Re: [PATCH 7/9] KVM: PPC: Emulate trap SRR1 flags properly

[Alexander Graf <agraf-l3A5Bk7waGM@public.gmane.org>]

On 08.01.2010, at 20:29, Hollis Blanchard wrote:

> On Thu, Jan 7, 2010 at 5:58 PM, Alexander Graf <agraf-l3A5Bk7waGM@public.gmane.org> wrote:
>> Book3S needs some flags in SRR1 to get to know details about an interrupt.
>> 
>> One such example is the trap instruction. It tells the guest kernel that
>> a program interrupt is due to a trap using a bit in SRR1.
>> 
>> This patch implements above behavior, making WARN_ON behave like WARN_ON.
> 
> ... "for Book S". It already works properly for Book E, thankyouverymuch. ;)
> 
>> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
>> index 338baf9..e283e44 100644
>> --- a/arch/powerpc/kvm/booke.c
>> +++ b/arch/powerpc/kvm/booke.c
>> @@ -82,8 +82,9 @@ static void kvmppc_booke_queue_irqprio(struct kvm_vcpu *vcpu,
>>        set_bit(priority, &vcpu->arch.pending_exceptions);
>>  }
>> 
>> -void kvmppc_core_queue_program(struct kvm_vcpu *vcpu)
>> +void kvmppc_core_queue_program(struct kvm_vcpu *vcpu, ulong flags)
>>  {
>> +       /* BookE does flags in ESR, so ignore those we get here */
>>        kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_PROGRAM);
>>  }
> 
> Actually, I think Book E prematurely sets ESR, since it's done before
> the program interrupt is actually delivered. Architecturally, I'm not
> sure if it's a problem, but philosophically I've always wanted it to
> work the way you've just implemented for Book S.
> 
> Anyways, since we can't test changes at the moment (Yu, can you?), I'd
> settle for a comment to the effect that Book E code *should* do this,
> but doesn't (rather than the comment above that says it's ok).

Hm, can't you just write up a patch that removes the comment I put in, does the ESR setting in the function and do an #ifdef in emulate.c?

That way we can incrementally improve things. This series is really about Book3S. Improving BookE should go in a different patch.

Alex--
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