Re: [Xen-devel] [PATCH v9 07/10] xen: remove workaround to inject evtchn_irq on irq enable

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 01.08.14 at 19:00, <stefano.stabellini@xxxxxxxxxxxxx> wrote:
> On Fri, 25 Jul 2014, Jan Beulich wrote:
>> but I still don't see why ARM needs what x86 (even for HVM) appears to
>> get along fine without.
> 
> Good question.
> x86 PV guests have in xen_irq_enable:
> 
> if (unlikely(vcpu->evtchn_upcall_pending))
>         xen_force_evtchn_callback();
> 
> Also xen_irq_enable_direct calls check_events.
> 
> I suspect that PV on HVM guests that get events via gsi interrupts get
> away without it because they only call VCPUOP_register_vcpu_info on
> secondary cpus.

But my pointer was specifically to pure HVM guests (among all the
other possible kinds)...

Jan


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