inital commit

CMakeLists.txt

@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.20)
+
+project(vrmode C)
+
+set(CMAKE_C_STANDARD 17)
+set(SRC_FILES main.c)
+set(LIBS -lnuma)
+
+add_executable(${PROJECT_NAME} ${SRC_FILES})
+target_link_libraries(${PROJECT_NAME} ${LIBS})
+install(TARGETS ${PROJECT_NAME} RUNTIME DESTINATION bin PERMISSIONS WORLD_EXECUTE WORLD_READ SETUID)

main.c

@@ -0,0 +1,185 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <numa.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+
+pid_t child_pid;
+
+const char* drm_sysfs_path = "/sys/class/drm";
+const char* rx6800xt_id = "fd4107589d5b1bb0\n";
+const char* auto_str = "auto\n";
+const char* manual_str = "manual\n";
+
+void sig_handler(int sig)
+{
+	if(child_pid != 0)
+		kill(child_pid, sig);
+}
+
+int find_gpu(const char* id)
+{
+	char path[255];
+	int i;
+
+	for(i = 0; i < 9; ++i)
+	{
+		snprintf(path, sizeof(path), "%s/card%i/device/unique_id", drm_sysfs_path, i);
+		if(access(path, F_OK) == 0)
+		{
+			char id[255] = {};
+			int id_fd = open(path, O_RDONLY);
+			if(id_fd < 0)
+				continue;
+			read(id_fd, id, sizeof(id)-1);
+			close(id_fd);
+
+			if(strcmp(id, rx6800xt_id) == 0)
+			{
+				snprintf(path, sizeof(path), "%s/card%i/device/power_dpm_force_performance_level", drm_sysfs_path, i);
+				int fd = open(path, O_RDONLY);
+				return i;
+			}
+		}
+	}
+	return -1;
+}
+
+bool set_gpu_mode(const char* level, const char* mode, int card)
+{
+	char path[255];
+
+	snprintf(path, sizeof(path), "%s/card%i/device/power_dpm_force_performance_level", drm_sysfs_path, card);
+	int level_fd = open(path, O_WRONLY);
+	if(level_fd < 0)
+	{
+		printf("Unable to open %s: %s\n", path, strerror(errno));
+		return false;
+	}
+	int ret = write(level_fd, level, strlen(level));
+	close(level_fd);
+	if(ret != strlen(level))
+	{
+		printf("Unable to write %s to %s: %s\n", level, path, strerror(errno));
+		return false;
+	}
+
+	snprintf(path, sizeof(path), "%s/card%i/device/pp_power_profile_mode", drm_sysfs_path, card);
+	int mode_fd = open(path, O_WRONLY);
+	if(mode_fd < 0)
+	{
+		printf("Unable to open %s: %s\n", path, strerror(errno));
+		return false;
+	}
+	ret = write(mode_fd, mode, strlen(mode));
+	close(mode_fd);
+	if(ret != strlen(mode))
+	{
+		printf("Unable to write %s to %s: %s\n", level, path, strerror(errno));
+		return false;
+	}
+	return true;
+}
+
+bool enable_vr_mode()
+{
+	int card = find_gpu(rx6800xt_id);
+
+	return set_gpu_mode(manual_str, "4\n", card);
+}
+
+void disable_vr_mode()
+{
+	int card = find_gpu(rx6800xt_id);
+	set_gpu_mode(auto_str, "0\n", card);
+}
+
+int main(int argc, char** argv)
+{
+	uid_t user = getuid();
+	uid_t effective_user = geteuid();
+	printf("User id %u, effective user %u\n", user, effective_user);
+
+	for(int i = 1; i < _NSIG; ++i)
+		signal(i, &sig_handler);
+
+	if(argc < 3)
+	{
+		printf("Usage: %s [base_numa_node] [command] [options...]\n", argv[0]);
+		return 1;
+	}
+
+	if(!enable_vr_mode())
+		return 1;
+
+	child_pid = fork();
+	if(child_pid == 0)
+	{
+		/*int ret = setpriority(PRIO_PROCESS, 0, -20);
+		if(ret)
+		{
+			printf("Warning: Cant set process priority\n");
+		}*/
+
+		int ret = setuid(user);
+		if(ret)
+		{
+			printf("Unable to setuid\n");
+			return 1;
+		}
+
+		ret = numa_available();
+		if(ret < 0)
+		{
+			printf("Warning: NUMA not available\n");
+		}
+		else
+		{
+			int requested_node = atoi(argv[1]);
+			if(numa_max_node() < requested_node+1)
+			{
+				printf("Numa nodes %i and %i requested, but only %i nodes available\n", requested_node, requested_node+1, numa_max_node()+1);
+				return 1;
+			}
+
+			struct bitmask* nodes = numa_allocate_nodemask();
+			numa_bitmask_setbit(nodes, requested_node);
+			numa_bitmask_setbit(nodes, requested_node+1);
+			printf("Using numa mask: ");
+			for(size_t i = 0; i < numa_max_node()+1; ++i)
+				printf("%i, ", numa_bitmask_isbitset(nodes, i));
+			putc('\n', stdout);
+			numa_bind(nodes);
+			numa_free_nodemask(nodes);
+		}
+
+		ret = execvp(argv[2], argv+2);
+		if(ret)
+		{
+			printf("Unable to exec %s: %s\n", argv[2], strerror(errno));
+			return 1;
+		}
+	}
+	else if(child_pid < 0)
+	{
+		printf("Unable to fork: %s\n", strerror(errno));
+		disable_vr_mode();
+		return 1;
+	}
+	else
+	{
+		int ret;
+		waitpid(child_pid, &ret, 0);
+		printf("Exiting vr mode\n");
+		disable_vr_mode();
+		return ret;
+	}
+
+	return 0;
+}