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

[Christian Zigotzky <chzigotzky@xenosoft.de>]

On 17 May 2021 at 09:42am, Nicholas Piggin wrote:
> Excerpts from Christian Zigotzky's message of May 15, 2021 11:46 pm:
>> On 15 May 2021 at 12:08pm Christophe Leroy wrote:
>>>
>>> Le 15/05/2021 à 11:48, Christian Zigotzky a écrit :
>>>> Hi All,
>>>>
>>>> I bisected today [1] and the bisecting itself was OK but the
>>>> reverting of the bad commit doesn't solve the issue. Do you have an
>>>> idea which commit could be resposible for this issue? Maybe the
>>>> bisecting wasn't successful. I will look in the kernel git log. Maybe
>>>> there is a commit that affected KVM HV on FSL P50x0 machines.
>>> If the uImage doesn't load, it may be because of the size of uImage.
>>>
>>> See https://github.com/linuxppc/issues/issues/208
>>>
>>> Is there a significant size difference with and without KVM HV ?
>>>
>>> Maybe you can try to remove another option to reduce the size of the
>>> uImage.
>> 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")?

Thanks in advance,

Christian