[Xen-devel] [RFC 04/16] vgic: move irq_to_pending out of lock

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

From: Andrii Anisov <andrii_anisov@xxxxxxxx>

For GICV2 pending_irq allocation is not concurrent, so reduce
some code under lock.

Signed-off-by: Andrii Anisov <andrii_anisov@xxxxxxxx>
---
 xen/arch/arm/vgic.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index a64633f..37857b1 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -267,17 +267,16 @@ bool vgic_migrate_irq(struct vcpu *old, struct vcpu *new, 
unsigned int irq)
     ASSERT(!is_lpi(irq));
 #endif
 
-    spin_lock_irqsave(&old->arch.vgic.lock, flags);
-
     p = irq_to_pending(old, irq);
 
     /* nothing to do for virtual interrupts */
     if ( p->desc == NULL )
     {
-        spin_unlock_irqrestore(&old->arch.vgic.lock, flags);
         return true;
     }
 
+    spin_lock_irqsave(&old->arch.vgic.lock, flags);
+
     /* migration already in progress, no need to do anything */
     if ( test_bit(GIC_IRQ_GUEST_MIGRATING, &p->status) )
     {
@@ -569,8 +568,6 @@ void vgic_inject_irq(struct domain *d, struct vcpu *v, 
unsigned int virq,
         return;
     }
 
-    spin_lock_irqsave(&v->arch.vgic.lock, flags);
-
     n = irq_to_pending(v, virq);
 #ifdef CONFIG_GICV3
     /* If an LPI has been removed, there is nothing to inject here. */
@@ -581,6 +578,8 @@ void vgic_inject_irq(struct domain *d, struct vcpu *v, 
unsigned int virq,
     }
 #endif
 
+    spin_lock_irqsave(&v->arch.vgic.lock, flags);
+
     set_bit(GIC_IRQ_GUEST_QUEUED, &n->status);
 
     if ( !list_empty(&n->inflight) )
-- 
2.7.4


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