Re: [Xen-devel] [PATCH 7/7] xen: Enable event channel of PV extension of HVM

[Sheng Yang <sheng@linux.intel.com>]

On Tuesday 09 March 2010 01:10:56 Stefano Stabellini wrote:
> I think that mapping interrupts into VIRQs is a bad idea: you should map
> interrupts into pirqs instead, the code exists already on the kernel
> side so we don't need to do any (ugly) change ther.

The code existed in the pv_ops dom0 side, but not in the upstream Linux. The 
latter is our target. We want this work to be accepted by upstream Linux soon.

Thanks.

-- 
regards
Yang, Sheng

> Look at xen_setup_pirqs() to get an idea about how it works, in my patch
> series enabling pirq\interrupt mappings is basically a one line change.
> Besides pirqs and interrupts can coexist without problems and even make
> pv on hvm work out of the box.
> 
> Even though you don't seem interested, I am still open on collaborating
> with you to complete this patch series.
> 
> On Mon, 8 Mar 2010, Sheng Yang wrote:
> > @@ -944,3 +958,51 @@ void __init xen_init_IRQ(void)
> >
> >         irq_ctx_init(smp_processor_id());
> >  }
> > +
> > +void __init xen_hvm_pv_evtchn_init_IRQ(void)
> > +{
> > +       int i;
> > +
> > +       xen_init_IRQ();
> > +       for (i = 0; i < NR_IRQS_LEGACY; i++) {
> > +               struct evtchn_bind_virq bind_virq;
> > +               struct irq_desc *desc = irq_to_desc(i);
> > +               int virq, evtchn;
> > +
> > +               virq = i + VIRQ_EMUL_PIN_START;
> > +               bind_virq.virq = virq;
> > +               bind_virq.vcpu = 0;
> > +
> > +               if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
> > +                                               &bind_virq) != 0)
> > +                       BUG();
> > +
> > +               evtchn = bind_virq.port;
> > +               evtchn_to_irq[evtchn] = i;
> > +               irq_info[i] = mk_virq_info(evtchn, virq);
> > +
> > +               desc->status = IRQ_DISABLED;
> > +               desc->action = NULL;
> > +               desc->depth = 1;
> > +
> > +               /*
> > +                * 16 old-style INTA-cycle interrupts:
> > +                */
> > +               set_irq_chip_and_handler_name(i, &xen_dynamic_chip,
> > +                                       handle_level_irq, "event");
> > +       }
> > +
> > +       /*
> > +        * Cover the whole vector space, no vector can escape
> > +        * us. (some of these will be overridden and become
> > +        * 'special' SMP interrupts)
> > +        */
> > +       for (i = 0; i < (NR_VECTORS - FIRST_EXTERNAL_VECTOR); i++) {
> > +               int vector = FIRST_EXTERNAL_VECTOR + i;
> > +               if (vector != IA32_SYSCALL_VECTOR)
> > +                       set_intr_gate(vector, interrupt[i]);
> > +       }
> > +
> > +       /* generic IPI for platform specific use, now used for HVM evtchn
> > */ +       alloc_intr_gate(X86_PLATFORM_IPI_VECTOR, x86_platform_ipi); +}
>