linux-user/main: support dfilter

This adds the -dfilter support to linux-user. There is a minor
checkpatch complaint about formatting which I've ignored for aesthetic
reasons.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

linux-user/main.c

@@ -3869,6 +3869,11 @@ static void handle_arg_log(const char *arg)
     qemu_set_log(mask);
 }
 
+static void handle_arg_dfilter(const char *arg)
+{
+    qemu_set_dfilter_ranges(arg, NULL);
+}
+
 static void handle_arg_log_filename(const char *arg)
 {
     qemu_set_log_filename(arg, &error_fatal);
@@ -4066,6 +4071,8 @@ static const struct qemu_argument arg_table[] = {
     {"d",          "QEMU_LOG",         true,  handle_arg_log,
      "item[,...]", "enable logging of specified items "
      "(use '-d help' for a list of items)"},
+    {"dfilter",    "QEMU_DFILTER",     true,  handle_arg_dfilter,
+     "range[,...]","filter logging based on address range"},
     {"D",          "QEMU_LOG_FILENAME", true, handle_arg_log_filename,
      "logfile",     "write logs to 'logfile' (default stderr)"},
     {"p",          "QEMU_PAGESIZE",    true,  handle_arg_pagesize,