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

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

evtchn_upcall_pending is already set by common code at vcpu creation,
therefore on ARM we also need to call vgic_vcpu_inject_irq for it.
Currently we do that from vgic_enable_irqs as a workaround.

Do this properly by introducing an appropriate arch specific hook:
arch_evtchn_inject. arch_evtchn_inject is called by map_vcpu_info to
inject the evtchn irq into the guest. On ARM is implemented by calling
vgic_vcpu_inject_irq, on x86 is unneeded.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
CC: JBeulich@suse.com
---

Changes in v9:
- use an arch hook.

Changes in v2:
- coding style fix;
- add comment;
- return an error if arch_set_info_guest is called without VGCF_online.
---
 xen/arch/arm/vgic.c         |   23 +++++++++--------------
 xen/common/domain.c         |    1 +
 xen/include/asm-arm/event.h |    2 ++
 xen/include/asm-x86/event.h |    2 ++
 4 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 299ae7e..474eebd 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -263,20 +263,10 @@ void vgic_enable_irqs(struct vcpu *v, uint32_t r, int n)
         v_target = d->arch.vgic.handler->get_target_vcpu(v, irq);
         p = irq_to_pending(v_target, irq);
         set_bit(GIC_IRQ_GUEST_ENABLED, &p->status);
-        /* We need to force the first injection of evtchn_irq because
-         * evtchn_upcall_pending is already set by common code on vcpu
-         * creation. */
-        if ( irq == v_target->domain->arch.evtchn_irq &&
-             vcpu_info(current, evtchn_upcall_pending) &&
-             list_empty(&p->inflight) )
-            vgic_vcpu_inject_irq(v_target, irq);
-        else {
-            unsigned long flags;
-            spin_lock_irqsave(&v_target->arch.vgic.lock, flags);
-            if ( !list_empty(&p->inflight) && !test_bit(GIC_IRQ_GUEST_VISIBLE, &p->status) )
-                gic_raise_guest_irq(v_target, irq, p->priority);
-            spin_unlock_irqrestore(&v_target->arch.vgic.lock, flags);
-        }
+        spin_lock_irqsave(&v_target->arch.vgic.lock, flags);
+        if ( !list_empty(&p->inflight) && !test_bit(GIC_IRQ_GUEST_VISIBLE, &p->status) )
+            gic_raise_guest_irq(v_target, irq, p->priority);
+        spin_unlock_irqrestore(&v_target->arch.vgic.lock, flags);
         if ( p->desc != NULL )
         {
             irq_set_affinity(p->desc, cpumask_of(v_target->processor));
@@ -432,6 +422,11 @@ void vgic_vcpu_inject_spi(struct domain *d, unsigned int irq)
     vgic_vcpu_inject_irq(v, irq);
 }
 
+void arch_evtchn_inject(struct vcpu *v)
+{
+    vgic_vcpu_inject_irq(v, v->domain->arch.evtchn_irq);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/common/domain.c b/xen/common/domain.c
index cd64aea..05d0049 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -1058,6 +1058,7 @@ int map_vcpu_info(struct vcpu *v, unsigned long gfn, unsigned offset)
     vcpu_info(v, evtchn_upcall_pending) = 1;
     for ( i = 0; i < BITS_PER_EVTCHN_WORD(d); i++ )
         set_bit(i, &vcpu_info(v, evtchn_pending_sel));
+    arch_evtchn_inject(v);
 
     return 0;
 }
diff --git a/xen/include/asm-arm/event.h b/xen/include/asm-arm/event.h
index 5330dfe..8c77427 100644
--- a/xen/include/asm-arm/event.h
+++ b/xen/include/asm-arm/event.h
@@ -56,6 +56,8 @@ static inline int arch_virq_is_global(int virq)
     return 1;
 }
 
+void arch_evtchn_inject(struct vcpu *v);
+
 #endif
 /*
  * Local variables:
diff --git a/xen/include/asm-x86/event.h b/xen/include/asm-x86/event.h
index a82062e..3c1a9d1 100644
--- a/xen/include/asm-x86/event.h
+++ b/xen/include/asm-x86/event.h
@@ -44,4 +44,6 @@ static inline int arch_virq_is_global(uint32_t virq)
     return 1;
 }
 
+static inline void arch_evtchn_inject(struct vcpu *v) { }
+
 #endif
-- 
1.7.10.4