KVM: PPC: Book3E: KVM HV host module doesn't work anymore

[Christian Zigotzky]

On 20/12/24 13:08 Christian Zigotzky wrote:
> On 18/12/24 15:41, Christian Zigotzky wrote:
>> On 18/12/24 12:10, Christian Zigotzky wrote:
>>> Hello,
>>>
>>> The KVM HV host module doesn't work anymore since the PowerPC 
>>> updates 6.13-1 [1] and PowerPC MM updates [2].
>>>
>>> We have tested it with our FSL P5020/P5040 boards [3].
>>>
>>> The guest kernel doesn't boot. There is no output via the serial 
>>> connection and no output via the graphics card. (QEMU)
>>>
>>> It boots without the PowerPC updates 6.13-1 [1] and PowerPC MM 
>>> updates [2].
>>>
>>> Is the problem already known? Is there already a solution? I have 
>>> seen many Book3S KVM HV updates. Have you perhaps forgotten Book3E?
>>>
>>> Thanks,
>>> Christian
>>>
>>> [1] 
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=42d9e8b7ccddee75989283cf7477305cfe3776ff
>>> [2] 
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5c00ff742bf5caf85f60e1c73999f99376fb865d
>>> [3] http://wiki.amiga.org/index.php?title=X5000
>>>
>>
>> I tried to bisect but without success. Link: 
>> https://github.com/chzigotzky/kernels/issues/4#issuecomment-2551460323
>>
>> -- Christian
>>
> It seems, that the PowerPC updates 6.13-1 aren't responsible for this 
> issue. I had to test the PowerPC updates 6.13-1 during the bisect. [1]
>
> Bisecting: 428 revisions left to test after this (roughly 9 steps)
> [42d9e8b7ccddee75989283cf7477305cfe3776ff] Merge tag 'powerpc-6.13-1' 
> of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
>
> Result:  git bisect good
>
> There aren't any changes in the PowerPC MM updates [2].
>
> Do you have another idea? I like KVM HV on my FSL P5040 system and use 
> it very often for testing. However, KVM HV is hardly used by our 
> users, so we could remove it from our kernels if it were not fixed. It 
> would save space to remove it.
>
> -- Christian
>
> [1] https://github.com/chzigotzky/kernels/issues/4
> [2] 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5c00ff742bf5caf85f60e1c73999f99376fb865d
Maybe the kvm updates [1] from Paolo Bonzini are responsible for this issue.

+ Paolo Bonzini

I have found some changes in the e500_mmu_host.c file 
(a/arch/powerpc/kvm/e500_mmu_host.c) in the kvm updates [1].

-- Christian

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9f16d5e6f220661f73b36a4be1b21575651d8833