KVM: optimize apic interrupt delivery

Most interrupt are delivered to only one vcpu. Use pre-build tables to
find interrupt destination instead of looping through all vcpus. In case
of logical mode loop only through vcpus in a logical cluster irq is sent
to.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 7118be0f2f2c..3ca89c451d6b 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -68,8 +68,13 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
         struct kvm_vcpu *vcpu, *lowest = NULL;
 
         if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
-                        kvm_is_dm_lowest_prio(irq))
+                        kvm_is_dm_lowest_prio(irq)) {
                 printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
+                irq->delivery_mode = APIC_DM_FIXED;
+        }
+
+        if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r))
+                return r;
 
         kvm_for_each_vcpu(i, vcpu, kvm) {
                 if (!kvm_apic_present(vcpu))