[Xen-devel] [PATCH v8 3/7] xen/arm: send IPIs to inject irqs into guest vcpus running on different pcpus

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

If we need to inject an irq into a VCPU that is running on a different
processor, we shouldn't just enqueue the irq into the lr_pending and
inflight lists and wait for something to interrupt the guest execution.
Send an IPI to the target pcpu so that Xen can inject the new interrupt
returning to guest.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

Changes in v4:
- check for is_running before vcpu_unblock;
- use smp_send_event_check_cpu instead of smp_send_event_check_mask.
---
 xen/arch/arm/vgic.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 5d242c8..0e9cc4a 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -648,6 +648,7 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int irq, 
int virtual)
     struct vgic_irq_rank *rank = vgic_irq_rank(v, 8, idx);
     struct pending_irq *iter, *n = irq_to_pending(v, irq);
     unsigned long flags;
+    bool_t running;
 
     spin_lock_irqsave(&v->arch.vgic.lock, flags);
 
@@ -683,7 +684,10 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int 
irq, int virtual)
 out:
     spin_unlock_irqrestore(&v->arch.vgic.lock, flags);
     /* we have a new higher priority irq, inject it into the guest */
+    running = v->is_running;
     vcpu_unblock(v);
+    if ( running && v != current )
+        smp_send_event_check_mask(cpumask_of(v->processor));
 }
 
 /*
-- 
1.7.2.5


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