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[RFC v1 1/2] accel/tcg: split CpusAccel into three TCG variants
|
From: |
Claudio Fontana |
|
Subject: |
[RFC v1 1/2] accel/tcg: split CpusAccel into three TCG variants |
|
Date: |
Wed, 14 Oct 2020 09:36:04 +0200 |
split up the CpusAccel tcg_cpus into three TCG variants:
tcg_cpus_rr (single threaded, round robin cpus)
tcg_cpus_icount (same as rr, but with instruction counting enabled)
tcg_cpus_mttcg (multi-threaded cpus)
Signed-off-by: Claudio Fontana <cfontana@suse.de>
---
accel/tcg/meson.build | 9 +-
accel/tcg/tcg-all.c | 8 +-
accel/tcg/tcg-cpus-icount.c | 145 +++++++++++
accel/tcg/tcg-cpus-icount.h | 20 ++
accel/tcg/tcg-cpus-mttcg.c | 118 +++++++++
accel/tcg/tcg-cpus-mttcg.h | 25 ++
accel/tcg/tcg-cpus-rr.c | 270 ++++++++++++++++++++
accel/tcg/tcg-cpus-rr.h | 23 ++
accel/tcg/tcg-cpus.c | 478 ++----------------------------------
accel/tcg/tcg-cpus.h | 9 +-
softmmu/icount.c | 2 +-
11 files changed, 647 insertions(+), 460 deletions(-)
create mode 100644 accel/tcg/tcg-cpus-icount.c
create mode 100644 accel/tcg/tcg-cpus-icount.h
create mode 100644 accel/tcg/tcg-cpus-mttcg.c
create mode 100644 accel/tcg/tcg-cpus-mttcg.h
create mode 100644 accel/tcg/tcg-cpus-rr.c
create mode 100644 accel/tcg/tcg-cpus-rr.h
diff --git a/accel/tcg/meson.build b/accel/tcg/meson.build
index 19b9343d5b..f39aab0a0c 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 fa1208158f..e42a028043 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 0000000000..43505e8f1f
--- /dev/null
+++ b/accel/tcg/tcg-cpus-icount.c
@@ -0,0 +1,145 @@
+/*
+ * QEMU System Emulator
+ *
+ * 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"
+
+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 0000000000..e2e25674c2
--- /dev/null
+++ b/accel/tcg/tcg-cpus-icount.h
@@ -0,0 +1,20 @@
+/*
+ * Accelerator CPUS Interface
+ *
+ * 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
+
+extern const CpusAccel tcg_cpus_icount;
+
+int64_t tcg_get_icount_limit(void);
+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 0000000000..2f5317d767
--- /dev/null
+++ b/accel/tcg/tcg-cpus-mttcg.c
@@ -0,0 +1,118 @@
+/*
+ * QEMU System Emulator
+ *
+ * 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"
+
+/*
+ * 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.
+ */
+
+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 0000000000..c8966b2f8a
--- /dev/null
+++ b/accel/tcg/tcg-cpus-mttcg.h
@@ -0,0 +1,25 @@
+/*
+ * Accelerator CPUS Interface
+ *
+ * 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
+
+extern const CpusAccel tcg_cpus_mttcg;
+
+/*
+ * 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.
+ */
+
+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 0000000000..b8fd33d9d3
--- /dev/null
+++ b/accel/tcg/tcg-cpus-rr.c
@@ -0,0 +1,270 @@
+/*
+ * QEMU System Emulator
+ *
+ * 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"
+
+/* 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;
+ }
+ }
+}
+
+/*
+ * 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.
+ */
+
+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 0000000000..155510cfd4
--- /dev/null
+++ b/accel/tcg/tcg-cpus-rr.h
@@ -0,0 +1,23 @@
+/*
+ * Accelerator CPUS Interface
+ *
+ * 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
+
+extern const CpusAccel tcg_cpus_rr;
+
+#define TCG_KICK_PERIOD (NANOSECONDS_PER_SECOND / 10)
+
+/* Kick all RR vCPUs. */
+void qemu_cpu_kick_rr_cpus(CPUState *unused);
+
+/* Single-threaded TCG */
+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 da1c63d8f6..e518cc7ed4 100644
--- a/accel/tcg/tcg-cpus.c
+++ b/accel/tcg/tcg-cpus.c
@@ -34,435 +34,9 @@
#include "tcg-cpus.h"
-/* Kick all RR vCPUs */
-static void qemu_cpu_kick_rr_cpus(void)
-{
- CPUState *cpu;
+/* common functionality among all TCG variants */
- 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);
- }
-
- 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 +92,36 @@ 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 +132,5 @@ 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 8b1d9d2abc..871e58507d 100644
--- a/accel/tcg/tcg-cpus.h
+++ b/accel/tcg/tcg-cpus.h
@@ -12,6 +12,13 @@
#include "sysemu/cpus.h"
-extern const CpusAccel tcg_cpus;
+#include "tcg-cpus-rr.h"
+#include "tcg-cpus-icount.h"
+#include "tcg-cpus-mttcg.h"
+
+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 */
diff --git a/softmmu/icount.c b/softmmu/icount.c
index 020a201a01..dbcd8c3594 100644
--- a/softmmu/icount.c
+++ b/softmmu/icount.c
@@ -396,7 +396,7 @@ void icount_start_warp_timer(void)
void icount_account_warp_timer(void)
{
- if (!icount_enabled() || !icount_sleep) {
+ if (!icount_sleep) {
return;
}
--
2.26.2