Re: [PATCH v2 06/10] KVM: x86: acknowledgment mechanism for async pf page ready notifications

[Paolo Bonzini]

On 25/05/20 16:41, Vitaly Kuznetsov wrote:
> +	case MSR_KVM_ASYNC_PF_ACK:
> +		if (data & 0x1) {
> +			vcpu->arch.apf.pageready_pending = false;
> +			kvm_check_async_pf_completion(vcpu);
> +		}
> +		break;
>  	case MSR_KVM_STEAL_TIME:
>  
>  		if (unlikely(!sched_info_on()))
> @@ -3183,6 +3189,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  	case MSR_KVM_ASYNC_PF_INT:
>  		msr_info->data = vcpu->arch.apf.msr_int_val;
>  		break;
> +	case MSR_KVM_ASYNC_PF_ACK:
> +		msr_info->data = 0;
> +		break;

How is the pageready_pending flag migrated?  Should we revert the
direction of the MSR (i.e. read the flag, and write 0 to clear it)?

Paolo