[Xen-devel] [PATCH v2 38/45] ARM: new VGIC: Implement arch_move_irqs()

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

When a VCPU moves to another CPU, we need to adjust the target affinity
of any hardware mapped vIRQs, to observe our "physical-follows-virtual"
policy.
Implement arch_move_irqs() to adjust the physical affinity of all hardware
mapped vIRQs targetting this VCPU.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
---
Changelog v1 ... v2:
- use irq_set_affinity() directly, avoid vgic_sync_hardware_irq() and lock

 xen/arch/arm/vgic/vgic.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/xen/arch/arm/vgic/vgic.c b/xen/arch/arm/vgic/vgic.c
index 73cd43f0fa..1aae68ff83 100644
--- a/xen/arch/arm/vgic/vgic.c
+++ b/xen/arch/arm/vgic/vgic.c
@@ -781,6 +781,45 @@ void gic_dump_vgic_info(struct vcpu *v)
     spin_unlock_irqrestore(&v->arch.vgic.ap_list_lock, flags);
 }
 
+/**
+ * arch_move_irqs() - migrate the physical affinity of hardware mapped vIRQs
+ * @v:  the vCPU, already assigned to the new pCPU
+ *
+ * arch_move_irqs() updates the physical affinity of all virtual IRQs
+ * targetting this given vCPU. This only affects hardware mapped IRQs. The
+ * new pCPU to target is already set in v->processor.
+ * This is called by the core code after a vCPU has been migrated to a new
+ * physical CPU.
+ */
+void arch_move_irqs(struct vcpu *v)
+{
+    struct domain *d = v->domain;
+    unsigned int i;
+
+    /* We only target SPIs with this function */
+    for ( i = 0; i < d->arch.vgic.nr_spis; i++ )
+    {
+        struct vgic_irq *irq = vgic_get_irq(d, NULL, i + VGIC_NR_PRIVATE_IRQS);
+        unsigned long flags;
+
+        if ( !irq )
+            continue;
+
+        spin_lock_irqsave(&irq->irq_lock, flags);
+
+        /* only vIRQs that are not on a vCPU yet , but targetting this vCPU */
+        if ( irq->hw && !irq->vcpu && irq->target_vcpu == v)
+        {
+            irq_desc_t *desc = irq_to_desc(irq->hwintid);
+
+            irq_set_affinity(desc, cpumask_of(v->processor));
+        }
+
+        spin_unlock_irqrestore(&irq->irq_lock, flags);
+        vgic_put_irq(d, irq);
+    }
+}
+
 struct irq_desc *vgic_get_hw_irq_desc(struct domain *d, struct vcpu *v,
                                       unsigned int virq)
 {
-- 
2.14.1


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