diff options
Diffstat (limited to 'accel/tcg')
| -rw-r--r-- | accel/tcg/meson.build | 9 | ||||
| -rw-r--r-- | accel/tcg/tcg-all.c | 8 | ||||
| -rw-r--r-- | accel/tcg/tcg-cpus-icount.c | 147 | ||||
| -rw-r--r-- | accel/tcg/tcg-cpus-icount.h | 17 | ||||
| -rw-r--r-- | accel/tcg/tcg-cpus-mttcg.c | 117 | ||||
| -rw-r--r-- | accel/tcg/tcg-cpus-mttcg.h | 21 | ||||
| -rw-r--r-- | accel/tcg/tcg-cpus-rr.c | 270 | ||||
| -rw-r--r-- | accel/tcg/tcg-cpus-rr.h | 20 | ||||
| -rw-r--r-- | accel/tcg/tcg-cpus.c | 484 | ||||
| -rw-r--r-- | accel/tcg/tcg-cpus.h | 13 |
10 files changed, 645 insertions, 461 deletions
diff --git a/accel/tcg/meson.build b/accel/tcg/meson.build index 19b9343..f39aab0 100644 --- a/accel/tcg/meson.build +++ b/accel/tcg/meson.build @@ -12,4 +12,11 @@ tcg_ss.add(when: 'CONFIG_SOFTMMU', if_false: files('user-exec-stub.c')) tcg_ss.add(when: 'CONFIG_PLUGIN', if_true: [files('plugin-gen.c'), libdl]) specific_ss.add_all(when: 'CONFIG_TCG', if_true: tcg_ss) -specific_ss.add(when: ['CONFIG_SOFTMMU', 'CONFIG_TCG'], if_true: files('tcg-all.c', 'cputlb.c', 'tcg-cpus.c')) +specific_ss.add(when: ['CONFIG_SOFTMMU', 'CONFIG_TCG'], if_true: files( + 'tcg-all.c', + 'cputlb.c', + 'tcg-cpus.c', + 'tcg-cpus-mttcg.c', + 'tcg-cpus-icount.c', + 'tcg-cpus-rr.c' +)) diff --git a/accel/tcg/tcg-all.c b/accel/tcg/tcg-all.c index fa12081..e42a028 100644 --- a/accel/tcg/tcg-all.c +++ b/accel/tcg/tcg-all.c @@ -104,8 +104,14 @@ static int tcg_init(MachineState *ms) tcg_exec_init(s->tb_size * 1024 * 1024); mttcg_enabled = s->mttcg_enabled; - cpus_register_accel(&tcg_cpus); + if (mttcg_enabled) { + cpus_register_accel(&tcg_cpus_mttcg); + } else if (icount_enabled()) { + cpus_register_accel(&tcg_cpus_icount); + } else { + cpus_register_accel(&tcg_cpus_rr); + } return 0; } diff --git a/accel/tcg/tcg-cpus-icount.c b/accel/tcg/tcg-cpus-icount.c new file mode 100644 index 0000000..d3af3af --- /dev/null +++ b/accel/tcg/tcg-cpus-icount.c @@ -0,0 +1,147 @@ +/* + * QEMU TCG Single Threaded vCPUs implementation using instruction counting + * + * Copyright (c) 2003-2008 Fabrice Bellard + * Copyright (c) 2014 Red Hat Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qemu-common.h" +#include "sysemu/tcg.h" +#include "sysemu/replay.h" +#include "qemu/main-loop.h" +#include "qemu/guest-random.h" +#include "exec/exec-all.h" +#include "hw/boards.h" + +#include "tcg-cpus.h" +#include "tcg-cpus-icount.h" +#include "tcg-cpus-rr.h" + +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); +} + +void handle_icount_deadline(void) +{ + assert(qemu_in_vcpu_thread()); + int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL, + QEMU_TIMER_ATTR_ALL); + + if (deadline == 0) { + notify_aio_contexts(); + } +} + +void prepare_icount_for_run(CPUState *cpu) +{ + 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(); + } +} + +void process_icount_data(CPUState *cpu) +{ + /* 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 void icount_handle_interrupt(CPUState *cpu, int mask) +{ + int old_mask = cpu->interrupt_request; + + tcg_handle_interrupt(cpu, mask); + if (qemu_cpu_is_self(cpu) && + !cpu->can_do_io + && (mask & ~old_mask) != 0) { + cpu_abort(cpu, "Raised interrupt while not in I/O function"); + } +} + +const CpusAccel tcg_cpus_icount = { + .create_vcpu_thread = tcg_start_vcpu_thread, + .kick_vcpu_thread = qemu_cpu_kick_rr_cpus, + + .handle_interrupt = icount_handle_interrupt, + .get_virtual_clock = icount_get, + .get_elapsed_ticks = icount_get, +}; diff --git a/accel/tcg/tcg-cpus-icount.h b/accel/tcg/tcg-cpus-icount.h new file mode 100644 index 0000000..cbcf76b --- /dev/null +++ b/accel/tcg/tcg-cpus-icount.h @@ -0,0 +1,17 @@ +/* + * QEMU TCG Single Threaded vCPUs implementation using instruction counting + * + * Copyright 2020 SUSE LLC + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef TCG_CPUS_ICOUNT_H +#define TCG_CPUS_ICOUNT_H + +void handle_icount_deadline(void); +void prepare_icount_for_run(CPUState *cpu); +void process_icount_data(CPUState *cpu); + +#endif /* TCG_CPUS_ICOUNT_H */ diff --git a/accel/tcg/tcg-cpus-mttcg.c b/accel/tcg/tcg-cpus-mttcg.c new file mode 100644 index 0000000..dac724f --- /dev/null +++ b/accel/tcg/tcg-cpus-mttcg.c @@ -0,0 +1,117 @@ +/* + * QEMU TCG Multi Threaded vCPUs implementation + * + * Copyright (c) 2003-2008 Fabrice Bellard + * Copyright (c) 2014 Red Hat Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qemu-common.h" +#include "sysemu/tcg.h" +#include "sysemu/replay.h" +#include "qemu/main-loop.h" +#include "qemu/guest-random.h" +#include "exec/exec-all.h" +#include "hw/boards.h" + +#include "tcg-cpus.h" +#include "tcg-cpus-mttcg.h" + +/* + * 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. + */ + +void *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); + qemu_mutex_unlock_iothread(); + rcu_unregister_thread(); + return NULL; +} + +static void mttcg_kick_vcpu_thread(CPUState *cpu) +{ + cpu_exit(cpu); +} + +const CpusAccel tcg_cpus_mttcg = { + .create_vcpu_thread = tcg_start_vcpu_thread, + .kick_vcpu_thread = mttcg_kick_vcpu_thread, + + .handle_interrupt = tcg_handle_interrupt, +}; diff --git a/accel/tcg/tcg-cpus-mttcg.h b/accel/tcg/tcg-cpus-mttcg.h new file mode 100644 index 0000000..d1bd771 --- /dev/null +++ b/accel/tcg/tcg-cpus-mttcg.h @@ -0,0 +1,21 @@ +/* + * QEMU TCG Multi Threaded vCPUs implementation + * + * Copyright 2020 SUSE LLC + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef TCG_CPUS_MTTCG_H +#define TCG_CPUS_MTTCG_H + +/* + * 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. + */ + +void *tcg_cpu_thread_fn(void *arg); + +#endif /* TCG_CPUS_MTTCG_H */ diff --git a/accel/tcg/tcg-cpus-rr.c b/accel/tcg/tcg-cpus-rr.c new file mode 100644 index 0000000..ad50a37 --- /dev/null +++ b/accel/tcg/tcg-cpus-rr.c @@ -0,0 +1,270 @@ +/* + * QEMU TCG Single Threaded vCPUs implementation + * + * Copyright (c) 2003-2008 Fabrice Bellard + * Copyright (c) 2014 Red Hat Inc. + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qemu-common.h" +#include "sysemu/tcg.h" +#include "sysemu/replay.h" +#include "qemu/main-loop.h" +#include "qemu/guest-random.h" +#include "exec/exec-all.h" +#include "hw/boards.h" + +#include "tcg-cpus.h" +#include "tcg-cpus-rr.h" +#include "tcg-cpus-icount.h" + +/* Kick all RR vCPUs */ +void qemu_cpu_kick_rr_cpus(CPUState *unused) +{ + CPUState *cpu; + + CPU_FOREACH(cpu) { + cpu_exit(cpu); + }; +} + +/* + * 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)); +} + +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) +{ + 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) +{ + if (tcg_kick_vcpu_timer && timer_pending(tcg_kick_vcpu_timer)) { + timer_del(tcg_kick_vcpu_timer); + } +} + +static void qemu_tcg_rr_wait_io_event(void) +{ + CPUState *cpu; + + while (all_cpu_threads_idle()) { + stop_tcg_kick_timer(); + qemu_cond_wait_iothread(first_cpu->halt_cond); + } + + start_tcg_kick_timer(); + + CPU_FOREACH(cpu) { + qemu_wait_io_event_common(cpu); + } +} + +/* + * 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); + break; + } + } +} + +/* + * 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. + */ + +void *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_iothread(first_cpu->halt_cond); + + /* 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(); + + if (icount_enabled()) { + /* 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(); + if (icount_enabled()) { + prepare_icount_for_run(cpu); + } + r = tcg_cpu_exec(cpu); + if (icount_enabled()) { + 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; +} + +const CpusAccel tcg_cpus_rr = { + .create_vcpu_thread = tcg_start_vcpu_thread, + .kick_vcpu_thread = qemu_cpu_kick_rr_cpus, + + .handle_interrupt = tcg_handle_interrupt, +}; diff --git a/accel/tcg/tcg-cpus-rr.h b/accel/tcg/tcg-cpus-rr.h new file mode 100644 index 0000000..1936fd1 --- /dev/null +++ b/accel/tcg/tcg-cpus-rr.h @@ -0,0 +1,20 @@ +/* + * QEMU TCG Single Threaded vCPUs implementation + * + * Copyright 2020 SUSE LLC + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef TCG_CPUS_RR_H +#define TCG_CPUS_RR_H + +#define TCG_KICK_PERIOD (NANOSECONDS_PER_SECOND / 10) + +/* Kick all RR vCPUs. */ +void qemu_cpu_kick_rr_cpus(CPUState *unused); + +void *tcg_rr_cpu_thread_fn(void *arg); + +#endif /* TCG_CPUS_RR_H */ diff --git a/accel/tcg/tcg-cpus.c b/accel/tcg/tcg-cpus.c index da1c63d..f2b9bbf 100644 --- a/accel/tcg/tcg-cpus.c +++ b/accel/tcg/tcg-cpus.c @@ -1,5 +1,7 @@ /* - * QEMU System Emulator + * QEMU TCG vCPU common functionality + * + * Functionality common to all TCG vCPU variants: mttcg, rr and icount. * * Copyright (c) 2003-2008 Fabrice Bellard * Copyright (c) 2014 Red Hat Inc. @@ -33,436 +35,12 @@ #include "hw/boards.h" #include "tcg-cpus.h" +#include "tcg-cpus-mttcg.h" +#include "tcg-cpus-rr.h" -/* Kick all RR vCPUs */ -static void qemu_cpu_kick_rr_cpus(void) -{ - CPUState *cpu; - - CPU_FOREACH(cpu) { - cpu_exit(cpu); - }; -} - -static void tcg_kick_vcpu_thread(CPUState *cpu) -{ - if (qemu_tcg_mttcg_enabled()) { - cpu_exit(cpu); - } else { - qemu_cpu_kick_rr_cpus(); - } -} - -/* - * 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)); -} - -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); - } -} - -static void qemu_tcg_destroy_vcpu(CPUState *cpu) -{ -} - -static void qemu_tcg_rr_wait_io_event(void) -{ - CPUState *cpu; - - while (all_cpu_threads_idle()) { - stop_tcg_kick_timer(); - qemu_cond_wait_iothread(first_cpu->halt_cond); - } +/* common functionality among all TCG variants */ - start_tcg_kick_timer(); - - CPU_FOREACH(cpu) { - qemu_wait_io_event_common(cpu); - } -} - -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 *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_iothread(first_cpu->halt_cond); - - /* 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; -} - -/* - * 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 *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; -} - -static void tcg_start_vcpu_thread(CPUState *cpu) +void tcg_start_vcpu_thread(CPUState *cpu) { char thread_name[VCPU_THREAD_NAME_SIZE]; static QemuCond *single_tcg_halt_cond; @@ -518,29 +96,36 @@ static void tcg_start_vcpu_thread(CPUState *cpu) } } -static int64_t tcg_get_virtual_clock(void) +void qemu_tcg_destroy_vcpu(CPUState *cpu) { - if (icount_enabled()) { - return icount_get(); - } - return cpu_get_clock(); + cpu_thread_signal_destroyed(cpu); } -static int64_t tcg_get_elapsed_ticks(void) +int tcg_cpu_exec(CPUState *cpu) { - if (icount_enabled()) { - return icount_get(); - } - return cpu_get_ticks(); + 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; } /* mask must never be zero, except for A20 change call */ -static void tcg_handle_interrupt(CPUState *cpu, int mask) +void tcg_handle_interrupt(CPUState *cpu, int mask) { - int old_mask; g_assert(qemu_mutex_iothread_locked()); - old_mask = cpu->interrupt_request; cpu->interrupt_request |= mask; /* @@ -551,20 +136,5 @@ static void tcg_handle_interrupt(CPUState *cpu, int mask) qemu_cpu_kick(cpu); } else { qatomic_set(&cpu_neg(cpu)->icount_decr.u16.high, -1); - if (icount_enabled() && - !cpu->can_do_io - && (mask & ~old_mask) != 0) { - cpu_abort(cpu, "Raised interrupt while not in I/O function"); - } } } - -const CpusAccel tcg_cpus = { - .create_vcpu_thread = tcg_start_vcpu_thread, - .kick_vcpu_thread = tcg_kick_vcpu_thread, - - .handle_interrupt = tcg_handle_interrupt, - - .get_virtual_clock = tcg_get_virtual_clock, - .get_elapsed_ticks = tcg_get_elapsed_ticks, -}; diff --git a/accel/tcg/tcg-cpus.h b/accel/tcg/tcg-cpus.h index 8b1d9d2..279ba72 100644 --- a/accel/tcg/tcg-cpus.h +++ b/accel/tcg/tcg-cpus.h @@ -1,5 +1,7 @@ /* - * Accelerator CPUS Interface + * QEMU TCG vCPU common functionality + * + * Functionality common to all TCG vcpu variants: mttcg, rr and icount. * * Copyright 2020 SUSE LLC * @@ -12,6 +14,13 @@ #include "sysemu/cpus.h" -extern const CpusAccel tcg_cpus; +extern const CpusAccel tcg_cpus_mttcg; +extern const CpusAccel tcg_cpus_icount; +extern const CpusAccel tcg_cpus_rr; + +void tcg_start_vcpu_thread(CPUState *cpu); +void qemu_tcg_destroy_vcpu(CPUState *cpu); +int tcg_cpu_exec(CPUState *cpu); +void tcg_handle_interrupt(CPUState *cpu, int mask); #endif /* TCG_CPUS_H */ |