[Qemu-devel] [PATCH v10.2 24/26] kvm-irqchip: introduce kvm_irqchip_update_msi_route_no_commit

[Peter Xu <peterx@redhat.com>]

We do gsi route commit for each irqchip route update before. This is not
efficient if we are updating lots of routes in the same time. This patch
introduce a new "no_commit" version of the update function, which can be
used when we update multiple route entries in a sequence.

This change also requires that we export kvm_irqchip_commit_routes() to
public.

Signed-off-by: Peter Xu <peterx@redhat.com>
---

After a second thought, a better way to do this is to introduce
another new function, rather than modifying the old
kvm_iqrchip_udpate_msi_route(). By doing this, I can avoid touch other
part of codes, also I can keep add_msi_route() and update_msi_route()
aligned since both of them will contain one commit phase.

Please review this v10.2 instead of v10 for this patch, and will use
this one in future versions if np.

 hw/intc/ioapic.c     |  3 ++-
 include/sysemu/kvm.h | 10 +++++++++-
 kvm-all.c            | 19 +++++++++++++++----
 kvm-stub.c           |  4 ++++
 target-i386/kvm.c    |  5 +++--
 5 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
index 0c34e3e..931aeaf 100644
--- a/hw/intc/ioapic.c
+++ b/hw/intc/ioapic.c
@@ -192,7 +192,8 @@ static void ioapic_update_kvm_routes(IOAPICCommonState *s)
             ioapic_entry_parse(s->ioredtbl[i], &info);
             msg.address = info.addr;
             msg.data = info.data;
-            kvm_irqchip_update_msi_route(kvm_state, i, msg, NULL);
+            kvm_irqchip_update_msi_route_no_commit(kvm_state, i,
+                                                   msg, NULL);
         }
         kvm_irqchip_commit_routes(kvm_state);
     }
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 0a16e0e..ba7e7f0 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -371,7 +371,6 @@ int kvm_set_irq(KVMState *s, int irq, int level);
 int kvm_irqchip_send_msi(KVMState *s, MSIMessage msg);
 
 void kvm_irqchip_add_irq_route(KVMState *s, int gsi, int irqchip, int pin);
-void kvm_irqchip_commit_routes(KVMState *s);
 
 void kvm_put_apic_state(DeviceState *d, struct kvm_lapic_state *kapic);
 void kvm_get_apic_state(DeviceState *d, struct kvm_lapic_state *kapic);
@@ -494,6 +493,15 @@ static inline void cpu_synchronize_post_init(CPUState *cpu)
 int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev);
 int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg,
                                  PCIDevice *dev);
+/*
+ * Same as kvm_irqchip_update_msi_route(), but need explicit
+ * kvm_irqchip_commit_routes() afterward. This is efficient when we
+ * need to update multiple MSI routes at the same time, to avoid
+ * unnecessary commits between updates.
+ */
+int kvm_irqchip_update_msi_route_no_commit(KVMState *s, int virq,
+                                           MSIMessage msg, PCIDevice *dev);
+void kvm_irqchip_commit_routes(KVMState *s);
 void kvm_irqchip_release_virq(KVMState *s, int virq);
 
 int kvm_irqchip_add_adapter_route(KVMState *s, AdapterInfo *adapter);
diff --git a/kvm-all.c b/kvm-all.c
index ca30a58..b896184 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1094,8 +1094,6 @@ static int kvm_update_routing_entry(KVMState *s,
 
         *entry = *new_entry;
 
-        kvm_irqchip_commit_routes(s);
-
         return 0;
     }
 
@@ -1280,8 +1278,8 @@ int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev)
     return virq;
 }
 
-int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg,
-                                 PCIDevice *dev)
+int kvm_irqchip_update_msi_route_no_commit(KVMState *s, int virq,
+                                           MSIMessage msg, PCIDevice *dev)
 {
     struct kvm_irq_routing_entry kroute = {};
 
@@ -1306,6 +1304,19 @@ int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg,
     return kvm_update_routing_entry(s, &kroute);
 }
 
+int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg,
+                                 PCIDevice *dev)
+{
+    int ret;
+
+    ret = kvm_irqchip_update_msi_route_no_commit(s, virq, msg, dev);
+    if (ret >= 0) {
+        kvm_irqchip_commit_routes(s);
+    }
+
+    return ret;
+}
+
 static int kvm_irqchip_assign_irqfd(KVMState *s, int fd, int rfd, int virq,
                                     bool assign)
 {
diff --git a/kvm-stub.c b/kvm-stub.c
index 982e590..64e23f6 100644
--- a/kvm-stub.c
+++ b/kvm-stub.c
@@ -135,6 +135,10 @@ int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg,
     return -ENOSYS;
 }
 
+void kvm_irqchip_commit_routes(KVMState *s)
+{
+}
+
 int kvm_irqchip_add_adapter_route(KVMState *s, AdapterInfo *adapter)
 {
     return -ENOSYS;
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index f02ba0a..62aec24 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -3376,9 +3376,10 @@ static void kvm_update_msi_routes_all(void *private, bool global,
     QLIST_FOREACH(entry, &msi_route_list, list) {
         cnt++;
         msg = pci_get_msi_message(entry->dev, entry->vector);
-        kvm_irqchip_update_msi_route(kvm_state, entry->virq,
-                                     msg, entry->dev);
+        kvm_irqchip_update_msi_route_no_commit(kvm_state, entry->virq,
+                                               msg, entry->dev);
     }
+    kvm_irqchip_commit_routes(kvm_state);
     trace_kvm_x86_update_msi_routes(cnt);
 }
 
-- 
2.4.11