[Qemu-devel] [PATCH v5 2/2] trace: Add 'vcpu' event property to trace guest vCPU

[Lluís Vilanova]

This property identifies events that trace vCPU-specific information.

It adds a "CPUState*" argument to events with the property, identifying
the vCPU raising the event. TCG translation events also have a
"TCGv_cpu" implicit argument that is later used as the "CPUState*"
argument at execution time.

Signed-off-by: Lluís Vilanova <address@hidden>
---
 docs/tracing.txt                         |   40 ++++++++++++++++++++++++++++++
 scripts/tracetool/__init__.py            |   24 +++++++++++++++++-
 scripts/tracetool/format/h.py            |    3 ++
 scripts/tracetool/format/tcg_h.py        |   13 ++++++++--
 scripts/tracetool/format/ust_events_c.py |    1 +
 5 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/docs/tracing.txt b/docs/tracing.txt
index 3853a6a..ade39e0 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -347,3 +347,43 @@ This will immediately call:
 and will generate the TCG code to call:
 
     void trace_foo(uint8_t a1, uint32_t a2);
+
+=== "vcpu" ===
+
+Identifies events that trace vCPU-specific information. The property adds a
+"CPUState*" argument that identifies the vCPU raising the event. If used
+together with the "tcg" property, it adds a second "TCGv_cpu" argument that
+identifies the vCPU when guest code is executed.
+
+The following example events:
+
+    foo(uint32_t a) "a=%x"
+    vcpu bar(uint32_t a) "cpu=%p a=%x"
+    tcg vcpu baz(uint32_t a) "cpu=%p a=%x", "cpu=%p a=%x"
+
+Can be used as:
+
+    #include "trace-tcg.h"
+    
+    CPUArchState *env;
+    TCGv_ptr cpu_env;
+    
+    void some_disassembly_func(...)
+    {
+        /* trace emitted at this point */
+        trace_foo(0xd1);
+        /* trace emitted at this point */
+        trace_bar(ENV_GET_CPU(env), 0xd2);
+        /* trace emitted at this point (env) and when guest code is executed 
(cpu_env) */
+        trace_baz_tcg(ENV_GET_CPU(env), cpu_env, 0xd3);
+    }
+
+If we assume code is translated by the vCPU with address 0xc1 and executed by
+the vCPU with address 0xc2, this would be an example output:
+
+    // at guest code translation
+    foo a=0xd1
+    bar cpu=0xc1 a=0xd2
+    baz_trans cpu=0xc1 a=0xd3
+    // at guest code execution
+    baz_exec cpu=0xc2 a=0xd3
diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
index 181675f..41feb23 100644
--- a/scripts/tracetool/__init__.py
+++ b/scripts/tracetool/__init__.py
@@ -6,7 +6,7 @@ Machinery for generating tracing-related intermediate files.
 """
 
 __author__     = "Lluís Vilanova <address@hidden>"
-__copyright__  = "Copyright 2012-2014, Lluís Vilanova <address@hidden>"
+__copyright__  = "Copyright 2012-2016, Lluís Vilanova <address@hidden>"
 __license__    = "GPL version 2 or (at your option) any later version"
 
 __maintainer__ = "Stefan Hajnoczi"
@@ -146,7 +146,7 @@ class Event(object):
                       "(?:(?:(?P<fmt_trans>\".+),)?\s*(?P<fmt>\".+))?"
                       "\s*")
 
-    _VALID_PROPS = set(["disable", "tcg", "tcg-trans", "tcg-exec"])
+    _VALID_PROPS = set(["disable", "tcg", "tcg-trans", "tcg-exec", "vcpu"])
 
     def __init__(self, name, props, fmt, args, orig=None):
         """
@@ -215,6 +215,19 @@ class Event(object):
         if "tcg" in props and isinstance(fmt, str):
             raise ValueError("Events with 'tcg' property must have two 
formats")
 
+        # add implicit arguments when using the 'vcpu' property
+        if "vcpu" in props:
+            assert "tcg-trans" not in props and "tcg-exec" not in props
+            # events with 'tcg-trans' and 'tcg-exec' are auto-generated, they
+            # have already been transformed
+            if "tcg" in props:
+                types = ["TCGv_cpu"] + args.types()
+                names = ["_tcg_cpu"] + args.names()
+            else:
+                types = ["CPUState *"] + args.types()
+                names = ["_cpu"] + args.names()
+            args = Arguments(zip(types, names))
+
         return Event(name, props, fmt, args)
 
     def __repr__(self):
@@ -270,6 +283,7 @@ def _read_events(fobj):
             event_trans.name += "_trans"
             event_trans.properties += ["tcg-trans"]
             event_trans.fmt = event.fmt[0]
+            # ignore TCG arguments
             args_trans = []
             for atrans, aorig in zip(
                     event_trans.transform(tracetool.transform.TCG_2_HOST).args,
@@ -279,6 +293,12 @@ def _read_events(fobj):
             event_trans.args = Arguments(args_trans)
             event_trans = event_trans.copy()
 
+            # trace the vCPU performing the translation
+            if "vcpu" in event_trans.properties:
+                event_trans.args = Arguments(zip(
+                    ["CPUState *"] + list(event_trans.args.types()),
+                    ["_cpu"] + list(event_trans.args.names())))
+
             event_exec = event.copy()
             event_exec.name += "_exec"
             event_exec.properties += ["tcg-exec"]
diff --git a/scripts/tracetool/format/h.py b/scripts/tracetool/format/h.py
index 9b39430..2bd68a2 100644
--- a/scripts/tracetool/format/h.py
+++ b/scripts/tracetool/format/h.py
@@ -6,7 +6,7 @@ trace/generated-tracers.h
 """
 
 __author__     = "Lluís Vilanova <address@hidden>"
-__copyright__  = "Copyright 2012-2014, Lluís Vilanova <address@hidden>"
+__copyright__  = "Copyright 2012-2016, Lluís Vilanova <address@hidden>"
 __license__    = "GPL version 2 or (at your option) any later version"
 
 __maintainer__ = "Stefan Hajnoczi"
@@ -23,6 +23,7 @@ def generate(events, backend):
         '#define TRACE__GENERATED_TRACERS_H',
         '',
         '#include "qemu-common.h"',
+        '#include "qemu/typedefs.h"',
         '')
 
     backend.generate_begin(events)
diff --git a/scripts/tracetool/format/tcg_h.py 
b/scripts/tracetool/format/tcg_h.py
index f676b66..acaa963 100644
--- a/scripts/tracetool/format/tcg_h.py
+++ b/scripts/tracetool/format/tcg_h.py
@@ -6,14 +6,14 @@ Generate .h file for TCG code generation.
 """
 
 __author__     = "Lluís Vilanova <address@hidden>"
-__copyright__  = "Copyright 2012-2014, Lluís Vilanova <address@hidden>"
+__copyright__  = "Copyright 2012-2016, Lluís Vilanova <address@hidden>"
 __license__    = "GPL version 2 or (at your option) any later version"
 
 __maintainer__ = "Stefan Hajnoczi"
 __email__      = "address@hidden"
 
 
-from tracetool import out
+from tracetool import out, Arguments
 
 
 def generate(events, backend):
@@ -38,10 +38,17 @@ def generate(events, backend):
         # get the original event definition
         e = e.original.original
 
+        if "vcpu" in e.properties:
+            args_api = Arguments(zip(
+                ["CPUState *"] + e.args.types(),
+                ["_cpu"] + e.args.names()))
+        else:
+            args_api = e.args
+
         out('static inline void %(name_tcg)s(%(args)s)',
             '{',
             name_tcg=e.api(e.QEMU_TRACE_TCG),
-            args=e.args)
+            args=args_api)
 
         if "disable" not in e.properties:
             out('    %(name_trans)s(%(argnames_trans)s);',
diff --git a/scripts/tracetool/format/ust_events_c.py 
b/scripts/tracetool/format/ust_events_c.py
index bc97093..ecb1f23 100644
--- a/scripts/tracetool/format/ust_events_c.py
+++ b/scripts/tracetool/format/ust_events_c.py
@@ -30,4 +30,5 @@ def generate(events, backend):
         ' */',
         '#pragma GCC diagnostic ignored "-Wredundant-decls"',
         '',
+        '#include "qemu/typedefs.h"',
         '#include "generated-ust-provider.h"')