# Re: \[PATCH v2 05/37\] KVM: PPC: Book3S HV: Ensure MSR\[ME\] is always set in guest MSR

- From: Daniel Axtens \<hidden\>
- Date: 2021-03-05 04:51:35 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2021/03/9521219
- Thread: https://ratatoskr.run/linuxppc-dev/2021/02/9521073/t.md

```text
>> This 'if' is technically redundant but you mention a future patch warning
>> on !(msr & MSR_ME) so I'm holding off on any judgement about the 'if' until
>> I get to that patch :)
>
> That's true. The warning is actually further down when we're setting up 
> the msr to run in guest mode. At this point the MSR I think comes from
> qemu (and arguably the guest setup code shouldn't need to know about HV
> specific MSR bits) so a warning here wouldn't be appropriate.
>
> I could remove the if, although the compiler might already do that.

Yes, I think the compiler is almost certainly going to remove that.

I'd probably not include the 'if' statement even though it probably gets
removed by the compiler but I think that's more a matter of taste than
anything else.

Kind regards,
Daniel

>
>> 
>> The patch seems sane to me, I agree that we don't want guests running with
>> MSR_ME=0 and kvmppc_set_msr_hv already ensures that the transactional state is
>> sane so this is another sanity-enforcement in the same sort of vein.
>> 
>> All up:
>> Reviewed-by: Daniel Axtens <redacted>
>
> Thanks,
> Nick
```