[PATCH V4] POWERPC: BOOK3S: KVM: Use the saved dar value and generic make_dsisr

Aneesh Kumar K.V aneesh.kumar at linux.vnet.ibm.com
Tue May 6 01:03:11 EST 2014

Olof Johansson <olofj at google.com> writes:

> 2014-05-05 7:43 GMT-07:00 Alexander Graf <agraf at suse.de>:
>> On 05/05/2014 04:26 PM, Aneesh Kumar K.V wrote:
>>> Alexander Graf <agraf at suse.de> writes:
>>>  On 05/04/2014 07:21 PM, Aneesh Kumar K.V wrote:
>>>>> Although it's optional IBM POWER cpus always had DAR value set on
>>>>> alignment interrupt. So don't try to compute these values.
>>>>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
>>>>> ---
>>>>> Changes from V3:
>>>>> * Use make_dsisr instead of checking feature flag to decide whether to
>>>>> use
>>>>>     saved dsisr or not
>>>>>  ....
>>>     ulong kvmppc_alignment_dar(struct kvm_vcpu *vcpu, unsigned int inst)
>>>>>    {
>>>>> +#ifdef CONFIG_PPC_BOOK3S_64
>>>>> +       return vcpu->arch.fault_dar;
>>>> How about PA6T and G5s?
>>>>  Paul mentioned that BOOK3S always had DAR value set on alignment
>>> interrupt. And the patch is to enable/collect correct DAR value when
>>> running with Little Endian PR guest. Now to limit the impact and to
>>> enable Little Endian PR guest, I ended up doing the conditional code
>>> only for book3s 64 for which we know for sure that we set DAR value.
>> Yes, and I'm asking whether we know that this statement holds true for
>> PA6T and G5 chips which I wouldn't consider IBM POWER. Since the G5 is at
>> least developed by IBM, I'd assume its semantics here are similar to
>> POWER4, but for PA6T I wouldn't be so sure.
> Thanks for looking out for us, obviously IBM doesn't (based on the reply a
> minute ago).

The reason I deferred the question to Paul is really because I don't
know enough about PA6T and G5 to comment. I intentionally restricted the
changes to BOOK3S_64 because I wanted to make sure I don't break
anything else. It is in no way to hint that others don't care.


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