mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

accel/tcg: split CpusAccel into three TCG variants

Browse Source 
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)

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20201015143217.29337-2-cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Claudio Fontana 2020-10-15 16:32:15 +02:00 committed by Richard Henderson
parent 2ecfc0657a
commit 45e077d751
11 changed files with 646 additions and 462 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
accel/tcg/meson.build
View File

@ -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]) 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_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'
))

8
accel/tcg/tcg-all.c
View File

@ -104,8 +104,14 @@ static int tcg_init(MachineState *ms)
tcg_exec_init(s->tb_size * 1024 * 1024); tcg_exec_init(s->tb_size * 1024 * 1024);
mttcg_enabled = s->mttcg_enabled; 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; return 0;
} }

147
accel/tcg/tcg-cpus-icount.c Normal file
View File

@ -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,
};

17
accel/tcg/tcg-cpus-icount.h Normal file
View File

@ -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 */

117
accel/tcg/tcg-cpus-mttcg.c Normal file
View File

@ -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,
};

21
accel/tcg/tcg-cpus-mttcg.h Normal file
View File

@ -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 */

270
accel/tcg/tcg-cpus-rr.c Normal file
View File

@ -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,
};

20
accel/tcg/tcg-cpus-rr.h Normal file
View File

@ -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 */

484
accel/tcg/tcg-cpus.c
View File

@ -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) 2003-2008 Fabrice Bellard
* Copyright (c) 2014 Red Hat Inc. * Copyright (c) 2014 Red Hat Inc.
@ -33,436 +35,12 @@
#include "hw/boards.h" #include "hw/boards.h"
#include "tcg-cpus.h" #include "tcg-cpus.h"
#include "tcg-cpus-mttcg.h"
#include "tcg-cpus-rr.h"
/* Kick all RR vCPUs */ /* common functionality among all TCG variants */
static void qemu_cpu_kick_rr_cpus(void)
{
CPUState *cpu;
CPU_FOREACH(cpu) { void tcg_start_vcpu_thread(CPUState *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)
{ {
char thread_name[VCPU_THREAD_NAME_SIZE]; char thread_name[VCPU_THREAD_NAME_SIZE];
static QemuCond *single_tcg_halt_cond; 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()) { cpu_thread_signal_destroyed(cpu);
return icount_get();
}
return cpu_get_clock();
} }
static int64_t tcg_get_elapsed_ticks(void) int tcg_cpu_exec(CPUState *cpu)
{ {
if (icount_enabled()) { int ret;
return icount_get(); #ifdef CONFIG_PROFILER
} int64_t ti;
return cpu_get_ticks(); #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 */ /* 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()); g_assert(qemu_mutex_iothread_locked());
old_mask = cpu->interrupt_request;
cpu->interrupt_request |= mask; cpu->interrupt_request |= mask;
/* /*
@ -551,20 +136,5 @@ static void tcg_handle_interrupt(CPUState *cpu, int mask)
qemu_cpu_kick(cpu); qemu_cpu_kick(cpu);
} else { } else {
qatomic_set(&cpu_neg(cpu)->icount_decr.u16.high, -1); 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,
};

13
accel/tcg/tcg-cpus.h
View File

@ -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 * Copyright 2020 SUSE LLC
* *
@ -12,6 +14,13 @@
#include "sysemu/cpus.h" #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 */ #endif /* TCG_CPUS_H */

2
softmmu/icount.c
View File

@ -396,7 +396,7 @@ void icount_start_warp_timer(void)
void icount_account_warp_timer(void) void icount_account_warp_timer(void)
{ {
if (!icount_enabled() || !icount_sleep) { if (!icount_sleep) {
return; return;
} }