[Xen-devel] [RFC PATCH 01/10] ARM: vGIC: remove rank lock from IRQ routing functions

[Andre Przywara <andre.przywara@xxxxxxx>]

gic_route_irq_to_guest() and gic_remove_irq_from_guest() take the rank
lock, however never actually access the rank structure.
Avoid taking the lock in those two functions and remove some more
unneeded code on the way.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
 xen/arch/arm/gic.c | 28 ++++------------------------
 1 file changed, 4 insertions(+), 24 deletions(-)

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index da19130..c734f66 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -136,25 +136,19 @@ void gic_route_irq_to_xen(struct irq_desc *desc, unsigned 
int priority)
 int gic_route_irq_to_guest(struct domain *d, unsigned int virq,
                            struct irq_desc *desc, unsigned int priority)
 {
-    unsigned long flags;
     /* Use vcpu0 to retrieve the pending_irq struct. Given that we only
      * route SPIs to guests, it doesn't make any difference. */
-    struct vcpu *v_target = vgic_get_target_vcpu(d->vcpu[0], virq);
-    struct vgic_irq_rank *rank = vgic_rank_irq(v_target, virq);
-    struct pending_irq *p = irq_to_pending(v_target, virq);
-    int res = -EBUSY;
+    struct pending_irq *p = irq_to_pending(d->vcpu[0], virq);
 
     ASSERT(spin_is_locked(&desc->lock));
     /* Caller has already checked that the IRQ is an SPI */
     ASSERT(virq >= 32);
     ASSERT(virq < vgic_num_irqs(d));
 
-    vgic_lock_rank(v_target, rank, flags);
-
     if ( p->desc ||
          /* The VIRQ should not be already enabled by the guest */
          test_bit(GIC_IRQ_GUEST_ENABLED, &p->status) )
-        goto out;
+        return -EBUSY;
 
     desc->handler = gic_hw_ops->gic_guest_irq_type;
     set_bit(_IRQ_GUEST, &desc->status);
@@ -164,29 +158,20 @@ int gic_route_irq_to_guest(struct domain *d, unsigned int 
virq,
     gic_set_irq_priority(desc, priority);
 
     p->desc = desc;
-    res = 0;
 
-out:
-    vgic_unlock_rank(v_target, rank, flags);
-
-    return res;
+    return 0;
 }
 
 /* This function only works with SPIs for now */
 int gic_remove_irq_from_guest(struct domain *d, unsigned int virq,
                               struct irq_desc *desc)
 {
-    struct vcpu *v_target = vgic_get_target_vcpu(d->vcpu[0], virq);
-    struct vgic_irq_rank *rank = vgic_rank_irq(v_target, virq);
-    struct pending_irq *p = irq_to_pending(v_target, virq);
-    unsigned long flags;
+    struct pending_irq *p = irq_to_pending(d->vcpu[0], virq);
 
     ASSERT(spin_is_locked(&desc->lock));
     ASSERT(test_bit(_IRQ_GUEST, &desc->status));
     ASSERT(p->desc == desc);
 
-    vgic_lock_rank(v_target, rank, flags);
-
     if ( d->is_dying )
     {
         desc->handler->shutdown(desc);
@@ -204,10 +189,7 @@ int gic_remove_irq_from_guest(struct domain *d, unsigned 
int virq,
          */
         if ( test_bit(_IRQ_INPROGRESS, &desc->status) ||
              !test_bit(_IRQ_DISABLED, &desc->status) )
-        {
-            vgic_unlock_rank(v_target, rank, flags);
             return -EBUSY;
-        }
     }
 
     clear_bit(_IRQ_GUEST, &desc->status);
@@ -215,8 +197,6 @@ int gic_remove_irq_from_guest(struct domain *d, unsigned 
int virq,
 
     p->desc = NULL;
 
-    vgic_unlock_rank(v_target, rank, flags);
-
     return 0;
 }
 
-- 
2.9.0


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