trace: add "-trace enable=..."

Allow enabling events without going through a file, for example:

   qemu-system-x86_64 -trace bdrv_aio_writev -trace bdrv_aio_readv

or with globbing too:

   qemu-system-x86_64 -trace 'bdrv_aio_*'

if an appropriate backend is enabled (simple, stderr, ftrace).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-id: 1452174932-28657-6-git-send-email-den@openvz.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/vl.c b/vl.c
index 6370efee5f..58cc0507fe 100644
--- a/vl.c
+++ b/vl.c
@@ -270,10 +270,14 @@ static QemuOptsList qemu_sandbox_opts = {
 
 static QemuOptsList qemu_trace_opts = {
     .name = "trace",
-    .implied_opt_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,
         },{
@@ -3900,10 +3904,13 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_trace:
             {
                 opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
-                                               optarg, false);
+                                               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);