Re: [kvm-ppc-devel] [PATCH 2 of 2] Add PowerPC KVM guest wait handling support

[Hollis B. <ho...@us...>]

On Thursday 03 April 2008 14:35:59 Jerone Young wrote:
> # HG changeset patch
> # User Jerone Young <jy...@us...>
> # Date 1207250241 18000
> # Node ID 3e781009d2f28c4691ccbb999bf679716f66f349
> # Parent  b7794c1fa50b531c9b84382c3f3d9a5466d86c0d
> Add PowerPC KVM guest wait handling support
>
> This patch handles a guest that is in a wait state. This ensures that the
> guest is not allways eating up 100% cpu when it is idle.
>
> Signed-off-by: Jerone Young <jy...@us...>
>
> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
> --- a/arch/powerpc/kvm/emulate.c
> +++ b/arch/powerpc/kvm/emulate.c
> @@ -269,6 +269,25 @@ int kvmppc_emulate_instruction(struct kv
>  		case 146:                                       /* mtmsr */
>  			rs = get_rs(inst);
>  			kvmppc_set_msr(vcpu, vcpu->arch.gpr[rs]);
> +
> +			/* handle guest vcpu that is in wait state */
> +			if (vcpu->arch.msr & MSR_WE) {
> +			/* XXX eventually replace with kvm_vcpu_block() */
> +				DECLARE_WAITQUEUE(wait, current);
> +
> +				add_wait_queue(&vcpu->wq, &wait);
> +
> +				while (!kvm_cpu_has_interrupt(vcpu)
> +					&& !signal_pending(current)
> +					&& !kvm_arch_vcpu_runnable(vcpu)) {
> +					set_current_state(TASK_INTERRUPTIBLE);
> +					schedule();
> +				}
> +
> +				__set_current_state(TASK_RUNNING);
> +				remove_wait_queue(&vcpu->wq, &wait);
> +			}
> +
>  			break;
>
>  		case 163:                                       /* wrteei */
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -164,13 +164,12 @@ void kvmppc_dump_vcpu(struct kvm_vcpu *v
>
>  int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
>  {
> -	/* XXX implement me */
> -	return 0;
> +	return !!(v->arch.pending_exceptions);
>  }
>
>  int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
>  {
> -	return 1;
> +	return !(v->arch.msr & MSR_WE);
>  }
>
>  /* Check if we are ready to deliver the interrupt */

Hmm, did you ever revise this patch? I don't see the corrected version.

-- 
Hollis Blanchard
IBM Linux Technology Center