Re: Qemu / KVM On Powermac G5 MP970

[Mark Cave-Ayland]

On 23/01/2023 14:42, Dan Whitehouse wrote:

> Hi Luigi,
> It doesn’t work for me at all:
>
> crab@powermac-g5:~/Documents/Qemu$ uname -a
> Linux powermac-g5 6.0.0-6-powerpc64 #1 SMP Debian 6.0.12-1 (2022-12-09) ppc64 
> GNU/Linux
>
> crab@powermac-g5:~/Documents/Qemu$ lsmod | grep kvm
> kvm_pr                110777  0
> kvm                   309830  1 kvm_pr
>
> #!/bin/bash
>
> qemu-system-ppc64 \
>    -boot c \
>    -M mac99,via=pmu \
>    -m 2048 \
>    --enable-kvm \
>    -drive file=/srv/Qemu/debian_64bit.qcow2,format=qcow2,media=disk \
>    -netdev user,id=mynet0,net=192.168.76.0/24,dhcpstart=192.168.76.10 \
>    -device sungem,netdev=mynet0 \
>    -monitor stdio
>
> Result:
>
> dmesg is flooded with:
>
> #!/bin/bash
>
> [22936.303544] Couldn't emulate instruction 0x00000000 (op 0 xop 0)
> [22936.315006] kvmppc_exit_pr_progint: emulation at 100 failed (00000000)
>
> Exactly as 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>
>
>
> Can you let me know:
>
> 1./ what is your host OS and kernel version?
> 2./ what version of Qemu you are using? (I’m using the version in Debian ports).
> 3./ what arguments are you using to start your guest?
>
> Does it also work in Libvirt?

Hi Dan,

Sorry for being late to this thread, but I got around to firing up my G4 Mac Mini 
earlier this evening to see what works and what doesn't work with KVM. My setup is as 
follows:

OS:

$ uname -a
Linux macmini 5.1.0-rc2+ #56 Wed Mar 27 00:38:43 GMT 2019 ppc GNU/Linux

Installation of Debian ports ppc32 distribution


QEMU:

commit 9548cbeffffd4253e38570d29b8cff0bf77c998f (HEAD -> master, origin/staging, 
origin/master, origin/HEAD)
Author: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Date:   Wed Jul 6 20:08:34 2022 +0300

    iotests/copy-before-write: specify required_fmts

    Declare that we need copy-before-write filter to avoid failure when
    filter is not whitelisted.

    Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
    Tested-by: Thomas Huth <thuth@redhat.com>
    Message-Id: <20220706170834.242277-1-vsementsov@yandex-team.ru>
    Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

  built using:

    './configure' '--target-list=ppc-softmmu' --disable-werror
    make V=1 install

With that setup I see the following results when attempting to boot OSs with 
KVM-PR:


OS X 10.2:

   -M mac99[,via=cuda]: boots to start of installer, then errors out with "The
                        Installer has quit due to an unexpected error. (exit
                        code 0)

      ./qemu-system-ppc -machine accel=kvm -cdrom osxdisk1.iso \
        -boot d -M mac99 -m 256 -prom-env 'boot-args=-v'

   -M mac99,via=pmu: boots to installer

      ./qemu-system-ppc -machine accel=kvm -cdrom osxdisk1.iso \
        -boot d -M mac99,via=pmu -m 256 -prom-env 'boot-args=-v'

   -M g3beige: boots to installer

      ./qemu-system-ppc -machine accel=kvm -cdrom osxdisk1.iso \
        -boot d -m 256 -prom-env 'boot-args=-v'


Debian ports PPC (debian-9.0-powerpc-NETINST-1.iso):

   -M mac99[,via=cuda]: hangs on yaboot (keyboard unresponsive?)

      ./qemu-system-ppc -machine accel=kvm -cdrom 
debian-9.0-powerpc-NETINST-1.iso \
        -boot d -m 256 -prom-env 'boot-args=-v'

   -M mac99,via=pmu: hangs on yaboot (keyboard unresponsive?)

      ./qemu-system-ppc -machine accel=kvm -cdrom 
debian-9.0-powerpc-NETINST-1.iso \
        -boot d -M mac99,via=pmu -m 256 -prom-env 'boot-args=-v'

   -M g3beige: hangs on yaboot (keyboard unresponsive?)

      ./qemu-system-ppc -machine accel=kvm -cdrom 
debian-9.0-powerpc-NETINST-1.iso \
        -boot d -m 256 -prom-env 'boot-args=-v'


MacOS 9:

   -M mac99[,via=cuda]: hangs on nanokernel initialisation

      ./qemu-system-ppc -machine accel=kvm -cdrom MacOS921.iso -boot d \
        -m 256 -prom-env 'boot-args=-v' -prom-env 'vga-ndrv?=false'

   -M mac99,via=pmu: hangs on MacOS grey background screen (requires
                     -prom-env 'vga-ndrv?=false' - why?)

      ./qemu-system-ppc -machine accel=kvm -cdrom MacOS921.iso -boot d \
        -M mac99,via=pmu -m 256 -prom-env 'boot-args=-v' -prom-env 
'vga-ndrv?=false'


The key thing is that there are two variables here: QEMU and the kernel. I did report 
some breakages in the kernel 4.x timeframe which were eventually fixed, so it might 
make sense to use the same kernel as luigi as a starting point with latest QEMU git, 
and then work backwards towards QEMU 3 and see if you can find the point at which 
things stop working.


ATB,

Mark.