From 19ab17d06c3969e303791df024b432054d78bbf8 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 22 Aug 2011 18:35:25 +0200 Subject: [PATCH] Replace qemu_system_cond with VCPU stop mechanism We can express the VCPU thread wakeup with the stop mechanism, saving both qemu_system_ready and the qemu_system_cond. For KVM threads, we can just enter the main loop as long as the thread is stopped. The central TCG thread is better held back before the loop as there can be side effects of the services called even when all CPUs are stopped. Creating VCPUs in stopped state will also be required for proper CPU hotplugging support. Signed-off-by: Jan Kiszka Signed-off-by: Anthony Liguori --- cpus.c | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) diff --git a/cpus.c b/cpus.c index b60410c403..b163efe4a8 100644 --- a/cpus.c +++ b/cpus.c @@ -644,11 +644,9 @@ static QemuThread io_thread; static QemuThread *tcg_cpu_thread; static QemuCond *tcg_halt_cond; -static int qemu_system_ready; /* cpu creation */ static QemuCond qemu_cpu_cond; /* system init */ -static QemuCond qemu_system_cond; static QemuCond qemu_pause_cond; static QemuCond qemu_work_cond; @@ -670,7 +668,6 @@ int qemu_init_main_loop(void) } qemu_cond_init(&qemu_cpu_cond); - qemu_cond_init(&qemu_system_cond); qemu_cond_init(&qemu_pause_cond); qemu_cond_init(&qemu_work_cond); qemu_cond_init(&qemu_io_proceeded_cond); @@ -684,8 +681,7 @@ int qemu_init_main_loop(void) void qemu_main_loop_start(void) { - qemu_system_ready = 1; - qemu_cond_broadcast(&qemu_system_cond); + resume_all_vcpus(); } void run_on_cpu(CPUState *env, void (*func)(void *data), void *data) @@ -796,11 +792,6 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) env->created = 1; qemu_cond_signal(&qemu_cpu_cond); - /* and wait for machine initialization */ - while (!qemu_system_ready) { - qemu_cond_wait(&qemu_system_cond, &qemu_global_mutex); - } - while (1) { if (cpu_can_run(env)) { r = kvm_cpu_exec(env); @@ -829,9 +820,9 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) } qemu_cond_signal(&qemu_cpu_cond); - /* and wait for machine initialization */ - while (!qemu_system_ready) { - qemu_cond_wait(&qemu_system_cond, &qemu_global_mutex); + /* wait for initial kick-off after machine start */ + while (first_cpu->stopped) { + qemu_cond_wait(tcg_halt_cond, &qemu_global_mutex); } while (1) { @@ -971,12 +962,12 @@ static void qemu_tcg_init_vcpu(void *_env) env->thread = g_malloc0(sizeof(QemuThread)); env->halt_cond = g_malloc0(sizeof(QemuCond)); qemu_cond_init(env->halt_cond); + tcg_halt_cond = env->halt_cond; qemu_thread_create(env->thread, qemu_tcg_cpu_thread_fn, env); while (env->created == 0) { qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex); } tcg_cpu_thread = env->thread; - tcg_halt_cond = env->halt_cond; } else { env->thread = tcg_cpu_thread; env->halt_cond = tcg_halt_cond; @@ -1000,6 +991,7 @@ void qemu_init_vcpu(void *_env) env->nr_cores = smp_cores; env->nr_threads = smp_threads; + env->stopped = 1; if (kvm_enabled()) { qemu_kvm_start_vcpu(env); } else { -- 2.34.1