> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Tuesday, July 17, 2012 10:31 PM
> To: Bhushan Bharat-R65777
> Cc: Wood Scott-B07421; Alexander Graf; kvm-ppc@xxxxxxxxxxxxxxx;
> kvm@xxxxxxxxxxxxxxx; bharatb.yadav@xxxxxxxxx; Benjamin Herrenschmidt; Kumar Gala
> Subject: Re: [PATCH 2/2 v2] KVM: PPC: booke: Add watchdog emulation
>
> On 07/17/2012 11:56 AM, Bhushan Bharat-R65777 wrote:
> >
> >
> >> -----Original Message-----
> >> From: Wood Scott-B07421
> >> Sent: Tuesday, July 17, 2012 10:08 PM
> >> To: Bhushan Bharat-R65777
> >> Cc: Wood Scott-B07421; Alexander Graf; kvm-ppc@xxxxxxxxxxxxxxx;
> >> kvm@xxxxxxxxxxxxxxx; bharatb.yadav@xxxxxxxxx; Benjamin Herrenschmidt;
> >> Kumar Gala
> >> Subject: Re: [PATCH 2/2 v2] KVM: PPC: booke: Add watchdog emulation
> >>
> >> On 07/17/2012 06:31 AM, Bhushan Bharat-R65777 wrote:
> >>>>>> int kvm_arch_vcpu_runnable(struct kvm_vcpu *v) {
> >>>>>> - return !(v->arch.shared->msr & MSR_WE) ||
> >>>>>> - !!(v->arch.pending_exceptions) ||
> >>>>>> - v->requests;
> >>>>>> + bool ret = !(v->arch.shared->msr & MSR_WE) ||
> >>>>>> + !!(v->arch.pending_exceptions) ||
> >>>>>> + v->requests;
> >>>>>> +
> >>>>>> + ret = ret || kvmppc_get_tsr_wrc(v);
> >>>>>
> >>>>> Why do you need to declare the cpu as non-runnable when a watchdog
> >>>>> event occured?
> >>>>
> >>>> It's the other way around -- it's always runnable when a watchdog
> >>>> exit is pending. It's like a pending exception.
> >>>
> >>> With the above check, Are we trying to handle the case where
> >>> watchdog interrupt bit in pending_exception is cleared by guest
> >>> after final expiry but before the qemu exit?
> >>
> >> No, we're just trying to test the actual condition we want to exit on.
> >> The watchdog interrupt might be masked (either with WIE or CE).
> >
> > If the interrupt is masked then still the pending_exception will be set.
>
> Not if it's masked by WIE -- and even when masked by CE, it's a bug that we
> currently consider the vcpu runnable. We shouldn't depend on that bug.
Scott can you please describe what is bug? What I remember is that if vcpu is not run-able then we halt vcpu and cannot cause qemu exit also.
Thanks
-Bharat
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