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

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Mon, 05 May 2014 19:56:22 +0530

Alexander Graf <[email-masked]> 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 <[email-masked]>
>> ---
>> 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.

-aneesh