When performing an MSI injection, let's first check if the translation
is already in the cache. If so, let's inject it quickly without
going through the whole translation process.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
virt/kvm/arm/vgic/vgic-its.c | 58 ++++++++++++++++++++++++++++++++++++
virt/kvm/arm/vgic/vgic.h | 1 +
2 files changed, 59 insertions(+)
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index bd76683781e8..3021cbf89b70 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -600,6 +600,42 @@ void vgic_its_invalidate_cache(struct kvm *kvm)
raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
}
+static struct vgic_irq *vgic_its_check_cache(struct kvm *kvm, phys_addr_t db,
+ u32 devid, u32 eventid)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct vgic_translation_cache_entry *cte;
+ struct vgic_irq *irq = NULL;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
+
+ list_for_each_entry(cte, &dist->lpi_translation_cache, entry) {
+ /*
+ * If we hit a NULL entry, there is nothing after this
+ * point.
+ */
+ if (!cte->irq)
+ break;
+
+ if (cte->db == db &&
+ cte->devid == devid &&
+ cte->eventid == eventid) {
+ /*
+ * Move this entry to the head, as it is the
+ * most recently used.
+ */
+ list_move(&cte->entry, &dist->lpi_translation_cache);
+ irq = cte->irq;
+ break;
+ }
+ }
+
+ raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+
+ return irq;
+}
+
int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
u32 devid, u32 eventid, struct vgic_irq **irq)
{
@@ -683,6 +719,25 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its,
return 0;
}
+int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi)
+{
+ struct vgic_irq *irq;
+ unsigned long flags;
+ phys_addr_t db;
+
+ db = (u64)msi->address_hi << 32 | msi->address_lo;
+ irq = vgic_its_check_cache(kvm, db, msi->devid, msi->data);
+
+ if (!irq)
+ return -1;
+
+ raw_spin_lock_irqsave(&irq->irq_lock, flags);
+ irq->pending_latch = true;
+ vgic_queue_irq_unlock(kvm, irq, flags);
+
+ return 0;
+}
+
/*
* Queries the KVM IO bus framework to get the ITS pointer from the given
* doorbell address.
@@ -694,6 +749,9 @@ int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi)
struct vgic_its *its;
int ret;
+ if (!vgic_its_inject_cached_translation(kvm, msi))
+ return 1;
+
its = vgic_msi_to_its(kvm, msi);
if (IS_ERR(its))
return PTR_ERR(its);
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 04335e997907..fb2c83d6f748 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -317,6 +317,7 @@ int vgic_copy_lpi_list(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 **intid_ptr);
int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
u32 devid, u32 eventid, struct vgic_irq **irq);
struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi);
+int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi);
void vgic_lpi_translation_cache_init(struct kvm *kvm);
void vgic_its_invalidate_cache(struct kvm *kvm);
--
2.20.1
