Re: [Qemu-ppc] [PATCH v4 2/2] target/ppc: move POWER9 DD1 workaround to init_proc_POWER9()

[Laurent Vivier]

On 04/07/2017 13:21, Laurent Vivier wrote:
> On 04/07/2017 13:15, Greg Kurz wrote:
>> On Tue,  4 Jul 2017 13:01:26 +0200
>> Laurent Vivier <address@hidden> wrote:
>>
>>> Commit 5f3066d ("target/ppc: Allow workarounds for POWER9 DD1")
>>> disables compatibility mode for POWER9 DD1 to allow to
>>> boot on POWER9 DD1 host with KVM.
>>>
>>> As the workaround has been added in kvmppc_host_cpu_class_init(),
>>> it applies only on CPU created with "-cpu host".
>>> As we want to be able to use also "-cpu POWER9" on a POWER9 DD1
>>> host, this patch moves the workaround from kvmppc_host_cpu_class_init()
>>> to init_proc_POWER9().
>>>
>>
>> As with ppc_cpu_initfn() in your previous version, init_proc_POWER9() is
>> called for every CPU instance.. ie, all CPU will adjust the @pcr_supported
>> class attribute...
>>
>> What about moving the workaround to ppc_POWER9_cpu_family_class_init()
>> instead ? This would just require to expose mfpvr() in some header.
> 
> I think I have already tried something like that, and I'm not sure the
> PVR is already set at this level of the initialization. But I'm going to
> try your patch.

oh, you check the host PVR, not the guest PVR.

Well, I'm not sure it's a good idea to modify the guest CPU property
according to the host CPU version. I let David to decide what is the
best solution here...

Thanks,
Laurent