Re: [Qemu-ppc] [RFC PATCH 04/17] KVM: PPC64: booke: Add guest computation mode for irq delivery

[Alexander Graf]

On 06.07.2012, at 01:51, Scott Wood <address@hidden> wrote:

> On 07/04/2012 08:40 AM, Alexander Graf wrote:
>> On 25.06.2012, at 14:26, Mihai Caraman wrote:
>>> @@ -381,7 +386,8 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu 
>>> *vcpu,
>>>            set_guest_esr(vcpu, vcpu->arch.queued_esr);
>>>        if (update_dear == true)
>>>            set_guest_dear(vcpu, vcpu->arch.queued_dear);
>>> -        kvmppc_set_msr(vcpu, vcpu->arch.shared->msr & msr_mask);
>>> +        kvmppc_set_msr(vcpu, (vcpu->arch.shared->msr & msr_mask)
>>> +                | msr_cm);
>> 
>> Please split this computation out into its own variable and apply the 
>> masking regardless. Something like
>> 
>> ulong new_msr = vcpu->arch.shared->msr;
>> if (vcpu->arch.epcr & SPRN_EPCR_ICM)
>>    new_msr |= MSR_CM;
>> new_msr &= msr_mask;
>> kvmppc_set_msr(vcpu, new_msr);
> 
> This will fail to clear MSR[CM] in the odd but legal situation where you
> have MSR[CM] set but EPCR[ICM] unset.

Ah. Good point. Then leave the msr_mask logic as before and only stretch it out 
into its own variable.

Alex

> 
> -Scott
>