KVM: PIC: Only commit irq routing when necessary

The current logic updates KVM's view of our interrupt map every time we
change it. While this is nice and bullet proof, it slows things down
badly for me. QEMU spends about 3 seconds on every start telling KVM what
news it has on its routing maps.

Instead, let's just synchronize the whole irq routing map as a whole when
we're done constructing it. For things that change during runtime, we can
still update the routing table on demand.

Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 3 insertions, 3 deletions

diff --git a/kvm-all.c b/kvm-all.c
index 76435f5759..c757dd262e 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -985,7 +985,7 @@ void kvm_init_irq_routing(KVMState *s)
     kvm_arch_init_irq_routing(s);
 }
 
-static void kvm_irqchip_commit_routes(KVMState *s)
+void kvm_irqchip_commit_routes(KVMState *s)
 {
     int ret;
 
@@ -1019,8 +1019,6 @@ static void kvm_add_routing_entry(KVMState *s,
     new->u = entry->u;
 
     set_gsi(s, entry->gsi);
-
-    kvm_irqchip_commit_routes(s);
 }
 
 static int kvm_update_routing_entry(KVMState *s,
@@ -1171,6 +1169,7 @@ int kvm_irqchip_send_msi(KVMState *s, MSIMessage msg)
         route->kroute.u.msi.data = le32_to_cpu(msg.data);
 
         kvm_add_routing_entry(s, &route->kroute);
+        kvm_irqchip_commit_routes(s);
 
         QTAILQ_INSERT_TAIL(&s->msi_hashtab[kvm_hash_msi(msg.data)], route,
                            entry);
@@ -1203,6 +1202,7 @@ int kvm_irqchip_add_msi_route(KVMState *s, MSIMessage msg)
     kroute.u.msi.data = le32_to_cpu(msg.data);
 
     kvm_add_routing_entry(s, &kroute);
+    kvm_irqchip_commit_routes(s);
 
     return virq;
 }