Re: Conflicting parameters on qemu call

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 <berrange(a)redhat.com&gt; wrote: >> On Fri, Aug 21, 2020 at 11:00:27AM +0200, Jan Walzer wrote: >>> On 21. Aug 2020, at 10:38, Daniel P. Berrangé <berrange(a)redhat.com&gt; 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..