qemu/system/cpus.c
Stefan Hajnoczi 7c754c787e qemu/main-loop: rename qemu_cond_wait_iothread() to qemu_cond_wait_bql()
The name "iothread" is overloaded. Use the term Big QEMU Lock (BQL)
instead, it is already widely used and unambiguous.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-4-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2024-01-08 10:45:43 -05:00

862 lines
19 KiB
C

/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* 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 "monitor/monitor.h"
#include "qemu/coroutine-tls.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-machine.h"
#include "qapi/qapi-commands-misc.h"
#include "qapi/qapi-events-run-state.h"
#include "qapi/qmp/qerror.h"
#include "exec/gdbstub.h"
#include "sysemu/hw_accel.h"
#include "exec/cpu-common.h"
#include "qemu/thread.h"
#include "qemu/main-loop.h"
#include "qemu/plugin.h"
#include "sysemu/cpus.h"
#include "qemu/guest-random.h"
#include "hw/nmi.h"
#include "sysemu/replay.h"
#include "sysemu/runstate.h"
#include "sysemu/cpu-timers.h"
#include "sysemu/whpx.h"
#include "hw/boards.h"
#include "hw/hw.h"
#include "trace.h"
#ifdef CONFIG_LINUX
#include <sys/prctl.h>
#ifndef PR_MCE_KILL
#define PR_MCE_KILL 33
#endif
#ifndef PR_MCE_KILL_SET
#define PR_MCE_KILL_SET 1
#endif
#ifndef PR_MCE_KILL_EARLY
#define PR_MCE_KILL_EARLY 1
#endif
#endif /* CONFIG_LINUX */
/* The Big QEMU Lock (BQL) */
static QemuMutex bql;
/*
* The chosen accelerator is supposed to register this.
*/
static const AccelOpsClass *cpus_accel;
bool cpu_is_stopped(CPUState *cpu)
{
return cpu->stopped || !runstate_is_running();
}
bool cpu_work_list_empty(CPUState *cpu)
{
return QSIMPLEQ_EMPTY_ATOMIC(&cpu->work_list);
}
bool cpu_thread_is_idle(CPUState *cpu)
{
if (cpu->stop || !cpu_work_list_empty(cpu)) {
return false;
}
if (cpu_is_stopped(cpu)) {
return true;
}
if (!cpu->halted || cpu_has_work(cpu)) {
return false;
}
if (cpus_accel->cpu_thread_is_idle) {
return cpus_accel->cpu_thread_is_idle(cpu);
}
return true;
}
bool all_cpu_threads_idle(void)
{
CPUState *cpu;
CPU_FOREACH(cpu) {
if (!cpu_thread_is_idle(cpu)) {
return false;
}
}
return true;
}
/***********************************************************/
void hw_error(const char *fmt, ...)
{
va_list ap;
CPUState *cpu;
va_start(ap, fmt);
fprintf(stderr, "qemu: hardware error: ");
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
CPU_FOREACH(cpu) {
fprintf(stderr, "CPU #%d:\n", cpu->cpu_index);
cpu_dump_state(cpu, stderr, CPU_DUMP_FPU);
}
va_end(ap);
abort();
}
void cpu_synchronize_all_states(void)
{
CPUState *cpu;
CPU_FOREACH(cpu) {
cpu_synchronize_state(cpu);
}
}
void cpu_synchronize_all_post_reset(void)
{
CPUState *cpu;
CPU_FOREACH(cpu) {
cpu_synchronize_post_reset(cpu);
}
}
void cpu_synchronize_all_post_init(void)
{
CPUState *cpu;
CPU_FOREACH(cpu) {
cpu_synchronize_post_init(cpu);
}
}
void cpu_synchronize_all_pre_loadvm(void)
{
CPUState *cpu;
CPU_FOREACH(cpu) {
cpu_synchronize_pre_loadvm(cpu);
}
}
void cpu_synchronize_state(CPUState *cpu)
{
if (cpus_accel->synchronize_state) {
cpus_accel->synchronize_state(cpu);
}
}
void cpu_synchronize_post_reset(CPUState *cpu)
{
if (cpus_accel->synchronize_post_reset) {
cpus_accel->synchronize_post_reset(cpu);
}
}
void cpu_synchronize_post_init(CPUState *cpu)
{
if (cpus_accel->synchronize_post_init) {
cpus_accel->synchronize_post_init(cpu);
}
}
void cpu_synchronize_pre_loadvm(CPUState *cpu)
{
if (cpus_accel->synchronize_pre_loadvm) {
cpus_accel->synchronize_pre_loadvm(cpu);
}
}
bool cpus_are_resettable(void)
{
if (cpus_accel->cpus_are_resettable) {
return cpus_accel->cpus_are_resettable();
}
return true;
}
void cpu_exec_reset_hold(CPUState *cpu)
{
if (cpus_accel->cpu_reset_hold) {
cpus_accel->cpu_reset_hold(cpu);
}
}
int64_t cpus_get_virtual_clock(void)
{
/*
* XXX
*
* need to check that cpus_accel is not NULL, because qcow2 calls
* qemu_get_clock_ns(CLOCK_VIRTUAL) without any accel initialized and
* with ticks disabled in some io-tests:
* 030 040 041 060 099 120 127 140 156 161 172 181 191 192 195 203 229 249 256 267
*
* is this expected?
*
* XXX
*/
if (cpus_accel && cpus_accel->get_virtual_clock) {
return cpus_accel->get_virtual_clock();
}
return cpu_get_clock();
}
/*
* return the time elapsed in VM between vm_start and vm_stop. Unless
* icount is active, cpus_get_elapsed_ticks() uses units of the host CPU cycle
* counter.
*/
int64_t cpus_get_elapsed_ticks(void)
{
if (cpus_accel->get_elapsed_ticks) {
return cpus_accel->get_elapsed_ticks();
}
return cpu_get_ticks();
}
static void generic_handle_interrupt(CPUState *cpu, int mask)
{
cpu->interrupt_request |= mask;
if (!qemu_cpu_is_self(cpu)) {
qemu_cpu_kick(cpu);
}
}
void cpu_interrupt(CPUState *cpu, int mask)
{
if (cpus_accel->handle_interrupt) {
cpus_accel->handle_interrupt(cpu, mask);
} else {
generic_handle_interrupt(cpu, mask);
}
}
/*
* True if the vm was previously suspended, and has not been woken or reset.
*/
static int vm_was_suspended;
void vm_set_suspended(bool suspended)
{
vm_was_suspended = suspended;
}
bool vm_get_suspended(void)
{
return vm_was_suspended;
}
static int do_vm_stop(RunState state, bool send_stop)
{
int ret = 0;
RunState oldstate = runstate_get();
if (runstate_is_live(oldstate)) {
vm_was_suspended = (oldstate == RUN_STATE_SUSPENDED);
runstate_set(state);
cpu_disable_ticks();
if (oldstate == RUN_STATE_RUNNING) {
pause_all_vcpus();
}
vm_state_notify(0, state);
if (send_stop) {
qapi_event_send_stop();
}
}
bdrv_drain_all();
ret = bdrv_flush_all();
trace_vm_stop_flush_all(ret);
return ret;
}
/* Special vm_stop() variant for terminating the process. Historically clients
* did not expect a QMP STOP event and so we need to retain compatibility.
*/
int vm_shutdown(void)
{
return do_vm_stop(RUN_STATE_SHUTDOWN, false);
}
bool cpu_can_run(CPUState *cpu)
{
if (cpu->stop) {
return false;
}
if (cpu_is_stopped(cpu)) {
return false;
}
return true;
}
void cpu_handle_guest_debug(CPUState *cpu)
{
if (replay_running_debug()) {
if (!cpu->singlestep_enabled) {
/*
* Report about the breakpoint and
* make a single step to skip it
*/
replay_breakpoint();
cpu_single_step(cpu, SSTEP_ENABLE);
} else {
cpu_single_step(cpu, 0);
}
} else {
gdb_set_stop_cpu(cpu);
qemu_system_debug_request();
cpu->stopped = true;
}
}
#ifdef CONFIG_LINUX
static void sigbus_reraise(void)
{
sigset_t set;
struct sigaction action;
memset(&action, 0, sizeof(action));
action.sa_handler = SIG_DFL;
if (!sigaction(SIGBUS, &action, NULL)) {
raise(SIGBUS);
sigemptyset(&set);
sigaddset(&set, SIGBUS);
pthread_sigmask(SIG_UNBLOCK, &set, NULL);
}
perror("Failed to re-raise SIGBUS!");
abort();
}
static void sigbus_handler(int n, siginfo_t *siginfo, void *ctx)
{
if (siginfo->si_code != BUS_MCEERR_AO && siginfo->si_code != BUS_MCEERR_AR) {
sigbus_reraise();
}
if (current_cpu) {
/* Called asynchronously in VCPU thread. */
if (kvm_on_sigbus_vcpu(current_cpu, siginfo->si_code, siginfo->si_addr)) {
sigbus_reraise();
}
} else {
/* Called synchronously (via signalfd) in main thread. */
if (kvm_on_sigbus(siginfo->si_code, siginfo->si_addr)) {
sigbus_reraise();
}
}
}
static void qemu_init_sigbus(void)
{
struct sigaction action;
/*
* ALERT: when modifying this, take care that SIGBUS forwarding in
* qemu_prealloc_mem() will continue working as expected.
*/
memset(&action, 0, sizeof(action));
action.sa_flags = SA_SIGINFO;
action.sa_sigaction = sigbus_handler;
sigaction(SIGBUS, &action, NULL);
prctl(PR_MCE_KILL, PR_MCE_KILL_SET, PR_MCE_KILL_EARLY, 0, 0);
}
#else /* !CONFIG_LINUX */
static void qemu_init_sigbus(void)
{
}
#endif /* !CONFIG_LINUX */
static QemuThread io_thread;
/* cpu creation */
static QemuCond qemu_cpu_cond;
/* system init */
static QemuCond qemu_pause_cond;
void qemu_init_cpu_loop(void)
{
qemu_init_sigbus();
qemu_cond_init(&qemu_cpu_cond);
qemu_cond_init(&qemu_pause_cond);
qemu_mutex_init(&bql);
qemu_thread_get_self(&io_thread);
}
void run_on_cpu(CPUState *cpu, run_on_cpu_func func, run_on_cpu_data data)
{
do_run_on_cpu(cpu, func, data, &bql);
}
static void qemu_cpu_stop(CPUState *cpu, bool exit)
{
g_assert(qemu_cpu_is_self(cpu));
cpu->stop = false;
cpu->stopped = true;
if (exit) {
cpu_exit(cpu);
}
qemu_cond_broadcast(&qemu_pause_cond);
}
void qemu_wait_io_event_common(CPUState *cpu)
{
qatomic_set_mb(&cpu->thread_kicked, false);
if (cpu->stop) {
qemu_cpu_stop(cpu, false);
}
process_queued_cpu_work(cpu);
}
void qemu_wait_io_event(CPUState *cpu)
{
bool slept = false;
while (cpu_thread_is_idle(cpu)) {
if (!slept) {
slept = true;
qemu_plugin_vcpu_idle_cb(cpu);
}
qemu_cond_wait(cpu->halt_cond, &bql);
}
if (slept) {
qemu_plugin_vcpu_resume_cb(cpu);
}
qemu_wait_io_event_common(cpu);
}
void cpus_kick_thread(CPUState *cpu)
{
if (cpu->thread_kicked) {
return;
}
cpu->thread_kicked = true;
#ifndef _WIN32
int err = pthread_kill(cpu->thread->thread, SIG_IPI);
if (err && err != ESRCH) {
fprintf(stderr, "qemu:%s: %s", __func__, strerror(err));
exit(1);
}
#else
qemu_sem_post(&cpu->sem);
#endif
}
void qemu_cpu_kick(CPUState *cpu)
{
qemu_cond_broadcast(cpu->halt_cond);
if (cpus_accel->kick_vcpu_thread) {
cpus_accel->kick_vcpu_thread(cpu);
} else { /* default */
cpus_kick_thread(cpu);
}
}
void qemu_cpu_kick_self(void)
{
assert(current_cpu);
cpus_kick_thread(current_cpu);
}
bool qemu_cpu_is_self(CPUState *cpu)
{
return qemu_thread_is_self(cpu->thread);
}
bool qemu_in_vcpu_thread(void)
{
return current_cpu && qemu_cpu_is_self(current_cpu);
}
QEMU_DEFINE_STATIC_CO_TLS(bool, bql_locked)
bool bql_locked(void)
{
return get_bql_locked();
}
bool qemu_in_main_thread(void)
{
return bql_locked();
}
/*
* The BQL is taken from so many places that it is worth profiling the
* callers directly, instead of funneling them all through a single function.
*/
void bql_lock_impl(const char *file, int line)
{
QemuMutexLockFunc bql_lock_fn = qatomic_read(&bql_mutex_lock_func);
g_assert(!bql_locked());
bql_lock_fn(&bql, file, line);
set_bql_locked(true);
}
void bql_unlock(void)
{
g_assert(bql_locked());
set_bql_locked(false);
qemu_mutex_unlock(&bql);
}
void qemu_cond_wait_bql(QemuCond *cond)
{
qemu_cond_wait(cond, &bql);
}
void qemu_cond_timedwait_bql(QemuCond *cond, int ms)
{
qemu_cond_timedwait(cond, &bql, ms);
}
/* signal CPU creation */
void cpu_thread_signal_created(CPUState *cpu)
{
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
}
/* signal CPU destruction */
void cpu_thread_signal_destroyed(CPUState *cpu)
{
cpu->created = false;
qemu_cond_signal(&qemu_cpu_cond);
}
static bool all_vcpus_paused(void)
{
CPUState *cpu;
CPU_FOREACH(cpu) {
if (!cpu->stopped) {
return false;
}
}
return true;
}
void pause_all_vcpus(void)
{
CPUState *cpu;
qemu_clock_enable(QEMU_CLOCK_VIRTUAL, false);
CPU_FOREACH(cpu) {
if (qemu_cpu_is_self(cpu)) {
qemu_cpu_stop(cpu, true);
} else {
cpu->stop = true;
qemu_cpu_kick(cpu);
}
}
/* We need to drop the replay_lock so any vCPU threads woken up
* can finish their replay tasks
*/
replay_mutex_unlock();
while (!all_vcpus_paused()) {
qemu_cond_wait(&qemu_pause_cond, &bql);
CPU_FOREACH(cpu) {
qemu_cpu_kick(cpu);
}
}
bql_unlock();
replay_mutex_lock();
bql_lock();
}
void cpu_resume(CPUState *cpu)
{
cpu->stop = false;
cpu->stopped = false;
qemu_cpu_kick(cpu);
}
void resume_all_vcpus(void)
{
CPUState *cpu;
if (!runstate_is_running()) {
return;
}
qemu_clock_enable(QEMU_CLOCK_VIRTUAL, true);
CPU_FOREACH(cpu) {
cpu_resume(cpu);
}
}
void cpu_remove_sync(CPUState *cpu)
{
cpu->stop = true;
cpu->unplug = true;
qemu_cpu_kick(cpu);
bql_unlock();
qemu_thread_join(cpu->thread);
bql_lock();
}
void cpus_register_accel(const AccelOpsClass *ops)
{
assert(ops != NULL);
assert(ops->create_vcpu_thread != NULL); /* mandatory */
cpus_accel = ops;
}
const AccelOpsClass *cpus_get_accel(void)
{
/* broken if we call this early */
assert(cpus_accel);
return cpus_accel;
}
void qemu_init_vcpu(CPUState *cpu)
{
MachineState *ms = MACHINE(qdev_get_machine());
cpu->nr_cores = machine_topo_get_cores_per_socket(ms);
cpu->nr_threads = ms->smp.threads;
cpu->stopped = true;
cpu->random_seed = qemu_guest_random_seed_thread_part1();
if (!cpu->as) {
/* If the target cpu hasn't set up any address spaces itself,
* give it the default one.
*/
cpu->num_ases = 1;
cpu_address_space_init(cpu, 0, "cpu-memory", cpu->memory);
}
/* accelerators all implement the AccelOpsClass */
g_assert(cpus_accel != NULL && cpus_accel->create_vcpu_thread != NULL);
cpus_accel->create_vcpu_thread(cpu);
while (!cpu->created) {
qemu_cond_wait(&qemu_cpu_cond, &bql);
}
}
void cpu_stop_current(void)
{
if (current_cpu) {
current_cpu->stop = true;
cpu_exit(current_cpu);
}
}
int vm_stop(RunState state)
{
if (qemu_in_vcpu_thread()) {
qemu_system_vmstop_request_prepare();
qemu_system_vmstop_request(state);
/*
* FIXME: should not return to device code in case
* vm_stop() has been requested.
*/
cpu_stop_current();
return 0;
}
return do_vm_stop(state, true);
}
/**
* Prepare for (re)starting the VM.
* Returns 0 if the vCPUs should be restarted, -1 on an error condition,
* and 1 otherwise.
*/
int vm_prepare_start(bool step_pending)
{
int ret = vm_was_suspended ? 1 : 0;
RunState state = vm_was_suspended ? RUN_STATE_SUSPENDED : RUN_STATE_RUNNING;
RunState requested;
qemu_vmstop_requested(&requested);
if (runstate_is_running() && requested == RUN_STATE__MAX) {
return -1;
}
/* Ensure that a STOP/RESUME pair of events is emitted if a
* vmstop request was pending. The BLOCK_IO_ERROR event, for
* example, according to documentation is always followed by
* the STOP event.
*/
if (runstate_is_running()) {
qapi_event_send_stop();
qapi_event_send_resume();
return -1;
}
/*
* WHPX accelerator needs to know whether we are going to step
* any CPUs, before starting the first one.
*/
if (cpus_accel->synchronize_pre_resume) {
cpus_accel->synchronize_pre_resume(step_pending);
}
/* We are sending this now, but the CPUs will be resumed shortly later */
qapi_event_send_resume();
cpu_enable_ticks();
runstate_set(state);
vm_state_notify(1, state);
vm_was_suspended = false;
return ret;
}
void vm_start(void)
{
if (!vm_prepare_start(false)) {
resume_all_vcpus();
}
}
void vm_resume(RunState state)
{
if (runstate_is_live(state)) {
vm_start();
} else {
runstate_set(state);
}
}
/* does a state transition even if the VM is already stopped,
current state is forgotten forever */
int vm_stop_force_state(RunState state)
{
if (runstate_is_live(runstate_get())) {
return vm_stop(state);
} else {
int ret;
runstate_set(state);
bdrv_drain_all();
/* Make sure to return an error if the flush in a previous vm_stop()
* failed. */
ret = bdrv_flush_all();
trace_vm_stop_flush_all(ret);
return ret;
}
}
void qmp_memsave(int64_t addr, int64_t size, const char *filename,
bool has_cpu, int64_t cpu_index, Error **errp)
{
FILE *f;
uint32_t l;
CPUState *cpu;
uint8_t buf[1024];
int64_t orig_addr = addr, orig_size = size;
if (!has_cpu) {
cpu_index = 0;
}
cpu = qemu_get_cpu(cpu_index);
if (cpu == NULL) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cpu-index",
"a CPU number");
return;
}
f = fopen(filename, "wb");
if (!f) {
error_setg_file_open(errp, errno, filename);
return;
}
while (size != 0) {
l = sizeof(buf);
if (l > size)
l = size;
if (cpu_memory_rw_debug(cpu, addr, buf, l, 0) != 0) {
error_setg(errp, "Invalid addr 0x%016" PRIx64 "/size %" PRId64
" specified", orig_addr, orig_size);
goto exit;
}
if (fwrite(buf, 1, l, f) != l) {
error_setg(errp, QERR_IO_ERROR);
goto exit;
}
addr += l;
size -= l;
}
exit:
fclose(f);
}
void qmp_pmemsave(int64_t addr, int64_t size, const char *filename,
Error **errp)
{
FILE *f;
uint32_t l;
uint8_t buf[1024];
f = fopen(filename, "wb");
if (!f) {
error_setg_file_open(errp, errno, filename);
return;
}
while (size != 0) {
l = sizeof(buf);
if (l > size)
l = size;
cpu_physical_memory_read(addr, buf, l);
if (fwrite(buf, 1, l, f) != l) {
error_setg(errp, QERR_IO_ERROR);
goto exit;
}
addr += l;
size -= l;
}
exit:
fclose(f);
}
void qmp_inject_nmi(Error **errp)
{
nmi_monitor_handle(monitor_get_cpu_index(monitor_cur()), errp);
}