kvm/msi: do explicit commit when adding msi routes

We invoke the kvm_irqchip_commit_routes() for each addition to MSI route
table, which is not efficient if we are adding lots of routes in some cases.

This patch lets callers invoke the kvm_irqchip_commit_routes(), so the
callers can decide how to optimize.

[1] https://lists.gnu.org/archive/html/qemu-devel/2021-11/msg00967.html

Signed-off-by: Longpeng <longpeng2@huawei.com>
Message-Id: <20220222141116.2091-3-longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 83d0988..31d467b 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -4940,16 +4940,18 @@ void kvm_arch_init_irq_routing(KVMState *s)
     kvm_gsi_routing_allowed = true;
 
     if (kvm_irqchip_is_split()) {
+        KVMRouteChange c = kvm_irqchip_begin_route_changes(s);
         int i;
 
         /* If the ioapic is in QEMU and the lapics are in KVM, reserve
            MSI routes for signaling interrupts to the local apics. */
         for (i = 0; i < IOAPIC_NUM_PINS; i++) {
-            if (kvm_irqchip_add_msi_route(s, 0, NULL) < 0) {
+            if (kvm_irqchip_add_msi_route(&c, 0, NULL) < 0) {
                 error_report("Could not enable split IRQ mode.");
                 exit(1);
             }
         }
+        kvm_irqchip_commit_route_changes(&c);
     }
 }