[Qemu-devel] [PATCH v7 5/9] qemu-log: new option -dfilter to limit output

[Alex Bennée]

When debugging big programs or system emulation sometimes you want both
the verbosity of cpu,exec et all but don't want to generate lots of logs
for unneeded stuff. This patch adds a new option -dfilter which allows
you to specify interesting address ranges in the form:

  -dfilter 0x8000..0x9000,0xffffffc000080000+0x200,...

Then logging code can use the new qemu_log_in_addr_range() function to
decide if it will output logging information for the given range.

Signed-off-by: Alex Bennée <address@hidden>

---

v2
  - More clean-ups to the documentation
v3
  - re-base
  - use GArray instead of GList to avoid cache bouncing
  - checkpatch fixes
v5
  - minor re-base conflicts
  - *did not* convert to -d dfilter=x fmt as easier to document
  - strtoul -> qemu_strtoul
  - fix a few checkpatch spacing warnings
  - made range operator .., - now intuitively subtracts from start
  - no added r-b tag as changes a bit
v6
  - make parsing suck less (stroull, strstr, err)
  - add some basic unit tests
---
 include/qemu/log.h   |  2 ++
 qemu-options.hx      | 18 +++++++++++
 tests/Makefile       |  4 +++
 tests/test-logging.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++
 util/log.c           | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 vl.c                 |  3 ++
 6 files changed, 187 insertions(+)
 create mode 100644 tests/test-logging.c

diff --git a/include/qemu/log.h b/include/qemu/log.h
index 22c4dec..c0225e1 100644
--- a/include/qemu/log.h
+++ b/include/qemu/log.h
@@ -132,6 +132,8 @@ static inline void qemu_set_log(int log_flags)
 }
 
 void qemu_set_log_filename(const char *filename);
+void qemu_set_dfilter_ranges(const char *ranges);
+bool qemu_log_in_addr_range(uint64_t addr);
 int qemu_str_to_log_mask(const char *str);
 
 /* Print a usage message listing all the valid logging categories
diff --git a/qemu-options.hx b/qemu-options.hx
index 2f0465e..c7e0486 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3094,6 +3094,24 @@ STEXI
 Output log in @var{logfile} instead of to stderr
 ETEXI
 
+DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \
+    "-dfilter range,..  filter debug output to range of addresses (useful for 
-d cpu,exec,etc..)\n",
+    QEMU_ARCH_ALL)
+STEXI
address@hidden -dfilter @var{range1}[,...]
address@hidden -dfilter
+Filter debug output to that relevant to a range of target addresses. The filter
+spec can be either @address@hidden, @address@hidden or
address@hidden@var{end} where @var{start} @var{end} and @var{size} are the
+addresses and sizes required. For example:
address@hidden
+    -dfilter 0x8000..0x9000,0xffffffc000080000+0x200,0xffffffc000060000-0x1000
address@hidden example
+Will dump output for any code in the 0x1000 sized block starting at 0x8000 and
+the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized
+block starting at 0xffffffc00005f000.
+ETEXI
+
 DEF("L", HAS_ARG, QEMU_OPTION_L, \
     "-L path         set the directory for the BIOS, VGA BIOS and keymaps\n",
     QEMU_ARCH_ALL)
diff --git a/tests/Makefile b/tests/Makefile
index 04e34b5..63e90e6 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -92,6 +92,8 @@ check-unit-$(CONFIG_GNUTLS) += 
tests/test-io-channel-tls$(EXESUF)
 check-unit-y += tests/test-io-channel-command$(EXESUF)
 check-unit-y += tests/test-io-channel-buffer$(EXESUF)
 check-unit-y += tests/test-base64$(EXESUF)
+gcov-files-test-logging-y = tests/test-logging.c
+check-unit-y += tests/test-logging$(EXESUF)
 
 check-block-$(CONFIG_POSIX) += tests/qemu-iotests-quick.sh
 
@@ -432,6 +434,8 @@ tests/test-timed-average$(EXESUF): 
tests/test-timed-average.o qemu-timer.o \
 tests/test-base64$(EXESUF): tests/test-base64.o \
        libqemuutil.a libqemustub.a
 
+tests/test-logging$(EXESUF): tests/test-logging.o $(test-util-obj-y)
+
 tests/test-qapi-types.c tests/test-qapi-types.h :\
 $(SRC_PATH)/tests/qapi-schema/qapi-schema-test.json 
$(SRC_PATH)/scripts/qapi-types.py $(qapi-py)
        $(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-types.py \
diff --git a/tests/test-logging.c b/tests/test-logging.c
new file mode 100644
index 0000000..c2dae49
--- /dev/null
+++ b/tests/test-logging.c
@@ -0,0 +1,75 @@
+/*
+ * logging unit-tests
+ *
+ * Copyright (C) 2016 Linaro Ltd.
+ *
+ *  Author: Alex Bennée <address@hidden>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to 
deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <glib.h>
+
+#include "qemu-common.h"
+#include "include/qemu/log.h"
+
+static void test_parse_range(void)
+{
+    qemu_set_dfilter_ranges("0x1000+0x100");
+
+    g_assert_false(qemu_log_in_addr_range(0xfff));
+    g_assert(qemu_log_in_addr_range(0x1000));
+    g_assert(qemu_log_in_addr_range(0x1100));
+    g_assert_false(qemu_log_in_addr_range(0x1101));
+
+    qemu_set_dfilter_ranges("0x1000-0x100");
+
+    g_assert_false(qemu_log_in_addr_range(0x1001));
+    g_assert(qemu_log_in_addr_range(0x1000));
+    g_assert(qemu_log_in_addr_range(0x0f00));
+    g_assert_false(qemu_log_in_addr_range(0x0e99));
+
+    qemu_set_dfilter_ranges("0x1000..0x1100");
+
+    g_assert_false(qemu_log_in_addr_range(0xfff));
+    g_assert(qemu_log_in_addr_range(0x1000));
+    g_assert(qemu_log_in_addr_range(0x1100));
+    g_assert_false(qemu_log_in_addr_range(0x1101));
+
+    qemu_set_dfilter_ranges("0x1000..0x1000");
+
+    g_assert_false(qemu_log_in_addr_range(0xfff));
+    g_assert(qemu_log_in_addr_range(0x1000));
+    g_assert_false(qemu_log_in_addr_range(0x1001));
+
+    qemu_set_dfilter_ranges("0x1000+0x100,0x2100-0x100,0x3000..0x3100");
+    g_assert(qemu_log_in_addr_range(0x1050));
+    g_assert(qemu_log_in_addr_range(0x2050));
+    g_assert(qemu_log_in_addr_range(0x3050));
+
+}
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+
+    g_test_add_func("/logging/parse_range", test_parse_range);
+
+    return g_test_run();
+}
diff --git a/util/log.c b/util/log.c
index c89b226..bd4a660 100644
--- a/util/log.c
+++ b/util/log.c
@@ -20,12 +20,14 @@
 #include "qemu/osdep.h"
 #include "qemu-common.h"
 #include "qemu/log.h"
+#include "qemu/range.h"
 #include "trace/control.h"
 
 static char *logfilename;
 FILE *qemu_logfile;
 int qemu_loglevel;
 static int log_append = 0;
+static GArray *debug_regions;
 
 void qemu_log(const char *fmt, ...)
 {
@@ -84,6 +86,89 @@ void qemu_set_log_filename(const char *filename)
     qemu_set_log(qemu_loglevel);
 }
 
+/* Returns true if addr is in our debug filter or no filter defined
+ */
+bool qemu_log_in_addr_range(uint64_t addr)
+{
+    if (debug_regions) {
+        int i = 0;
+        for (i = 0; i < debug_regions->len; i++) {
+            struct Range *range = &g_array_index(debug_regions, Range, i);
+            if (addr >= range->begin && addr <= range->end) {
+                return true;
+            }
+        }
+        return false;
+    } else {
+        return true;
+    }
+}
+
+
+void qemu_set_dfilter_ranges(const char *filter_spec)
+{
+    gchar **ranges = g_strsplit(filter_spec, ",", 0);
+    if (ranges) {
+        gchar **next = ranges;
+        gchar *r = *next++;
+        debug_regions = g_array_sized_new(FALSE, FALSE,
+                                          sizeof(Range), 
g_strv_length(ranges));
+        while (r) {
+            char *range_op = strstr(r, "-");
+            char *r2 = range_op ? range_op + 1 : NULL;
+            if (!range_op) {
+                range_op = strstr(r, "+");
+                r2 = range_op ? range_op + 1 : NULL;
+            }
+            if (!range_op) {
+                range_op = strstr(r, "..");
+                r2 = range_op ? range_op + 2 : NULL;
+            }
+            if (range_op) {
+                struct Range range;
+                int err;
+                const char *e = NULL;
+
+                err = qemu_strtoull(r, &e, 0, &range.begin);
+
+                g_assert(e == range_op);
+
+                switch (*range_op) {
+                case '+':
+                {
+                    unsigned long len;
+                    err |= qemu_strtoull(r2, NULL, 0, &len);
+                    range.end = range.begin + len;
+                    break;
+                }
+                case '-':
+                {
+                    unsigned long len;
+                    err |= qemu_strtoull(r2, NULL, 0, &len);
+                    range.end = range.begin;
+                    range.begin = range.end - len;
+                    break;
+                }
+                case '.':
+                    err |= qemu_strtoull(r2, NULL, 0, &range.end);
+                    break;
+                default:
+                    g_assert_not_reached();
+                }
+                if (err) {
+                    g_error("Failed to parse range in: %s", r);
+                } else {
+                    g_array_append_val(debug_regions, range);
+                }
+            } else {
+                g_error("Bad range specifier in: %s", r);
+            }
+            r = *next++;
+        }
+        g_strfreev(ranges);
+    }
+}
+
 const QEMULogItem qemu_log_items[] = {
     { CPU_LOG_TB_OUT_ASM, "out_asm",
       "show generated host assembly code for each compiled TB" },
diff --git a/vl.c b/vl.c
index b87e292..753afb1 100644
--- a/vl.c
+++ b/vl.c
@@ -3353,6 +3353,9 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_D:
                 log_file = optarg;
                 break;
+            case QEMU_OPTION_DFILTER:
+                qemu_set_dfilter_ranges(optarg);
+                break;
             case QEMU_OPTION_s:
                 add_device_config(DEV_GDB, "tcp::" DEFAULT_GDBSTUB_PORT);
                 break;
-- 
2.7.1