Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

* Support for jemalloc
* qemu_mutex_lock_iothread "No such process" fix
* cutils: qemu_strto* wrappers
* iohandler.c simplification
* Many other fixes and misc patches.

And some MTTCG work (with Emilio's fixes squashed):
* Signal-free TCG kick
* Removing spinlock in favor of QemuMutex
* User-mode emulation multi-threading fixes/docs

# gpg: Signature made Thu 10 Sep 2015 09:03:07 BST using RSA key ID 78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>"

* remotes/bonzini/tags/for-upstream: (44 commits)
  cutils: work around platform differences in strto{l,ul,ll,ull}
  cpu-exec: fix lock hierarchy for user-mode emulation
  exec: make mmap_lock/mmap_unlock globally available
  tcg: comment on which functions have to be called with mmap_lock held
  tcg: add memory barriers in page_find_alloc accesses
  remove unused spinlock.
  replace spinlock by QemuMutex.
  cpus: remove tcg_halt_cond and tcg_cpu_thread globals
  cpus: protect work list with work_mutex
  scripts/dump-guest-memory.py: fix after RAMBlock change
  configure: Add support for jemalloc
  add macro file for coccinelle
  configure: factor out adding disas configure
  vhost-scsi: fix wrong vhost-scsi firmware path
  checkpatch: remove tests that are not relevant outside the kernel
  checkpatch: adapt some tests to QEMU
  CODING_STYLE: update mixed declaration rules
  qmp: Add example usage of strto*l() qemu wrapper
  cutils: Add qemu_strtoull() wrapper
  cutils: Add qemu_strtoll() wrapper
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 51 insertions, 79 deletions

diff --git a/cpus.c b/cpus.c
index c1e74d9824..dddd056454 100644
--- a/cpus.c
+++ b/cpus.c
@@ -661,14 +661,6 @@ static void cpu_handle_guest_debug(CPUState *cpu)
     cpu->stopped = true;
 }
 
-static void cpu_signal(int sig)
-{
-    if (current_cpu) {
-        cpu_exit(current_cpu);
-    }
-    exit_request = 1;
-}
-
 #ifdef CONFIG_LINUX
 static void sigbus_reraise(void)
 {
@@ -781,29 +773,11 @@ static void qemu_kvm_init_cpu_signals(CPUState *cpu)
     }
 }
 
-static void qemu_tcg_init_cpu_signals(void)
-{
-    sigset_t set;
-    struct sigaction sigact;
-
-    memset(&sigact, 0, sizeof(sigact));
-    sigact.sa_handler = cpu_signal;
-    sigaction(SIG_IPI, &sigact, NULL);
-
-    sigemptyset(&set);
-    sigaddset(&set, SIG_IPI);
-    pthread_sigmask(SIG_UNBLOCK, &set, NULL);
-}
-
 #else /* _WIN32 */
 static void qemu_kvm_init_cpu_signals(CPUState *cpu)
 {
     abort();
 }
-
-static void qemu_tcg_init_cpu_signals(void)
-{
-}
 #endif /* _WIN32 */
 
 static QemuMutex qemu_global_mutex;
@@ -812,9 +786,6 @@ static unsigned iothread_requesting_mutex;
 
 static QemuThread io_thread;
 
-static QemuThread *tcg_cpu_thread;
-static QemuCond *tcg_halt_cond;
-
 /* cpu creation */
 static QemuCond qemu_cpu_cond;
 /* system init */
@@ -845,6 +816,8 @@ void run_on_cpu(CPUState *cpu, void (*func)(void *data), void *data)
     wi.func = func;
     wi.data = data;
     wi.free = false;
+
+    qemu_mutex_lock(&cpu->work_mutex);
     if (cpu->queued_work_first == NULL) {
         cpu->queued_work_first = &wi;
     } else {
@@ -853,9 +826,10 @@ void run_on_cpu(CPUState *cpu, void (*func)(void *data), void *data)
     cpu->queued_work_last = &wi;
     wi.next = NULL;
     wi.done = false;
+    qemu_mutex_unlock(&cpu->work_mutex);
 
     qemu_cpu_kick(cpu);
-    while (!wi.done) {
+    while (!atomic_mb_read(&wi.done)) {
         CPUState *self_cpu = current_cpu;
 
         qemu_cond_wait(&qemu_work_cond, &qemu_global_mutex);
@@ -876,6 +850,8 @@ void async_run_on_cpu(CPUState *cpu, void (*func)(void *data), void *data)
     wi->func = func;
     wi->data = data;
     wi->free = true;
+
+    qemu_mutex_lock(&cpu->work_mutex);
     if (cpu->queued_work_first == NULL) {
         cpu->queued_work_first = wi;
     } else {
@@ -884,6 +860,7 @@ void async_run_on_cpu(CPUState *cpu, void (*func)(void *data), void *data)
     cpu->queued_work_last = wi;
     wi->next = NULL;
     wi->done = false;
+    qemu_mutex_unlock(&cpu->work_mutex);
 
     qemu_cpu_kick(cpu);
 }
@@ -896,15 +873,23 @@ static void flush_queued_work(CPUState *cpu)
         return;
     }
 
-    while ((wi = cpu->queued_work_first)) {
+    qemu_mutex_lock(&cpu->work_mutex);
+    while (cpu->queued_work_first != NULL) {
+        wi = cpu->queued_work_first;
         cpu->queued_work_first = wi->next;
+        if (!cpu->queued_work_first) {
+            cpu->queued_work_last = NULL;
+        }
+        qemu_mutex_unlock(&cpu->work_mutex);
         wi->func(wi->data);
-        wi->done = true;
+        qemu_mutex_lock(&cpu->work_mutex);
         if (wi->free) {
             g_free(wi);
+        } else {
+            atomic_mb_set(&wi->done, true);
         }
     }
-    cpu->queued_work_last = NULL;
+    qemu_mutex_unlock(&cpu->work_mutex);
     qemu_cond_broadcast(&qemu_work_cond);
 }
 
@@ -919,15 +904,13 @@ static void qemu_wait_io_event_common(CPUState *cpu)
     cpu->thread_kicked = false;
 }
 
-static void qemu_tcg_wait_io_event(void)
+static void qemu_tcg_wait_io_event(CPUState *cpu)
 {
-    CPUState *cpu;
-
     while (all_cpu_threads_idle()) {
        /* Start accounting real time to the virtual clock if the CPUs
           are idle.  */
         qemu_clock_warp(QEMU_CLOCK_VIRTUAL);
-        qemu_cond_wait(tcg_halt_cond, &qemu_global_mutex);
+        qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex);
     }
 
     while (iothread_requesting_mutex) {
@@ -1041,7 +1024,6 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
     rcu_register_thread();
 
     qemu_mutex_lock_iothread();
-    qemu_tcg_init_cpu_signals();
     qemu_thread_get_self(cpu->thread);
 
     CPU_FOREACH(cpu) {
@@ -1053,7 +1035,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
 
     /* wait for initial kick-off after machine start */
     while (first_cpu->stopped) {
-        qemu_cond_wait(tcg_halt_cond, &qemu_global_mutex);
+        qemu_cond_wait(first_cpu->halt_cond, &qemu_global_mutex);
 
         /* process any pending work */
         CPU_FOREACH(cpu) {
@@ -1062,7 +1044,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
     }
 
     /* process any pending work */
-    exit_request = 1;
+    atomic_mb_set(&exit_request, 1);
 
     while (1) {
         tcg_exec_all();
@@ -1074,7 +1056,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
                 qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
             }
         }
-        qemu_tcg_wait_io_event();
+        qemu_tcg_wait_io_event(QTAILQ_FIRST(&cpus));
     }
 
     return NULL;
@@ -1085,61 +1067,47 @@ static void qemu_cpu_kick_thread(CPUState *cpu)
 #ifndef _WIN32
     int err;
 
+    if (cpu->thread_kicked) {
+        return;
+    }
+    cpu->thread_kicked = true;
     err = pthread_kill(cpu->thread->thread, SIG_IPI);
     if (err) {
         fprintf(stderr, "qemu:%s: %s", __func__, strerror(err));
         exit(1);
     }
 #else /* _WIN32 */
-    if (!qemu_cpu_is_self(cpu)) {
-        CONTEXT tcgContext;
-
-        if (SuspendThread(cpu->hThread) == (DWORD)-1) {
-            fprintf(stderr, "qemu:%s: GetLastError:%lu\n", __func__,
-                    GetLastError());
-            exit(1);
-        }
-
-        /* On multi-core systems, we are not sure that the thread is actually
-         * suspended until we can get the context.
-         */
-        tcgContext.ContextFlags = CONTEXT_CONTROL;
-        while (GetThreadContext(cpu->hThread, &tcgContext) != 0) {
-            continue;
-        }
-
-        cpu_signal(0);
+    abort();
+#endif
+}
 
-        if (ResumeThread(cpu->hThread) == (DWORD)-1) {
-            fprintf(stderr, "qemu:%s: GetLastError:%lu\n", __func__,
-                    GetLastError());
-            exit(1);
-        }
+static void qemu_cpu_kick_no_halt(void)
+{
+    CPUState *cpu;
+    /* Ensure whatever caused the exit has reached the CPU threads before
+     * writing exit_request.
+     */
+    atomic_mb_set(&exit_request, 1);
+    cpu = atomic_mb_read(&tcg_current_cpu);
+    if (cpu) {
+        cpu_exit(cpu);
     }
-#endif
 }
 
 void qemu_cpu_kick(CPUState *cpu)
 {
     qemu_cond_broadcast(cpu->halt_cond);
-    if (!tcg_enabled() && !cpu->thread_kicked) {
+    if (tcg_enabled()) {
+        qemu_cpu_kick_no_halt();
+    } else {
         qemu_cpu_kick_thread(cpu);
-        cpu->thread_kicked = true;
     }
 }
 
 void qemu_cpu_kick_self(void)
 {
-#ifndef _WIN32
     assert(current_cpu);
-
-    if (!current_cpu->thread_kicked) {
-        qemu_cpu_kick_thread(current_cpu);
-        current_cpu->thread_kicked = true;
-    }
-#else
-    abort();
-#endif
+    qemu_cpu_kick_thread(current_cpu);
 }
 
 bool qemu_cpu_is_self(CPUState *cpu)
@@ -1166,12 +1134,12 @@ void qemu_mutex_lock_iothread(void)
      * TCG code execution.
      */
     if (!tcg_enabled() || qemu_in_vcpu_thread() ||
-        !first_cpu || !first_cpu->thread) {
+        !first_cpu || !first_cpu->created) {
         qemu_mutex_lock(&qemu_global_mutex);
         atomic_dec(&iothread_requesting_mutex);
     } else {
         if (qemu_mutex_trylock(&qemu_global_mutex)) {
-            qemu_cpu_kick_thread(first_cpu);
+            qemu_cpu_kick_no_halt();
             qemu_mutex_lock(&qemu_global_mutex);
         }
         atomic_dec(&iothread_requesting_mutex);
@@ -1251,6 +1219,8 @@ void resume_all_vcpus(void)
 static void qemu_tcg_init_vcpu(CPUState *cpu)
 {
     char thread_name[VCPU_THREAD_NAME_SIZE];
+    static QemuCond *tcg_halt_cond;
+    static QemuThread *tcg_cpu_thread;
 
     tcg_cpu_address_space_init(cpu, cpu->as);
 
@@ -1440,7 +1410,9 @@ static void tcg_exec_all(void)
             break;
         }
     }
-    exit_request = 0;
+
+    /* Pairs with smp_wmb in qemu_cpu_kick.  */
+    atomic_mb_set(&exit_request, 0);
 }
 
 void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg)