[Qemu-devel] [PATCH 2/2] Add support for generating a systemtap tapset static probes

[Daniel P. Berrange]

From: Daniel P. Berrange <address@hidden>

This introduces generation of a qemu.stp/qemu-system-XXX.stp
files which provides tapsets with friendly names for static
probes & their arguments. Instead of

    probe process("qemu").mark("qemu_malloc") {
        printf("Malloc %d %p\n", $arg1, $arg2);
    }

It is now possible todo

    probe qemu.system.i386.qemu_malloc {
        printf("Malloc %d %p\n", size, ptr);
    }

There is one tapset defined per target arch.

* Makefile: Generate a qemu.stp file for systemtap
* tracetool: Support for generating systemtap tapsets

Signed-off-by: Daniel P. Berrange <address@hidden>
---
 Makefile.target |   19 +++++++++++-
 configure       |    7 ++++
 tracetool       |   92 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 117 insertions(+), 1 deletions(-)

diff --git a/Makefile.target b/Makefile.target
index 91e6e74..a5e6410 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -40,7 +40,20 @@ kvm.o kvm-all.o vhost.o vhost_net.o: 
QEMU_CFLAGS+=$(KVM_CFLAGS)
 config-target.h: config-target.h-timestamp
 config-target.h-timestamp: config-target.mak
 
-all: $(PROGS)
+ifdef CONFIG_SYSTEMTAP_TRACE
+trace: $(QEMU_PROG).stp
+
+$(QEMU_PROG).stp:
+       $(call quiet-command,sh $(SRC_PATH)/tracetool \
+               --$(TRACE_BACKEND) \
+               --bindir $(bindir) \
+               --target $(TARGET_ARCH) \
+               -s < $(SRC_PATH)/trace-events > $(QEMU_PROG).stp,"  GEN   
$(QEMU_PROG).stp")
+else
+trace:
+endif
+
+all: $(PROGS) trace
 
 # Dummy command so that make thinks it has done something
        @true
@@ -348,6 +361,10 @@ ifneq ($(STRIP),)
        $(STRIP) $(patsubst %,"$(DESTDIR)$(bindir)/%",$(PROGS))
 endif
 endif
+ifdef CONFIG_SYSTEMTAP_TRACE
+       $(INSTALL_DIR) "$(DESTDIR)$(datadir)/../systemtap/tapset"
+       $(INSTALL_DATA) $(QEMU_PROG).stp 
"$(DESTDIR)$(datadir)/../systemtap/tapset"
+endif
 
 # Include automatically generated dependency files
 -include $(wildcard *.d */*.d)
diff --git a/configure b/configure
index f8dad3e..e560f87 100755
--- a/configure
+++ b/configure
@@ -2192,6 +2192,10 @@ EOF
     echo
     exit 1
   fi
+  trace_backend_stap="no"
+  if has 'stap' ; then
+    trace_backend_stap="yes"
+  fi
 fi
 
 ##########################################
@@ -2645,6 +2649,9 @@ fi
 if test "$trace_backend" = "simple"; then
   trace_file="\"$trace_file-%u\""
 fi
+if test "$trace_backend" = "dtrace" -a "$trace_backend_stap" = "yes" ; then
+  echo "CONFIG_SYSTEMTAP_TRACE=y" >> $config_host_mak
+fi
 echo "CONFIG_TRACE_FILE=$trace_file" >> $config_host_mak
 
 echo "TOOLS=$tools" >> $config_host_mak
diff --git a/tracetool b/tracetool
index 5b6636a..d797ab7 100755
--- a/tracetool
+++ b/tracetool
@@ -26,6 +26,12 @@ Output formats:
   -h    Generate .h file
   -c    Generate .c file
   -d    Generate .d file (DTrace only)
+  -s    Generate .stp file (DTrace with SystemTAP only)
+
+Options:
+  --bindir [bindir]  QEMU binary install location
+  --target [arch]    QEMU target architecture
+
 EOF
     exit 1
 }
@@ -390,6 +396,54 @@ linetod_end_dtrace()
 EOF
 }
 
+linetos_begin_dtrace()
+{
+    return
+}
+
+linetos_dtrace()
+{
+    local name args arglist state
+    name=$(get_name "$1")
+    args=$(get_args "$1")
+    arglist=$(get_argnames "$1", "")
+    state=$(get_state "$1")
+    if [ "$state" = "0" ] ; then
+        name=${name##disable }
+    fi
+
+    if [ "$target" = "i386" ]
+    then
+      binary="qemu"
+    else
+      binary="qemu-system-$target"
+    fi
+
+    # Define prototype for probe arguments
+    cat <<EOF
+probe qemu.system.$target.$name = process("$bindir/$binary").mark("$name")
+{
+EOF
+
+    i=1
+    for arg in $arglist
+    do
+        cat <<EOF
+  $arg = \$arg$i;
+EOF
+       i="$((i+1))"
+    done
+
+    cat <<EOF
+}
+EOF
+}
+
+linetos_end_dtrace()
+{
+    return
+}
+
 # Process stdin by calling begin, line, and end functions for the backend
 convert()
 {
@@ -455,6 +509,24 @@ tracetod()
     convert d
 }
 
+tracetos()
+{
+    if [ $backend != "dtrace" ]; then
+       echo "SystemTAP tapset generator not applicable to $backend backend"
+       exit 1
+    fi
+    if [ -z "$target" ]; then
+       echo "--target is required for SystemTAP tapset generator"
+       exit 1
+    fi
+    if [ -z "$bindir" ]; then
+       echo "--bindir is required for SystemTAP tapset generator"
+       exit 1
+    fi
+    echo "/* This file is autogenerated by tracetool, do not edit. */"
+    convert s
+}
+
 # Choose backend
 case "$1" in
 "--nop" | "--simple" | "--ust" | "--dtrace") backend="${1#--}" ;;
@@ -462,10 +534,30 @@ case "$1" in
 esac
 shift
 
+bindir=
+case "$1" in
+  "--bindir")
+    bindir=$2
+    shift
+    shift
+    ;;
+esac
+
+target=
+case "$1" in
+  "--target")
+    target=$2
+    shift
+    shift
+    ;;
+esac
+
+
 case "$1" in
 "-h") tracetoh ;;
 "-c") tracetoc ;;
 "-d") tracetod ;;
+"-s") tracetos ;;
 "--check-backend") exit 0 ;; # used by ./configure to test for backend
 *) usage ;;
 esac
-- 
1.7.2.3