From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47308) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fYGXr-0005hR-1N for qemu-devel@nongnu.org; Wed, 27 Jun 2018 15:56:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fYGXn-000525-Ve for qemu-devel@nongnu.org; Wed, 27 Jun 2018 15:56:03 -0400 Received: from mout.kundenserver.de ([212.227.126.130]:33321) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fYGXn-00051X-La for qemu-devel@nongnu.org; Wed, 27 Jun 2018 15:55:59 -0400 Received: from [192.168.100.1] ([78.238.229.36]) by mrelayeu.kundenserver.de (mreue005 [212.227.15.167]) with ESMTPSA (Nemesis) id 0Mczwc-1fpFAF3guY-00IEKN for ; Wed, 27 Jun 2018 21:55:58 +0200 References: <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> <20180627085217.blrsx5lmu4sau4fd@sirius.home.kraxel.org> <5d591d6c-ccc4-cc86-ebbc-3c66a6817c70@redhat.com> <4c86fb26-f7c3-e66e-33a2-dbbfe2e70960@vivier.eu> <20180627184453.GC2424@work-vm> From: Laurent Vivier Message-ID: Date: Wed, 27 Jun 2018 21:55:56 +0200 MIME-Version: 1.0 In-Reply-To: <20180627184453.GC2424@work-vm> 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: qemu-devel@nongnu.org Le 27/06/2018 à 20:44, Dr. David Alan Gilbert a écrit : > * Laurent Vivier (laurent@vivier.eu) wrote: >> Le 27/06/2018 à 15:33, Philippe Mathieu-Daudé a écrit : >>> On 06/27/2018 06:09 AM, Thomas Huth wrote: >>>> On 27.06.2018 10:52, Gerd Hoffmann wrote: >>>>> Hi, >>>>> >>>>>>> Is QEMU still useful on 32-bit hosts? Honest question! >>>>>> >>>>>> I guess it depends on what 32-bit hosts you consider. If you look at only >>>>>> x86 vs. x86_64 then probably x86 is not that important any more but for some >>>>>> embedded systems/SoCs 32bit might still be common and QEMU useful for those >>>>>> (also as host not only emulated). >>>>> >>>>> Well. I've used kvm with an 32bit arm soc (cubietruck). It's very >>>>> slow. And all the arm architecture improvements to support kvm better >>>>> are for aarch64 only. >>>>> >>>>>> Another option might be to not support audio/hda on 32bit hosts. It's not >>>>>> nice either but a lot nicer than dropping support for 32bit hosts >>>>>> alltogether to fix a problem in device emulation. >>>>> >>>>> But it also is not useful and a waste of resources to maintain 32bit >>>>> host compatibility if nobody actually uses that ... >>>>> >>>>> For me testbuilds are the only reason to compile qemu for 32bit hosts. >>>>> Since years. >>>> >>>> Well, while that's true for you, me and likely most of us developers, >>>> you can not know whether this is also true for all users of qemu. Thus >>>> this needs to be announced first for a couple of releases so that people >>>> have a chance to speak up whether they still need this or not. As >>>> mentioned earlier, embedded devices are often still 32-bit and I know >>>> that there really are people who use QEMU on embedded devices. >>>> >>>> But I think we could at least announce now already that we intend to >>>> drop support for 32-bit hosts in the future (maybe not in 2 releases >>>> already, but, let's say in 2020? 2020 is already the EOL of Python 2, so >>>> that will rule out a bunch of other legacy hosts, too). >>> >>> linux-user is certainly widely used on ARMv6 / ARMv7. >>> >>> Known user cases: >>> >>> - run ARMv7 binaries on ARMv6 >>> - run armhf binaries on armel >>> - run x86-64 binaries on ARMv7 >>> >> >> I run i386 binaries on ARMv6. > > Do you know if that model has the 64bit atomics (ldrexd/strexd)? http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0489e/Cihbghef.html "ARM LDREXB, LDREXH, LDREXD, STREXB, STREXD, and STREXH are available in ARMv6K and above." Laurent