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authorDaniel P. Berrange <berrange@redhat.com>2015-09-01 14:48:02 +0100
committerDaniel P. Berrange <berrange@redhat.com>2015-10-20 14:59:04 +0100
commit10817bf09d5f8cb22711fb0ee8d8da49f6f05f89 (patch)
tree735f6b70cedecd57843b9108cb68e2359e147e0c /util
parent57cb38b3833c5215131b983f181b26d6ba9b8d35 (diff)
downloadhqemu-10817bf09d5f8cb22711fb0ee8d8da49f6f05f89.zip
hqemu-10817bf09d5f8cb22711fb0ee8d8da49f6f05f89.tar.gz
coroutine: move into libqemuutil.a library
The coroutine files are currently referenced by the block-obj-y variable. The coroutine functionality though is already used by more than just the block code. eg migration code uses coroutine yield. In the future the I/O channel code will also use the coroutine yield functionality. Since the coroutine code is nicely self-contained it can be easily built as part of the libqemuutil.a library, making it widely available. The headers are also moved into include/qemu, instead of the include/block directory, since they are now part of the util codebase, and the impl was never in the block/ directory either. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Diffstat (limited to 'util')
-rw-r--r--util/Makefile.objs3
-rw-r--r--util/coroutine-gthread.c198
-rw-r--r--util/coroutine-sigaltstack.c293
-rw-r--r--util/coroutine-ucontext.c194
-rw-r--r--util/coroutine-win32.c101
-rw-r--r--util/qemu-coroutine-io.c91
-rw-r--r--util/qemu-coroutine-lock.c186
-rw-r--r--util/qemu-coroutine-sleep.c41
-rw-r--r--util/qemu-coroutine.c146
9 files changed, 1253 insertions, 0 deletions
diff --git a/util/Makefile.objs b/util/Makefile.objs
index 114d657..d8d7e7a 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -18,3 +18,6 @@ util-obj-y += getauxval.o
util-obj-y += readline.o
util-obj-y += rfifolock.o
util-obj-y += rcu.o
+util-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
+util-obj-y += qemu-coroutine-sleep.o
+util-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o
diff --git a/util/coroutine-gthread.c b/util/coroutine-gthread.c
new file mode 100644
index 0000000..0bcd778
--- /dev/null
+++ b/util/coroutine-gthread.c
@@ -0,0 +1,198 @@
+/*
+ * GThread coroutine initialization code
+ *
+ * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
+ * Copyright (C) 2011 Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.0 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <glib.h>
+#include "qemu-common.h"
+#include "qemu/coroutine_int.h"
+
+typedef struct {
+ Coroutine base;
+ GThread *thread;
+ bool runnable;
+ bool free_on_thread_exit;
+ CoroutineAction action;
+} CoroutineGThread;
+
+static CompatGMutex coroutine_lock;
+static CompatGCond coroutine_cond;
+
+/* GLib 2.31 and beyond deprecated various parts of the thread API,
+ * but the new interfaces are not available in older GLib versions
+ * so we have to cope with both.
+ */
+#if GLIB_CHECK_VERSION(2, 31, 0)
+/* Awkwardly, the GPrivate API doesn't provide a way to update the
+ * GDestroyNotify handler for the coroutine key dynamically. So instead
+ * we track whether or not the CoroutineGThread should be freed on
+ * thread exit / coroutine key update using the free_on_thread_exit
+ * field.
+ */
+static void coroutine_destroy_notify(gpointer data)
+{
+ CoroutineGThread *co = data;
+ if (co && co->free_on_thread_exit) {
+ g_free(co);
+ }
+}
+
+static GPrivate coroutine_key = G_PRIVATE_INIT(coroutine_destroy_notify);
+
+static inline CoroutineGThread *get_coroutine_key(void)
+{
+ return g_private_get(&coroutine_key);
+}
+
+static inline void set_coroutine_key(CoroutineGThread *co,
+ bool free_on_thread_exit)
+{
+ /* Unlike g_static_private_set() this does not call the GDestroyNotify
+ * if the previous value of the key was NULL. Fortunately we only need
+ * the GDestroyNotify in the non-NULL key case.
+ */
+ co->free_on_thread_exit = free_on_thread_exit;
+ g_private_replace(&coroutine_key, co);
+}
+
+static inline GThread *create_thread(GThreadFunc func, gpointer data)
+{
+ return g_thread_new("coroutine", func, data);
+}
+
+#else
+
+/* Handle older GLib versions */
+
+static GStaticPrivate coroutine_key = G_STATIC_PRIVATE_INIT;
+
+static inline CoroutineGThread *get_coroutine_key(void)
+{
+ return g_static_private_get(&coroutine_key);
+}
+
+static inline void set_coroutine_key(CoroutineGThread *co,
+ bool free_on_thread_exit)
+{
+ g_static_private_set(&coroutine_key, co,
+ free_on_thread_exit ? (GDestroyNotify)g_free : NULL);
+}
+
+static inline GThread *create_thread(GThreadFunc func, gpointer data)
+{
+ return g_thread_create_full(func, data, 0, TRUE, TRUE,
+ G_THREAD_PRIORITY_NORMAL, NULL);
+}
+
+#endif
+
+
+static void __attribute__((constructor)) coroutine_init(void)
+{
+#if !GLIB_CHECK_VERSION(2, 31, 0)
+ if (!g_thread_supported()) {
+ g_thread_init(NULL);
+ }
+#endif
+}
+
+static void coroutine_wait_runnable_locked(CoroutineGThread *co)
+{
+ while (!co->runnable) {
+ g_cond_wait(&coroutine_cond, &coroutine_lock);
+ }
+}
+
+static void coroutine_wait_runnable(CoroutineGThread *co)
+{
+ g_mutex_lock(&coroutine_lock);
+ coroutine_wait_runnable_locked(co);
+ g_mutex_unlock(&coroutine_lock);
+}
+
+static gpointer coroutine_thread(gpointer opaque)
+{
+ CoroutineGThread *co = opaque;
+
+ set_coroutine_key(co, false);
+ coroutine_wait_runnable(co);
+ co->base.entry(co->base.entry_arg);
+ qemu_coroutine_switch(&co->base, co->base.caller, COROUTINE_TERMINATE);
+ return NULL;
+}
+
+Coroutine *qemu_coroutine_new(void)
+{
+ CoroutineGThread *co;
+
+ co = g_malloc0(sizeof(*co));
+ co->thread = create_thread(coroutine_thread, co);
+ if (!co->thread) {
+ g_free(co);
+ return NULL;
+ }
+ return &co->base;
+}
+
+void qemu_coroutine_delete(Coroutine *co_)
+{
+ CoroutineGThread *co = DO_UPCAST(CoroutineGThread, base, co_);
+
+ g_thread_join(co->thread);
+ g_free(co);
+}
+
+CoroutineAction qemu_coroutine_switch(Coroutine *from_,
+ Coroutine *to_,
+ CoroutineAction action)
+{
+ CoroutineGThread *from = DO_UPCAST(CoroutineGThread, base, from_);
+ CoroutineGThread *to = DO_UPCAST(CoroutineGThread, base, to_);
+
+ g_mutex_lock(&coroutine_lock);
+ from->runnable = false;
+ from->action = action;
+ to->runnable = true;
+ to->action = action;
+ g_cond_broadcast(&coroutine_cond);
+
+ if (action != COROUTINE_TERMINATE) {
+ coroutine_wait_runnable_locked(from);
+ }
+ g_mutex_unlock(&coroutine_lock);
+ return from->action;
+}
+
+Coroutine *qemu_coroutine_self(void)
+{
+ CoroutineGThread *co = get_coroutine_key();
+ if (!co) {
+ co = g_malloc0(sizeof(*co));
+ co->runnable = true;
+ set_coroutine_key(co, true);
+ }
+
+ return &co->base;
+}
+
+bool qemu_in_coroutine(void)
+{
+ CoroutineGThread *co = get_coroutine_key();
+
+ return co && co->base.caller;
+}
diff --git a/util/coroutine-sigaltstack.c b/util/coroutine-sigaltstack.c
new file mode 100644
index 0000000..39842a4
--- /dev/null
+++ b/util/coroutine-sigaltstack.c
@@ -0,0 +1,293 @@
+/*
+ * sigaltstack coroutine initialization code
+ *
+ * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
+ * Copyright (C) 2011 Kevin Wolf <kwolf@redhat.com>
+ * Copyright (C) 2012 Alex Barcelo <abarcelo@ac.upc.edu>
+** This file is partly based on pth_mctx.c, from the GNU Portable Threads
+** Copyright (c) 1999-2006 Ralf S. Engelschall <rse@engelschall.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* XXX Is there a nicer way to disable glibc's stack check for longjmp? */
+#ifdef _FORTIFY_SOURCE
+#undef _FORTIFY_SOURCE
+#endif
+#include <stdlib.h>
+#include <setjmp.h>
+#include <stdint.h>
+#include <pthread.h>
+#include <signal.h>
+#include "qemu-common.h"
+#include "qemu/coroutine_int.h"
+
+typedef struct {
+ Coroutine base;
+ void *stack;
+ sigjmp_buf env;
+} CoroutineUContext;
+
+/**
+ * Per-thread coroutine bookkeeping
+ */
+typedef struct {
+ /** Currently executing coroutine */
+ Coroutine *current;
+
+ /** The default coroutine */
+ CoroutineUContext leader;
+
+ /** Information for the signal handler (trampoline) */
+ sigjmp_buf tr_reenter;
+ volatile sig_atomic_t tr_called;
+ void *tr_handler;
+} CoroutineThreadState;
+
+static pthread_key_t thread_state_key;
+
+static CoroutineThreadState *coroutine_get_thread_state(void)
+{
+ CoroutineThreadState *s = pthread_getspecific(thread_state_key);
+
+ if (!s) {
+ s = g_malloc0(sizeof(*s));
+ s->current = &s->leader.base;
+ pthread_setspecific(thread_state_key, s);
+ }
+ return s;
+}
+
+static void qemu_coroutine_thread_cleanup(void *opaque)
+{
+ CoroutineThreadState *s = opaque;
+
+ g_free(s);
+}
+
+static void __attribute__((constructor)) coroutine_init(void)
+{
+ int ret;
+
+ ret = pthread_key_create(&thread_state_key, qemu_coroutine_thread_cleanup);
+ if (ret != 0) {
+ fprintf(stderr, "unable to create leader key: %s\n", strerror(errno));
+ abort();
+ }
+}
+
+/* "boot" function
+ * This is what starts the coroutine, is called from the trampoline
+ * (from the signal handler when it is not signal handling, read ahead
+ * for more information).
+ */
+static void coroutine_bootstrap(CoroutineUContext *self, Coroutine *co)
+{
+ /* Initialize longjmp environment and switch back the caller */
+ if (!sigsetjmp(self->env, 0)) {
+ siglongjmp(*(sigjmp_buf *)co->entry_arg, 1);
+ }
+
+ while (true) {
+ co->entry(co->entry_arg);
+ qemu_coroutine_switch(co, co->caller, COROUTINE_TERMINATE);
+ }
+}
+
+/*
+ * This is used as the signal handler. This is called with the brand new stack
+ * (thanks to sigaltstack). We have to return, given that this is a signal
+ * handler and the sigmask and some other things are changed.
+ */
+static void coroutine_trampoline(int signal)
+{
+ CoroutineUContext *self;
+ Coroutine *co;
+ CoroutineThreadState *coTS;
+
+ /* Get the thread specific information */
+ coTS = coroutine_get_thread_state();
+ self = coTS->tr_handler;
+ coTS->tr_called = 1;
+ co = &self->base;
+
+ /*
+ * Here we have to do a bit of a ping pong between the caller, given that
+ * this is a signal handler and we have to do a return "soon". Then the
+ * caller can reestablish everything and do a siglongjmp here again.
+ */
+ if (!sigsetjmp(coTS->tr_reenter, 0)) {
+ return;
+ }
+
+ /*
+ * Ok, the caller has siglongjmp'ed back to us, so now prepare
+ * us for the real machine state switching. We have to jump
+ * into another function here to get a new stack context for
+ * the auto variables (which have to be auto-variables
+ * because the start of the thread happens later). Else with
+ * PIC (i.e. Position Independent Code which is used when PTH
+ * is built as a shared library) most platforms would
+ * horrible core dump as experience showed.
+ */
+ coroutine_bootstrap(self, co);
+}
+
+Coroutine *qemu_coroutine_new(void)
+{
+ const size_t stack_size = 1 << 20;
+ CoroutineUContext *co;
+ CoroutineThreadState *coTS;
+ struct sigaction sa;
+ struct sigaction osa;
+ stack_t ss;
+ stack_t oss;
+ sigset_t sigs;
+ sigset_t osigs;
+ sigjmp_buf old_env;
+
+ /* The way to manipulate stack is with the sigaltstack function. We
+ * prepare a stack, with it delivering a signal to ourselves and then
+ * put sigsetjmp/siglongjmp where needed.
+ * This has been done keeping coroutine-ucontext as a model and with the
+ * pth ideas (GNU Portable Threads). See coroutine-ucontext for the basics
+ * of the coroutines and see pth_mctx.c (from the pth project) for the
+ * sigaltstack way of manipulating stacks.
+ */
+
+ co = g_malloc0(sizeof(*co));
+ co->stack = g_malloc(stack_size);
+ co->base.entry_arg = &old_env; /* stash away our jmp_buf */
+
+ coTS = coroutine_get_thread_state();
+ coTS->tr_handler = co;
+
+ /*
+ * Preserve the SIGUSR2 signal state, block SIGUSR2,
+ * and establish our signal handler. The signal will
+ * later transfer control onto the signal stack.
+ */
+ sigemptyset(&sigs);
+ sigaddset(&sigs, SIGUSR2);
+ pthread_sigmask(SIG_BLOCK, &sigs, &osigs);
+ sa.sa_handler = coroutine_trampoline;
+ sigfillset(&sa.sa_mask);
+ sa.sa_flags = SA_ONSTACK;
+ if (sigaction(SIGUSR2, &sa, &osa) != 0) {
+ abort();
+ }
+
+ /*
+ * Set the new stack.
+ */
+ ss.ss_sp = co->stack;
+ ss.ss_size = stack_size;
+ ss.ss_flags = 0;
+ if (sigaltstack(&ss, &oss) < 0) {
+ abort();
+ }
+
+ /*
+ * Now transfer control onto the signal stack and set it up.
+ * It will return immediately via "return" after the sigsetjmp()
+ * was performed. Be careful here with race conditions. The
+ * signal can be delivered the first time sigsuspend() is
+ * called.
+ */
+ coTS->tr_called = 0;
+ pthread_kill(pthread_self(), SIGUSR2);
+ sigfillset(&sigs);
+ sigdelset(&sigs, SIGUSR2);
+ while (!coTS->tr_called) {
+ sigsuspend(&sigs);
+ }
+
+ /*
+ * Inform the system that we are back off the signal stack by
+ * removing the alternative signal stack. Be careful here: It
+ * first has to be disabled, before it can be removed.
+ */
+ sigaltstack(NULL, &ss);
+ ss.ss_flags = SS_DISABLE;
+ if (sigaltstack(&ss, NULL) < 0) {
+ abort();
+ }
+ sigaltstack(NULL, &ss);
+ if (!(oss.ss_flags & SS_DISABLE)) {
+ sigaltstack(&oss, NULL);
+ }
+
+ /*
+ * Restore the old SIGUSR2 signal handler and mask
+ */
+ sigaction(SIGUSR2, &osa, NULL);
+ pthread_sigmask(SIG_SETMASK, &osigs, NULL);
+
+ /*
+ * Now enter the trampoline again, but this time not as a signal
+ * handler. Instead we jump into it directly. The functionally
+ * redundant ping-pong pointer arithmetic is necessary to avoid
+ * type-conversion warnings related to the `volatile' qualifier and
+ * the fact that `jmp_buf' usually is an array type.
+ */
+ if (!sigsetjmp(old_env, 0)) {
+ siglongjmp(coTS->tr_reenter, 1);
+ }
+
+ /*
+ * Ok, we returned again, so now we're finished
+ */
+
+ return &co->base;
+}
+
+void qemu_coroutine_delete(Coroutine *co_)
+{
+ CoroutineUContext *co = DO_UPCAST(CoroutineUContext, base, co_);
+
+ g_free(co->stack);
+ g_free(co);
+}
+
+CoroutineAction qemu_coroutine_switch(Coroutine *from_, Coroutine *to_,
+ CoroutineAction action)
+{
+ CoroutineUContext *from = DO_UPCAST(CoroutineUContext, base, from_);
+ CoroutineUContext *to = DO_UPCAST(CoroutineUContext, base, to_);
+ CoroutineThreadState *s = coroutine_get_thread_state();
+ int ret;
+
+ s->current = to_;
+
+ ret = sigsetjmp(from->env, 0);
+ if (ret == 0) {
+ siglongjmp(to->env, action);
+ }
+ return ret;
+}
+
+Coroutine *qemu_coroutine_self(void)
+{
+ CoroutineThreadState *s = coroutine_get_thread_state();
+
+ return s->current;
+}
+
+bool qemu_in_coroutine(void)
+{
+ CoroutineThreadState *s = pthread_getspecific(thread_state_key);
+
+ return s && s->current->caller;
+}
+
diff --git a/util/coroutine-ucontext.c b/util/coroutine-ucontext.c
new file mode 100644
index 0000000..26cbebb
--- /dev/null
+++ b/util/coroutine-ucontext.c
@@ -0,0 +1,194 @@
+/*
+ * ucontext coroutine initialization code
+ *
+ * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
+ * Copyright (C) 2011 Kevin Wolf <kwolf@redhat.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.0 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* XXX Is there a nicer way to disable glibc's stack check for longjmp? */
+#ifdef _FORTIFY_SOURCE
+#undef _FORTIFY_SOURCE
+#endif
+#include <stdlib.h>
+#include <setjmp.h>
+#include <stdint.h>
+#include <ucontext.h>
+#include "qemu-common.h"
+#include "qemu/coroutine_int.h"
+
+#ifdef CONFIG_VALGRIND_H
+#include <valgrind/valgrind.h>
+#endif
+
+typedef struct {
+ Coroutine base;
+ void *stack;
+ sigjmp_buf env;
+
+#ifdef CONFIG_VALGRIND_H
+ unsigned int valgrind_stack_id;
+#endif
+
+} CoroutineUContext;
+
+/**
+ * Per-thread coroutine bookkeeping
+ */
+static __thread CoroutineUContext leader;
+static __thread Coroutine *current;
+
+/*
+ * va_args to makecontext() must be type 'int', so passing
+ * the pointer we need may require several int args. This
+ * union is a quick hack to let us do that
+ */
+union cc_arg {
+ void *p;
+ int i[2];
+};
+
+static void coroutine_trampoline(int i0, int i1)
+{
+ union cc_arg arg;
+ CoroutineUContext *self;
+ Coroutine *co;
+
+ arg.i[0] = i0;
+ arg.i[1] = i1;
+ self = arg.p;
+ co = &self->base;
+
+ /* Initialize longjmp environment and switch back the caller */
+ if (!sigsetjmp(self->env, 0)) {
+ siglongjmp(*(sigjmp_buf *)co->entry_arg, 1);
+ }
+
+ while (true) {
+ co->entry(co->entry_arg);
+ qemu_coroutine_switch(co, co->caller, COROUTINE_TERMINATE);
+ }
+}
+
+Coroutine *qemu_coroutine_new(void)
+{
+ const size_t stack_size = 1 << 20;
+ CoroutineUContext *co;
+ ucontext_t old_uc, uc;
+ sigjmp_buf old_env;
+ union cc_arg arg = {0};
+
+ /* The ucontext functions preserve signal masks which incurs a
+ * system call overhead. sigsetjmp(buf, 0)/siglongjmp() does not
+ * preserve signal masks but only works on the current stack.
+ * Since we need a way to create and switch to a new stack, use
+ * the ucontext functions for that but sigsetjmp()/siglongjmp() for
+ * everything else.
+ */
+
+ if (getcontext(&uc) == -1) {
+ abort();
+ }
+
+ co = g_malloc0(sizeof(*co));
+ co->stack = g_malloc(stack_size);
+ co->base.entry_arg = &old_env; /* stash away our jmp_buf */
+
+ uc.uc_link = &old_uc;
+ uc.uc_stack.ss_sp = co->stack;
+ uc.uc_stack.ss_size = stack_size;
+ uc.uc_stack.ss_flags = 0;
+
+#ifdef CONFIG_VALGRIND_H
+ co->valgrind_stack_id =
+ VALGRIND_STACK_REGISTER(co->stack, co->stack + stack_size);
+#endif
+
+ arg.p = co;
+
+ makecontext(&uc, (void (*)(void))coroutine_trampoline,
+ 2, arg.i[0], arg.i[1]);
+
+ /* swapcontext() in, siglongjmp() back out */
+ if (!sigsetjmp(old_env, 0)) {
+ swapcontext(&old_uc, &uc);
+ }
+ return &co->base;
+}
+
+#ifdef CONFIG_VALGRIND_H
+#ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
+/* Work around an unused variable in the valgrind.h macro... */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-but-set-variable"
+#endif
+static inline void valgrind_stack_deregister(CoroutineUContext *co)
+{
+ VALGRIND_STACK_DEREGISTER(co->valgrind_stack_id);
+}
+#ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE
+#pragma GCC diagnostic pop
+#endif
+#endif
+
+void qemu_coroutine_delete(Coroutine *co_)
+{
+ CoroutineUContext *co = DO_UPCAST(CoroutineUContext, base, co_);
+
+#ifdef CONFIG_VALGRIND_H
+ valgrind_stack_deregister(co);
+#endif
+
+ g_free(co->stack);
+ g_free(co);
+}
+
+/* This function is marked noinline to prevent GCC from inlining it
+ * into coroutine_trampoline(). If we allow it to do that then it
+ * hoists the code to get the address of the TLS variable "current"
+ * out of the while() loop. This is an invalid transformation because
+ * the sigsetjmp() call may be called when running thread A but
+ * return in thread B, and so we might be in a different thread
+ * context each time round the loop.
+ */
+CoroutineAction __attribute__((noinline))
+qemu_coroutine_switch(Coroutine *from_, Coroutine *to_,
+ CoroutineAction action)
+{
+ CoroutineUContext *from = DO_UPCAST(CoroutineUContext, base, from_);
+ CoroutineUContext *to = DO_UPCAST(CoroutineUContext, base, to_);
+ int ret;
+
+ current = to_;
+
+ ret = sigsetjmp(from->env, 0);
+ if (ret == 0) {
+ siglongjmp(to->env, action);
+ }
+ return ret;
+}
+
+Coroutine *qemu_coroutine_self(void)
+{
+ if (!current) {
+ current = &leader.base;
+ }
+ return current;
+}
+
+bool qemu_in_coroutine(void)
+{
+ return current && current->caller;
+}
diff --git a/util/coroutine-win32.c b/util/coroutine-win32.c
new file mode 100644
index 0000000..4f922c5
--- /dev/null
+++ b/util/coroutine-win32.c
@@ -0,0 +1,101 @@
+/*
+ * Win32 coroutine initialization code
+ *
+ * Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com>
+ *
+ * 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/coroutine_int.h"
+
+typedef struct
+{
+ Coroutine base;
+
+ LPVOID fiber;
+ CoroutineAction action;
+} CoroutineWin32;
+
+static __thread CoroutineWin32 leader;
+static __thread Coroutine *current;
+
+/* This function is marked noinline to prevent GCC from inlining it
+ * into coroutine_trampoline(). If we allow it to do that then it
+ * hoists the code to get the address of the TLS variable "current"
+ * out of the while() loop. This is an invalid transformation because
+ * the SwitchToFiber() call may be called when running thread A but
+ * return in thread B, and so we might be in a different thread
+ * context each time round the loop.
+ */
+CoroutineAction __attribute__((noinline))
+qemu_coroutine_switch(Coroutine *from_, Coroutine *to_,
+ CoroutineAction action)
+{
+ CoroutineWin32 *from = DO_UPCAST(CoroutineWin32, base, from_);
+ CoroutineWin32 *to = DO_UPCAST(CoroutineWin32, base, to_);
+
+ current = to_;
+
+ to->action = action;
+ SwitchToFiber(to->fiber);
+ return from->action;
+}
+
+static void CALLBACK coroutine_trampoline(void *co_)
+{
+ Coroutine *co = co_;
+
+ while (true) {
+ co->entry(co->entry_arg);
+ qemu_coroutine_switch(co, co->caller, COROUTINE_TERMINATE);
+ }
+}
+
+Coroutine *qemu_coroutine_new(void)
+{
+ const size_t stack_size = 1 << 20;
+ CoroutineWin32 *co;
+
+ co = g_malloc0(sizeof(*co));
+ co->fiber = CreateFiber(stack_size, coroutine_trampoline, &co->base);
+ return &co->base;
+}
+
+void qemu_coroutine_delete(Coroutine *co_)
+{
+ CoroutineWin32 *co = DO_UPCAST(CoroutineWin32, base, co_);
+
+ DeleteFiber(co->fiber);
+ g_free(co);
+}
+
+Coroutine *qemu_coroutine_self(void)
+{
+ if (!current) {
+ current = &leader.base;
+ leader.fiber = ConvertThreadToFiber(NULL);
+ }
+ return current;
+}
+
+bool qemu_in_coroutine(void)
+{
+ return current && current->caller;
+}
diff --git a/util/qemu-coroutine-io.c b/util/qemu-coroutine-io.c
new file mode 100644
index 0000000..e1eae73
--- /dev/null
+++ b/util/qemu-coroutine-io.c
@@ -0,0 +1,91 @@
+/*
+ * Coroutine-aware I/O functions
+ *
+ * Copyright (C) 2009-2010 Nippon Telegraph and Telephone Corporation.
+ * Copyright (c) 2011, 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-common.h"
+#include "qemu/sockets.h"
+#include "qemu/coroutine.h"
+#include "qemu/iov.h"
+#include "qemu/main-loop.h"
+
+ssize_t coroutine_fn
+qemu_co_sendv_recvv(int sockfd, struct iovec *iov, unsigned iov_cnt,
+ size_t offset, size_t bytes, bool do_send)
+{
+ size_t done = 0;
+ ssize_t ret;
+ int err;
+ while (done < bytes) {
+ ret = iov_send_recv(sockfd, iov, iov_cnt,
+ offset + done, bytes - done, do_send);
+ if (ret > 0) {
+ done += ret;
+ } else if (ret < 0) {
+ err = socket_error();
+ if (err == EAGAIN || err == EWOULDBLOCK) {
+ qemu_coroutine_yield();
+ } else if (done == 0) {
+ return -err;
+ } else {
+ break;
+ }
+ } else if (ret == 0 && !do_send) {
+ /* write (send) should never return 0.
+ * read (recv) returns 0 for end-of-file (-data).
+ * In both cases there's little point retrying,
+ * but we do for write anyway, just in case */
+ break;
+ }
+ }
+ return done;
+}
+
+ssize_t coroutine_fn
+qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send)
+{
+ struct iovec iov = { .iov_base = buf, .iov_len = bytes };
+ return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send);
+}
+
+typedef struct {
+ Coroutine *co;
+ int fd;
+} FDYieldUntilData;
+
+static void fd_coroutine_enter(void *opaque)
+{
+ FDYieldUntilData *data = opaque;
+ qemu_set_fd_handler(data->fd, NULL, NULL, NULL);
+ qemu_coroutine_enter(data->co, NULL);
+}
+
+void coroutine_fn yield_until_fd_readable(int fd)
+{
+ FDYieldUntilData data;
+
+ assert(qemu_in_coroutine());
+ data.co = qemu_coroutine_self();
+ data.fd = fd;
+ qemu_set_fd_handler(fd, fd_coroutine_enter, NULL, &data);
+ qemu_coroutine_yield();
+}
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
new file mode 100644
index 0000000..130ee19
--- /dev/null
+++ b/util/qemu-coroutine-lock.c
@@ -0,0 +1,186 @@
+/*
+ * coroutine queues and locks
+ *
+ * Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com>
+ *
+ * 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/coroutine.h"
+#include "qemu/coroutine_int.h"
+#include "qemu/queue.h"
+#include "trace.h"
+
+void qemu_co_queue_init(CoQueue *queue)
+{
+ QTAILQ_INIT(&queue->entries);
+}
+
+void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
+{
+ Coroutine *self = qemu_coroutine_self();
+ QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
+ qemu_coroutine_yield();
+ assert(qemu_in_coroutine());
+}
+
+/**
+ * qemu_co_queue_run_restart:
+ *
+ * Enter each coroutine that was previously marked for restart by
+ * qemu_co_queue_next() or qemu_co_queue_restart_all(). This function is
+ * invoked by the core coroutine code when the current coroutine yields or
+ * terminates.
+ */
+void qemu_co_queue_run_restart(Coroutine *co)
+{
+ Coroutine *next;
+
+ trace_qemu_co_queue_run_restart(co);
+ while ((next = QTAILQ_FIRST(&co->co_queue_wakeup))) {
+ QTAILQ_REMOVE(&co->co_queue_wakeup, next, co_queue_next);
+ qemu_coroutine_enter(next, NULL);
+ }
+}
+
+static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
+{
+ Coroutine *self = qemu_coroutine_self();
+ Coroutine *next;
+
+ if (QTAILQ_EMPTY(&queue->entries)) {
+ return false;
+ }
+
+ while ((next = QTAILQ_FIRST(&queue->entries)) != NULL) {
+ QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
+ QTAILQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next);
+ trace_qemu_co_queue_next(next);
+ if (single) {
+ break;
+ }
+ }
+ return true;
+}
+
+bool coroutine_fn qemu_co_queue_next(CoQueue *queue)
+{
+ assert(qemu_in_coroutine());
+ return qemu_co_queue_do_restart(queue, true);
+}
+
+void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue)
+{
+ assert(qemu_in_coroutine());
+ qemu_co_queue_do_restart(queue, false);
+}
+
+bool qemu_co_enter_next(CoQueue *queue)
+{
+ Coroutine *next;
+
+ next = QTAILQ_FIRST(&queue->entries);
+ if (!next) {
+ return false;
+ }
+
+ QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
+ qemu_coroutine_enter(next, NULL);
+ return true;
+}
+
+bool qemu_co_queue_empty(CoQueue *queue)
+{
+ return QTAILQ_FIRST(&queue->entries) == NULL;
+}
+
+void qemu_co_mutex_init(CoMutex *mutex)
+{
+ memset(mutex, 0, sizeof(*mutex));
+ qemu_co_queue_init(&mutex->queue);
+}
+
+void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
+{
+ Coroutine *self = qemu_coroutine_self();
+
+ trace_qemu_co_mutex_lock_entry(mutex, self);
+
+ while (mutex->locked) {
+ qemu_co_queue_wait(&mutex->queue);
+ }
+
+ mutex->locked = true;
+
+ trace_qemu_co_mutex_lock_return(mutex, self);
+}
+
+void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
+{
+ Coroutine *self = qemu_coroutine_self();
+
+ trace_qemu_co_mutex_unlock_entry(mutex, self);
+
+ assert(mutex->locked == true);
+ assert(qemu_in_coroutine());
+
+ mutex->locked = false;
+ qemu_co_queue_next(&mutex->queue);
+
+ trace_qemu_co_mutex_unlock_return(mutex, self);
+}
+
+void qemu_co_rwlock_init(CoRwlock *lock)
+{
+ memset(lock, 0, sizeof(*lock));
+ qemu_co_queue_init(&lock->queue);
+}
+
+void qemu_co_rwlock_rdlock(CoRwlock *lock)
+{
+ while (lock->writer) {
+ qemu_co_queue_wait(&lock->queue);
+ }
+ lock->reader++;
+}
+
+void qemu_co_rwlock_unlock(CoRwlock *lock)
+{
+ assert(qemu_in_coroutine());
+ if (lock->writer) {
+ lock->writer = false;
+ qemu_co_queue_restart_all(&lock->queue);
+ } else {
+ lock->reader--;
+ assert(lock->reader >= 0);
+ /* Wakeup only one waiting writer */
+ if (!lock->reader) {
+ qemu_co_queue_next(&lock->queue);
+ }
+ }
+}
+
+void qemu_co_rwlock_wrlock(CoRwlock *lock)
+{
+ while (lock->writer || lock->reader) {
+ qemu_co_queue_wait(&lock->queue);
+ }
+ lock->writer = true;
+}
diff --git a/util/qemu-coroutine-sleep.c b/util/qemu-coroutine-sleep.c
new file mode 100644
index 0000000..b35db56
--- /dev/null
+++ b/util/qemu-coroutine-sleep.c
@@ -0,0 +1,41 @@
+/*
+ * QEMU coroutine sleep
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qemu/coroutine.h"
+#include "qemu/timer.h"
+#include "block/aio.h"
+
+typedef struct CoSleepCB {
+ QEMUTimer *ts;
+ Coroutine *co;
+} CoSleepCB;
+
+static void co_sleep_cb(void *opaque)
+{
+ CoSleepCB *sleep_cb = opaque;
+
+ qemu_coroutine_enter(sleep_cb->co, NULL);
+}
+
+void coroutine_fn co_aio_sleep_ns(AioContext *ctx, QEMUClockType type,
+ int64_t ns)
+{
+ CoSleepCB sleep_cb = {
+ .co = qemu_coroutine_self(),
+ };
+ sleep_cb.ts = aio_timer_new(ctx, type, SCALE_NS, co_sleep_cb, &sleep_cb);
+ timer_mod(sleep_cb.ts, qemu_clock_get_ns(type) + ns);
+ qemu_coroutine_yield();
+ timer_del(sleep_cb.ts);
+ timer_free(sleep_cb.ts);
+}
diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
new file mode 100644
index 0000000..8953560
--- /dev/null
+++ b/util/qemu-coroutine.c
@@ -0,0 +1,146 @@
+/*
+ * QEMU coroutines
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
+ * Kevin Wolf <kwolf@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "trace.h"
+#include "qemu-common.h"
+#include "qemu/thread.h"
+#include "qemu/atomic.h"
+#include "qemu/coroutine.h"
+#include "qemu/coroutine_int.h"
+
+enum {
+ POOL_BATCH_SIZE = 64,
+};
+
+/** Free list to speed up creation */
+static QSLIST_HEAD(, Coroutine) release_pool = QSLIST_HEAD_INITIALIZER(pool);
+static unsigned int release_pool_size;
+static __thread QSLIST_HEAD(, Coroutine) alloc_pool = QSLIST_HEAD_INITIALIZER(pool);
+static __thread unsigned int alloc_pool_size;
+static __thread Notifier coroutine_pool_cleanup_notifier;
+
+static void coroutine_pool_cleanup(Notifier *n, void *value)
+{
+ Coroutine *co;
+ Coroutine *tmp;
+
+ QSLIST_FOREACH_SAFE(co, &alloc_pool, pool_next, tmp) {
+ QSLIST_REMOVE_HEAD(&alloc_pool, pool_next);
+ qemu_coroutine_delete(co);
+ }
+}
+
+Coroutine *qemu_coroutine_create(CoroutineEntry *entry)
+{
+ Coroutine *co = NULL;
+
+ if (CONFIG_COROUTINE_POOL) {
+ co = QSLIST_FIRST(&alloc_pool);
+ if (!co) {
+ if (release_pool_size > POOL_BATCH_SIZE) {
+ /* Slow path; a good place to register the destructor, too. */
+ if (!coroutine_pool_cleanup_notifier.notify) {
+ coroutine_pool_cleanup_notifier.notify = coroutine_pool_cleanup;
+ qemu_thread_atexit_add(&coroutine_pool_cleanup_notifier);
+ }
+
+ /* This is not exact; there could be a little skew between
+ * release_pool_size and the actual size of release_pool. But
+ * it is just a heuristic, it does not need to be perfect.
+ */
+ alloc_pool_size = atomic_xchg(&release_pool_size, 0);
+ QSLIST_MOVE_ATOMIC(&alloc_pool, &release_pool);
+ co = QSLIST_FIRST(&alloc_pool);
+ }
+ }
+ if (co) {
+ QSLIST_REMOVE_HEAD(&alloc_pool, pool_next);
+ alloc_pool_size--;
+ }
+ }
+
+ if (!co) {
+ co = qemu_coroutine_new();
+ }
+
+ co->entry = entry;
+ QTAILQ_INIT(&co->co_queue_wakeup);
+ return co;
+}
+
+static void coroutine_delete(Coroutine *co)
+{
+ co->caller = NULL;
+
+ if (CONFIG_COROUTINE_POOL) {
+ if (release_pool_size < POOL_BATCH_SIZE * 2) {
+ QSLIST_INSERT_HEAD_ATOMIC(&release_pool, co, pool_next);
+ atomic_inc(&release_pool_size);
+ return;
+ }
+ if (alloc_pool_size < POOL_BATCH_SIZE) {
+ QSLIST_INSERT_HEAD(&alloc_pool, co, pool_next);
+ alloc_pool_size++;
+ return;
+ }
+ }
+
+ qemu_coroutine_delete(co);
+}
+
+void qemu_coroutine_enter(Coroutine *co, void *opaque)
+{
+ Coroutine *self = qemu_coroutine_self();
+ CoroutineAction ret;
+
+ trace_qemu_coroutine_enter(self, co, opaque);
+
+ if (co->caller) {
+ fprintf(stderr, "Co-routine re-entered recursively\n");
+ abort();
+ }
+
+ co->caller = self;
+ co->entry_arg = opaque;
+ ret = qemu_coroutine_switch(self, co, COROUTINE_ENTER);
+
+ qemu_co_queue_run_restart(co);
+
+ switch (ret) {
+ case COROUTINE_YIELD:
+ return;
+ case COROUTINE_TERMINATE:
+ trace_qemu_coroutine_terminate(co);
+ coroutine_delete(co);
+ return;
+ default:
+ abort();
+ }
+}
+
+void coroutine_fn qemu_coroutine_yield(void)
+{
+ Coroutine *self = qemu_coroutine_self();
+ Coroutine *to = self->caller;
+
+ trace_qemu_coroutine_yield(self, to);
+
+ if (!to) {
+ fprintf(stderr, "Co-routine is yielding to no one\n");
+ abort();
+ }
+
+ self->caller = NULL;
+ qemu_coroutine_switch(self, to, COROUTINE_YIELD);
+}
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