#include "hw/nmi.h"
#include "sysemu/replay.h"
-#ifndef _WIN32
-#include "qemu/compatfd.h"
-#endif
-
#ifdef CONFIG_LINUX
#include <sys/prctl.h>
static bool default_mttcg_enabled(void)
{
- QemuOpts *icount_opts = qemu_find_opts_singleton("icount");
- const char *rr = qemu_opt_get(icount_opts, "rr");
-
- if (rr || TCG_OVERSIZED_GUEST) {
+ if (use_icount || TCG_OVERSIZED_GUEST) {
return false;
} else {
#ifdef TARGET_SUPPORTS_MTTCG
if (strcmp(t, "multi") == 0) {
if (TCG_OVERSIZED_GUEST) {
error_setg(errp, "No MTTCG when guest word size > hosts");
+ } else if (use_icount) {
+ error_setg(errp, "No MTTCG when icount is enabled");
} else {
+#ifndef TARGET_SUPPORT_MTTCG
+ error_report("Guest not yet converted to MTTCG - "
+ "you may get unexpected results");
+#endif
if (!check_tcg_memory_orders_compatible()) {
error_report("Guest expects a stronger memory ordering "
"than the host provides");
- error_printf("This may cause strange/hard to debug errors");
+ error_printf("This may cause strange/hard to debug errors\n");
}
mttcg_enabled = true;
}
static void qemu_cpu_kick_rr_cpu(void)
{
CPUState *cpu;
- atomic_mb_set(&exit_request, 1);
do {
cpu = atomic_mb_read(&tcg_current_rr_cpu);
if (cpu) {
} while (cpu != atomic_mb_read(&tcg_current_rr_cpu));
}
+static void do_nothing(CPUState *cpu, run_on_cpu_data unused)
+{
+}
+
+void qemu_timer_notify_cb(void *opaque, QEMUClockType type)
+{
+ if (!use_icount || type != QEMU_CLOCK_VIRTUAL) {
+ qemu_notify_event();
+ return;
+ }
+
+ if (!qemu_in_vcpu_thread() && first_cpu) {
+ /* qemu_cpu_kick is not enough to kick a halted CPU out of
+ * qemu_tcg_wait_io_event. async_run_on_cpu, instead,
+ * causes cpu_thread_is_idle to return false. This way,
+ * handle_icount_deadline can run.
+ */
+ async_run_on_cpu(first_cpu, do_nothing, RUN_ON_CPU_NULL);
+ }
+}
+
static void kick_tcg_thread(void *opaque)
{
timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick());
static void start_tcg_kick_timer(void)
{
- if (!tcg_kick_vcpu_timer && CPU_NEXT(first_cpu)) {
+ if (!mttcg_enabled && !tcg_kick_vcpu_timer && CPU_NEXT(first_cpu)) {
tcg_kick_vcpu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
kick_tcg_thread, NULL);
timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick());
abort();
}
-static void sigbus_handler(int n, struct qemu_signalfd_siginfo *siginfo,
- void *ctx)
+static void sigbus_handler(int n, siginfo_t *siginfo, void *ctx)
{
- if (kvm_on_sigbus(siginfo->ssi_code,
- (void *)(intptr_t)siginfo->ssi_addr)) {
+ if (siginfo->si_code != BUS_MCEERR_AO && siginfo->si_code != BUS_MCEERR_AR) {
sigbus_reraise();
}
+
+ if (current_cpu) {
+ /* Called asynchronously in VCPU thread. */
+ if (kvm_on_sigbus_vcpu(current_cpu, siginfo->si_code, siginfo->si_addr)) {
+ sigbus_reraise();
+ }
+ } else {
+ /* Called synchronously (via signalfd) in main thread. */
+ if (kvm_on_sigbus(siginfo->si_code, siginfo->si_addr)) {
+ sigbus_reraise();
+ }
+ }
}
static void qemu_init_sigbus(void)
memset(&action, 0, sizeof(action));
action.sa_flags = SA_SIGINFO;
- action.sa_sigaction = (void (*)(int, siginfo_t*, void*))sigbus_handler;
+ action.sa_sigaction = sigbus_handler;
sigaction(SIGBUS, &action, NULL);
prctl(PR_MCE_KILL, PR_MCE_KILL_SET, PR_MCE_KILL_EARLY, 0, 0);
}
-
-static void qemu_kvm_eat_signals(CPUState *cpu)
-{
- struct timespec ts = { 0, 0 };
- siginfo_t siginfo;
- sigset_t waitset;
- sigset_t chkset;
- int r;
-
- sigemptyset(&waitset);
- sigaddset(&waitset, SIG_IPI);
- sigaddset(&waitset, SIGBUS);
-
- do {
- r = sigtimedwait(&waitset, &siginfo, &ts);
- if (r == -1 && !(errno == EAGAIN || errno == EINTR)) {
- perror("sigtimedwait");
- exit(1);
- }
-
- switch (r) {
- case SIGBUS:
- if (kvm_on_sigbus_vcpu(cpu, siginfo.si_code, siginfo.si_addr)) {
- sigbus_reraise();
- }
- break;
- default:
- break;
- }
-
- r = sigpending(&chkset);
- if (r == -1) {
- perror("sigpending");
- exit(1);
- }
- } while (sigismember(&chkset, SIG_IPI) || sigismember(&chkset, SIGBUS));
-}
-
#else /* !CONFIG_LINUX */
-
static void qemu_init_sigbus(void)
{
}
-
-static void qemu_kvm_eat_signals(CPUState *cpu)
-{
-}
#endif /* !CONFIG_LINUX */
-#ifndef _WIN32
-static void dummy_signal(int sig)
-{
-}
-
-static void qemu_kvm_init_cpu_signals(CPUState *cpu)
-{
- int r;
- sigset_t set;
- struct sigaction sigact;
-
- memset(&sigact, 0, sizeof(sigact));
- sigact.sa_handler = dummy_signal;
- sigaction(SIG_IPI, &sigact, NULL);
-
- pthread_sigmask(SIG_BLOCK, NULL, &set);
- sigdelset(&set, SIG_IPI);
- sigdelset(&set, SIGBUS);
- r = kvm_set_signal_mask(cpu, &set);
- if (r) {
- fprintf(stderr, "kvm_set_signal_mask: %s\n", strerror(-r));
- exit(1);
- }
-}
-
-#else /* _WIN32 */
-static void qemu_kvm_init_cpu_signals(CPUState *cpu)
-{
- abort();
-}
-#endif /* _WIN32 */
-
static QemuMutex qemu_global_mutex;
-static QemuCond qemu_io_proceeded_cond;
-static unsigned iothread_requesting_mutex;
static QemuThread io_thread;
qemu_init_sigbus();
qemu_cond_init(&qemu_cpu_cond);
qemu_cond_init(&qemu_pause_cond);
- qemu_cond_init(&qemu_io_proceeded_cond);
qemu_mutex_init(&qemu_global_mutex);
qemu_thread_get_self(&io_thread);
static void qemu_wait_io_event_common(CPUState *cpu)
{
+ atomic_mb_set(&cpu->thread_kicked, false);
if (cpu->stop) {
cpu->stop = false;
cpu->stopped = true;
qemu_cond_broadcast(&qemu_pause_cond);
}
process_queued_cpu_work(cpu);
- cpu->thread_kicked = false;
+}
+
+static bool qemu_tcg_should_sleep(CPUState *cpu)
+{
+ if (mttcg_enabled) {
+ return cpu_thread_is_idle(cpu);
+ } else {
+ return all_cpu_threads_idle();
+ }
}
static void qemu_tcg_wait_io_event(CPUState *cpu)
{
- while (all_cpu_threads_idle()) {
+ while (qemu_tcg_should_sleep(cpu)) {
stop_tcg_kick_timer();
qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex);
}
start_tcg_kick_timer();
- while (iothread_requesting_mutex) {
- qemu_cond_wait(&qemu_io_proceeded_cond, &qemu_global_mutex);
- }
-
- CPU_FOREACH(cpu) {
- qemu_wait_io_event_common(cpu);
- }
+ qemu_wait_io_event_common(cpu);
}
static void qemu_kvm_wait_io_event(CPUState *cpu)
qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex);
}
- qemu_kvm_eat_signals(cpu);
qemu_wait_io_event_common(cpu);
}
exit(1);
}
- qemu_kvm_init_cpu_signals(cpu);
+ kvm_init_cpu_signals(cpu);
/* signal CPU creation */
cpu->created = true;
qemu_thread_get_self(cpu->thread);
cpu->thread_id = qemu_get_thread_id();
cpu->can_do_io = 1;
+ current_cpu = cpu;
sigemptyset(&waitset);
sigaddset(&waitset, SIG_IPI);
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
- current_cpu = cpu;
while (1) {
- current_cpu = NULL;
qemu_mutex_unlock_iothread();
do {
int sig;
exit(1);
}
qemu_mutex_lock_iothread();
- current_cpu = cpu;
qemu_wait_io_event_common(cpu);
}
static void handle_icount_deadline(void)
{
+ assert(qemu_in_vcpu_thread());
if (use_icount) {
int64_t deadline =
qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
if (deadline == 0) {
+ /* Wake up other AioContexts. */
qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
+ qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
}
}
}
cpu->icount_decr.u16.low = decr;
cpu->icount_extra = count;
}
+ qemu_mutex_unlock_iothread();
cpu_exec_start(cpu);
ret = cpu_exec(cpu);
cpu_exec_end(cpu);
+ qemu_mutex_lock_iothread();
#ifdef CONFIG_PROFILER
tcg_time += profile_getclock() - ti;
#endif
* elsewhere.
*/
-static void *qemu_tcg_cpu_thread_fn(void *arg)
+static void *qemu_tcg_rr_cpu_thread_fn(void *arg)
{
CPUState *cpu = arg;
/* process any pending work */
CPU_FOREACH(cpu) {
+ current_cpu = cpu;
qemu_wait_io_event_common(cpu);
}
}
start_tcg_kick_timer();
- /* process any pending work */
- atomic_mb_set(&exit_request, 1);
-
cpu = first_cpu;
+ /* process any pending work */
+ cpu->exit_request = 1;
+
while (1) {
/* Account partial waits to QEMU_CLOCK_VIRTUAL. */
qemu_account_warp_timer();
+ /* Run the timers here. This is much more efficient than
+ * waking up the I/O thread and waiting for completion.
+ */
+ handle_icount_deadline();
+
if (!cpu) {
cpu = first_cpu;
}
- for (; cpu != NULL && !exit_request; cpu = CPU_NEXT(cpu)) {
+ while (cpu && !cpu->queued_work_first && !cpu->exit_request) {
+
atomic_mb_set(&tcg_current_rr_cpu, cpu);
+ current_cpu = cpu;
qemu_clock_enable(QEMU_CLOCK_VIRTUAL,
(cpu->singlestep_enabled & SSTEP_NOTIMER) == 0);
if (r == EXCP_DEBUG) {
cpu_handle_guest_debug(cpu);
break;
+ } else if (r == EXCP_ATOMIC) {
+ qemu_mutex_unlock_iothread();
+ cpu_exec_step_atomic(cpu);
+ qemu_mutex_lock_iothread();
+ break;
}
- } else if (cpu->stop || cpu->stopped) {
+ } else if (cpu->stop) {
if (cpu->unplug) {
cpu = CPU_NEXT(cpu);
}
break;
}
- } /* for cpu.. */
+ cpu = CPU_NEXT(cpu);
+ } /* while (cpu && !cpu->exit_request).. */
+
/* Does not need atomic_mb_set because a spurious wakeup is okay. */
atomic_set(&tcg_current_rr_cpu, NULL);
- /* Pairs with smp_wmb in qemu_cpu_kick. */
- atomic_mb_set(&exit_request, 0);
-
- handle_icount_deadline();
+ if (cpu && cpu->exit_request) {
+ atomic_mb_set(&cpu->exit_request, 0);
+ }
- qemu_tcg_wait_io_event(QTAILQ_FIRST(&cpus));
+ qemu_tcg_wait_io_event(cpu ? cpu : QTAILQ_FIRST(&cpus));
deal_with_unplugged_cpus();
}
{
CPUState *cpu = arg;
int r;
+
+ qemu_mutex_lock_iothread();
qemu_thread_get_self(cpu->thread);
- qemu_mutex_lock(&qemu_global_mutex);
cpu->thread_id = qemu_get_thread_id();
cpu->created = true;
}
#endif
+/* Multi-threaded TCG
+ *
+ * In the multi-threaded case each vCPU has its own thread. The TLS
+ * variable current_cpu can be used deep in the code to find the
+ * current CPUState for a given thread.
+ */
+
+static void *qemu_tcg_cpu_thread_fn(void *arg)
+{
+ CPUState *cpu = arg;
+
+ rcu_register_thread();
+
+ qemu_mutex_lock_iothread();
+ qemu_thread_get_self(cpu->thread);
+
+ cpu->thread_id = qemu_get_thread_id();
+ cpu->created = true;
+ cpu->can_do_io = 1;
+ current_cpu = cpu;
+ qemu_cond_signal(&qemu_cpu_cond);
+
+ /* process any pending work */
+ cpu->exit_request = 1;
+
+ while (1) {
+ if (cpu_can_run(cpu)) {
+ int r;
+ r = tcg_cpu_exec(cpu);
+ switch (r) {
+ case EXCP_DEBUG:
+ cpu_handle_guest_debug(cpu);
+ break;
+ case EXCP_HALTED:
+ /* during start-up the vCPU is reset and the thread is
+ * kicked several times. If we don't ensure we go back
+ * to sleep in the halted state we won't cleanly
+ * start-up when the vCPU is enabled.
+ *
+ * cpu->halted should ensure we sleep in wait_io_event
+ */
+ g_assert(cpu->halted);
+ break;
+ case EXCP_ATOMIC:
+ qemu_mutex_unlock_iothread();
+ cpu_exec_step_atomic(cpu);
+ qemu_mutex_lock_iothread();
+ default:
+ /* Ignore everything else? */
+ break;
+ }
+ }
+
+ handle_icount_deadline();
+
+ atomic_mb_set(&cpu->exit_request, 0);
+ qemu_tcg_wait_io_event(cpu);
+ }
+
+ return NULL;
+}
+
static void qemu_cpu_kick_thread(CPUState *cpu)
{
#ifndef _WIN32
qemu_cond_broadcast(cpu->halt_cond);
if (tcg_enabled()) {
cpu_exit(cpu);
- /* Also ensure current RR cpu is kicked */
+ /* NOP unless doing single-thread RR */
qemu_cpu_kick_rr_cpu();
} else {
if (hax_enabled()) {
void qemu_mutex_lock_iothread(void)
{
- atomic_inc(&iothread_requesting_mutex);
- /* In the simple case there is no need to bump the VCPU thread out of
- * TCG code execution.
- */
- if (!tcg_enabled() || qemu_in_vcpu_thread() ||
- !first_cpu || !first_cpu->created) {
- qemu_mutex_lock(&qemu_global_mutex);
- atomic_dec(&iothread_requesting_mutex);
- } else {
- if (qemu_mutex_trylock(&qemu_global_mutex)) {
- qemu_cpu_kick_rr_cpu();
- qemu_mutex_lock(&qemu_global_mutex);
- }
- atomic_dec(&iothread_requesting_mutex);
- qemu_cond_broadcast(&qemu_io_proceeded_cond);
- }
+ g_assert(!qemu_mutex_iothread_locked());
+ qemu_mutex_lock(&qemu_global_mutex);
iothread_locked = true;
}
void qemu_mutex_unlock_iothread(void)
{
+ g_assert(qemu_mutex_iothread_locked());
iothread_locked = false;
qemu_mutex_unlock(&qemu_global_mutex);
}
if (qemu_in_vcpu_thread()) {
cpu_stop_current();
- if (!kvm_enabled()) {
- CPU_FOREACH(cpu) {
- cpu->stop = false;
- cpu->stopped = true;
- }
- return;
- }
}
while (!all_vcpus_paused()) {
static void qemu_tcg_init_vcpu(CPUState *cpu)
{
char thread_name[VCPU_THREAD_NAME_SIZE];
- static QemuCond *tcg_halt_cond;
- static QemuThread *tcg_cpu_thread;
+ static QemuCond *single_tcg_halt_cond;
+ static QemuThread *single_tcg_cpu_thread;
- /* share a single thread for all cpus with TCG */
- if (!tcg_cpu_thread) {
+ if (qemu_tcg_mttcg_enabled() || !single_tcg_cpu_thread) {
cpu->thread = g_malloc0(sizeof(QemuThread));
cpu->halt_cond = g_malloc0(sizeof(QemuCond));
qemu_cond_init(cpu->halt_cond);
- tcg_halt_cond = cpu->halt_cond;
- snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/TCG",
+
+ if (qemu_tcg_mttcg_enabled()) {
+ /* create a thread per vCPU with TCG (MTTCG) */
+ parallel_cpus = true;
+ snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/TCG",
cpu->cpu_index);
- qemu_thread_create(cpu->thread, thread_name, qemu_tcg_cpu_thread_fn,
- cpu, QEMU_THREAD_JOINABLE);
+
+ qemu_thread_create(cpu->thread, thread_name, qemu_tcg_cpu_thread_fn,
+ cpu, QEMU_THREAD_JOINABLE);
+
+ } else {
+ /* share a single thread for all cpus with TCG */
+ snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "ALL CPUs/TCG");
+ qemu_thread_create(cpu->thread, thread_name,
+ qemu_tcg_rr_cpu_thread_fn,
+ cpu, QEMU_THREAD_JOINABLE);
+
+ single_tcg_halt_cond = cpu->halt_cond;
+ single_tcg_cpu_thread = cpu->thread;
+ }
#ifdef _WIN32
cpu->hThread = qemu_thread_get_handle(cpu->thread);
#endif
while (!cpu->created) {
qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex);
}
- tcg_cpu_thread = cpu->thread;
} else {
- cpu->thread = tcg_cpu_thread;
- cpu->halt_cond = tcg_halt_cond;
+ /* For non-MTTCG cases we share the thread */
+ cpu->thread = single_tcg_cpu_thread;
+ cpu->halt_cond = single_tcg_halt_cond;
}
}
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