[Linux PPC] KVM PR and KVM HV do not work if the kernel was compiled with PREEMPT

[Madhavan Srinivasan]

On 2/17/26 3:14 PM, Christian Zigotzky wrote:
> On 17/02/26 10:03, Shrikanth Hegde wrote:
>>
>>
>> On 2/17/26 2:22 PM, Christian Zigotzky wrote:
>>> Hi,
>>>
>>> Thank you for your patch. I tested the latest git kernel with your 
>>> patch today. Unfortunately the system freezes while booting the VM 
>>> with KVM HV.
>>>
>>> Cheers,
>>> Christian
>>>
>>>
>> Would it be possible to share the console log or boot log of KVM to the
>> point it freezes?
>
> Unfortunately there aren't any error messages.
>
> I also tried it with:
>
> gdb --args qemu-system-ppc64 -M ppce500 -cpu e5500 -m 1024 -kernel 
> uImage-7.0-preempt -drive 
> format=raw,file=void-live-powerpc-20230317-updated2.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 -enable-kvm -smp 4
>
> and with gdb in the guest:
>
> qemu-system-ppc64 -s -S -M ppce500 -cpu e5500 -m 1024 -kernel 
> uImage-7.0-preempt -drive 
> format=raw,file=void-live-powerpc-20230317-updated2.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 -enable-kvm -smp 4
>
> The system freezed without any error messages.
can you please share the config.
I tried kvm-hv in my power8/power9 and seems to boot fine without any 
issues with today's upstream
Maddy