@@ -15,6 +15,7 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <xen/list_sort.h>
#include <xen/sched.h>
#include <asm/bug.h>
#include <asm/event.h>
@@ -183,6 +184,64 @@ static struct vcpu *vgic_target_oracle(struct vgic_irq *irq)
return NULL;
}
+/*
+ * The order of items in the ap_lists defines how we'll pack things in LRs as
+ * well, the first items in the list being the first things populated in the
+ * LRs.
+ *
+ * A hard rule is that active interrupts can never be pushed out of the LRs
+ * (and therefore take priority) since we cannot reliably trap on deactivation
+ * of IRQs and therefore they have to be present in the LRs.
+ *
+ * Otherwise things should be sorted by the priority field and the GIC
+ * hardware support will take care of preemption of priority groups etc.
+ *
+ * Return negative if "a" sorts before "b", 0 to preserve order, and positive
+ * to sort "b" before "a".
+ */
+static int vgic_irq_cmp(void *priv, struct list_head *a, struct list_head *b)
+{
+ struct vgic_irq *irqa = container_of(a, struct vgic_irq, ap_list);
+ struct vgic_irq *irqb = container_of(b, struct vgic_irq, ap_list);
+ bool penda, pendb;
+ int ret;
+
+ spin_lock(&irqa->irq_lock);
+ spin_lock(&irqb->irq_lock);
+
+ if ( irqa->active || irqb->active )
+ {
+ ret = (int)irqb->active - (int)irqa->active;
+ goto out;
+ }
+
+ penda = irqa->enabled && irq_is_pending(irqa);
+ pendb = irqb->enabled && irq_is_pending(irqb);
+
+ if ( !penda || !pendb )
+ {
+ ret = (int)pendb - (int)penda;
+ goto out;
+ }
+
+ /* Both pending and enabled, sort by priority */
+ ret = irqa->priority - irqb->priority;
+out:
+ spin_unlock(&irqb->irq_lock);
+ spin_unlock(&irqa->irq_lock);
+ return ret;
+}
+
+/* Must be called with the ap_list_lock held */
+static void vgic_sort_ap_list(struct vcpu *vcpu)
+{
+ struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic;
+
+ ASSERT(spin_is_locked(&vgic_cpu->ap_list_lock));
+
+ list_sort(NULL, &vgic_cpu->ap_list_head, vgic_irq_cmp);
+}
+
/*
* Only valid injection if changing level for level-triggered IRQs or for a
* rising edge.
Adds the sorting function to cover the case where you have more IRQs to consider than you have LRs. We consider their priorities. This uses the new sort_list() implementation imported from Linux. This is based on Linux commit 8e4447457965, written by Christoffer Dall. Signed-off-by: Andre Przywara <andre.przywara@linaro.org> --- Changelog v1 ... v2: - split off Linux' list_sort() implementation xen/arch/arm/vgic/vgic.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+)