mirror of
https://github.com/qemu/qemu.git
synced 2024-12-05 17:53:36 +08:00
3e9418e160
This reverts commit 15124e1420
. It breaks
debuggability of qemu and is no longer needed as the problem has
now been addressed in a different way.
Instead we provide a comment about why these signals must be
handled asynchronously.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
[PMM: added comment]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
511 lines
13 KiB
C
511 lines
13 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-common.h"
|
|
#include "qemu/timer.h"
|
|
#include "qemu/sockets.h" // struct in_addr needed for libslirp.h
|
|
#include "sysemu/qtest.h"
|
|
#include "slirp/libslirp.h"
|
|
#include "qemu/main-loop.h"
|
|
#include "block/aio.h"
|
|
|
|
#ifndef _WIN32
|
|
|
|
#include "qemu/compatfd.h"
|
|
|
|
/* If we have signalfd, we mask out the signals we want to handle and then
|
|
* use signalfd to listen for them. We rely on whatever the current signal
|
|
* handler is to dispatch the signals when we receive them.
|
|
*/
|
|
static void sigfd_handler(void *opaque)
|
|
{
|
|
int fd = (intptr_t)opaque;
|
|
struct qemu_signalfd_siginfo info;
|
|
struct sigaction action;
|
|
ssize_t len;
|
|
|
|
while (1) {
|
|
do {
|
|
len = read(fd, &info, sizeof(info));
|
|
} while (len == -1 && errno == EINTR);
|
|
|
|
if (len == -1 && errno == EAGAIN) {
|
|
break;
|
|
}
|
|
|
|
if (len != sizeof(info)) {
|
|
printf("read from sigfd returned %zd: %m\n", len);
|
|
return;
|
|
}
|
|
|
|
sigaction(info.ssi_signo, NULL, &action);
|
|
if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
|
|
action.sa_sigaction(info.ssi_signo,
|
|
(siginfo_t *)&info, NULL);
|
|
} else if (action.sa_handler) {
|
|
action.sa_handler(info.ssi_signo);
|
|
}
|
|
}
|
|
}
|
|
|
|
static int qemu_signal_init(void)
|
|
{
|
|
int sigfd;
|
|
sigset_t set;
|
|
|
|
/*
|
|
* SIG_IPI must be blocked in the main thread and must not be caught
|
|
* by sigwait() in the signal thread. Otherwise, the cpu thread will
|
|
* not catch it reliably.
|
|
*/
|
|
sigemptyset(&set);
|
|
sigaddset(&set, SIG_IPI);
|
|
sigaddset(&set, SIGIO);
|
|
sigaddset(&set, SIGALRM);
|
|
sigaddset(&set, SIGBUS);
|
|
/* SIGINT cannot be handled via signalfd, so that ^C can be used
|
|
* to interrupt QEMU when it is being run under gdb. SIGHUP and
|
|
* SIGTERM are also handled asynchronously, even though it is not
|
|
* strictly necessary, because they use the same handler as SIGINT.
|
|
*/
|
|
pthread_sigmask(SIG_BLOCK, &set, NULL);
|
|
|
|
sigdelset(&set, SIG_IPI);
|
|
sigfd = qemu_signalfd(&set);
|
|
if (sigfd == -1) {
|
|
fprintf(stderr, "failed to create signalfd\n");
|
|
return -errno;
|
|
}
|
|
|
|
fcntl_setfl(sigfd, O_NONBLOCK);
|
|
|
|
qemu_set_fd_handler2(sigfd, NULL, sigfd_handler, NULL,
|
|
(void *)(intptr_t)sigfd);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#else /* _WIN32 */
|
|
|
|
static int qemu_signal_init(void)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static AioContext *qemu_aio_context;
|
|
|
|
AioContext *qemu_get_aio_context(void)
|
|
{
|
|
return qemu_aio_context;
|
|
}
|
|
|
|
void qemu_notify_event(void)
|
|
{
|
|
if (!qemu_aio_context) {
|
|
return;
|
|
}
|
|
aio_notify(qemu_aio_context);
|
|
}
|
|
|
|
static GArray *gpollfds;
|
|
|
|
int qemu_init_main_loop(Error **errp)
|
|
{
|
|
int ret;
|
|
GSource *src;
|
|
Error *local_error = NULL;
|
|
|
|
init_clocks();
|
|
|
|
ret = qemu_signal_init();
|
|
if (ret) {
|
|
return ret;
|
|
}
|
|
|
|
qemu_aio_context = aio_context_new(&local_error);
|
|
if (!qemu_aio_context) {
|
|
error_propagate(errp, local_error);
|
|
return -EMFILE;
|
|
}
|
|
gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
|
|
src = aio_get_g_source(qemu_aio_context);
|
|
g_source_attach(src, NULL);
|
|
g_source_unref(src);
|
|
return 0;
|
|
}
|
|
|
|
static int max_priority;
|
|
|
|
#ifndef _WIN32
|
|
static int glib_pollfds_idx;
|
|
static int glib_n_poll_fds;
|
|
|
|
static void glib_pollfds_fill(int64_t *cur_timeout)
|
|
{
|
|
GMainContext *context = g_main_context_default();
|
|
int timeout = 0;
|
|
int64_t timeout_ns;
|
|
int n;
|
|
|
|
g_main_context_prepare(context, &max_priority);
|
|
|
|
glib_pollfds_idx = gpollfds->len;
|
|
n = glib_n_poll_fds;
|
|
do {
|
|
GPollFD *pfds;
|
|
glib_n_poll_fds = n;
|
|
g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds);
|
|
pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
|
|
n = g_main_context_query(context, max_priority, &timeout, pfds,
|
|
glib_n_poll_fds);
|
|
} while (n != glib_n_poll_fds);
|
|
|
|
if (timeout < 0) {
|
|
timeout_ns = -1;
|
|
} else {
|
|
timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS;
|
|
}
|
|
|
|
*cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout);
|
|
}
|
|
|
|
static void glib_pollfds_poll(void)
|
|
{
|
|
GMainContext *context = g_main_context_default();
|
|
GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
|
|
|
|
if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
|
|
g_main_context_dispatch(context);
|
|
}
|
|
}
|
|
|
|
#define MAX_MAIN_LOOP_SPIN (1000)
|
|
|
|
static int os_host_main_loop_wait(int64_t timeout)
|
|
{
|
|
int ret;
|
|
static int spin_counter;
|
|
|
|
glib_pollfds_fill(&timeout);
|
|
|
|
/* If the I/O thread is very busy or we are incorrectly busy waiting in
|
|
* the I/O thread, this can lead to starvation of the BQL such that the
|
|
* VCPU threads never run. To make sure we can detect the later case,
|
|
* print a message to the screen. If we run into this condition, create
|
|
* a fake timeout in order to give the VCPU threads a chance to run.
|
|
*/
|
|
if (!timeout && (spin_counter > MAX_MAIN_LOOP_SPIN)) {
|
|
static bool notified;
|
|
|
|
if (!notified && !qtest_enabled()) {
|
|
fprintf(stderr,
|
|
"main-loop: WARNING: I/O thread spun for %d iterations\n",
|
|
MAX_MAIN_LOOP_SPIN);
|
|
notified = true;
|
|
}
|
|
|
|
timeout = SCALE_MS;
|
|
}
|
|
|
|
if (timeout) {
|
|
spin_counter = 0;
|
|
qemu_mutex_unlock_iothread();
|
|
} else {
|
|
spin_counter++;
|
|
}
|
|
|
|
ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout);
|
|
|
|
if (timeout) {
|
|
qemu_mutex_lock_iothread();
|
|
}
|
|
|
|
glib_pollfds_poll();
|
|
return ret;
|
|
}
|
|
#else
|
|
/***********************************************************/
|
|
/* Polling handling */
|
|
|
|
typedef struct PollingEntry {
|
|
PollingFunc *func;
|
|
void *opaque;
|
|
struct PollingEntry *next;
|
|
} PollingEntry;
|
|
|
|
static PollingEntry *first_polling_entry;
|
|
|
|
int qemu_add_polling_cb(PollingFunc *func, void *opaque)
|
|
{
|
|
PollingEntry **ppe, *pe;
|
|
pe = g_malloc0(sizeof(PollingEntry));
|
|
pe->func = func;
|
|
pe->opaque = opaque;
|
|
for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
|
|
*ppe = pe;
|
|
return 0;
|
|
}
|
|
|
|
void qemu_del_polling_cb(PollingFunc *func, void *opaque)
|
|
{
|
|
PollingEntry **ppe, *pe;
|
|
for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
|
|
pe = *ppe;
|
|
if (pe->func == func && pe->opaque == opaque) {
|
|
*ppe = pe->next;
|
|
g_free(pe);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/***********************************************************/
|
|
/* Wait objects support */
|
|
typedef struct WaitObjects {
|
|
int num;
|
|
int revents[MAXIMUM_WAIT_OBJECTS + 1];
|
|
HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
|
|
WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
|
|
void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
|
|
} WaitObjects;
|
|
|
|
static WaitObjects wait_objects = {0};
|
|
|
|
int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
|
|
{
|
|
WaitObjects *w = &wait_objects;
|
|
if (w->num >= MAXIMUM_WAIT_OBJECTS) {
|
|
return -1;
|
|
}
|
|
w->events[w->num] = handle;
|
|
w->func[w->num] = func;
|
|
w->opaque[w->num] = opaque;
|
|
w->revents[w->num] = 0;
|
|
w->num++;
|
|
return 0;
|
|
}
|
|
|
|
void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
|
|
{
|
|
int i, found;
|
|
WaitObjects *w = &wait_objects;
|
|
|
|
found = 0;
|
|
for (i = 0; i < w->num; i++) {
|
|
if (w->events[i] == handle) {
|
|
found = 1;
|
|
}
|
|
if (found) {
|
|
w->events[i] = w->events[i + 1];
|
|
w->func[i] = w->func[i + 1];
|
|
w->opaque[i] = w->opaque[i + 1];
|
|
w->revents[i] = w->revents[i + 1];
|
|
}
|
|
}
|
|
if (found) {
|
|
w->num--;
|
|
}
|
|
}
|
|
|
|
void qemu_fd_register(int fd)
|
|
{
|
|
WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
|
|
FD_READ | FD_ACCEPT | FD_CLOSE |
|
|
FD_CONNECT | FD_WRITE | FD_OOB);
|
|
}
|
|
|
|
static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
|
|
fd_set *xfds)
|
|
{
|
|
int nfds = -1;
|
|
int i;
|
|
|
|
for (i = 0; i < pollfds->len; i++) {
|
|
GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
|
|
int fd = pfd->fd;
|
|
int events = pfd->events;
|
|
if (events & G_IO_IN) {
|
|
FD_SET(fd, rfds);
|
|
nfds = MAX(nfds, fd);
|
|
}
|
|
if (events & G_IO_OUT) {
|
|
FD_SET(fd, wfds);
|
|
nfds = MAX(nfds, fd);
|
|
}
|
|
if (events & G_IO_PRI) {
|
|
FD_SET(fd, xfds);
|
|
nfds = MAX(nfds, fd);
|
|
}
|
|
}
|
|
return nfds;
|
|
}
|
|
|
|
static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
|
|
fd_set *wfds, fd_set *xfds)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < pollfds->len; i++) {
|
|
GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
|
|
int fd = pfd->fd;
|
|
int revents = 0;
|
|
|
|
if (FD_ISSET(fd, rfds)) {
|
|
revents |= G_IO_IN;
|
|
}
|
|
if (FD_ISSET(fd, wfds)) {
|
|
revents |= G_IO_OUT;
|
|
}
|
|
if (FD_ISSET(fd, xfds)) {
|
|
revents |= G_IO_PRI;
|
|
}
|
|
pfd->revents = revents & pfd->events;
|
|
}
|
|
}
|
|
|
|
static int os_host_main_loop_wait(int64_t timeout)
|
|
{
|
|
GMainContext *context = g_main_context_default();
|
|
GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
|
|
int select_ret = 0;
|
|
int g_poll_ret, ret, i, n_poll_fds;
|
|
PollingEntry *pe;
|
|
WaitObjects *w = &wait_objects;
|
|
gint poll_timeout;
|
|
int64_t poll_timeout_ns;
|
|
static struct timeval tv0;
|
|
fd_set rfds, wfds, xfds;
|
|
int nfds;
|
|
|
|
/* XXX: need to suppress polling by better using win32 events */
|
|
ret = 0;
|
|
for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
|
|
ret |= pe->func(pe->opaque);
|
|
}
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
|
|
FD_ZERO(&rfds);
|
|
FD_ZERO(&wfds);
|
|
FD_ZERO(&xfds);
|
|
nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
|
|
if (nfds >= 0) {
|
|
select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
|
|
if (select_ret != 0) {
|
|
timeout = 0;
|
|
}
|
|
if (select_ret > 0) {
|
|
pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
|
|
}
|
|
}
|
|
|
|
g_main_context_prepare(context, &max_priority);
|
|
n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
|
|
poll_fds, ARRAY_SIZE(poll_fds));
|
|
g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));
|
|
|
|
for (i = 0; i < w->num; i++) {
|
|
poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];
|
|
poll_fds[n_poll_fds + i].events = G_IO_IN;
|
|
}
|
|
|
|
if (poll_timeout < 0) {
|
|
poll_timeout_ns = -1;
|
|
} else {
|
|
poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS;
|
|
}
|
|
|
|
poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout);
|
|
|
|
qemu_mutex_unlock_iothread();
|
|
g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns);
|
|
|
|
qemu_mutex_lock_iothread();
|
|
if (g_poll_ret > 0) {
|
|
for (i = 0; i < w->num; i++) {
|
|
w->revents[i] = poll_fds[n_poll_fds + i].revents;
|
|
}
|
|
for (i = 0; i < w->num; i++) {
|
|
if (w->revents[i] && w->func[i]) {
|
|
w->func[i](w->opaque[i]);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
|
|
g_main_context_dispatch(context);
|
|
}
|
|
|
|
return select_ret || g_poll_ret;
|
|
}
|
|
#endif
|
|
|
|
int main_loop_wait(int nonblocking)
|
|
{
|
|
int ret;
|
|
uint32_t timeout = UINT32_MAX;
|
|
int64_t timeout_ns;
|
|
|
|
if (nonblocking) {
|
|
timeout = 0;
|
|
}
|
|
|
|
/* poll any events */
|
|
g_array_set_size(gpollfds, 0); /* reset for new iteration */
|
|
/* XXX: separate device handlers from system ones */
|
|
#ifdef CONFIG_SLIRP
|
|
slirp_pollfds_fill(gpollfds, &timeout);
|
|
#endif
|
|
qemu_iohandler_fill(gpollfds);
|
|
|
|
if (timeout == UINT32_MAX) {
|
|
timeout_ns = -1;
|
|
} else {
|
|
timeout_ns = (uint64_t)timeout * (int64_t)(SCALE_MS);
|
|
}
|
|
|
|
timeout_ns = qemu_soonest_timeout(timeout_ns,
|
|
timerlistgroup_deadline_ns(
|
|
&main_loop_tlg));
|
|
|
|
ret = os_host_main_loop_wait(timeout_ns);
|
|
qemu_iohandler_poll(gpollfds, ret);
|
|
#ifdef CONFIG_SLIRP
|
|
slirp_pollfds_poll(gpollfds, (ret < 0));
|
|
#endif
|
|
|
|
qemu_clock_run_all_timers();
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Functions to operate on the main QEMU AioContext. */
|
|
|
|
QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
|
|
{
|
|
return aio_bh_new(qemu_aio_context, cb, opaque);
|
|
}
|