On Tue, 2 Feb 2010, Ian Campbell wrote:
> It looks like you are using evtchn's for all interrupt injection,
> including any emulated or passthrough devices which may be present.
> Using evtchn's for PV devices obviously makes sense but I think this
> needs to coexist with emulated interrupt injection for non-PV devices so
> the IOAPIC/APIC should not be mutually exclusive with using PV evtchns.
>
Indeed.
Evtchn's for PV devices are more than welcome, but this:
> diff --git a/xen/arch/x86/hvm/irq.c b/xen/arch/x86/hvm/irq.c
> --- a/xen/arch/x86/hvm/irq.c
> +++ b/xen/arch/x86/hvm/irq.c
> @@ -46,8 +46,18 @@ static void __hvm_pci_intx_assert(
> if ( (hvm_irq->pci_link_assert_count[link]++ == 0) && isa_irq &&
> (hvm_irq->gsi_assert_count[isa_irq]++ == 0) )
> {
> - vioapic_irq_positive_edge(d, isa_irq);
> - vpic_irq_positive_edge(d, isa_irq);
> + if ( !is_hybrid_evtchn_enabled_domain(d) )
> + {
> + vioapic_irq_positive_edge(d, isa_irq);
> + vpic_irq_positive_edge(d, isa_irq);
> + }
> + else
> + {
> + /* TODO fix the critical region here */
> + spin_unlock(&d->arch.hvm_domain.irq_lock);
> + send_guest_global_virq(d, VIRQ_EMUL_PIN(isa_irq));
> + spin_lock(&d->arch.hvm_domain.irq_lock);
> + }
> }
> }
>
and this:
> @@ -101,11 +114,21 @@ void hvm_isa_irq_assert(
> if ( !__test_and_set_bit(isa_irq, &hvm_irq->isa_irq.i) &&
> (hvm_irq->gsi_assert_count[gsi]++ == 0) )
> {
> - vioapic_irq_positive_edge(d, gsi);
> - vpic_irq_positive_edge(d, isa_irq);
> + if ( !is_hybrid_evtchn_enabled_domain(d) )
> + {
> + vioapic_irq_positive_edge(d, gsi);
> + vpic_irq_positive_edge(d, isa_irq);
> + }
> + else
> + {
> + send_virq = 1;
> + }
> }
>
and this:
> @@ -120,7 +143,10 @@ void hvm_isa_irq_deassert(
>
> if ( __test_and_clear_bit(isa_irq, &hvm_irq->isa_irq.i) &&
> (--hvm_irq->gsi_assert_count[gsi] == 0) )
> - vpic_irq_negative_edge(d, isa_irq);
> + {
> + if ( !is_hybrid_evtchn_enabled_domain(d) )
> + vpic_irq_negative_edge(d, isa_irq);
> + }
>
> spin_unlock(&d->arch.hvm_domain.irq_lock);
> }
>
I think they are a very bad idea and a maintenance pain, especially when
you think about pci passthrought.
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