kvm: Flush coalesced MMIO buffer periodly

Commit Message

Sheng Yang Jan. 21, 2010, 9:37 a.m. UTC

None

Patch

diff --git a/qemu-kvm.c b/qemu-kvm.c
index 599c3d6..38f890c 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -463,6 +463,12 @@  static void kvm_create_vcpu(CPUState *env, int id)
         goto err_fd;
     }
 
+#ifdef KVM_CAP_COALESCED_MMIO
+    if (kvm_state->coalesced_mmio && !kvm_state->coalesced_mmio_ring)
+        kvm_state->coalesced_mmio_ring = (void *) env->kvm_run +
+		kvm_state->coalesced_mmio * PAGE_SIZE;
+#endif
+
     return;
   err_fd:
     close(env->kvm_fd);
@@ -927,8 +933,7 @@  int kvm_run(CPUState *env)
 
 #if defined(KVM_CAP_COALESCED_MMIO)
     if (kvm_state->coalesced_mmio) {
-        struct kvm_coalesced_mmio_ring *ring =
-            (void *) run + kvm_state->coalesced_mmio * PAGE_SIZE;
+        struct kvm_coalesced_mmio_ring *ring = kvm_state->coalesced_mmio_ring;
         while (ring->first != ring->last) {
             cpu_physical_memory_rw(ring->coalesced_mmio[ring->first].phys_addr,
                            &ring->coalesced_mmio[ring->first].data[0],
@@ -2073,6 +2078,29 @@  static void io_thread_wakeup(void *opaque)
     }
 }
 
+#ifdef KVM_CAP_COALESCED_MMIO
+
+/* flush interval is 1/25 second */
+#define KVM_COALESCED_MMIO_FLUSH_INTERVAL    40000000LL
+
+static void flush_coalesced_mmio_buffer(void *opaque)
+{
+    if (kvm_state->coalesced_mmio_ring) {
+        struct kvm_coalesced_mmio_ring *ring =
+            kvm_state->coalesced_mmio_ring;
+        while (ring->first != ring->last) {
+            cpu_physical_memory_rw(ring->coalesced_mmio[ring->first].phys_addr,
+                           &ring->coalesced_mmio[ring->first].data[0],
+                           ring->coalesced_mmio[ring->first].len, 1);
+            smp_wmb();
+            ring->first = (ring->first + 1) % KVM_COALESCED_MMIO_MAX;
+        }
+    }
+    qemu_mod_timer(kvm_state->coalesced_mmio_timer,
+           qemu_get_clock(host_clock) + KVM_COALESCED_MMIO_FLUSH_INTERVAL);
+}
+#endif
+
 int kvm_main_loop(void)
 {
     int fds[2];
@@ -2117,6 +2145,15 @@  int kvm_main_loop(void)
     io_thread_sigfd = sigfd;
     cpu_single_env = NULL;
 
+#ifdef KVM_CAP_COALESCED_MMIO
+    if (kvm_state->coalesced_mmio) {
+        kvm_state->coalesced_mmio_timer =
+            qemu_new_timer(host_clock, flush_coalesced_mmio_buffer, NULL);
+        qemu_mod_timer(kvm_state->coalesced_mmio_timer,
+            qemu_get_clock(host_clock) + KVM_COALESCED_MMIO_FLUSH_INTERVAL);
+    }
+#endif
+
     while (1) {
         main_loop_wait(1000);
         if (qemu_shutdown_requested()) {
@@ -2135,6 +2172,12 @@  int kvm_main_loop(void)
         }
     }
 
+#ifdef KVM_CAP_COALESCED_MMIO
+    if (kvm_state->coalesced_mmio) {
+        qemu_del_timer(kvm_state->coalesced_mmio_timer);
+        qemu_free_timer(kvm_state->coalesced_mmio_timer);
+    }
+#endif
     pause_all_threads();
     pthread_mutex_unlock(&qemu_mutex);
 
diff --git a/qemu-kvm.h b/qemu-kvm.h
index 6b3e5a1..17f9d1b 100644
--- a/qemu-kvm.h
+++ b/qemu-kvm.h
@@ -1144,6 +1144,8 @@  typedef struct KVMState {
     int fd;
     int vmfd;
     int coalesced_mmio;
+    struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
+    struct QEMUTimer *coalesced_mmio_timer;
     int broken_set_mem_region;
     int migration_log;
     int vcpu_events;