On Tue, Dec 09, 2025 at 09:34:11AM +0100, Christian Zigotzky wrote:

quoted

On 09 December 2025 at 07:01 am, Gautam Menghani [off-list ref] wrote:

On Mon, Dec 08, 2025 at 07:06:14AM +0100, Christian Zigotzky wrote:

quoted

quoted

quoted

On 08 December 2025 at 06:51 am, Gautam Menghani [off-list ref] wrote:

Hi Christian,

Thanks for the report. Can you also please share the QEMU command line
you were using? That would be helpful.

Thanks,
Gautam

Hi Gautam,

Here is the command line:

qemu-system-ppc64 -M ppce500 -cpu e5500 -m 1024 -kernel uImage -drive format=raw,file=void-live-powerpc-20230317.img,index=0,if=virtio -netdev user,id=mynet0 -device virtio-net,netdev=mynet0 -append "rw root=/dev/vda" -device virtio-gpu-pci -device virtio-mouse-pci -device virtio-keyboard-pci -device pci-ohci,id=newusb -audiodev id=sndbe,driver=pa,server=/run/user/1000/pulse/native -device usb-audio,bus=newusb.0 -enable-kvm -smp 4 -fsdev local,security_model=passthrough,id=fsdev0,path=/home/amigaone/Music -device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=hostshare -display gtk

Were you running a KVM guest? Did you see the problem with the latest
kernel installed in the guest?

Yes, the latest git kernel doesn’t boot.

But the final kernel 6.18.0 boots without any problems.

I tried booting a TCG ppce500 guest with your config and I can see that
the commit 2997876c4a1a5 causes a boot failure. Reverting it works fine.

Command line used:

qemu-system-ppc64 -M ppce500 -cpu e5500 -smp 1 -m 4G \
    -display none -serial stdio \
    -kernel /home/gautam/src/linux/arch/powerpc/boot/uImage \
    -drive file=/home/gautam/src/qemu-ppc-boot/buildroot/qemu_ppc64_e5500-latest/rootfs.ext2,if=virtio,format=raw \
    -append "console=ttyS0 rootwait root=/dev/vda" \


But I was not able to boot a KVM guest on top of this TCG guest. I even
went back all the way to 5.15

./qemu-system-ppc64 \
        -M ppce500 -cpu e5500 \
        --enable-kvm  \
        -m 1024 -kernel uImage \
        -drive file=/tmp/rootfs.ext2,if=virtio,format=raw \
        -append "console=ttyS0 rootwait root=/dev/vda" -serial mon:stdio -nographic

Bad kernel stack pointer fffff8 at 0
Oops: Bad kernel stack pointer, sig: 6 [#1]
BE PAGE_SIZE=4K  SMP NR_CPUS=4 QEMU e500
Modules linked in:
CPU: 0 UID: 0 PID: 1508 Comm: qemu-system-ppc Not tainted 6.18.0-a4-powerpc64-smp #45 VOLUNTARY
Hardware name: QEMU ppce500 e5500 0x80240020 QEMU e500
NIP:  0000000000000000 LR: 0000000000000000 CTR: 0000000000000000
REGS: c00000003fffbd20 TRAP: 0400   Not tainted  (6.18.0-a4-powerpc64-smp)
MSR:  0000000010000000 <>  CR: 00000000  XER: 00000000
IRQMASK: 0
GPR00: 0000000000000000 0000000000fffff8 0000000000000000 0000000002c00000
GPR04: 0000000000000000 0000000000000000 0000000045504150 0000000004000000
GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR12: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR24: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR28: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
NIP [0000000000000000] 0x0
LR [0000000000000000] 0x0
Call Trace:
Code: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
---[ end trace 0000000000000000 ]---

note: qemu-system-ppc[1508] exited with irqs disabled


Thanks,
Gautam