1 /*
2 * QEMU KVM support -- x86 virtual RAPL msr
3 *
4 * Copyright 2024 Red Hat, Inc. 2024
5 *
6 * Author:
7 * Anthony Harivel <aharivel@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
11 *
12 */
13
14 #include "qemu/osdep.h"
15 #include "qemu/error-report.h"
16 #include "vmsr_energy.h"
17 #include "io/channel.h"
18 #include "io/channel-socket.h"
19 #include "hw/boards.h"
20 #include "cpu.h"
21 #include "host-cpu.h"
22
vmsr_compute_default_paths(void)23 char *vmsr_compute_default_paths(void)
24 {
25 g_autofree char *state = qemu_get_local_state_dir();
26
27 return g_build_filename(state, "run", "qemu-vmsr-helper.sock", NULL);
28 }
29
is_rapl_enabled(void)30 int is_rapl_enabled(void)
31 {
32 const char *path = "/sys/class/powercap/intel-rapl/enabled";
33 FILE *file = fopen(path, "r");
34 int value = 0;
35
36 if (file != NULL) {
37 if (fscanf(file, "%d", &value) != 1) {
38 error_report("INTEL RAPL not enabled");
39 }
40 fclose(file);
41 } else {
42 error_report("Error opening %s", path);
43 }
44
45 return value;
46 }
47
vmsr_open_socket(const char * path)48 QIOChannelSocket *vmsr_open_socket(const char *path)
49 {
50 g_autofree char *socket_path = NULL;
51
52 socket_path = g_strdup(path);
53
54 SocketAddress saddr = {
55 .type = SOCKET_ADDRESS_TYPE_UNIX,
56 .u.q_unix.path = socket_path
57 };
58
59 QIOChannelSocket *sioc = qio_channel_socket_new();
60
61 qio_channel_set_name(QIO_CHANNEL(sioc), "vmsr-helper");
62 if (qio_channel_socket_connect_sync(sioc, &saddr, NULL) < 0) {
63 /* Close socket. */
64 qio_channel_close(QIO_CHANNEL(sioc), NULL);
65 object_unref(OBJECT(sioc));
66 sioc = NULL;
67 goto out;
68 }
69
70 qio_channel_set_delay(QIO_CHANNEL(sioc), false);
71 out:
72 return sioc;
73 }
74
vmsr_read_msr(uint32_t reg,uint32_t cpu_id,uint32_t tid,QIOChannelSocket * sioc)75 uint64_t vmsr_read_msr(uint32_t reg, uint32_t cpu_id, uint32_t tid,
76 QIOChannelSocket *sioc)
77 {
78 uint64_t data = 0;
79 int r = 0;
80 Error *local_err = NULL;
81 uint32_t buffer[3];
82 /*
83 * Send the required arguments:
84 * 1. RAPL MSR register to read
85 * 2. On which CPU ID
86 * 3. From which vCPU (Thread ID)
87 */
88 buffer[0] = reg;
89 buffer[1] = cpu_id;
90 buffer[2] = tid;
91
92 r = qio_channel_write_all(QIO_CHANNEL(sioc),
93 (char *)buffer, sizeof(buffer),
94 &local_err);
95 if (r < 0) {
96 goto out_close;
97 }
98
99 r = qio_channel_read(QIO_CHANNEL(sioc),
100 (char *)&data, sizeof(data),
101 &local_err);
102 if (r < 0) {
103 data = 0;
104 goto out_close;
105 }
106
107 out_close:
108 return data;
109 }
110
111 /* Retrieve the max number of physical package */
vmsr_get_max_physical_package(unsigned int max_cpus)112 unsigned int vmsr_get_max_physical_package(unsigned int max_cpus)
113 {
114 const char *dir = "/sys/devices/system/cpu/";
115 const char *topo_path = "topology/physical_package_id";
116 g_autofree int *uniquePackages = g_new0(int, max_cpus);
117 unsigned int packageCount = 0;
118 FILE *file = NULL;
119
120 for (int i = 0; i < max_cpus; i++) {
121 g_autofree char *filePath = NULL;
122 g_autofree char *cpuid = g_strdup_printf("cpu%d", i);
123
124 filePath = g_build_filename(dir, cpuid, topo_path, NULL);
125
126 file = fopen(filePath, "r");
127
128 if (file == NULL) {
129 error_report("Error opening physical_package_id file");
130 return 0;
131 }
132
133 char packageId[10];
134 if (fgets(packageId, sizeof(packageId), file) == NULL) {
135 packageCount = 0;
136 }
137
138 fclose(file);
139
140 int currentPackageId = atoi(packageId);
141
142 bool isUnique = true;
143 for (int j = 0; j < packageCount; j++) {
144 if (uniquePackages[j] == currentPackageId) {
145 isUnique = false;
146 break;
147 }
148 }
149
150 if (isUnique) {
151 uniquePackages[packageCount] = currentPackageId;
152 packageCount++;
153
154 if (packageCount >= max_cpus) {
155 break;
156 }
157 }
158 }
159
160 return (packageCount == 0) ? 1 : packageCount;
161 }
162
163 /* Retrieve the max number of physical cpu on the host */
vmsr_get_maxcpus(void)164 unsigned int vmsr_get_maxcpus(void)
165 {
166 GDir *dir;
167 const gchar *entry_name;
168 unsigned int cpu_count = 0;
169 const char *path = "/sys/devices/system/cpu/";
170
171 dir = g_dir_open(path, 0, NULL);
172 if (dir == NULL) {
173 error_report("Unable to open cpu directory");
174 return -1;
175 }
176
177 while ((entry_name = g_dir_read_name(dir)) != NULL) {
178 if (g_ascii_strncasecmp(entry_name, "cpu", 3) == 0 &&
179 isdigit(entry_name[3])) {
180 cpu_count++;
181 }
182 }
183
184 g_dir_close(dir);
185
186 return cpu_count;
187 }
188
189 /* Count the number of physical cpu on each packages */
vmsr_count_cpus_per_package(unsigned int * package_count,unsigned int max_pkgs)190 unsigned int vmsr_count_cpus_per_package(unsigned int *package_count,
191 unsigned int max_pkgs)
192 {
193 g_autofree char *file_contents = NULL;
194 g_autofree char *path = NULL;
195 g_autofree char *path_name = NULL;
196 gsize length;
197
198 /* Iterate over cpus and count cpus in each package */
199 for (int cpu_id = 0; ; cpu_id++) {
200 path_name = g_strdup_printf("/sys/devices/system/cpu/cpu%d/"
201 "topology/physical_package_id", cpu_id);
202
203 path = g_build_filename(path_name, NULL);
204
205 if (!g_file_get_contents(path, &file_contents, &length, NULL)) {
206 break; /* No more cpus */
207 }
208
209 /* Get the physical package ID for this CPU */
210 int package_id = atoi(file_contents);
211
212 /* Check if the package ID is within the known number of packages */
213 if (package_id >= 0 && package_id < max_pkgs) {
214 /* If yes, count the cpu for this package*/
215 package_count[package_id]++;
216 }
217 }
218
219 return 0;
220 }
221
222 /* Get the physical package id from a given cpu id */
vmsr_get_physical_package_id(int cpu_id)223 int vmsr_get_physical_package_id(int cpu_id)
224 {
225 g_autofree char *file_contents = NULL;
226 g_autofree char *file_path = NULL;
227 int package_id = -1;
228 gsize length;
229
230 file_path = g_strdup_printf("/sys/devices/system/cpu/cpu%d"
231 "/topology/physical_package_id", cpu_id);
232
233 if (!g_file_get_contents(file_path, &file_contents, &length, NULL)) {
234 goto out;
235 }
236
237 package_id = atoi(file_contents);
238
239 out:
240 return package_id;
241 }
242
243 /* Read the scheduled time for a given thread of a give pid */
vmsr_read_thread_stat(pid_t pid,unsigned int thread_id,unsigned long long * utime,unsigned long long * stime,unsigned int * cpu_id)244 void vmsr_read_thread_stat(pid_t pid,
245 unsigned int thread_id,
246 unsigned long long *utime,
247 unsigned long long *stime,
248 unsigned int *cpu_id)
249 {
250 g_autofree char *path = NULL;
251 g_autofree char *path_name = NULL;
252
253 path_name = g_strdup_printf("/proc/%u/task/%d/stat", pid, thread_id);
254
255 path = g_build_filename(path_name, NULL);
256
257 FILE *file = fopen(path, "r");
258 if (file == NULL) {
259 error_report("Error opening %s", path_name);
260 return;
261 }
262
263 if (fscanf(file, "%*d (%*[^)]) %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u"
264 " %llu %llu %*d %*d %*d %*d %*d %*d %*u %*u %*d %*u %*u"
265 " %*u %*u %*u %*u %*u %*u %*u %*u %*u %*d %*u %*u %u",
266 utime, stime, cpu_id) != 3)
267 {
268 fclose(file);
269 error_report("Error fscanf did not report the right amount of items");
270 return;
271 }
272
273 fclose(file);
274 }
275
276 /* Read QEMU stat task folder to retrieve all QEMU threads ID */
vmsr_get_thread_ids(pid_t pid,unsigned int * num_threads)277 pid_t *vmsr_get_thread_ids(pid_t pid, unsigned int *num_threads)
278 {
279 g_autofree char *task_path = g_strdup_printf("%d/task", pid);
280 g_autofree char *path = g_build_filename("/proc", task_path, NULL);
281
282 DIR *dir = opendir(path);
283 if (dir == NULL) {
284 error_report("Error opening /proc/qemu/task");
285 return NULL;
286 }
287
288 pid_t *thread_ids = NULL;
289 unsigned int thread_count = 0;
290
291 g_autofree struct dirent *ent = NULL;
292 while ((ent = readdir(dir)) != NULL) {
293 if (ent->d_name[0] == '.') {
294 continue;
295 }
296 pid_t tid = atoi(ent->d_name);
297 if (pid != tid) {
298 thread_ids = g_renew(pid_t, thread_ids, (thread_count + 1));
299 thread_ids[thread_count] = tid;
300 thread_count++;
301 }
302 }
303
304 closedir(dir);
305
306 *num_threads = thread_count;
307 return thread_ids;
308 }
309
vmsr_delta_ticks(vmsr_thread_stat * thd_stat,int i)310 void vmsr_delta_ticks(vmsr_thread_stat *thd_stat, int i)
311 {
312 thd_stat[i].delta_ticks = (thd_stat[i].utime[1] + thd_stat[i].stime[1])
313 - (thd_stat[i].utime[0] + thd_stat[i].stime[0]);
314 }
315
vmsr_get_ratio(uint64_t e_delta,unsigned long long delta_ticks,unsigned int maxticks)316 double vmsr_get_ratio(uint64_t e_delta,
317 unsigned long long delta_ticks,
318 unsigned int maxticks)
319 {
320 return (e_delta / 100.0) * ((100.0 / maxticks) * delta_ticks);
321 }
322
vmsr_init_topo_info(X86CPUTopoInfo * topo_info,const MachineState * ms)323 void vmsr_init_topo_info(X86CPUTopoInfo *topo_info,
324 const MachineState *ms)
325 {
326 topo_info->dies_per_pkg = ms->smp.dies;
327 topo_info->modules_per_die = ms->smp.modules;
328 topo_info->cores_per_module = ms->smp.cores;
329 topo_info->threads_per_core = ms->smp.threads;
330 }
331
332