<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">On 21. Aug 2020, at 13:55, Daniel P. Berrangé <<a href="mailto:berrange@redhat.com" class="">berrange@redhat.com</a>> wrote:<div><blockquote type="cite" class=""><div class=""><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class="">On Fri, Aug 21, 2020 at 01:38:23PM +0200, Jan Walzer wrote:</span><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">On 21. Aug 2020, at 11:20, Daniel P. Berrangé <<a href="mailto:berrange@redhat.com" class="">berrange@redhat.com</a>> wrote:<br class=""><blockquote type="cite" class="">On Fri, Aug 21, 2020 at 11:19:14AM +0200, Jan Walzer wrote:<br class=""><blockquote type="cite" class="">Hi Daniel,<br class=""><blockquote type="cite" class="">On 21. Aug 2020, at 11:07, Daniel P. Berrangé <<a href="mailto:berrange@redhat.com" class="">berrange@redhat.com</a>> wrote:<br class="">On Fri, Aug 21, 2020 at 11:00:27AM +0200, Jan Walzer wrote:<br class=""><blockquote type="cite" class="">On 21. Aug 2020, at 10:38, Daniel P. Berrangé <<a href="mailto:berrange@redhat.com" class="">berrange@redhat.com</a>> wrote:<br class=""><blockquote type="cite" class="">On Thu, Aug 20, 2020 at 08:11:30PM +0200, Jan Walzer wrote:<br class=""><blockquote type="cite" class="">Hi Lists,<br class=""><br class="">I currently have the issue of wanting to use emu-system-x86_64 on a ppc64le platform.<br class=""><br class="">It is imperative to pass the "-accel tcg,thread=multi” parameter to qemu<span class="Apple-converted-space"> </span><br class="">when starting an instance, as without that, it will only use one thread<span class="Apple-converted-space"> </span><br class="">and hence of limited/no use.<br class=""><br class="">The problem is, that libvirt itself, passes “-machine q35,accel=tcg” to<br class="">qemu, which is a different parameter, that conflicts with the other one.<br class=""><br class="">Can we discuss, if I either have overlooked something, or is there a workaround, or is this a bug?<br class=""></blockquote><br class="">What you're trying todo is intentionally not available.<br class=""><br class="">The memory ordering constraints needed for running x86_64 guests on ppc64<br class="">hosts cannot be satisfied, so multi-threaded TCG is not available.<br class=""><br class="">For any guest/host combination where multi-thread TCG is safe to use, QEMU<br class="">will enable it automatically, so nothing is required in libvirt.<br class=""></blockquote><br class=""><br class="">Hi Daniel,<br class="">Thanks for the answer. I’ve read (and understand) the warnings and their implications.<br class=""><br class="">So there’s not even an “I know what I’m Doing”-Switch?<br class=""></blockquote><br class="">[…]<br class=""><qemu:commandline><br class=""> <qemu:arg value='-accel'/><br class=""> <qemu:arg value='tcg,thread=multi'/><br class=""></qemu:commandline><br class=""></blockquote><br class="">As I wrote: This is what I’m already doing<br class="">The Problem is that this conflicts with, libvirt already using the parameter: “-machine ..,accel=tcg”<br class="">And I can’t get libvirt, to stop passing this parameter.<br class=""></blockquote><br class="">It shouldn't matter. QEMU should aggregate the settings from the<br class="">multiple args, with latter args overriding earlier args if there is<br class="">any duplication..<br class=""></blockquote><br class=""><br class="">That was what I thought to, but:<br class=""><br class=""># qemu-system-x86_64 -machine q35,accel=tcg -accel tcg,thread=multi --smp 8 -m 8<br class="">Unable to init server: Could not connect: Connection refused<br class="">qemu-system-x86_64: The -accel and "-machine accel=" options are incompatible<br class=""><br class=""># qemu-system-x86_64 --version<br class="">QEMU emulator version 5.0.0 (Debian 1:5.0-14)<br class="">Copyright (c) 2003-2020 Fabrice Bellard and the QEMU Project developers<br class=""><br class="">I’m already discussing that on qemu list:<br class=""><a href="https://lists.nongnu.org/archive/html/qemu-ppc/2020-08/msg00338.html" class="">https://lists.nongnu.org/archive/html/qemu-ppc/2020-08/msg00338.html</a><<a href="https://lists.nongnu.org/archive/html/qemu-ppc/2020-08/msg00338.html" class="">https://lists.nongnu.org/archive/html/qemu-ppc/2020-08/msg00338.html</a>><br class=""><br class="">But I’d like to track that issue in multiple directions.<br class=""></blockquote><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class="">Ok, this is an intentionally backwards incompatible change in QEMU 5.0.0.</span><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class="">So you're out of luck until libvirt changes to using "-accel" too.</span><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""></div></blockquote></div><br class=""><div class="">So that’s why I’m writing here on the libvirt lists - I assume this means looking for a bug report or creating one.</div><div class=""><br class=""></div><div class="">… 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 ;(</div><div class=""><br class=""></div><div class="">Thanks for your help,</div><div class="">Greetings, Jan</div><div class=""><br class=""></div><div class=""><br class=""></div></body></html>