kvm: qemu: stop/start cpus before/after devices

[Marcelo Tosatti <mtosatti@xxxxxxxxxx>]

From: Yaniv Kamay <yaniv@xxxxxxxxxxxx>

Stop cpus before devices when stopping the VM, start cpus after devices
when starting VM.

Acked-by: Dor Laor <dlaor@xxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>

diff --git a/qemu/qemu-kvm.c b/qemu/qemu-kvm.c
index 93af6ea..4164368 100644
--- a/qemu/qemu-kvm.c
+++ b/qemu/qemu-kvm.c
@@ -285,7 +285,7 @@ static int all_threads_paused(void)
     return 1;
 }
 
-static void pause_all_threads(void)
+void qemu_kvm_pause_all_threads(void)
 {
     CPUState *penv = first_cpu;
 
@@ -305,7 +305,7 @@ static void pause_all_threads(void)
 	qemu_cond_wait(&qemu_pause_cond);
 }
 
-static void resume_all_threads(void)
+void qemu_kvm_resume_all_threads(void)
 {
     CPUState *penv = first_cpu;
 
@@ -319,14 +319,6 @@ static void resume_all_threads(void)
     }
 }
 
-static void kvm_vm_state_change_handler(void *context, int running, int reason)
-{
-    if (running)
-	resume_all_threads();
-    else
-	pause_all_threads();
-}
-
 static void update_regs_for_sipi(CPUState *env)
 {
     kvm_arch_update_regs_for_sipi(env);
@@ -371,7 +363,7 @@ static void qemu_kvm_system_reset(void)
 {
     CPUState *penv = first_cpu;
 
-    pause_all_threads();
+    qemu_kvm_pause_all_threads();
 
     qemu_system_reset();
 
@@ -380,7 +372,7 @@ static void qemu_kvm_system_reset(void)
         penv = (CPUState *)penv->next_cpu;
     }
 
-    resume_all_threads();
+    qemu_kvm_resume_all_threads();
 }
 
 static int kvm_main_loop_cpu(CPUState *env)
@@ -466,7 +458,6 @@ int kvm_init_ap(void)
 #ifdef TARGET_I386
     kvm_tpr_opt_setup();
 #endif
-    qemu_add_vm_change_state_handler(kvm_vm_state_change_handler, NULL);
 
     signal(SIG_IPI, sig_ipi_handler);
     return 0;
@@ -610,7 +601,7 @@ int kvm_main_loop(void)
 #endif
     }
 
-    pause_all_threads();
+    qemu_kvm_pause_all_threads();
     pthread_mutex_unlock(&qemu_mutex);
 
     return 0;
diff --git a/qemu/qemu-kvm.h b/qemu/qemu-kvm.h
index c0549df..ca59af8 100644
--- a/qemu/qemu-kvm.h
+++ b/qemu/qemu-kvm.h
@@ -119,6 +119,9 @@ int qemu_kvm_register_coalesced_mmio(target_phys_addr_t addr,
 int qemu_kvm_unregister_coalesced_mmio(target_phys_addr_t addr,
 				       unsigned int size);
 
+void qemu_kvm_pause_all_threads(void);
+void qemu_kvm_resume_all_threads(void);
+
 int kvm_coalesce_mmio_region(target_phys_addr_t start, ram_addr_t size);
 int kvm_uncoalesce_mmio_region(target_phys_addr_t start, ram_addr_t size);
 
diff --git a/qemu/vl.c b/qemu/vl.c
index 7ae266e..c52d2d7 100644
--- a/qemu/vl.c
+++ b/qemu/vl.c
@@ -3596,6 +3596,8 @@ void vm_start(void)
         cpu_enable_ticks();
         vm_running = 1;
         vm_state_notify(1, 0);
+        if (kvm_enabled())
+            qemu_kvm_resume_all_threads();
         qemu_rearm_alarm_timer(alarm_timer);
     }
 }
@@ -3605,6 +3607,8 @@ void vm_stop(int reason)
     if (vm_running) {
         cpu_disable_ticks();
         vm_running = 0;
+        if (kvm_enabled())
+            qemu_kvm_pause_all_threads();
         vm_state_notify(0, reason);
     }
 }
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