[PATCH 2/3] qemu-kvm: Introduce single vcpu pause/resume

[Jan Kiszka <jan.kiszka@web.de>]

Small helpers that allow to pause and resume only a single vcpu thread.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
---
 qemu/qemu-kvm.c |   29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

Index: b/qemu/qemu-kvm.c
===================================================================
--- a/qemu/qemu-kvm.c
+++ b/qemu/qemu-kvm.c
@@ -207,6 +207,17 @@ static int all_threads_paused(void)
     return 1;
 }
 
+static void pause_vcpu_thread(int index)
+{
+    assert(cpu_single_env->cpu_index != index);
+
+    vcpu_info[index].stop = 1;
+    pthread_kill(vcpu_info[index].thread, SIG_IPI);
+
+    while (!vcpu_info[index].stopped)
+	qemu_cond_wait(&qemu_pause_cond);
+}
+
 static void pause_all_threads(void)
 {
     int i;
@@ -221,17 +232,21 @@ static void pause_all_threads(void)
 	qemu_cond_wait(&qemu_pause_cond);
 }
 
+static void resume_vcpu_thread(int index)
+{
+    assert(!cpu_single_env);
+
+    vcpu_info[index].stop = 0;
+    vcpu_info[index].stopped = 0;
+    pthread_kill(vcpu_info[index].thread, SIG_IPI);
+}
+
 static void resume_all_threads(void)
 {
     int i;
 
-    assert(!cpu_single_env);
-
-    for (i = 0; i < smp_cpus; ++i) {
-	vcpu_info[i].stop = 0;
-	vcpu_info[i].stopped = 0;
-	pthread_kill(vcpu_info[i].thread, SIG_IPI);
-    }
+    for (i = 0; i < smp_cpus; ++i)
+	resume_vcpu_thread(i);
 }
 
 static void kvm_vm_state_change_handler(void *context, int running)