Add --loglevel argument for the run command

Add --loglevel command line argument, with the possible values of 'error',
'warning', 'info' or 'debug' to control what messages kvmtool displays. The
argument functions similarly to the Linux kernel parameter, when lower
verbosity levels hide all message with a higher verbosity (for example,
'warning' hides info and debug messages, allows warning and error
messsages).

The default level is 'info', to match the current behaviour. --debug has
been kept as a legacy option, which might be removed in the future.

Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20230707151119.81208-5-alexandru.elisei@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

3 files changed, 44 insertions, 6 deletions

diff --git a/builtin-run.c b/builtin-run.c
index 190a226e..b1a27fda 100644
--- a/builtin-run.c
+++ b/builtin-run.c
@@ -58,8 +58,7 @@
 __thread struct kvm_cpu *current_kvm_cpu;
 
 static int  kvm_run_wrapper;
-
-bool do_debug_print = false;
+int loglevel = LOGLEVEL_INFO;
 
 static const char * const run_usage[] = {
 	"lkvm run [<options>] [<kernel image>]",
@@ -146,6 +145,27 @@ static int mem_parser(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
+static int loglevel_parser(const struct option *opt, const char *arg, int unset)
+{
+	if (strcmp(opt->long_name, "debug") == 0) {
+		loglevel = LOGLEVEL_DEBUG;
+		return 0;
+	}
+
+	if (strcmp(arg, "debug") == 0)
+		loglevel = LOGLEVEL_DEBUG;
+	else if (strcmp(arg, "info") == 0)
+		loglevel = LOGLEVEL_INFO;
+	else if (strcmp(arg, "warning") == 0)
+		loglevel = LOGLEVEL_WARNING;
+	else if (strcmp(arg, "error") == 0)
+		loglevel = LOGLEVEL_ERROR;
+	else
+		die("Unknown loglevel: %s", arg);
+
+	return 0;
+}
+
 #ifndef OPT_ARCH_RUN
 #define OPT_ARCH_RUN(...)
 #endif
@@ -215,6 +235,8 @@ static int mem_parser(const struct option *opt, const char *arg, int unset)
 		     VIRTIO_TRANS_OPT_HELP_SHORT,		        \
 		     "Type of virtio transport",			\
 		     virtio_transport_parser, NULL),			\
+	OPT_CALLBACK('\0', "loglevel", NULL, "[error|warning|info|debug]",\
+			"Set the verbosity level", loglevel_parser, NULL),\
 									\
 	OPT_GROUP("Kernel options:"),					\
 	OPT_STRING('k', "kernel", &(cfg)->kernel_filename, "kernel",	\
@@ -241,8 +263,10 @@ static int mem_parser(const struct option *opt, const char *arg, int unset)
 		     vfio_device_parser, kvm),				\
 									\
 	OPT_GROUP("Debug options:"),					\
-	OPT_BOOLEAN('\0', "debug", &do_debug_print,			\
-			"Enable debug messages"),			\
+	OPT_CALLBACK_NOOPT('\0', "debug", kvm, NULL,			\
+			"Enable debug messages (deprecated, use "	\
+			"--loglevel=debug instead)",			\
+			loglevel_parser, NULL),				\
 	OPT_BOOLEAN('\0', "debug-single-step", &(cfg)->single_step,	\
 			"Enable single stepping"),			\
 	OPT_BOOLEAN('\0', "debug-ioport", &(cfg)->ioport_debug,		\
diff --git a/include/kvm/util.h b/include/kvm/util.h
index 68d568d0..ac8515f8 100644
--- a/include/kvm/util.h
+++ b/include/kvm/util.h
@@ -32,7 +32,10 @@
 #endif
 #endif
 
-extern bool do_debug_print;
+#define LOGLEVEL_ERROR		0
+#define LOGLEVEL_WARNING	1
+#define LOGLEVEL_INFO		2
+#define LOGLEVEL_DEBUG		3
 
 #define PROT_RW (PROT_READ|PROT_WRITE)
 #define MAP_ANON_NORESERVE (MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE)
@@ -45,9 +48,11 @@ extern void pr_info(const char *err, ...) __attribute__((format (printf, 1, 2)))
 extern void __pr_debug(const char *debug, ...) __attribute__((format (printf, 1, 2)));
 extern void set_die_routine(void (*routine)(const char *err, va_list params) NORETURN);
 
+extern int loglevel;
+
 #define pr_debug(fmt, ...)						\
 	do {								\
-		if (do_debug_print)					\
+		if (loglevel >= LOGLEVEL_DEBUG)				\
 			__pr_debug("(%s) %s:%d: " fmt, __FILE__,	\
 				__func__, __LINE__, ##__VA_ARGS__);	\
 	} while (0)
diff --git a/util/util.c b/util/util.c
index 7cf62edc..bab4bb39 100644
--- a/util/util.c
+++ b/util/util.c
@@ -56,6 +56,9 @@ void pr_err(const char *err, ...)
 {
 	va_list params;
 
+	if (loglevel < LOGLEVEL_ERROR)
+		return;
+
 	va_start(params, err);
 	error_builtin(err, params);
 	va_end(params);
@@ -65,6 +68,9 @@ void pr_warning(const char *warn, ...)
 {
 	va_list params;
 
+	if (loglevel < LOGLEVEL_WARNING)
+		return;
+
 	va_start(params, warn);
 	warn_builtin(warn, params);
 	va_end(params);
@@ -74,6 +80,9 @@ void pr_info(const char *info, ...)
 {
 	va_list params;
 
+	if (loglevel < LOGLEVEL_INFO)
+		return;
+
 	va_start(params, info);
 	info_builtin(info, params);
 	va_end(params);