Re: [PATCH v3 2/2] KVM: x86/xen: Stop Xen timer before changing IRQ

[Paolo Bonzini]

On 8/9/22 16:16, David Woodhouse wrote:
> I find the new version a bit harder to follow, with its init-then-stop-
> then-start logic:
>
> 	case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
> 		if (data->u.timer.port &&
> 		    data->u.timer.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) {
> 			r = -EINVAL;
> 			break;
>                  }
>
> 		if (!vcpu->arch.xen.timer.function)
> 			kvm_xen_init_timer(vcpu);
>
> 		/* Stop the timer (if it's running) before changing the vector */
> 		kvm_xen_stop_timer(vcpu);
> 		vcpu->arch.xen.timer_virq = data->u.timer.port;


I think this is fine, if anything the kvm_xen_stop_timer() call could be 
placed in an "else" but I'm leaning towards applying this version of the 
patch.

Paolo