cpus: extract out TCG-specific code to accel/tcg

TCG is the first accelerator to register a "CpusAccel" interface
on initialization, providing functions for starting a vcpu,
kicking a vcpu, sychronizing state and getting virtual clock
and ticks.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
[added const]
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1 insertions, 504 deletions

diff --git a/softmmu/cpus.c b/softmmu/cpus.c
index f932fc1f74..25f12e3ee9 100644
--- a/softmmu/cpus.c
+++ b/softmmu/cpus.c
@@ -24,27 +24,19 @@
 
 #include "qemu/osdep.h"
 #include "qemu-common.h"
-#include "qemu/config-file.h"
-#include "qemu/cutils.h"
-#include "migration/vmstate.h"
 #include "monitor/monitor.h"
 #include "qapi/error.h"
 #include "qapi/qapi-commands-misc.h"
 #include "qapi/qapi-events-run-state.h"
 #include "qapi/qmp/qerror.h"
-#include "qemu/error-report.h"
-#include "qemu/qemu-print.h"
 #include "sysemu/tcg.h"
-#include "sysemu/block-backend.h"
 #include "exec/gdbstub.h"
-#include "sysemu/dma.h"
 #include "sysemu/hw_accel.h"
 #include "sysemu/kvm.h"
 #include "sysemu/hax.h"
 #include "sysemu/hvf.h"
 #include "sysemu/whpx.h"
 #include "exec/exec-all.h"
-
 #include "qemu/thread.h"
 #include "qemu/plugin.h"
 #include "sysemu/cpus.h"
@@ -124,79 +116,6 @@ bool all_cpu_threads_idle(void)
     return true;
 }
 
-bool mttcg_enabled;
-
-
-/***********************************************************/
-/* TCG vCPU kick timer
- *
- * The kick timer is responsible for moving single threaded vCPU
- * emulation on to the next vCPU. If more than one vCPU is running a
- * timer event with force a cpu->exit so the next vCPU can get
- * scheduled.
- *
- * The timer is removed if all vCPUs are idle and restarted again once
- * idleness is complete.
- */
-
-static QEMUTimer *tcg_kick_vcpu_timer;
-static CPUState *tcg_current_rr_cpu;
-
-#define TCG_KICK_PERIOD (NANOSECONDS_PER_SECOND / 10)
-
-static inline int64_t qemu_tcg_next_kick(void)
-{
-    return qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + TCG_KICK_PERIOD;
-}
-
-/* Kick the currently round-robin scheduled vCPU to next */
-static void qemu_cpu_kick_rr_next_cpu(void)
-{
-    CPUState *cpu;
-    do {
-        cpu = qatomic_mb_read(&tcg_current_rr_cpu);
-        if (cpu) {
-            cpu_exit(cpu);
-        }
-    } while (cpu != qatomic_mb_read(&tcg_current_rr_cpu));
-}
-
-/* Kick all RR vCPUs */
-static void qemu_cpu_kick_rr_cpus(void)
-{
-    CPUState *cpu;
-
-    CPU_FOREACH(cpu) {
-        cpu_exit(cpu);
-    };
-}
-
-static void kick_tcg_thread(void *opaque)
-{
-    timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick());
-    qemu_cpu_kick_rr_next_cpu();
-}
-
-static void start_tcg_kick_timer(void)
-{
-    assert(!mttcg_enabled);
-    if (!tcg_kick_vcpu_timer && CPU_NEXT(first_cpu)) {
-        tcg_kick_vcpu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
-                                           kick_tcg_thread, NULL);
-    }
-    if (tcg_kick_vcpu_timer && !timer_pending(tcg_kick_vcpu_timer)) {
-        timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick());
-    }
-}
-
-static void stop_tcg_kick_timer(void)
-{
-    assert(!mttcg_enabled);
-    if (tcg_kick_vcpu_timer && timer_pending(tcg_kick_vcpu_timer)) {
-        timer_del(tcg_kick_vcpu_timer);
-    }
-}
-
 /***********************************************************/
 void hw_error(const char *fmt, ...)
 {
@@ -328,9 +247,7 @@ int64_t cpus_get_virtual_clock(void)
     if (cpus_accel && cpus_accel->get_virtual_clock) {
         return cpus_accel->get_virtual_clock();
     }
-    if (icount_enabled()) {
-        return icount_get();
-    } else if (qtest_enabled()) { /* for qtest_clock_warp */
+    if (qtest_enabled()) { /* for qtest_clock_warp */
         return qtest_get_virtual_clock();
     }
     return cpu_get_clock();
@@ -346,9 +263,6 @@ int64_t cpus_get_elapsed_ticks(void)
     if (cpus_accel && cpus_accel->get_elapsed_ticks) {
         return cpus_accel->get_elapsed_ticks();
     }
-    if (icount_enabled()) {
-        return icount_get();
-    }
     return cpu_get_ticks();
 }
 
@@ -482,10 +396,6 @@ static void qemu_kvm_destroy_vcpu(CPUState *cpu)
     }
 }
 
-static void qemu_tcg_destroy_vcpu(CPUState *cpu)
-{
-}
-
 static void qemu_cpu_stop(CPUState *cpu, bool exit)
 {
     g_assert(qemu_cpu_is_self(cpu));
@@ -506,22 +416,6 @@ void qemu_wait_io_event_common(CPUState *cpu)
     process_queued_cpu_work(cpu);
 }
 
-static void qemu_tcg_rr_wait_io_event(void)
-{
-    CPUState *cpu;
-
-    while (all_cpu_threads_idle()) {
-        stop_tcg_kick_timer();
-        qemu_cond_wait(first_cpu->halt_cond, &qemu_global_mutex);
-    }
-
-    start_tcg_kick_timer();
-
-    CPU_FOREACH(cpu) {
-        qemu_wait_io_event_common(cpu);
-    }
-}
-
 void qemu_wait_io_event(CPUState *cpu)
 {
     bool slept = false;
@@ -633,259 +527,6 @@ static void *qemu_dummy_cpu_thread_fn(void *arg)
 #endif
 }
 
-static int64_t tcg_get_icount_limit(void)
-{
-    int64_t deadline;
-
-    if (replay_mode != REPLAY_MODE_PLAY) {
-        /*
-         * Include all the timers, because they may need an attention.
-         * Too long CPU execution may create unnecessary delay in UI.
-         */
-        deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
-                                              QEMU_TIMER_ATTR_ALL);
-        /* Check realtime timers, because they help with input processing */
-        deadline = qemu_soonest_timeout(deadline,
-                qemu_clock_deadline_ns_all(QEMU_CLOCK_REALTIME,
-                                           QEMU_TIMER_ATTR_ALL));
-
-        /* Maintain prior (possibly buggy) behaviour where if no deadline
-         * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than
-         * INT32_MAX nanoseconds ahead, we still use INT32_MAX
-         * nanoseconds.
-         */
-        if ((deadline < 0) || (deadline > INT32_MAX)) {
-            deadline = INT32_MAX;
-        }
-
-        return icount_round(deadline);
-    } else {
-        return replay_get_instructions();
-    }
-}
-
-static void notify_aio_contexts(void)
-{
-    /* Wake up other AioContexts.  */
-    qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
-    qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
-}
-
-static void handle_icount_deadline(void)
-{
-    assert(qemu_in_vcpu_thread());
-    if (icount_enabled()) {
-        int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
-                                                      QEMU_TIMER_ATTR_ALL);
-
-        if (deadline == 0) {
-            notify_aio_contexts();
-        }
-    }
-}
-
-static void prepare_icount_for_run(CPUState *cpu)
-{
-    if (icount_enabled()) {
-        int insns_left;
-
-        /* These should always be cleared by process_icount_data after
-         * each vCPU execution. However u16.high can be raised
-         * asynchronously by cpu_exit/cpu_interrupt/tcg_handle_interrupt
-         */
-        g_assert(cpu_neg(cpu)->icount_decr.u16.low == 0);
-        g_assert(cpu->icount_extra == 0);
-
-        cpu->icount_budget = tcg_get_icount_limit();
-        insns_left = MIN(0xffff, cpu->icount_budget);
-        cpu_neg(cpu)->icount_decr.u16.low = insns_left;
-        cpu->icount_extra = cpu->icount_budget - insns_left;
-
-        replay_mutex_lock();
-
-        if (cpu->icount_budget == 0 && replay_has_checkpoint()) {
-            notify_aio_contexts();
-        }
-    }
-}
-
-static void process_icount_data(CPUState *cpu)
-{
-    if (icount_enabled()) {
-        /* Account for executed instructions */
-        icount_update(cpu);
-
-        /* Reset the counters */
-        cpu_neg(cpu)->icount_decr.u16.low = 0;
-        cpu->icount_extra = 0;
-        cpu->icount_budget = 0;
-
-        replay_account_executed_instructions();
-
-        replay_mutex_unlock();
-    }
-}
-
-
-static int tcg_cpu_exec(CPUState *cpu)
-{
-    int ret;
-#ifdef CONFIG_PROFILER
-    int64_t ti;
-#endif
-
-    assert(tcg_enabled());
-#ifdef CONFIG_PROFILER
-    ti = profile_getclock();
-#endif
-    cpu_exec_start(cpu);
-    ret = cpu_exec(cpu);
-    cpu_exec_end(cpu);
-#ifdef CONFIG_PROFILER
-    qatomic_set(&tcg_ctx->prof.cpu_exec_time,
-               tcg_ctx->prof.cpu_exec_time + profile_getclock() - ti);
-#endif
-    return ret;
-}
-
-/* Destroy any remaining vCPUs which have been unplugged and have
- * finished running
- */
-static void deal_with_unplugged_cpus(void)
-{
-    CPUState *cpu;
-
-    CPU_FOREACH(cpu) {
-        if (cpu->unplug && !cpu_can_run(cpu)) {
-            qemu_tcg_destroy_vcpu(cpu);
-            cpu_thread_signal_destroyed(cpu);
-            break;
-        }
-    }
-}
-
-/* Single-threaded TCG
- *
- * In the single-threaded case each vCPU is simulated in turn. If
- * there is more than a single vCPU we create a simple timer to kick
- * the vCPU and ensure we don't get stuck in a tight loop in one vCPU.
- * This is done explicitly rather than relying on side-effects
- * elsewhere.
- */
-
-static void *qemu_tcg_rr_cpu_thread_fn(void *arg)
-{
-    CPUState *cpu = arg;
-
-    assert(tcg_enabled());
-    rcu_register_thread();
-    tcg_register_thread();
-
-    qemu_mutex_lock_iothread();
-    qemu_thread_get_self(cpu->thread);
-
-    cpu->thread_id = qemu_get_thread_id();
-    cpu->can_do_io = 1;
-    cpu_thread_signal_created(cpu);
-    qemu_guest_random_seed_thread_part2(cpu->random_seed);
-
-    /* wait for initial kick-off after machine start */
-    while (first_cpu->stopped) {
-        qemu_cond_wait(first_cpu->halt_cond, &qemu_global_mutex);
-
-        /* process any pending work */
-        CPU_FOREACH(cpu) {
-            current_cpu = cpu;
-            qemu_wait_io_event_common(cpu);
-        }
-    }
-
-    start_tcg_kick_timer();
-
-    cpu = first_cpu;
-
-    /* process any pending work */
-    cpu->exit_request = 1;
-
-    while (1) {
-        qemu_mutex_unlock_iothread();
-        replay_mutex_lock();
-        qemu_mutex_lock_iothread();
-        /* Account partial waits to QEMU_CLOCK_VIRTUAL.  */
-        icount_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();
-
-        replay_mutex_unlock();
-
-        if (!cpu) {
-            cpu = first_cpu;
-        }
-
-        while (cpu && cpu_work_list_empty(cpu) && !cpu->exit_request) {
-
-            qatomic_mb_set(&tcg_current_rr_cpu, cpu);
-            current_cpu = cpu;
-
-            qemu_clock_enable(QEMU_CLOCK_VIRTUAL,
-                              (cpu->singlestep_enabled & SSTEP_NOTIMER) == 0);
-
-            if (cpu_can_run(cpu)) {
-                int r;
-
-                qemu_mutex_unlock_iothread();
-                prepare_icount_for_run(cpu);
-
-                r = tcg_cpu_exec(cpu);
-
-                process_icount_data(cpu);
-                qemu_mutex_lock_iothread();
-
-                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) {
-                if (cpu->unplug) {
-                    cpu = CPU_NEXT(cpu);
-                }
-                break;
-            }
-
-            cpu = CPU_NEXT(cpu);
-        } /* while (cpu && !cpu->exit_request).. */
-
-        /* Does not need qatomic_mb_set because a spurious wakeup is okay.  */
-        qatomic_set(&tcg_current_rr_cpu, NULL);
-
-        if (cpu && cpu->exit_request) {
-            qatomic_mb_set(&cpu->exit_request, 0);
-        }
-
-        if (icount_enabled() && all_cpu_threads_idle()) {
-            /*
-             * When all cpus are sleeping (e.g in WFI), to avoid a deadlock
-             * in the main_loop, wake it up in order to start the warp timer.
-             */
-            qemu_notify_event();
-        }
-
-        qemu_tcg_rr_wait_io_event();
-        deal_with_unplugged_cpus();
-    }
-
-    rcu_unregister_thread();
-    return NULL;
-}
-
 static void *qemu_hax_cpu_thread_fn(void *arg)
 {
     CPUState *cpu = arg;
@@ -1005,76 +646,6 @@ static void CALLBACK dummy_apc_func(ULONG_PTR unused)
 }
 #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;
-
-    assert(tcg_enabled());
-    g_assert(!icount_enabled());
-
-    rcu_register_thread();
-    tcg_register_thread();
-
-    qemu_mutex_lock_iothread();
-    qemu_thread_get_self(cpu->thread);
-
-    cpu->thread_id = qemu_get_thread_id();
-    cpu->can_do_io = 1;
-    current_cpu = cpu;
-    cpu_thread_signal_created(cpu);
-    qemu_guest_random_seed_thread_part2(cpu->random_seed);
-
-    /* process any pending work */
-    cpu->exit_request = 1;
-
-    do {
-        if (cpu_can_run(cpu)) {
-            int r;
-            qemu_mutex_unlock_iothread();
-            r = tcg_cpu_exec(cpu);
-            qemu_mutex_lock_iothread();
-            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;
-            }
-        }
-
-        qatomic_mb_set(&cpu->exit_request, 0);
-        qemu_wait_io_event(cpu);
-    } while (!cpu->unplug || cpu_can_run(cpu));
-
-    qemu_tcg_destroy_vcpu(cpu);
-    cpu_thread_signal_destroyed(cpu);
-    qemu_mutex_unlock_iothread();
-    rcu_unregister_thread();
-    return NULL;
-}
-
 void cpus_kick_thread(CPUState *cpu)
 {
 #ifndef _WIN32
@@ -1105,15 +676,8 @@ void cpus_kick_thread(CPUState *cpu)
 void qemu_cpu_kick(CPUState *cpu)
 {
     qemu_cond_broadcast(cpu->halt_cond);
-
     if (cpus_accel && cpus_accel->kick_vcpu_thread) {
         cpus_accel->kick_vcpu_thread(cpu);
-    } else if (tcg_enabled()) {
-        if (qemu_tcg_mttcg_enabled()) {
-            cpu_exit(cpu);
-        } else {
-            qemu_cpu_kick_rr_cpus();
-        }
     } else {
         if (hax_enabled()) {
             /*
@@ -1269,71 +833,6 @@ void cpu_remove_sync(CPUState *cpu)
     qemu_mutex_lock_iothread();
 }
 
-static void qemu_tcg_init_vcpu(CPUState *cpu)
-{
-    char thread_name[VCPU_THREAD_NAME_SIZE];
-    static QemuCond *single_tcg_halt_cond;
-    static QemuThread *single_tcg_cpu_thread;
-    static int tcg_region_inited;
-
-    assert(tcg_enabled());
-    /*
-     * Initialize TCG regions--once. Now is a good time, because:
-     * (1) TCG's init context, prologue and target globals have been set up.
-     * (2) qemu_tcg_mttcg_enabled() works now (TCG init code runs before the
-     *     -accel flag is processed, so the check doesn't work then).
-     */
-    if (!tcg_region_inited) {
-        tcg_region_inited = 1;
-        tcg_region_init();
-        /*
-         * If MTTCG, and we will create multiple cpus,
-         * then we will have cpus running in parallel.
-         */
-        if (qemu_tcg_mttcg_enabled()) {
-            MachineState *ms = MACHINE(qdev_get_machine());
-            if (ms->smp.max_cpus > 1) {
-                parallel_cpus = true;
-            }
-        }
-    }
-
-    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);
-
-        if (qemu_tcg_mttcg_enabled()) {
-            /* create a thread per vCPU with TCG (MTTCG) */
-            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);
-
-        } 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
-    } else {
-        /* For non-MTTCG cases we share the thread */
-        cpu->thread = single_tcg_cpu_thread;
-        cpu->halt_cond = single_tcg_halt_cond;
-        cpu->thread_id = first_cpu->thread_id;
-        cpu->can_do_io = 1;
-        cpu->created = true;
-    }
-}
-
 static void qemu_hax_start_vcpu(CPUState *cpu)
 {
     char thread_name[VCPU_THREAD_NAME_SIZE];
@@ -1444,8 +943,6 @@ void qemu_init_vcpu(CPUState *cpu)
         qemu_hax_start_vcpu(cpu);
     } else if (hvf_enabled()) {
         qemu_hvf_start_vcpu(cpu);
-    } else if (tcg_enabled()) {
-        qemu_tcg_init_vcpu(cpu);
     } else if (whpx_enabled()) {
         qemu_whpx_start_vcpu(cpu);
     } else {