On a successful translation, preserve the parameters in the LPI
translation cache. Each translation is reusing the last slot
in the list, naturally evincting the least recently used entry.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
virt/kvm/arm/vgic/vgic-its.c | 41 ++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 5758504fd934..bc370b6c5afa 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -538,6 +538,45 @@ static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm,
return 0;
}
+static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its,
+ u32 devid, u32 eventid,
+ struct vgic_irq *irq)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct vgic_translation_cache_entry *cte;
+ unsigned long flags;
+
+ /* Do not cache a directly injected interrupt */
+ if (irq->hw)
+ return;
+
+ raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
+
+ /* Always reuse the last entry (LRU policy) */
+ cte = list_last_entry(&dist->lpi_translation_cache,
+ typeof(*cte), entry);
+
+ /*
+ * Caching the translation implies having an extra reference
+ * to the interrupt, so drop the potential reference on what
+ * was in the cache, and increment it on the new interrupt.
+ */
+ if (cte->irq)
+ __vgic_put_lpi_locked(kvm, cte->irq);
+
+ vgic_get_irq_kref(irq);
+
+ cte->db = its->vgic_its_base + GITS_TRANSLATER;
+ cte->devid = devid;
+ cte->eventid = eventid;
+ cte->irq = irq;
+
+ /* Move the new translation to the head of the list */
+ list_move(&cte->entry, &dist->lpi_translation_cache);
+
+ raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+}
+
int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
u32 devid, u32 eventid, struct vgic_irq **irq)
{
@@ -558,6 +597,8 @@ int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
if (!vcpu->arch.vgic_cpu.lpis_enabled)
return -EBUSY;
+ vgic_its_cache_translation(kvm, its, devid, eventid, ite->irq);
+
*irq = ite->irq;
return 0;
}
--
2.20.1
