Re: [PATCH v2] xen/events: remove event handling recursion detection

[JÃrgen GroÃ]

On 28.11.19 22:37, Boris Ostrovsky wrote:
> On 11/28/19 3:45 AM, Juergen Gross wrote:
> > -
> >   static void __xen_evtchn_do_upcall(void)
> >   {
> >   	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
> > -	int cpu = get_cpu();
> > -	unsigned count;
> > +	int cpu = smp_processor_id();
> >   
> >   	do {
> >   		vcpu_info->evtchn_upcall_pending = 0;
> >   
> > -		if (__this_cpu_inc_return(xed_nesting_count) - 1)
> > -			goto out;
> > -
> >   		xen_evtchn_handle_events(cpu);
> >   
> >   		BUG_ON(!irqs_disabled());
> >   
> > -		count = __this_cpu_read(xed_nesting_count);
> > -		__this_cpu_write(xed_nesting_count, 0);
> > -	} while (count != 1 || vcpu_info->evtchn_upcall_pending);
> > -
> > -out:
> > +		rmb(); /* Hypervisor can set upcall pending. */
>
> virt_rmb() perhaps then?

Yes, that's better.


Juergen