accel/kvm/kvm-all: Refactor per-vcpu dirty ring reaping

Add a non-required argument 'CPUState' to kvm_dirty_ring_reap so
that it can cover single vcpu dirty-ring-reaping scenario.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <c32001242875e83b0d9f78f396fe2dcd380ba9e8.1656177590.git.huangy81@chinatelecom.cn>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

accel/kvm/kvm-all.c

@@ -757,17 +757,20 @@ static uint32_t kvm_dirty_ring_reap_one(KVMState *s, CPUState *cpu)
 }
 
 /* Must be with slots_lock held */
-static uint64_t kvm_dirty_ring_reap_locked(KVMState *s)
+static uint64_t kvm_dirty_ring_reap_locked(KVMState *s, CPUState* cpu)
 {
     int ret;
-    CPUState *cpu;
     uint64_t total = 0;
     int64_t stamp;
 
     stamp = get_clock();
 
-    CPU_FOREACH(cpu) {
-        total += kvm_dirty_ring_reap_one(s, cpu);
+    if (cpu) {
+        total = kvm_dirty_ring_reap_one(s, cpu);
+    } else {
+        CPU_FOREACH(cpu) {
+            total += kvm_dirty_ring_reap_one(s, cpu);
+        }
     }
 
     if (total) {
@@ -788,7 +791,7 @@ static uint64_t kvm_dirty_ring_reap_locked(KVMState *s)
  * Currently for simplicity, we must hold BQL before calling this.  We can
  * consider to drop the BQL if we're clear with all the race conditions.
  */
-static uint64_t kvm_dirty_ring_reap(KVMState *s)
+static uint64_t kvm_dirty_ring_reap(KVMState *s, CPUState *cpu)
 {
     uint64_t total;
 
@@ -808,7 +811,7 @@ static uint64_t kvm_dirty_ring_reap(KVMState *s)
      *     reset below.
      */
     kvm_slots_lock();
-    total = kvm_dirty_ring_reap_locked(s);
+    total = kvm_dirty_ring_reap_locked(s, cpu);
     kvm_slots_unlock();
 
     return total;
@@ -855,7 +858,7 @@ static void kvm_dirty_ring_flush(void)
      * vcpus out in a synchronous way.
      */
     kvm_cpu_synchronize_kick_all();
-    kvm_dirty_ring_reap(kvm_state);
+    kvm_dirty_ring_reap(kvm_state, NULL);
     trace_kvm_dirty_ring_flush(1);
 }
 
@@ -1399,7 +1402,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
                  * Not easy.  Let's cross the fingers until it's fixed.
                  */
                 if (kvm_state->kvm_dirty_ring_size) {
-                    kvm_dirty_ring_reap_locked(kvm_state);
+                    kvm_dirty_ring_reap_locked(kvm_state, NULL);
                 } else {
                     kvm_slot_get_dirty_log(kvm_state, mem);
                 }
@@ -1471,7 +1474,7 @@ static void *kvm_dirty_ring_reaper_thread(void *data)
         r->reaper_state = KVM_DIRTY_RING_REAPER_REAPING;
 
         qemu_mutex_lock_iothread();
-        kvm_dirty_ring_reap(s);
+        kvm_dirty_ring_reap(s, NULL);
         qemu_mutex_unlock_iothread();
 
         r->reaper_iteration++;
@@ -2967,7 +2970,7 @@ int kvm_cpu_exec(CPUState *cpu)
              */
             trace_kvm_dirty_ring_full(cpu->cpu_index);
             qemu_mutex_lock_iothread();
-            kvm_dirty_ring_reap(kvm_state);
+            kvm_dirty_ring_reap(kvm_state, NULL);
             qemu_mutex_unlock_iothread();
             ret = 0;
             break;