From 6588b8845e7387438d4b91ea86e7cb6d838b3108 Mon Sep 17 00:00:00 2001
From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Date: Fri, 16 Jan 2026 15:30:23 -0800
Subject: [PATCH] tools/power/x86/intel-speed-select: Allow non root users

When permitted by the file /dev/isst_interface, allow to issue commands
for non root users.

When user id is non root, check if  "/dev/isst_interface" can still be
opened. If this file can be opened, allow all read only commands.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 .../x86/intel-speed-select/isst-config.c      | 39 ++++++++++++++++++-
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/tools/power/x86/intel-speed-select/isst-config.c b/tools/power/x86/intel-speed-select/isst-config.c
index 558138eea75e9..807feb17bb817 100644
--- a/tools/power/x86/intel-speed-select/isst-config.c
+++ b/tools/power/x86/intel-speed-select/isst-config.c
@@ -80,6 +80,18 @@ struct cpu_topology {
 	short die_id;
 };
 
+static int read_only;
+
+static void check_privilege(void)
+{
+	if (!read_only)
+		return;
+
+	isst_display_error_info_message(1, "Insufficient privileges", 0, 0);
+	isst_ctdp_display_information_end(outf);
+	exit(1);
+}
+
 FILE *get_output_file(void)
 {
 	return outf;
@@ -1578,6 +1590,8 @@ free_mask:
 
 static void set_tdp_level(int arg)
 {
+	check_privilege();
+
 	if (cmd_help) {
 		fprintf(stderr, "Set Config TDP level\n");
 		fprintf(stderr,
@@ -2046,6 +2060,8 @@ static void set_pbf_enable(int arg)
 {
 	int enable = arg;
 
+	check_privilege();
+
 	if (cmd_help) {
 		if (enable) {
 			fprintf(stderr,
@@ -2212,6 +2228,8 @@ static void set_fact_enable(int arg)
 	int i, ret, enable = arg;
 	struct isst_id id;
 
+	check_privilege();
+
 	if (cmd_help) {
 		if (enable) {
 			fprintf(stderr,
@@ -2361,6 +2379,8 @@ static void set_clos_enable(int arg)
 {
 	int enable = arg;
 
+	check_privilege();
+
 	if (cmd_help) {
 		if (enable) {
 			fprintf(stderr,
@@ -2491,6 +2511,8 @@ static void set_clos_config_for_cpu(struct isst_id *id, void *arg1, void *arg2,
 
 static void set_clos_config(int arg)
 {
+	check_privilege();
+
 	if (cmd_help) {
 		fprintf(stderr,
 			"Set core-power configuration for one of the four clos ids\n");
@@ -2556,6 +2578,8 @@ static void set_clos_assoc_for_cpu(struct isst_id *id, void *arg1, void *arg2, v
 
 static void set_clos_assoc(int arg)
 {
+	check_privilege();
+
 	if (cmd_help) {
 		fprintf(stderr, "Associate a clos id to a CPU\n");
 		fprintf(stderr,
@@ -2637,6 +2661,8 @@ static void set_turbo_mode(int arg)
 	int i, disable = arg;
 	struct isst_id id;
 
+	check_privilege();
+
 	if (cmd_help) {
 		if (disable)
 			fprintf(stderr, "Set turbo mode disable\n");
@@ -2682,6 +2708,7 @@ static void get_set_trl(struct isst_id *id, void *arg1, void *arg2, void *arg3,
 	}
 
 	if (set) {
+		check_privilege();
 		ret = isst_set_trl(id, fact_trl);
 		isst_display_result(id, outf, "turbo-mode", "set-trl", ret);
 		return;
@@ -3204,8 +3231,16 @@ static void cmdline(int argc, char **argv)
 	};
 
 	if (geteuid() != 0) {
-		fprintf(stderr, "Must run as root\n");
-		exit(0);
+		int fd;
+
+		fd = open(pathname, O_RDWR);
+		if (fd < 0) {
+			fprintf(stderr, "Must run as root\n");
+			exit(0);
+		}
+		fprintf(stderr, "\nNot running as root, Only read only operations are supported\n");
+		close(fd);
+		read_only = 1;
 	}
 
 	ret = update_cpu_model();
-- 
2.47.3