[FSL P50x0] KVM HV doesn't work anymore

[Nicholas Piggin]

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