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

From: Christian Zigotzky <chzigotzky@xenosoft.de>
To: Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	"kvm-ppc@vger.kernel.org" <kvm-ppc@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: Darren Stevens <darren@stevens-zone.net>,
	"R.T.Dickinson" <rtd2@xtra.co.nz>,
	mad skateman <madskateman@gmail.com>,
	Christian Zigotzky <info@xenosoft.de>
Subject: Re: [FSL P50x0] KVM HV doesn't work anymore
Date: Wed, 19 May 2021 13:52:16 +0200	[thread overview]
Message-ID: <acf63821-2030-90fa-f178-b2baeb0c4784@xenosoft.de> (raw)
In-Reply-To: <1621410977.cgh0d6nvlo.astroid@bobo.none>

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

Cheers,
Christian