| Thanks to all of you for replying. I’ll keep an eye on things and keep testing from time to time - I suspect that I very much lack the skills to make much of a contribution in terms of either kernel, kvm or qemu hacking. I’m also aware that my interest is deprecated hardware. I suspect that were I fortunate enough to have Talos hardware kvm would be a very different story as I believe that that architecture has proper hardware support for virtualisation where on G5 its a bit of a “hack”. Having said that, I do have hardware that I would be more than happy to help use for testing, and I possess rudimentary development / systems administration skills so if I can assist in any way, please either let me know via this list, or contact me on Libera IRC (I am “crab” in #debianppc / #debian-ports).
Thanks again, and much respect and appreciation to all of you for your work.
Dan On 15 Jan 2023, at 14:25, BALATON Zoltan <balaton@eik.bme.hu> wrote:
On Sun, 15 Jan 2023, Daniel Henrique Barboza wrote:Ccing Mark
On 1/12/23 11:18, Dan Whitehouse wrote:
Hi all,
I have a Powermac G5 running Debian (from Ports) with kernel version:
Linux powermac-g5 6.0.0-6-powerpc64 #1 SMP Debian 6.0.12-1 (2022-12-09) ppc64 GNU/Linux
My aim is to get Qemu working with KVM acceleration, although I am unsure if that is even possible.
Any attempt to do so seems to result in the behaviour described here:
Re: [PATCH 2/9] target/ppc: add errp to kvmppc_read_int_cpu_dt() <https://www.mail-archive.com/qemu-devel@nongnu.org/msg898334.html>
mail-archive.com <https://www.mail-archive.com/qemu-devel@nongnu.org/msg898334.html>
apple-touch-icon-114x114.png <https://www.mail-archive.com/qemu-devel@nongnu.org/msg898334.html>
<https://www.mail-archive.com/qemu-devel@nongnu.org/msg898334.html>
I have managed (after a fair bit of struggle to get Debian working under qemu (without kvm) and I also got MacOS 9 working as well (albeit with horribly garbled colours).
Ive seen some posts on the KVM mailing list that may refer to whatever is going wrong here:
'Re: [PATCH] kvm-pr: manage illegal instructions' <https://marc.info/?l=kvm-ppc&m=146364192030854&w=2>
marc.info <https://marc.info/?l=kvm-ppc&m=146364192030854&w=2>
<https://marc.info/?l=kvm-ppc&m=146364192030854&w=2>
<https://marc.info/?l=kvm-ppc&m=146364192030854&w=2>
And it may well be the case that this is a KVM issue more than a Qemu wrong and I’m therefore posting in the wrong list (in which case apologies). As you can see though there has been no activity since 2016.
I took a look at the thread and I'm not entirely convinced that QEMU is 100%
in the clear. The root issue seems to be kvm-pr kernel code though.
Mark managed to run kvm-pr in a G5 in the past so I believe he can help you
with any pointers. What I can say that you'll have a bumpy road ahead -
I think he did that on G4 but maybe also on G5, I don't know. I only know about this blog which shows it running on newer CPU (in that case POWER9):https://www.talospace.com/search/label/KVMwhich may have some useful info also for G5 but some of that like KMV-HV and newer MMU modes are not applicable to G5.I’d be grateful if either someone could confirm that this is a non starter or give me any pointers.
It's not a non-starter - it's feasible and it was done before. But I'd say you're in for some heavy kernel (and probably QEMU) hacking to make it work properly.
You'll probably have to dig deeper into KVM to understand what's causing the problem. I don't know much about how to debug that but here are some links that may help:https://arkivm.github.io/kernel%20development/2020/11/01/qemu-kvm-1gb-pages/https://www.linux-kvm.org/page/Perf_eventsI don't know how relevant or up to date these are, I've only tried to debug this once on G5 emulated by QEMU on X86_64 as I don't have PPC hardware but hit a QEMU problem in emiulated KVM that I could not overcome:https://lists.nongnu.org/archive/html/qemu-ppc/2021-06/msg00146.htmlNot sure if that helps but that's all I have. If you find out something it might be helpful for others to post it here.Regards,BALATON Zoltan
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