Re: [FSL P50x0] KVM HV doesn't work anymore

[Christian Zigotzky <chzigotzky@xenosoft.de>]

On 20 May 21 at 01:07am, Nicholas Piggin wrote:
> Excerpts from Christian Zigotzky's message of May 19, 2021 9:52 pm:
>> On 19 May 2021 at 09:57 am, Nicholas Piggin wrote:
>>> Excerpts from Christian Zigotzky's message of May 17, 2021 7:42 pm:
>>>> On 17 May 2021 at 09:42am, Nicholas Piggin wrote:
>>>>> Excerpts from Christian Zigotzky's message of May 15, 2021 11:46 pm:
>>>>>> I tried it but it doesn't solve the issue. The uImage works without
>>>>>> KVM
>>>>>> HV in a virtual e5500 QEMU machine.
>>>>> Any more progress with this? I would say that bisect might have just
>>>>> been a bit unstable and maybe by chance some things did not crash so
>>>>> it's pointing to the wrong patch.
>>>>>
>>>>> Upstream merge of powerpc-5.13-1 was good and powerpc-5.13-2 was bad?
>>>>>
>>>>> Between that looks like some KVM MMU rework. You could try the patch
>>>>> before this one b1c5356e873c ("KVM: PPC: Convert to the gfn-based MMU
>>>>> notifier callbacks"). That won't revert cleanly so just try run the
>>>>> tree at that point. If it works, test the patch and see if it fails.
>>>>>
>>>>> Thanks,
>>>>> Nick
>>>> Hi Nick,
>>>>
>>>> Thanks a lot for your answer. Yes, there is a little bit of progress.
>>>> The RC2 of kernel 5.13 successfully boots with -smp 3 in a virtual e5500
>>>> QEMU machine.
>>>> -smp 4 doesn't work anymore since the PowerPC updates 5.13-2. I used
>>>> -smp 4 before 5.13 because my FSL P5040 machine has 4 cores.
>>>>
>>>> Could you please post a patch for reverting the commit before
>>>> b1c5356e873c ("KVM: PPC: Convert to the gfn-based MMU notifier callbacks")?
>>> You could `git checkout b1c5356e873c~1`
>>>
>>> Thanks,
>>> Nick
>> Hi Nick,
>>
>> Thanks for your answer. I checked out the commit b1c5356e873c~1 (HEAD is
>> now at d923ff258423 KVM: MIPS/MMU: Convert to the gfn-based MMU notifier
>> callbacks).
>> The kernel boots with '-smp 4' without any problems.
>> After that I patched with the probable first bad commit (KVM: PPC:
>> Convert to the gfn-based MMU notifier callbacks). The kernel also boots
>> with this patch. That means, this isn't the first bad commit.
>> Further information:
>> https://forum.hyperion-entertainment.com/viewtopic.php?p=53267#p53267
> Hmm, okay that probably rules out those notifier changes then.
>
> Can you remind me were you able to rule these out as suspects?
>
> 8f6cc75a97d1 powerpc: move norestart trap flag to bit 0
> 8dc7f0229b78 powerpc: remove partial register save logic
> c45ba4f44f6b powerpc: clean up do_page_fault
> d738ee8d56de powerpc/64e/interrupt: handle bad_page_fault in C
> ceff77efa4f8 powerpc/64e/interrupt: Use new interrupt context tracking scheme
> 097157e16cf8 powerpc/64e/interrupt: reconcile irq soft-mask state in C
> 3db8aa10de9a powerpc/64e/interrupt: NMI save irq soft-mask state in C
> 0c2472de23ae powerpc/64e/interrupt: use new interrupt return
> dc6231821a14 powerpc/interrupt: update common interrupt code for
> 4228b2c3d20e powerpc/64e/interrupt: always save nvgprs on interrupt
> 5a5a893c4ad8 powerpc/syscall: switch user_exit_irqoff and trace_hardirqs_off order
>
> Thanks,
> Nick
Hi Nick,

Thanks for your answer. Smp 4 still doesn't work on quad core e5500 
CPUs. I use -smp 3 currently. Shall I checkout the commits above (in 
your last answer) and test them? Do you prefer a commit for testing?

Thanks,
Christian