Le 27/06/2018 à 20:44, Dr. David Alan Gilbert a écrit : > * Laurent Vivier ([email protected]) 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
