[PATCH 4/5] kvm: irqchip: support defer to commit the route

["Longpeng(Mike)" <longpeng2@huawei.com>]

The kvm_irqchip_commit_routes() is relatively expensive, so
provide the users a choice to commit the route immediately
or not when they add msi/msix route.

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
---
 accel/kvm/kvm-all.c    | 10 +++++++---
 accel/stubs/kvm-stub.c |  3 ++-
 hw/misc/ivshmem.c      |  2 +-
 hw/vfio/pci.c          |  2 +-
 hw/virtio/virtio-pci.c |  2 +-
 include/sysemu/kvm.h   |  4 +++-
 target/i386/kvm/kvm.c  |  2 +-
 7 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 0125c17..1f788a2 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1950,7 +1950,8 @@ int kvm_irqchip_send_msi(KVMState *s, MSIMessage msg)
     return kvm_set_irq(s, route->kroute.gsi, 1);
 }
 
-int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev)
+int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev,
+                              bool defer_commit)
 {
     struct kvm_irq_routing_entry kroute = {};
     int virq;
@@ -1993,7 +1994,9 @@ int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev)
 
     kvm_add_routing_entry(s, &kroute);
     kvm_arch_add_msi_route_post(&kroute, vector, dev);
-    kvm_irqchip_commit_routes(s);
+    if (!defer_commit) {
+        kvm_irqchip_commit_routes(s);
+    }
 
     return virq;
 }
@@ -2151,7 +2154,8 @@ int kvm_irqchip_send_msi(KVMState *s, MSIMessage msg)
     abort();
 }
 
-int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev)
+int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev,
+                              bool defer_commit)
 {
     return -ENOSYS;
 }
diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
index 5b1d00a..d5caaca 100644
--- a/accel/stubs/kvm-stub.c
+++ b/accel/stubs/kvm-stub.c
@@ -81,7 +81,8 @@ int kvm_on_sigbus(int code, void *addr)
 }
 
 #ifndef CONFIG_USER_ONLY
-int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev)
+int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev,
+                              bool defer_commit)
 {
     return -ENOSYS;
 }
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index 1ba4a98..98b14cc 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -429,7 +429,7 @@ static void ivshmem_add_kvm_msi_virq(IVShmemState *s, int vector,
     IVSHMEM_DPRINTF("ivshmem_add_kvm_msi_virq vector:%d\n", vector);
     assert(!s->msi_vectors[vector].pdev);
 
-    ret = kvm_irqchip_add_msi_route(kvm_state, vector, pdev);
+    ret = kvm_irqchip_add_msi_route(kvm_state, vector, pdev, false);
     if (ret < 0) {
         error_setg(errp, "kvm_irqchip_add_msi_route failed");
         return;
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index ca37fb7..3ab67d6 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -427,7 +427,7 @@ static void vfio_add_kvm_msi_virq(VFIOPCIDevice *vdev, VFIOMSIVector *vector,
         return;
     }
 
-    virq = kvm_irqchip_add_msi_route(kvm_state, vector_n, &vdev->pdev);
+    virq = kvm_irqchip_add_msi_route(kvm_state, vector_n, &vdev->pdev, false);
     if (virq < 0) {
         event_notifier_cleanup(&vector->kvm_interrupt);
         return;
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 433060a..7e2d021 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -684,7 +684,7 @@ static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,
     int ret;
 
     if (irqfd->users == 0) {
-        ret = kvm_irqchip_add_msi_route(kvm_state, vector, &proxy->pci_dev);
+        ret = kvm_irqchip_add_msi_route(kvm_state, vector, &proxy->pci_dev, false);
         if (ret < 0) {
             return ret;
         }
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index a1ab1ee..1932dc0 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -473,9 +473,11 @@ void kvm_init_cpu_signals(CPUState *cpu);
  *          message.
  * @dev:    Owner PCI device to add the route. If @dev is specified
  *          as @NULL, an empty MSI message will be inited.
+ * @defer_commit:   Defer to commit new route to the KVM core.
  * @return: virq (>=0) when success, errno (<0) when failed.
  */
-int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev);
+int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev,
+                              bool defer_commit);
 int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg,
                                  PCIDevice *dev);
 void kvm_irqchip_commit_routes(KVMState *s);
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index e69abe4..896406b 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -4724,7 +4724,7 @@ void kvm_arch_init_irq_routing(KVMState *s)
         /* 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(s, 0, NULL, false) < 0) {
                 error_report("Could not enable split IRQ mode.");
                 exit(1);
             }
-- 
1.8.3.1