cpus-common: move CPU list management to common code

Add a mutex for the CPU list to system emulation, as it will be used to
manage safe work.  Abstract manipulation of the CPU list in new functions
cpu_list_add and cpu_list_remove.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/cpus-common.c b/cpus-common.c
new file mode 100644
index 0000000000..fda3848b7d
--- /dev/null
+++ b/cpus-common.c
@@ -0,0 +1,83 @@
+/*
+ * CPU thread main loop - common bits for user and system mode emulation
+ *
+ *  Copyright (c) 2003-2005 Fabrice Bellard
+ *
+ * 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 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 "qemu/osdep.h"
+#include "exec/cpu-common.h"
+#include "qom/cpu.h"
+#include "sysemu/cpus.h"
+
+static QemuMutex qemu_cpu_list_lock;
+
+void qemu_init_cpu_list(void)
+{
+    qemu_mutex_init(&qemu_cpu_list_lock);
+}
+
+void cpu_list_lock(void)
+{
+    qemu_mutex_lock(&qemu_cpu_list_lock);
+}
+
+void cpu_list_unlock(void)
+{
+    qemu_mutex_unlock(&qemu_cpu_list_lock);
+}
+
+static bool cpu_index_auto_assigned;
+
+static int cpu_get_free_index(void)
+{
+    CPUState *some_cpu;
+    int cpu_index = 0;
+
+    cpu_index_auto_assigned = true;
+    CPU_FOREACH(some_cpu) {
+        cpu_index++;
+    }
+    return cpu_index;
+}
+
+void cpu_list_add(CPUState *cpu)
+{
+    qemu_mutex_lock(&qemu_cpu_list_lock);
+    if (cpu->cpu_index == UNASSIGNED_CPU_INDEX) {
+        cpu->cpu_index = cpu_get_free_index();
+        assert(cpu->cpu_index != UNASSIGNED_CPU_INDEX);
+    } else {
+        assert(!cpu_index_auto_assigned);
+    }
+    QTAILQ_INSERT_TAIL(&cpus, cpu, node);
+    qemu_mutex_unlock(&qemu_cpu_list_lock);
+}
+
+void cpu_list_remove(CPUState *cpu)
+{
+    qemu_mutex_lock(&qemu_cpu_list_lock);
+    if (!QTAILQ_IN_USE(cpu, node)) {
+        /* there is nothing to undo since cpu_exec_init() hasn't been called */
+        qemu_mutex_unlock(&qemu_cpu_list_lock);
+        return;
+    }
+
+    assert(!(cpu_index_auto_assigned && cpu != QTAILQ_LAST(&cpus, CPUTailQ)));
+
+    QTAILQ_REMOVE(&cpus, cpu, node);
+    cpu->cpu_index = UNASSIGNED_CPU_INDEX;
+    qemu_mutex_unlock(&qemu_cpu_list_lock);
+}