From: Pavel Dovgalyuk <pavel.dovga...@ispras.ru>
This patch adds support for dynamically loaded plugins. Every plugin
is a dynamic library with a set of optional exported functions that
will be called from QEMU.
Signed-off-by: Pavel Dovgalyuk <pavel.dovga...@ispras.ru>
[AJB: moved to using trace point API]
Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
---
ajb
- moved to tracepoint interface (bind_to_tracepoints)
- now in trace/ and include/plugins/
---
include/plugins/plugins.h | 14 ++++
include/qemu/plugins.h | 18 +++++
qemu-options.hx | 10 +++
trace/Makefile.objs | 1 +
trace/plugins.c | 139 ++++++++++++++++++++++++++++++++++++++
vl.c | 8 +++
6 files changed, 190 insertions(+)
create mode 100644 include/plugins/plugins.h
create mode 100644 include/qemu/plugins.h
create mode 100644 trace/plugins.c
diff --git a/include/plugins/plugins.h b/include/plugins/plugins.h
new file mode 100644
index 0000000000..54ac53cb32
--- /dev/null
+++ b/include/plugins/plugins.h
@@ -0,0 +1,14 @@
+#ifndef PLUGINS_INTERFACE_H
+#define PLUGINS_INTERFACE_H
+
+#include <stdbool.h>
+#include <stdio.h>
+
+/* Mandatory Plugin interfaces */
+
+bool plugin_init(const char *args);
+char *plugin_status(void);
+
+/* Other optional hooks are defined by available trace-points */
+
+#endif /* PLUGINS_INTERFACE_H */
diff --git a/include/qemu/plugins.h b/include/qemu/plugins.h
new file mode 100644
index 0000000000..c86bb7ae67
--- /dev/null
+++ b/include/qemu/plugins.h
@@ -0,0 +1,18 @@
+#ifndef PLUGINS_H
+#define PLUGINS_H
+
+#ifdef CONFIG_TRACE_PLUGIN
+
+void qemu_plugin_parse_cmd_args(const char *optarg);
+void qemu_plugin_load(const char *filename, const char *args);
+void qemu_plugins_init(void);
+
+#else
+
+static inline void qemu_plugin_parse_cmd_args(const char *optarg) { }
+static inline void qemu_plugin_load(const char *filename, const char *args) { }
+static inline void qemu_plugins_init(void) { }
+
+#endif
+
+#endif /* PLUGINS_H */
diff --git a/qemu-options.hx b/qemu-options.hx
index f139459e80..87206dd79f 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3892,6 +3892,16 @@ STEXI
Enable synchronization profiling.
ETEXI
+#ifdef CONFIG_TRACE_PLUGIN
+DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, \
+ "-plugin file=<file>[,args=<args>] load <dso> plugin with
<args>\n", QEMU_ARCH_ALL)
+STEXI
+@item -plugin file=@var{file}[,args=@var{args}]
+@findex -plugin
+Load @var{file} plugin passing @var{args} arguments.
+ETEXI
+#endif
+
STEXI
@end table
ETEXI
diff --git a/trace/Makefile.objs b/trace/Makefile.objs
index afd571c3ec..4977f654a5 100644
--- a/trace/Makefile.objs
+++ b/trace/Makefile.objs
@@ -54,6 +54,7 @@ $(obj)/generated-tcg-tracers.h-timestamp:
$(SRC_PATH)/trace-events $(BUILD_DIR)/
util-obj-$(CONFIG_TRACE_SIMPLE) += simple.o
util-obj-$(CONFIG_TRACE_FTRACE) += ftrace.o
+util-obj-$(CONFIG_TRACE_PLUGIN) += plugins.o
util-obj-y += control.o
target-obj-y += control-target.o
util-obj-y += qmp.o
diff --git a/trace/plugins.c b/trace/plugins.c
new file mode 100644
index 0000000000..25aec2ff70
--- /dev/null
+++ b/trace/plugins.c
@@ -0,0 +1,139 @@
+/*
+ * Plugin Support
+ *
+ *
+ * Copyright (c) 2018 Pavel Dovgalyuk <pavel.dovga...@ispras.ru>
+ * Copyright (c) 2018 Alex Bennée <alex.ben...@linaro.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include <gmodule.h>
+#include "qemu-common.h"
+#include "qemu/error-report.h"
+#include "qemu/plugins.h"
+#include "qemu/queue.h"
+#include "qemu/option.h"
+#include "trace/control.h"
+
+typedef bool (*PluginInitFunc)(const char *);
+typedef char * (*PluginStatusFunc)(void);
+
+typedef struct QemuPluginInfo {
+ const char *filename;
+ const char *args;
+ GModule *g_module;
+
+ PluginInitFunc init;
+ PluginStatusFunc status;
+
+ GPtrArray *events;
+
+ QLIST_ENTRY(QemuPluginInfo) next;
+} QemuPluginInfo;
+
+static QLIST_HEAD(, QemuPluginInfo) qemu_plugins
+ = QLIST_HEAD_INITIALIZER(qemu_plugins);
+
+static QemuOptsList qemu_plugin_opts = {
+ .name = "plugin",
+ .head = QTAILQ_HEAD_INITIALIZER(qemu_plugin_opts.head),
+ .desc = {
+ {
+ .name = "file",
+ .type = QEMU_OPT_STRING,
+ },{
+ .name = "args",
+ .type = QEMU_OPT_STRING,
+ },
+ { /* end of list */ }
+ },
+};
+
+void qemu_plugin_parse_cmd_args(const char *optarg)
+{
+ QemuOpts *opts = qemu_opts_parse_noisily(&qemu_plugin_opts, optarg, false);
+ qemu_plugin_load(qemu_opt_get(opts, "file"),
+ qemu_opt_get(opts, "args"));
+}
+
+static int bind_to_tracepoints(GModule *g_module, GPtrArray *events)
+{
+ int count = 0;
+ TraceEventIter iter;
+ TraceEvent *ev;
+
+ trace_event_iter_init(&iter, "*");
+ while ((ev = trace_event_iter_next(&iter)) != NULL) {
+ const char *name = trace_event_get_name(ev);
+ gpointer fn;
+
+ if (g_module_symbol(g_module, name, &fn)) {
+ ev->plugin = (uintptr_t) fn;
+ trace_event_set_state_dynamic(ev, true);
+ count++;
+ }
+ }
+
+ return count;
+}
+
+void qemu_plugin_load(const char *filename, const char *args)
+{
+ GModule *g_module;
+ QemuPluginInfo *info = NULL;
+ if (!filename) {
+ error_report("plugin name was not specified");
+ return;
+ }
+ g_module = g_module_open(filename,
+ G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL);
+ if (!g_module) {
+ error_report("can't load plugin '%s'", filename);
+ return;
+ }
+ info = g_new0(QemuPluginInfo, 1);
+ info->filename = g_strdup(filename);
+ info->g_module = g_module;
+
+ if (!g_module_symbol(g_module, "plugin_init",
+ (gpointer *) &info->init)) {
+ error_report("all plugins must provide a plugin_init hook");
+ return;
+ }
+
+ if (!g_module_symbol(g_module, "plugin_status",
+ (gpointer *) &info->status)) {
+ error_report("all plugins must provide a plugin_status hook");
+ return;
+ }
+
+ /* OK we can now see how many events might have bindings */
+ info->events = g_ptr_array_new();
+
+ if (bind_to_tracepoints(g_module, info->events) < 0) {
+ error_report("failed to bind any events");
+ return;
+ }
+
+ /* Save the args, we will initialise later on once everything is
+ set up */
+ if (args) {
+ info->args = g_strdup(args);
+ }
+
+ QLIST_INSERT_HEAD(&qemu_plugins, info, next);
+
+ return;
+}
+
+void qemu_plugins_init(void)
+{
+ QemuPluginInfo *info;
+ QLIST_FOREACH(info, &qemu_plugins, next) {
+ if (info->init) {
+ info->init(info->args);
+ }
+ }
+}
diff --git a/vl.c b/vl.c
index 795e025445..b46ef5032f 100644
--- a/vl.c
+++ b/vl.c
@@ -130,6 +130,7 @@ int main(int argc, char **argv)
#include "qapi/qapi-commands-run-state.h"
#include "qapi/qmp/qerror.h"
#include "sysemu/iothread.h"
+#include "qemu/plugins.h"
#define MAX_VIRTIO_CONSOLES 1
@@ -3884,6 +3885,11 @@ int main(int argc, char **argv, char **envp)
case QEMU_OPTION_enable_sync_profile:
qsp_enable();
break;
+#ifdef CONFIG_TRACE_PLUGIN
+ case QEMU_OPTION_plugin:
+ qemu_plugin_parse_cmd_args(optarg);
+ break;
+#endif
case QEMU_OPTION_nouserconfig:
/* Nothing to be parsed here. Especially, do not error out
below. */
break;
@@ -4449,6 +4455,8 @@ int main(int argc, char **argv, char **envp)
}
parse_numa_opts(current_machine);
+ qemu_plugins_init();
+
/* do monitor/qmp handling at preconfig state if requested */
main_loop();
--
2.17.1
