On 21. Aug 2020, at 13:55, Daniel P. Berrangé <berra...@redhat.com> wrote: > On Fri, Aug 21, 2020 at 01:38:23PM +0200, Jan Walzer wrote: >> On 21. Aug 2020, at 11:20, Daniel P. Berrangé <berra...@redhat.com> wrote: >>> On Fri, Aug 21, 2020 at 11:19:14AM +0200, Jan Walzer wrote: >>>> Hi Daniel, >>>>> On 21. Aug 2020, at 11:07, Daniel P. Berrangé <berra...@redhat.com> wrote: >>>>> On Fri, Aug 21, 2020 at 11:00:27AM +0200, Jan Walzer wrote: >>>>>> On 21. Aug 2020, at 10:38, Daniel P. Berrangé <berra...@redhat.com> >>>>>> wrote: >>>>>>> On Thu, Aug 20, 2020 at 08:11:30PM +0200, Jan Walzer wrote: >>>>>>>> Hi Lists, >>>>>>>> >>>>>>>> I currently have the issue of wanting to use emu-system-x86_64 on a >>>>>>>> ppc64le platform. >>>>>>>> >>>>>>>> It is imperative to pass the "-accel tcg,thread=multi” parameter to >>>>>>>> qemu >>>>>>>> when starting an instance, as without that, it will only use one >>>>>>>> thread >>>>>>>> and hence of limited/no use. >>>>>>>> >>>>>>>> The problem is, that libvirt itself, passes “-machine q35,accel=tcg” to >>>>>>>> qemu, which is a different parameter, that conflicts with the other >>>>>>>> one. >>>>>>>> >>>>>>>> Can we discuss, if I either have overlooked something, or is there a >>>>>>>> workaround, or is this a bug? >>>>>>> >>>>>>> What you're trying todo is intentionally not available. >>>>>>> >>>>>>> The memory ordering constraints needed for running x86_64 guests on >>>>>>> ppc64 >>>>>>> hosts cannot be satisfied, so multi-threaded TCG is not available. >>>>>>> >>>>>>> For any guest/host combination where multi-thread TCG is safe to use, >>>>>>> QEMU >>>>>>> will enable it automatically, so nothing is required in libvirt. >>>>>> >>>>>> >>>>>> Hi Daniel, >>>>>> Thanks for the answer. I’ve read (and understand) the warnings and their >>>>>> implications. >>>>>> >>>>>> So there’s not even an “I know what I’m Doing”-Switch? >>>>> >>>>> […] >>>>> <qemu:commandline> >>>>> <qemu:arg value='-accel'/> >>>>> <qemu:arg value='tcg,thread=multi'/> >>>>> </qemu:commandline> >>>> >>>> As I wrote: This is what I’m already doing >>>> The Problem is that this conflicts with, libvirt already using the >>>> parameter: “-machine ..,accel=tcg” >>>> And I can’t get libvirt, to stop passing this parameter. >>> >>> It shouldn't matter. QEMU should aggregate the settings from the >>> multiple args, with latter args overriding earlier args if there is >>> any duplication.. >> >> >> That was what I thought to, but: >> >> # qemu-system-x86_64 -machine q35,accel=tcg -accel tcg,thread=multi --smp 8 >> -m 8 >> Unable to init server: Could not connect: Connection refused >> qemu-system-x86_64: The -accel and "-machine accel=" options are incompatible >> >> # qemu-system-x86_64 --version >> QEMU emulator version 5.0.0 (Debian 1:5.0-14) >> Copyright (c) 2003-2020 Fabrice Bellard and the QEMU Project developers >> >> I’m already discussing that on qemu list: >> https://lists.nongnu.org/archive/html/qemu-ppc/2020-08/msg00338.html >> <https://lists.nongnu.org/archive/html/qemu-ppc/2020-08/msg00338.html><https://lists.nongnu.org/archive/html/qemu-ppc/2020-08/msg00338.html >> <https://lists.nongnu.org/archive/html/qemu-ppc/2020-08/msg00338.html>> >> >> But I’d like to track that issue in multiple directions. > > Ok, this is an intentionally backwards incompatible change in QEMU 5.0.0. > So you're out of luck until libvirt changes to using "-accel" too.
So that’s why I’m writing here on the libvirt lists - I assume this means looking for a bug report or creating one. … and for me: probably creating a really dirty workaround, by writing a wrapper, that’s called instead of the binary which adjusts the command line parameters ;( Thanks for your help, Greetings, Jan
