Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

# gpg: Signature made Tue 28 Jun 2016 22:27:20 BST
# gpg:                using RSA key 0x9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/tracing-pull-request:
  trace: [*-user] Add events to trace guest syscalls in syscall emulation mode
  trace: enable tracing in qemu-img
  qemu-img: move common options parsing before commands processing
  trace: enable tracing in qemu-nbd
  trace: enable tracing in qemu-io
  trace: move qemu_trace_opts to trace/control.c
  doc: move text describing --trace to specific .texi file
  doc: sync help description for --trace with man for qemu.1

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

14 files changed, 205 insertions, 97 deletions

diff --git a/Makefile b/Makefile
index 7087fc273b..9d12dc614f 100644
--- a/Makefile
+++ b/Makefile
@@ -564,8 +564,9 @@ qemu.1: qemu-doc.texi qemu-options.texi qemu-monitor.texi qemu-monitor-info.texi
 	  perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< qemu.pod && \
 	  $(POD2MAN) --section=1 --center=" " --release=" " qemu.pod > $@, \
 	  "  GEN   $@")
+qemu.1: qemu-option-trace.texi
 
-qemu-img.1: qemu-img.texi qemu-img-cmds.texi
+qemu-img.1: qemu-img.texi qemu-option-trace.texi qemu-img-cmds.texi
 	$(call quiet-command, \
 	  perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< qemu-img.pod && \
 	  $(POD2MAN) --section=1 --center=" " --release=" " qemu-img.pod > $@, \
@@ -577,7 +578,7 @@ fsdev/virtfs-proxy-helper.1: fsdev/virtfs-proxy-helper.texi
 	  $(POD2MAN) --section=1 --center=" " --release=" " fsdev/virtfs-proxy-helper.pod > $@, \
 	  "  GEN   $@")
 
-qemu-nbd.8: qemu-nbd.texi
+qemu-nbd.8: qemu-nbd.texi qemu-option-trace.texi
 	$(call quiet-command, \
 	  perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< qemu-nbd.pod && \
 	  $(POD2MAN) --section=8 --center=" " --release=" " qemu-nbd.pod > $@, \
@@ -595,7 +596,7 @@ info: qemu-doc.info qemu-tech.info
 pdf: qemu-doc.pdf qemu-tech.pdf
 
 qemu-doc.dvi qemu-doc.html qemu-doc.info qemu-doc.pdf: \
-	qemu-img.texi qemu-nbd.texi qemu-options.texi \
+	qemu-img.texi qemu-nbd.texi qemu-options.texi qemu-option-trace.texi \
 	qemu-monitor.texi qemu-img-cmds.texi qemu-ga.texi \
 	qemu-monitor-info.texi
 
diff --git a/bsd-user/syscall.c b/bsd-user/syscall.c
index a9fe8693c1..66492aaf5d 100644
--- a/bsd-user/syscall.c
+++ b/bsd-user/syscall.c
@@ -315,12 +315,14 @@ abi_long do_freebsd_syscall(void *cpu_env, int num, abi_long arg1,
                             abi_long arg5, abi_long arg6, abi_long arg7,
                             abi_long arg8)
 {
+    CPUState *cpu = ENV_GET_CPU(cpu_env);
     abi_long ret;
     void *p;
 
 #ifdef DEBUG
     gemu_log("freebsd syscall %d\n", num);
 #endif
+    trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
     if(do_strace)
         print_freebsd_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
 
@@ -400,6 +402,7 @@ abi_long do_freebsd_syscall(void *cpu_env, int num, abi_long arg1,
 #endif
     if (do_strace)
         print_freebsd_syscall_ret(num, ret);
+    trace_guest_user_syscall_ret(cpu, num, ret);
     return ret;
  efault:
     ret = -TARGET_EFAULT;
@@ -410,12 +413,14 @@ abi_long do_netbsd_syscall(void *cpu_env, int num, abi_long arg1,
                            abi_long arg2, abi_long arg3, abi_long arg4,
                            abi_long arg5, abi_long arg6)
 {
+    CPUState *cpu = ENV_GET_CPU(cpu_env);
     abi_long ret;
     void *p;
 
 #ifdef DEBUG
     gemu_log("netbsd syscall %d\n", num);
 #endif
+    trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, 0, 0);
     if(do_strace)
         print_netbsd_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
 
@@ -472,6 +477,7 @@ abi_long do_netbsd_syscall(void *cpu_env, int num, abi_long arg1,
 #endif
     if (do_strace)
         print_netbsd_syscall_ret(num, ret);
+    trace_guest_user_syscall_ret(cpu, num, ret);
     return ret;
  efault:
     ret = -TARGET_EFAULT;
@@ -482,12 +488,14 @@ abi_long do_openbsd_syscall(void *cpu_env, int num, abi_long arg1,
                             abi_long arg2, abi_long arg3, abi_long arg4,
                             abi_long arg5, abi_long arg6)
 {
+    CPUState *cpu = ENV_GET_CPU(cpu_env);
     abi_long ret;
     void *p;
 
 #ifdef DEBUG
     gemu_log("openbsd syscall %d\n", num);
 #endif
+    trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, 0, 0);
     if(do_strace)
         print_openbsd_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
 
@@ -544,6 +552,7 @@ abi_long do_openbsd_syscall(void *cpu_env, int num, abi_long arg1,
 #endif
     if (do_strace)
         print_openbsd_syscall_ret(num, ret);
+    trace_guest_user_syscall_ret(cpu, num, ret);
     return ret;
  efault:
     ret = -TARGET_EFAULT;
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index d3d7ee600a..28ee45a937 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6802,6 +6802,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
 #ifdef DEBUG
     gemu_log("syscall %d", num);
 #endif
+    trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
     if(do_strace)
         print_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
 
@@ -11245,6 +11246,7 @@ fail:
 #endif
     if(do_strace)
         print_syscall_ret(num, ret);
+    trace_guest_user_syscall_ret(cpu, num, ret);
     return ret;
 efault:
     ret = -TARGET_EFAULT;
diff --git a/qemu-img.c b/qemu-img.c
index 14e2661a5c..3322a1e5fc 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -32,6 +32,7 @@
 #include "qemu/config-file.h"
 #include "qemu/option.h"
 #include "qemu/error-report.h"
+#include "qemu/log.h"
 #include "qom/object_interfaces.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/block-backend.h"
@@ -39,6 +40,7 @@
 #include "block/blockjob.h"
 #include "block/qapi.h"
 #include "crypto/init.h"
+#include "trace/control.h"
 #include <getopt.h>
 
 #define QEMU_IMG_VERSION "qemu-img version " QEMU_VERSION QEMU_PKGVERSION \
@@ -91,9 +93,14 @@ static void QEMU_NORETURN help(void)
 {
     const char *help_msg =
            QEMU_IMG_VERSION
-           "usage: qemu-img command [command options]\n"
+           "usage: qemu-img [standard options] command [command options]\n"
            "QEMU disk image utility\n"
            "\n"
+           "    '-h', '--help'       display this help and exit\n"
+           "    '-V', '--version'    output version information and exit\n"
+           "    '-T', '--trace'      [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
+           "                         specify tracing options\n"
+           "\n"
            "Command syntax:\n"
 #define DEF(option, callback, arg_string)        \
            "  " arg_string "\n"
@@ -3803,10 +3810,12 @@ int main(int argc, char **argv)
     const img_cmd_t *cmd;
     const char *cmdname;
     Error *local_error = NULL;
+    char *trace_file = NULL;
     int c;
     static const struct option long_options[] = {
         {"help", no_argument, 0, 'h'},
-        {"version", no_argument, 0, 'v'},
+        {"version", no_argument, 0, 'V'},
+        {"trace", required_argument, NULL, 'T'},
         {0, 0, 0, 0}
     };
 
@@ -3829,27 +3838,48 @@ int main(int argc, char **argv)
     if (argc < 2) {
         error_exit("Not enough arguments");
     }
-    cmdname = argv[1];
 
     qemu_add_opts(&qemu_object_opts);
     qemu_add_opts(&qemu_source_opts);
+    qemu_add_opts(&qemu_trace_opts);
 
-    /* find the command */
-    for (cmd = img_cmds; cmd->name != NULL; cmd++) {
-        if (!strcmp(cmdname, cmd->name)) {
-            return cmd->handler(argc - 1, argv + 1);
+    while ((c = getopt_long(argc, argv, "+hVT:", long_options, NULL)) != -1) {
+        switch (c) {
+        case 'h':
+            help();
+            return 0;
+        case 'V':
+            printf(QEMU_IMG_VERSION);
+            return 0;
+        case 'T':
+            g_free(trace_file);
+            trace_file = trace_opt_parse(optarg);
+            break;
         }
     }
 
-    c = getopt_long(argc, argv, "h", long_options, NULL);
+    cmdname = argv[optind];
 
-    if (c == 'h') {
-        help();
-    }
-    if (c == 'v') {
-        printf(QEMU_IMG_VERSION);
+    /* reset getopt_long scanning */
+    argc -= optind;
+    if (argc < 1) {
         return 0;
     }
+    argv += optind;
+    optind = 1;
+
+    if (!trace_init_backends()) {
+        exit(1);
+    }
+    trace_init_file(trace_file);
+    qemu_set_log(LOG_TRACE);
+
+    /* find the command */
+    for (cmd = img_cmds; cmd->name != NULL; cmd++) {
+        if (!strcmp(cmdname, cmd->name)) {
+            return cmd->handler(argc, argv);
+        }
+    }
 
     /* not found */
     error_exit("Command not found: %s", cmdname);
diff --git a/qemu-img.texi b/qemu-img.texi
index cbe50e9b88..449a19c710 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -1,6 +1,6 @@
 @example
 @c man begin SYNOPSIS
-@command{qemu-img} @var{command} [@var{command} @var{options}]
+@command{qemu-img} [@var{standard} @var{options}] @var{command} [@var{command} @var{options}]
 @c man end
 @end example
 
@@ -16,6 +16,17 @@ inconsistent state.
 
 @c man begin OPTIONS
 
+Standard options:
+@table @option
+@item -h, --help
+Display this help and exit
+@item -V, --version
+Display version information and exit
+@item -T, --trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
+@findex --trace
+@include qemu-option-trace.texi
+@end table
+
 The following commands are supported:
 
 @include qemu-img-cmds.texi
diff --git a/qemu-io.c b/qemu-io.c
index d977a6e553..db129eac5f 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -18,6 +18,7 @@
 #include "qemu/option.h"
 #include "qemu/config-file.h"
 #include "qemu/readline.h"
+#include "qemu/log.h"
 #include "qapi/qmp/qstring.h"
 #include "qom/object_interfaces.h"
 #include "sysemu/block-backend.h"
@@ -253,7 +254,9 @@ static void usage(const char *name)
 "  -k, --native-aio     use kernel AIO implementation (on Linux only)\n"
 "  -t, --cache=MODE     use the given cache mode for the image\n"
 "  -d, --discard=MODE   use the given discard mode for the image\n"
-"  -T, --trace FILE     enable trace events listed in the given file\n"
+"  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
+"                       specify tracing options\n"
+"                       see qemu-img(1) man page for full description\n"
 "  -h, --help           display this help and exit\n"
 "  -V, --version        output version information and exit\n"
 "\n"
@@ -458,6 +461,7 @@ int main(int argc, char **argv)
     Error *local_error = NULL;
     QDict *opts = NULL;
     const char *format = NULL;
+    char *trace_file = NULL;
 
 #ifdef CONFIG_POSIX
     signal(SIGPIPE, SIG_IGN);
@@ -470,6 +474,7 @@ int main(int argc, char **argv)
 
     module_call_init(MODULE_INIT_QOM);
     qemu_add_opts(&qemu_object_opts);
+    qemu_add_opts(&qemu_trace_opts);
     bdrv_init();
 
     while ((c = getopt_long(argc, argv, sopt, lopt, &opt_index)) != -1) {
@@ -509,9 +514,8 @@ int main(int argc, char **argv)
             }
             break;
         case 'T':
-            if (!trace_init_backends()) {
-                exit(1); /* error message will have been printed */
-            }
+            g_free(trace_file);
+            trace_file = trace_opt_parse(optarg);
             break;
         case 'V':
             printf("%s version %s\n", progname, QEMU_VERSION);
@@ -557,6 +561,12 @@ int main(int argc, char **argv)
         exit(1);
     }
 
+    if (!trace_init_backends()) {
+        exit(1);
+    }
+    trace_init_file(trace_file);
+    qemu_set_log(LOG_TRACE);
+
     /* initialize commands */
     qemuio_add_command(&quit_cmd);
     qemuio_add_command(&open_cmd);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 9519db324b..321f02bd15 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -27,12 +27,14 @@
 #include "qemu/error-report.h"
 #include "qemu/config-file.h"
 #include "qemu/bswap.h"
+#include "qemu/log.h"
 #include "block/snapshot.h"
 #include "qapi/util.h"
 #include "qapi/qmp/qstring.h"
 #include "qom/object_interfaces.h"
 #include "io/channel-socket.h"
 #include "crypto/init.h"
+#include "trace/control.h"
 
 #include <getopt.h>
 #include <libgen.h>
@@ -88,6 +90,8 @@ static void usage(const char *name)
 "General purpose options:\n"
 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
 "                            passwords and/or encryption keys\n"
+"  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
+"                            specify tracing options\n"
 #ifdef __linux__
 "Kernel NBD client support:\n"
 "  -c, --connect=DEV         connect FILE to the local NBD device DEV\n"
@@ -470,7 +474,7 @@ int main(int argc, char **argv)
     off_t fd_size;
     QemuOpts *sn_opts = NULL;
     const char *sn_id_or_name = NULL;
-    const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:";
+    const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:";
     struct option lopt[] = {
         { "help", no_argument, NULL, 'h' },
         { "version", no_argument, NULL, 'V' },
@@ -498,6 +502,7 @@ int main(int argc, char **argv)
         { "export-name", required_argument, NULL, 'x' },
         { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
         { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
+        { "trace", required_argument, NULL, 'T' },
         { NULL, 0, NULL, 0 }
     };
     int ch;
@@ -518,6 +523,7 @@ int main(int argc, char **argv)
     const char *tlscredsid = NULL;
     bool imageOpts = false;
     bool writethrough = true;
+    char *trace_file = NULL;
 
     /* The client thread uses SIGTERM to interrupt the server.  A signal
      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
@@ -531,6 +537,7 @@ int main(int argc, char **argv)
 
     module_call_init(MODULE_INIT_QOM);
     qemu_add_opts(&qemu_object_opts);
+    qemu_add_opts(&qemu_trace_opts);
     qemu_init_exec_dir(argv[0]);
 
     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
@@ -703,6 +710,10 @@ int main(int argc, char **argv)
         case QEMU_NBD_OPT_IMAGE_OPTS:
             imageOpts = true;
             break;
+        case 'T':
+            g_free(trace_file);
+            trace_file = trace_opt_parse(optarg);
+            break;
         }
     }
 
@@ -718,6 +729,12 @@ int main(int argc, char **argv)
         exit(EXIT_FAILURE);
     }
 
+    if (!trace_init_backends()) {
+        exit(1);
+    }
+    trace_init_file(trace_file);
+    qemu_set_log(LOG_TRACE);
+
     if (tlscredsid) {
         if (sockpath) {
             error_report("TLS is only supported with IPv4/IPv6");
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index 9f23343450..91ebf04b5b 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -92,6 +92,9 @@ Display extra debugging information
 Display this help and exit
 @item -V, --version
 Display version information and exit
+@item -T, --trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
+@findex --trace
+@include qemu-option-trace.texi
 @end table
 
 @c man end
diff --git a/qemu-option-trace.texi b/qemu-option-trace.texi
new file mode 100644
index 0000000000..693ab5a3e1
--- /dev/null
+++ b/qemu-option-trace.texi
@@ -0,0 +1,25 @@
+Specify tracing options.
+
+@table @option
+@item [enable=]@var{pattern}
+Immediately enable events matching @var{pattern}.
+The file must contain one event name (as listed in the @file{trace-events-all}
+file) per line; globbing patterns are accepted too.  This option is only
+available if QEMU has been compiled with the @var{simple}, @var{stderr}
+or @var{ftrace} tracing backend.  To specify multiple events or patterns,
+specify the @option{-trace} option multiple times.
+
+Use @code{-trace help} to print a list of names of trace points.
+
+@item events=@var{file}
+Immediately enable events listed in @var{file}.
+The file must contain one event name (as listed in the @file{trace-events-all}
+file) per line; globbing patterns are accepted too.  This option is only
+available if QEMU has been compiled with the @var{simple}, @var{stderr} or
+@var{ftrace} tracing backend.
+
+@item file=@var{file}
+Log output traces to @var{file}.
+This option is only available if QEMU has been compiled with
+the @var{simple} tracing backend.
+@end table
diff --git a/qemu-options.hx b/qemu-options.hx
index 44c658fd4e..a95a936e55 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3669,34 +3669,9 @@ DEF("trace", HAS_ARG, QEMU_OPTION_trace,
 STEXI
 HXCOMM This line is not accurate, as some sub-options are backend-specific but
 HXCOMM HX does not support conditional compilation of text.
-@item -trace [events=@var{file}][,file=@var{file}]
+@item -trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
 @findex -trace
-
-Specify tracing options.
-
-@table @option
-@item [enable=]@var{pattern}
-Immediately enable events matching @var{pattern}.
-The file must contain one event name (as listed in the @file{trace-events-all}
-file) per line; globbing patterns are accepted too.  This option is only
-available if QEMU has been compiled with the @var{simple}, @var{stderr}
-or @var{ftrace} tracing backend.  To specify multiple events or patterns,
-specify the @option{-trace} option multiple times.
-
-Use @code{-trace help} to print a list of names of trace points.
-
-@item events=@var{file}
-Immediately enable events listed in @var{file}.
-The file must contain one event name (as listed in the @file{trace-events-all}
-file) per line; globbing patterns are accepted too.  This option is only
-available if QEMU has been compiled with the @var{simple}, @var{stderr} or
-@var{ftrace} tracing backend.
-
-@item file=@var{file}
-Log output traces to @var{file}.
-This option is only available if QEMU has been compiled with
-the @var{simple} tracing backend.
-@end table
+@include qemu-option-trace.texi
 ETEXI
 
 HXCOMM Internal use
diff --git a/trace-events b/trace-events
index 9d76de8574..476705996b 100644
--- a/trace-events
+++ b/trace-events
@@ -156,3 +156,19 @@ memory_region_tb_write(int cpu_index, uint64_t addr, uint64_t value, unsigned si
 #
 # Targets: TCG(all)
 disable vcpu tcg guest_mem_before(TCGv vaddr, uint8_t info) "info=%d", "vaddr=0x%016"PRIx64" info=%d"
+
+# @num: System call number.
+# @arg*: System call argument value.
+#
+# Start executing a guest system call in syscall emulation mode.
+#
+# Targets: TCG(all)
+disable vcpu guest_user_syscall(uint64_t num, uint64_t arg1, uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5, uint64_t arg6, uint64_t arg7, uint64_t arg8) "num=0x%016"PRIx64" arg1=0x%016"PRIx64" arg2=0x%016"PRIx64" arg3=0x%016"PRIx64" arg4=0x%016"PRIx64" arg5=0x%016"PRIx64" arg6=0x%016"PRIx64" arg7=0x%016"PRIx64" arg8=0x%016"PRIx64
+
+# @num: System call number.
+# @ret: System call result value.
+#
+# Finish executing a guest system call in syscall emulation mode.
+#
+# Targets: TCG(all)
+disable vcpu guest_user_syscall_ret(uint64_t num, uint64_t ret) "num=0x%016"PRIx64" ret=0x%016"PRIx64
diff --git a/trace/control.c b/trace/control.c
index e1556a3570..86de8b9983 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -21,11 +21,33 @@
 #endif
 #include "qapi/error.h"
 #include "qemu/error-report.h"
+#include "qemu/config-file.h"
 #include "monitor/monitor.h"
 
 int trace_events_enabled_count;
 bool trace_events_dstate[TRACE_EVENT_COUNT];
 
+QemuOptsList qemu_trace_opts = {
+    .name = "trace",
+    .implied_opt_name = "enable",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
+    .desc = {
+        {
+            .name = "enable",
+            .type = QEMU_OPT_STRING,
+        },
+        {
+            .name = "events",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "file",
+            .type = QEMU_OPT_STRING,
+        },
+        { /* end of list */ }
+    },
+};
+
+
 TraceEvent *trace_event_name(const char *name)
 {
     assert(name != NULL);
@@ -142,7 +164,7 @@ void trace_enable_events(const char *line_buf)
     }
 }
 
-void trace_init_events(const char *fname)
+static void trace_init_events(const char *fname)
 {
     Location loc;
     FILE *fp;
@@ -217,3 +239,21 @@ bool trace_init_backends(void)
 
     return true;
 }
+
+char *trace_opt_parse(const char *optarg)
+{
+    char *trace_file;
+    QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
+                                             optarg, true);
+    if (!opts) {
+        exit(1);
+    }
+    if (qemu_opt_get(opts, "enable")) {
+        trace_enable_events(qemu_opt_get(opts, "enable"));
+    }
+    trace_init_events(qemu_opt_get(opts, "events"));
+    trace_file = g_strdup(qemu_opt_get(opts, "file"));
+    qemu_opts_del(opts);
+
+    return trace_file;
+}
diff --git a/trace/control.h b/trace/control.h
index e2ba6d4de1..a2dd3eaedf 100644
--- a/trace/control.h
+++ b/trace/control.h
@@ -160,17 +160,6 @@ static void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
 bool trace_init_backends(void);
 
 /**
- * trace_init_events:
- * @events: Name of file with events to be enabled at startup; may be NULL.
- *          Corresponds to commandline option "-trace events=...".
- *
- * Read the list of enabled tracing events.
- *
- * Returns: Whether the backends could be successfully initialized.
- */
-void trace_init_events(const char *file);
-
-/**
  * trace_init_file:
  * @file:   Name of trace output file; may be NULL.
  *          Corresponds to commandline option "-trace file=...".
@@ -197,6 +186,20 @@ void trace_list_events(void);
  */
 void trace_enable_events(const char *line_buf);
 
+/**
+ * Definition of QEMU options describing trace subsystem configuration
+ */
+extern QemuOptsList qemu_trace_opts;
+
+/**
+ * trace_opt_parse:
+ * @optarg: A string argument of --trace command line argument
+ *
+ * Initialize tracing subsystem.
+ *
+ * Returns the filename to save trace to.  It must be freed with g_free().
+ */
+char *trace_opt_parse(const char *optarg);
 
 #include "trace/control-internal.h"
 
diff --git a/vl.c b/vl.c
index 4c1f9aee1f..90cf638121 100644
--- a/vl.c
+++ b/vl.c
@@ -262,26 +262,6 @@ static QemuOptsList qemu_sandbox_opts = {
     },
 };
 
-static QemuOptsList qemu_trace_opts = {
-    .name = "trace",
-    .implied_opt_name = "enable",
-    .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
-    .desc = {
-        {
-            .name = "enable",
-            .type = QEMU_OPT_STRING,
-        },
-        {
-            .name = "events",
-            .type = QEMU_OPT_STRING,
-        },{
-            .name = "file",
-            .type = QEMU_OPT_STRING,
-        },
-        { /* end of list */ }
-    },
-};
-
 static QemuOptsList qemu_option_rom_opts = {
     .name = "option-rom",
     .implied_opt_name = "romfile",
@@ -3864,23 +3844,9 @@ int main(int argc, char **argv, char **envp)
                 xen_mode = XEN_ATTACH;
                 break;
             case QEMU_OPTION_trace:
-            {
-                opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
-                                               optarg, true);
-                if (!opts) {
-                    exit(1);
-                }
-                if (qemu_opt_get(opts, "enable")) {
-                    trace_enable_events(qemu_opt_get(opts, "enable"));
-                }
-                trace_init_events(qemu_opt_get(opts, "events"));
-                if (trace_file) {
-                    g_free(trace_file);
-                }
-                trace_file = g_strdup(qemu_opt_get(opts, "file"));
-                qemu_opts_del(opts);
+                g_free(trace_file);
+                trace_file = trace_opt_parse(optarg);
                 break;
-            }
             case QEMU_OPTION_readconfig:
                 {
                     int ret = qemu_read_config_file(optarg);