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

Pull request

# gpg: Signature made Mon 01 Feb 2021 15:46:52 GMT
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha-gitlab/tags/tracing-pull-request:
  trace: update docs with meson build information
  trace: document how to specify multiple --trace patterns
  simpletrace: build() missing 2 required positional arguments
  trace: make the 'log' backend timestamp configurable
  error: rename error_with_timestamp to message_with_timestamp
  trace: add meson custom_target() depend_files for tracetool
  tracetool: also strip %l and %ll from systemtap format strings
  tracetool: fix "PRI" macro decoding
  trace: recommend "log" backend for getting started with tracing
  tracing: convert documentation to rST
  trace: fix simpletrace doc mismerge

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

10 files changed, 214 insertions, 119 deletions

diff --git a/docs/devel/index.rst b/docs/devel/index.rst
index ea0e1e17ae..98a7016a9b 100644
--- a/docs/devel/index.rst
+++ b/docs/devel/index.rst
@@ -28,6 +28,7 @@ Contents:
    secure-coding-practices
    tcg
    tcg-icount
+   tracing
    multi-thread-tcg
    tcg-plugins
    bitops
diff --git a/docs/devel/tracing.txt b/docs/devel/tracing.rst
index dba43fc7a4..ba83954899 100644
--- a/docs/devel/tracing.txt
+++ b/docs/devel/tracing.rst
@@ -1,71 +1,94 @@
-= Tracing =
+=======
+Tracing
+=======
 
-== Introduction ==
+Introduction
+============
 
 This document describes the tracing infrastructure in QEMU and how to use it
 for debugging, profiling, and observing execution.
 
-== Quickstart ==
+Quickstart
+==========
 
-1. Build with the 'simple' trace backend:
+Enable tracing of ``memory_region_ops_read`` and ``memory_region_ops_write``
+events::
 
-    ./configure --enable-trace-backends=simple
-    make
+    $ qemu --trace "memory_region_ops_*" ...
+    ...
+    719585@1608130130.441188:memory_region_ops_read cpu 0 mr 0x562fdfbb3820 addr 0x3cc value 0x67 size 1
+    719585@1608130130.441190:memory_region_ops_write cpu 0 mr 0x562fdfbd2f00 addr 0x3d4 value 0x70e size 2
 
-2. Create a file with the events you want to trace:
+This output comes from the "log" trace backend that is enabled by default when
+``./configure --enable-trace-backends=BACKENDS`` was not explicitly specified.
 
-   echo memory_region_ops_read >/tmp/events
+Multiple patterns can be specified by repeating the ``--trace`` option::
 
-3. Run the virtual machine to produce a trace file:
+    $ qemu --trace "kvm_*" --trace "virtio_*" ...
 
-    qemu --trace events=/tmp/events ... # your normal QEMU invocation
+When patterns are used frequently it is more convenient to store them in a
+file to avoid long command-line options::
 
-4. Pretty-print the binary trace file:
+    $ echo "memory_region_ops_*" >/tmp/events
+    $ echo "kvm_*" >>/tmp/events
+    $ qemu --trace events=/tmp/events ...
 
-    ./scripts/simpletrace.py trace-events-all trace-* # Override * with QEMU <pid>
+Trace events
+============
 
-== Trace events ==
+Sub-directory setup
+-------------------
 
-=== Sub-directory setup ===
-
-Each directory in the source tree can declare a set of static trace events
-in a local "trace-events" file. All directories which contain "trace-events"
-files must be listed in the "trace-events-subdirs" make variable in the top
-level Makefile.objs. During build, the "trace-events" file in each listed
-subdirectory will be processed by the "tracetool" script to generate code for
-the trace events.
+Each directory in the source tree can declare a set of trace events in a local
+"trace-events" file. All directories which contain "trace-events" files must be
+listed in the "trace_events_subdirs" variable in the top level meson.build
+file. During build, the "trace-events" file in each listed subdirectory will be
+processed by the "tracetool" script to generate code for the trace events.
 
 The individual "trace-events" files are merged into a "trace-events-all" file,
 which is also installed into "/usr/share/qemu" with the name "trace-events".
 This merged file is to be used by the "simpletrace.py" script to later analyse
 traces in the simpletrace data format.
 
-In the sub-directory the following files will be automatically generated
+The following files are automatically generated in <builddir>/trace/ during the
+build:
+
+ - trace-<subdir>.c - the trace event state declarations
+ - trace-<subdir>.h - the trace event enums and probe functions
+ - trace-dtrace-<subdir>.h - DTrace event probe specification
+ - trace-dtrace-<subdir>.dtrace - DTrace event probe helper declaration
+ - trace-dtrace-<subdir>.o - binary DTrace provider (generated by dtrace)
+ - trace-ust-<subdir>.h - UST event probe helper declarations
 
- - trace.c - the trace event state declarations
- - trace.h - the trace event enums and probe functions
- - trace-dtrace.h - DTrace event probe specification
- - trace-dtrace.dtrace - DTrace event probe helper declaration
- - trace-dtrace.o - binary DTrace provider (generated by dtrace)
- - trace-ust.h - UST event probe helper declarations
+Here <subdir> is the sub-directory path with '/' replaced by '_'. For example,
+"accel/kvm" becomes "accel_kvm" and the final filename for "trace-<subdir>.c"
+becomes "trace-accel_kvm.c".
 
-Source files in the sub-directory should #include the local 'trace.h' file,
-without any sub-directory path prefix. eg io/channel-buffer.c would do
+Source files in the source tree do not directly include generated files in
+"<builddir>/trace/". Instead they #include the local "trace.h" file, without
+any sub-directory path prefix. eg io/channel-buffer.c would do::
 
   #include "trace.h"
 
-To access the 'io/trace.h' file. While it is possible to include a trace.h
-file from outside a source file's own sub-directory, this is discouraged in
-general. It is strongly preferred that all events be declared directly in
-the sub-directory that uses them. The only exception is where there are some
-shared trace events defined in the top level directory trace-events file.
-The top level directory generates trace files with a filename prefix of
-"trace/trace-root" instead of just "trace". This is to avoid ambiguity between
-a trace.h in the current directory, vs the top level directory.
+The "io/trace.h" file must be created manually with an #include of the
+corresponding "trace/trace-<subdir>.h" file that will be generated in the
+builddir::
+
+  $ echo '#include "trace/trace-io.h"' >io/trace.h
+
+While it is possible to include a trace.h file from outside a source file's own
+sub-directory, this is discouraged in general. It is strongly preferred that
+all events be declared directly in the sub-directory that uses them. The only
+exception is where there are some shared trace events defined in the top level
+directory trace-events file.  The top level directory generates trace files
+with a filename prefix of "trace/trace-root" instead of just "trace". This is
+to avoid ambiguity between a trace.h in the current directory, vs the top level
+directory.
 
-=== Using trace events ===
+Using trace events
+------------------
 
-Trace events are invoked directly from source code like this:
+Trace events are invoked directly from source code like this::
 
     #include "trace.h"  /* needed for trace event prototype */
     
@@ -82,7 +105,8 @@ Trace events are invoked directly from source code like this:
         return ptr;
     }
 
-=== Declaring trace events ===
+Declaring trace events
+----------------------
 
 The "tracetool" script produces the trace.h header file which is included by
 every source file that uses trace events.  Since many source files include
@@ -116,13 +140,14 @@ Format strings must not end with a newline character.  It is the responsibility
 of backends to adapt line ending for proper logging.
 
 Each event declaration will start with the event name, then its arguments,
-finally a format string for pretty-printing. For example:
+finally a format string for pretty-printing. For example::
 
     qemu_vmalloc(size_t size, void *ptr) "size %zu ptr %p"
     qemu_vfree(void *ptr) "ptr %p"
 
 
-=== Hints for adding new trace events ===
+Hints for adding new trace events
+---------------------------------
 
 1. Trace state changes in the code.  Interesting points in the code usually
    involve a state change like starting, stopping, allocating, freeing.  State
@@ -141,7 +166,8 @@ finally a format string for pretty-printing. For example:
 4. Name trace events after their function.  If there are multiple trace events
    in one function, append a unique distinguisher at the end of the name.
 
-== Generic interface and monitor commands ==
+Generic interface and monitor commands
+======================================
 
 You can programmatically query and control the state of trace events through a
 backend-agnostic interface provided by the header "trace/control.h".
@@ -152,11 +178,11 @@ header "trace/control.h" to see which routines are backend-dependent).
 
 The state of events can also be queried and modified through monitor commands:
 
-* info trace-events
+* ``info trace-events``
   View available trace events and their state.  State 1 means enabled, state 0
   means disabled.
 
-* trace-event NAME on|off
+* ``trace-event NAME on|off``
   Enable/disable a given trace event or a group of events (using wildcards).
 
 The "--trace events=<file>" command line argument can be used to enable the
@@ -170,11 +196,12 @@ to enable an entire family of events but one noisy event needs to be disabled.
 Wildcard matching is supported in both the monitor command "trace-event" and the
 events list file. That means you can enable/disable the events having a common
 prefix in a batch. For example, virtio-blk trace events could be enabled using
-the following monitor command:
+the following monitor command::
 
     trace-event virtio_blk_* on
 
-== Trace backends ==
+Trace backends
+==============
 
 The "tracetool" script automates tedious trace event code generation and also
 keeps the trace event declarations independent of the trace backend.  The trace
@@ -182,9 +209,9 @@ events are not tightly coupled to a specific trace backend, such as LTTng or
 SystemTap.  Support for trace backends can be added by extending the "tracetool"
 script.
 
-The trace backends are chosen at configure time:
+The trace backends are chosen at configure time::
 
-    ./configure --enable-trace-backends=simple
+    ./configure --enable-trace-backends=simple,dtrace
 
 For a list of supported trace backends, try ./configure --help or see below.
 If multiple backends are enabled, the trace is sent to them all.
@@ -194,7 +221,8 @@ If no backends are explicitly selected, configure will default to the
 
 The following subsections describe the supported trace backends.
 
-=== Nop ===
+Nop
+---
 
 The "nop" backend generates empty trace event functions so that the compiler
 can optimize out trace events completely.  This imposes no performance
@@ -203,7 +231,8 @@ penalty.
 Note that regardless of the selected trace backend, events with the "disable"
 property will be generated with the "nop" backend.
 
-=== Log ===
+Log
+---
 
 The "log" backend sends trace events directly to standard error.  This
 effectively turns trace events into debug printfs.
@@ -211,30 +240,56 @@ effectively turns trace events into debug printfs.
 This is the simplest backend and can be used together with existing code that
 uses DPRINTF().
 
-=== Simpletrace ===
+The -msg timestamp=on|off command-line option controls whether or not to print
+the tid/timestamp prefix for each trace event.
+
+Simpletrace
+-----------
+
+The "simple" backend writes binary trace logs to a file from a thread, making
+it lower overhead than the "log" backend. A Python API is available for writing
+offline trace file analysis scripts. It may not be as powerful as
+platform-specific or third-party trace backends but it is portable and has no
+special library dependencies.
+
+Monitor commands
+~~~~~~~~~~~~~~~~
+
+* ``trace-file on|off|flush|set <path>``
+  Enable/disable/flush the trace file or set the trace file name.
+
+Analyzing trace files
+~~~~~~~~~~~~~~~~~~~~~
+
+The "simple" backend produces binary trace files that can be formatted with the
+simpletrace.py script.  The script takes the "trace-events-all" file and the
+binary trace::
+
+    ./scripts/simpletrace.py trace-events-all trace-12345
 
-The "simple" backend supports common use cases and comes as part of the QEMU
-source tree.  It may not be as powerful as platform-specific or third-party
-trace backends but it is portable.  This is the recommended trace backend
-unless you have specific needs for more advanced backends.
+You must ensure that the same "trace-events-all" file was used to build QEMU,
+otherwise trace event declarations may have changed and output will not be
+consistent.
 
-=== Ftrace ===
+Ftrace
+------
 
 The "ftrace" backend writes trace data to ftrace marker. This effectively
 sends trace events to ftrace ring buffer, and you can compare qemu trace
 data and kernel(especially kvm.ko when using KVM) trace data.
 
-if you use KVM, enable kvm events in ftrace:
+if you use KVM, enable kvm events in ftrace::
 
    # echo 1 > /sys/kernel/debug/tracing/events/kvm/enable
 
-After running qemu by root user, you can get the trace:
+After running qemu by root user, you can get the trace::
 
    # cat /sys/kernel/debug/tracing/trace
 
 Restriction: "ftrace" backend is restricted to Linux only.
 
-=== Syslog ===
+Syslog
+------
 
 The "syslog" backend sends trace events using the POSIX syslog API. The log
 is opened specifying the LOG_DAEMON facility and LOG_PID option (so events
@@ -246,24 +301,8 @@ NOTE: syslog may squash duplicate consecutive trace events and apply rate
 
 Restriction: "syslog" backend is restricted to POSIX compliant OS.
 
-==== Monitor commands ====
-
-* trace-file on|off|flush|set <path>
-  Enable/disable/flush the trace file or set the trace file name.
-
-==== Analyzing trace files ====
-
-The "simple" backend produces binary trace files that can be formatted with the
-simpletrace.py script.  The script takes the "trace-events-all" file and the
-binary trace:
-
-    ./scripts/simpletrace.py trace-events-all trace-12345
-
-You must ensure that the same "trace-events-all" file was used to build QEMU,
-otherwise trace event declarations may have changed and output will not be
-consistent.
-
-=== LTTng Userspace Tracer ===
+LTTng Userspace Tracer
+----------------------
 
 The "ust" backend uses the LTTng Userspace Tracer library.  There are no
 monitor commands built into QEMU, instead UST utilities should be used to list,
@@ -275,43 +314,44 @@ lttng-sessiond daemon for the current user prior to running any instance of
 QEMU.
 
 While running an instrumented QEMU, LTTng should be able to list all available
-events:
+events::
 
     lttng list -u
 
-Create tracing session:
+Create tracing session::
 
     lttng create mysession
 
-Enable events:
+Enable events::
 
     lttng enable-event qemu:g_malloc -u
 
 Where the events can either be a comma-separated list of events, or "-a" to
-enable all tracepoint events. Start and stop tracing as needed:
+enable all tracepoint events. Start and stop tracing as needed::
 
     lttng start
     lttng stop
 
-View the trace:
+View the trace::
 
     lttng view
 
-Destroy tracing session:
+Destroy tracing session::
 
     lttng destroy
 
-Babeltrace can be used at any later time to view the trace:
+Babeltrace can be used at any later time to view the trace::
 
     babeltrace $HOME/lttng-traces/mysession-<date>-<time>
 
-=== SystemTap ===
+SystemTap
+---------
 
 The "dtrace" backend uses DTrace sdt probes but has only been tested with
 SystemTap.  When SystemTap support is detected a .stp file with wrapper probes
 is generated to make use in scripts more convenient.  This step can also be
 performed manually after a build in order to change the binary name in the .stp
-probes:
+probes::
 
     scripts/tracetool.py --backends=dtrace --format=stap \
                          --binary path/to/qemu-binary \
@@ -325,12 +365,14 @@ To facilitate simple usage of systemtap where there merely needs to be printf
 logging of certain probes, a helper script "qemu-trace-stap" is provided.
 Consult its manual page for guidance on its usage.
 
-== Trace event properties ==
+Trace event properties
+======================
 
 Each event in the "trace-events-all" file can be prefixed with a space-separated
 list of zero or more of the following event properties.
 
-=== "disable" ===
+"disable"
+---------
 
 If a specific trace event is going to be invoked a huge number of times, this
 might have a noticeable performance impact even when the event is
@@ -348,6 +390,8 @@ guard such computations, so they are skipped if the event has been either
 compile-time disabled or run-time disabled. If the event is compile-time
 disabled, this check will have no performance impact.
 
+::
+
     #include "trace.h"  /* needed for trace event prototype */
     
     void *qemu_vmalloc(size_t size)
@@ -367,7 +411,8 @@ disabled, this check will have no performance impact.
         return ptr;
     }
 
-=== "tcg" ===
+"tcg"
+-----
 
 Guest code generated by TCG can be traced by defining an event with the "tcg"
 event property. Internally, this property generates two events:
@@ -384,11 +429,11 @@ mix of native and TCG types, and "trace_<eventname>_tcg" will gracefully forward
 them to the "<eventname>_trans" and "<eventname>_exec" events. Since TCG values
 are not known at translation time, these are ignored by the "<eventname>_trans"
 event. Because of this, the entry in the "trace-events" file needs two printing
-formats (separated by a comma):
+formats (separated by a comma)::
 
     tcg foo(uint8_t a1, TCGv_i32 a2) "a1=%d", "a1=%d a2=%d"
 
-For example:
+For example::
 
     #include "trace-tcg.h"
     
@@ -399,15 +444,16 @@ For example:
         trace_foo_tcg(a1, a2);
     }
 
-This will immediately call:
+This will immediately call::
 
     void trace_foo_trans(uint8_t a1);
 
-and will generate the TCG code to call:
+and will generate the TCG code to call::
 
     void trace_foo(uint8_t a1, uint32_t a2);
 
-=== "vcpu" ===
+"vcpu"
+------
 
 Identifies events that trace vCPU-specific information. It implicitly adds a
 "CPUState*" argument, and extends the tracing print format to show the vCPU
@@ -418,13 +464,13 @@ points to the vCPU when guest code is executed (usually the "cpu_env" variable).
 The "tcg" and "vcpu" properties are currently only honored in the root
 ./trace-events file.
 
-The following example events:
+The following example events::
 
     foo(uint32_t a) "a=%x"
     vcpu bar(uint32_t a) "a=%x"
     tcg vcpu baz(uint32_t a) "a=%x", "a=%x"
 
-Can be used as:
+Can be used as::
 
     #include "trace-tcg.h"
     
@@ -442,7 +488,7 @@ Can be used as:
     }
 
 If the translating vCPU has address 0xc1 and code is later executed by vCPU
-0xc2, this would be an example output:
+0xc2, this would be an example output::
 
     // at guest code translation
     foo a=0xd1
diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
index a5ad95ff1b..9d197daca3 100644
--- a/include/qemu/error-report.h
+++ b/include/qemu/error-report.h
@@ -74,7 +74,7 @@ void error_init(const char *argv0);
 
 const char *error_get_progname(void);
 
-extern bool error_with_timestamp;
+extern bool message_with_timestamp;
 extern bool error_with_guestname;
 extern const char *error_guest_name;
 
diff --git a/meson.build b/meson.build
index f00b7754fd..2d8b433ff0 100644
--- a/meson.build
+++ b/meson.build
@@ -1632,6 +1632,31 @@ tracetool = [
   python, files('scripts/tracetool.py'),
    '--backend=' + config_host['TRACE_BACKENDS']
 ]
+tracetool_depends = files(
+  'scripts/tracetool/backend/log.py',
+  'scripts/tracetool/backend/__init__.py',
+  'scripts/tracetool/backend/dtrace.py',
+  'scripts/tracetool/backend/ftrace.py',
+  'scripts/tracetool/backend/simple.py',
+  'scripts/tracetool/backend/syslog.py',
+  'scripts/tracetool/backend/ust.py',
+  'scripts/tracetool/format/tcg_h.py',
+  'scripts/tracetool/format/ust_events_c.py',
+  'scripts/tracetool/format/ust_events_h.py',
+  'scripts/tracetool/format/__init__.py',
+  'scripts/tracetool/format/d.py',
+  'scripts/tracetool/format/tcg_helper_c.py',
+  'scripts/tracetool/format/simpletrace_stap.py',
+  'scripts/tracetool/format/c.py',
+  'scripts/tracetool/format/h.py',
+  'scripts/tracetool/format/tcg_helper_h.py',
+  'scripts/tracetool/format/log_stap.py',
+  'scripts/tracetool/format/stap.py',
+  'scripts/tracetool/format/tcg_helper_wrapper_h.py',
+  'scripts/tracetool/__init__.py',
+  'scripts/tracetool/transform.py',
+  'scripts/tracetool/vcpu.py'
+)
 
 qemu_version_cmd = [find_program('scripts/qemu-version.sh'),
                     meson.current_source_dir(),
@@ -2219,7 +2244,8 @@ foreach target : target_dirs
                         '--target-type=' + target_type,
                         '--probe-prefix=qemu.' + target_type + '.' + target_name,
                         '@INPUT@', '@OUTPUT@'
-                      ])
+                      ],
+                      depend_files: tracetool_depends)
       endforeach
     endif
   endforeach
diff --git a/scripts/simpletrace.py b/scripts/simpletrace.py
index 20f0026066..d61fb0bd87 100755
--- a/scripts/simpletrace.py
+++ b/scripts/simpletrace.py
@@ -174,7 +174,9 @@ def process(events, log, analyzer, read_header=True):
     if read_header:
         read_trace_header(log)
 
-    dropped_event = Event.build("Dropped_Event(uint64_t num_events_dropped)")
+    frameinfo = inspect.getframeinfo(inspect.currentframe())
+    dropped_event = Event.build("Dropped_Event(uint64_t num_events_dropped)",
+                                frameinfo.lineno + 1, frameinfo.filename)
     edict = {"dropped": dropped_event}
     idtoname = {dropped_event_id: "dropped"}
 
diff --git a/scripts/tracetool/backend/log.py b/scripts/tracetool/backend/log.py
index bc43dbb4f4..17ba1cd90e 100644
--- a/scripts/tracetool/backend/log.py
+++ b/scripts/tracetool/backend/log.py
@@ -20,6 +20,7 @@ PUBLIC = True
 
 def generate_h_begin(events, group):
     out('#include "qemu/log-for-trace.h"',
+        '#include "qemu/error-report.h"',
         '')
 
 
@@ -35,14 +36,20 @@ def generate_h(event, group):
         cond = "trace_event_get_state(%s)" % ("TRACE_" + event.name.upper())
 
     out('    if (%(cond)s && qemu_loglevel_mask(LOG_TRACE)) {',
-        '        struct timeval _now;',
-        '        gettimeofday(&_now, NULL);',
+        '        if (message_with_timestamp) {',
+        '            struct timeval _now;',
+        '            gettimeofday(&_now, NULL);',
         '#line %(event_lineno)d "%(event_filename)s"',
-        '        qemu_log("%%d@%%zu.%%06zu:%(name)s " %(fmt)s "\\n",',
-        '                 qemu_get_thread_id(),',
-        '                 (size_t)_now.tv_sec, (size_t)_now.tv_usec',
-        '                 %(argnames)s);',
+        '            qemu_log("%%d@%%zu.%%06zu:%(name)s " %(fmt)s "\\n",',
+        '                     qemu_get_thread_id(),',
+        '                     (size_t)_now.tv_sec, (size_t)_now.tv_usec',
+        '                     %(argnames)s);',
         '#line %(out_next_lineno)d "%(out_filename)s"',
+        '        } else {',
+        '#line %(event_lineno)d "%(event_filename)s"',
+        '            qemu_log("%(name)s " %(fmt)s "\\n"%(argnames)s);',
+        '#line %(out_next_lineno)d "%(out_filename)s"',
+        '        }',
         '    }',
         cond=cond,
         event_lineno=event.lineno,
diff --git a/scripts/tracetool/format/log_stap.py b/scripts/tracetool/format/log_stap.py
index b486beb672..0b6549d534 100644
--- a/scripts/tracetool/format/log_stap.py
+++ b/scripts/tracetool/format/log_stap.py
@@ -54,6 +54,7 @@ def c_fmt_to_stap(fmt):
             else:
                 if state == STATE_MACRO:
                     bits.append(c_macro_to_format(macro))
+                    macro = ""
                 state = STATE_LITERAL
         elif fmt[i] == ' ' or fmt[i] == '\t':
             if state == STATE_MACRO:
@@ -77,7 +78,12 @@ def c_fmt_to_stap(fmt):
     elif state == STATE_LITERAL:
         bits.append(literal)
 
-    fmt = re.sub("%(\d*)z(x|u|d)", "%\\1\\2", "".join(bits))
+    # All variables in systemtap are 64-bit in size
+    # The "%l" integer size qualifier is thus redundant
+    # and "%ll" is not valid at all. Similarly the size_t
+    # based "%z" size qualifier is not valid. We just
+    # strip all size qualifiers for sanity.
+    fmt = re.sub("%(\d*)(l+|z)(x|u|d)", "%\\1\\3", "".join(bits))
     return fmt
 
 def generate(events, backend, group):
diff --git a/softmmu/vl.c b/softmmu/vl.c
index a8876b8965..bd55468669 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -737,7 +737,7 @@ static void realtime_init(void)
 
 static void configure_msg(QemuOpts *opts)
 {
-    error_with_timestamp = qemu_opt_get_bool(opts, "timestamp", false);
+    message_with_timestamp = qemu_opt_get_bool(opts, "timestamp", false);
     error_with_guestname = qemu_opt_get_bool(opts, "guest-name", false);
 }
 
diff --git a/trace/meson.build b/trace/meson.build
index a0be8f9b0d..08f83a15c3 100644
--- a/trace/meson.build
+++ b/trace/meson.build
@@ -12,17 +12,20 @@ foreach dir : [ '.' ] + trace_events_subdirs
   trace_h = custom_target(fmt.format('trace', 'h'),
                           output: fmt.format('trace', 'h'),
                           input: trace_events_file,
-                          command: [ tracetool, group, '--format=h', '@INPUT@', '@OUTPUT@' ])
+                          command: [ tracetool, group, '--format=h', '@INPUT@', '@OUTPUT@' ],
+                          depend_files: tracetool_depends)
   genh += trace_h
   trace_c = custom_target(fmt.format('trace', 'c'),
                           output: fmt.format('trace', 'c'),
                           input: trace_events_file,
-                          command: [ tracetool, group, '--format=c', '@INPUT@', '@OUTPUT@' ])
+                          command: [ tracetool, group, '--format=c', '@INPUT@', '@OUTPUT@' ],
+                          depend_files: tracetool_depends)
   if 'CONFIG_TRACE_UST' in config_host
     trace_ust_h = custom_target(fmt.format('trace-ust', 'h'),
                                 output: fmt.format('trace-ust', 'h'),
                                 input: trace_events_file,
-                                command: [ tracetool, group, '--format=ust-events-h', '@INPUT@', '@OUTPUT@' ])
+                                command: [ tracetool, group, '--format=ust-events-h', '@INPUT@', '@OUTPUT@' ],
+                                depend_files: tracetool_depends)
     trace_ss.add(trace_ust_h, lttng, urcubp)
     genh += trace_ust_h
   endif
@@ -31,7 +34,8 @@ foreach dir : [ '.' ] + trace_events_subdirs
     trace_dtrace = custom_target(fmt.format('trace-dtrace', 'dtrace'),
                                  output: fmt.format('trace-dtrace', 'dtrace'),
                                  input: trace_events_file,
-                                 command: [ tracetool, group, '--format=d', '@INPUT@', '@OUTPUT@' ])
+                                 command: [ tracetool, group, '--format=d', '@INPUT@', '@OUTPUT@' ],
+                                 depend_files: tracetool_depends)
     trace_dtrace_h = custom_target(fmt.format('trace-dtrace', 'h'),
                                    output: fmt.format('trace-dtrace', 'h'),
                                    input: trace_dtrace,
@@ -66,7 +70,8 @@ foreach d : [
   gen = custom_target(d[0],
                 output: d[0],
                 input: meson.source_root() / 'trace-events',
-                command: [ tracetool, '--group=root', '--format=@0@'.format(d[1]), '@INPUT@', '@OUTPUT@' ])
+                command: [ tracetool, '--group=root', '--format=@0@'.format(d[1]), '@INPUT@', '@OUTPUT@' ],
+                depend_files: tracetool_depends)
   specific_ss.add(when: 'CONFIG_TCG', if_true: gen)
 endforeach
 
@@ -74,11 +79,13 @@ if 'CONFIG_TRACE_UST' in config_host
   trace_ust_all_h = custom_target('trace-ust-all.h',
                                   output: 'trace-ust-all.h',
                                   input: trace_events_files,
-                                  command: [ tracetool, '--group=all', '--format=ust-events-h', '@INPUT@', '@OUTPUT@' ])
+                                  command: [ tracetool, '--group=all', '--format=ust-events-h', '@INPUT@', '@OUTPUT@' ],
+                                  depend_files: tracetool_depends)
   trace_ust_all_c = custom_target('trace-ust-all.c',
                                   output: 'trace-ust-all.c',
                                   input: trace_events_files,
-                                  command: [ tracetool, '--group=all', '--format=ust-events-c', '@INPUT@', '@OUTPUT@' ])
+                                  command: [ tracetool, '--group=all', '--format=ust-events-c', '@INPUT@', '@OUTPUT@' ],
+                                  depend_files: tracetool_depends)
   trace_ss.add(trace_ust_all_h, trace_ust_all_c)
   genh += trace_ust_all_h
 endif
diff --git a/util/qemu-error.c b/util/qemu-error.c
index aa30f03564..52a9e013c4 100644
--- a/util/qemu-error.c
+++ b/util/qemu-error.c
@@ -25,7 +25,7 @@ typedef enum {
 } report_type;
 
 /* Prepend timestamp to messages */
-bool error_with_timestamp;
+bool message_with_timestamp;
 bool error_with_guestname;
 const char *error_guest_name;
 
@@ -208,7 +208,7 @@ static void vreport(report_type type, const char *fmt, va_list ap)
     GTimeVal tv;
     gchar *timestr;
 
-    if (error_with_timestamp && !monitor_cur()) {
+    if (message_with_timestamp && !monitor_cur()) {
         g_get_current_time(&tv);
         timestr = g_time_val_to_iso8601(&tv);
         error_printf("%s ", timestr);