to test their 64 bit code. Next time I see > them I'll see if they are still using it. > > My feeling is although probably not widespread it certainly can be handy. > >> >> Regards, >> Daniel > > > -- > Alex Bennée >