Re: [PATCH] KVM: LAPIC: Narrow down the timer fastpath to tscdeadline timer

[Paolo Bonzini]

On 5/10/22 16:15, Sean Christopherson wrote:
> >   
> > -static fastpath_t handle_fastpath_preemption_timer(struct kvm_vcpu *vcpu)
> > +static bool __handle_preemption_timer(struct kvm_vcpu *vcpu)
> >   {
> >   	struct vcpu_vmx *vmx = to_vmx(vcpu);
> >   
> >   	if (!vmx->req_immediate_exit &&
> >   	    !unlikely(vmx->loaded_vmcs->hv_timer_soft_disabled)) {
> >   		kvm_lapic_expired_hv_timer(vcpu);
> > -		return EXIT_FASTPATH_REENTER_GUEST;
> > +		return true;
> >   	}
> >   
> > +	return false;
> It's a bit odd for the non-fastpath case, but I'd prefer to return fastpath_t
> instead of a bool from the inner helper, e.g.

Yeah, enum > bool almost always (or negative errno).  But I also agree 
that using the fast path for periodic or oneshot timers is not 
inherently a bad idea.

Paolo