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1 | /* | |
2 | * Virtio Balloon Device | |
3 | * | |
4 | * Copyright IBM, Corp. 2008 | |
5 | * Copyright (C) 2011 Red Hat, Inc. | |
6 | * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com> | |
7 | * | |
8 | * Authors: | |
9 | * Anthony Liguori <aliguori@us.ibm.com> | |
10 | * | |
11 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
12 | * the COPYING file in the top-level directory. | |
13 | * | |
14 | */ | |
15 | ||
16 | #include "qemu/iov.h" | |
17 | #include "qemu/timer.h" | |
18 | #include "qemu-common.h" | |
19 | #include "virtio.h" | |
20 | #include "pc.h" | |
21 | #include "cpu.h" | |
22 | #include "sysemu/balloon.h" | |
23 | #include "virtio-balloon.h" | |
24 | #include "sysemu/kvm.h" | |
25 | #include "exec/address-spaces.h" | |
26 | #include "qapi/visitor.h" | |
27 | ||
28 | #if defined(__linux__) | |
29 | #include <sys/mman.h> | |
30 | #endif | |
31 | ||
32 | typedef struct VirtIOBalloon | |
33 | { | |
34 | VirtIODevice vdev; | |
35 | VirtQueue *ivq, *dvq, *svq; | |
36 | uint32_t num_pages; | |
37 | uint32_t actual; | |
38 | uint64_t stats[VIRTIO_BALLOON_S_NR]; | |
39 | VirtQueueElement stats_vq_elem; | |
40 | size_t stats_vq_offset; | |
41 | QEMUTimer *stats_timer; | |
42 | int64_t stats_last_update; | |
43 | int64_t stats_poll_interval; | |
44 | DeviceState *qdev; | |
45 | } VirtIOBalloon; | |
46 | ||
47 | static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev) | |
48 | { | |
49 | return (VirtIOBalloon *)vdev; | |
50 | } | |
51 | ||
52 | static void balloon_page(void *addr, int deflate) | |
53 | { | |
54 | #if defined(__linux__) | |
55 | if (!kvm_enabled() || kvm_has_sync_mmu()) | |
56 | qemu_madvise(addr, TARGET_PAGE_SIZE, | |
57 | deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED); | |
58 | #endif | |
59 | } | |
60 | ||
61 | static const char *balloon_stat_names[] = { | |
62 | [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in", | |
63 | [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out", | |
64 | [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults", | |
65 | [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults", | |
66 | [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory", | |
67 | [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory", | |
68 | [VIRTIO_BALLOON_S_NR] = NULL | |
69 | }; | |
70 | ||
71 | /* | |
72 | * reset_stats - Mark all items in the stats array as unset | |
73 | * | |
74 | * This function needs to be called at device intialization and before | |
75 | * before updating to a set of newly-generated stats. This will ensure that no | |
76 | * stale values stick around in case the guest reports a subset of the supported | |
77 | * statistics. | |
78 | */ | |
79 | static inline void reset_stats(VirtIOBalloon *dev) | |
80 | { | |
81 | int i; | |
82 | for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1); | |
83 | } | |
84 | ||
85 | static bool balloon_stats_supported(const VirtIOBalloon *s) | |
86 | { | |
87 | return s->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ); | |
88 | } | |
89 | ||
90 | static bool balloon_stats_enabled(const VirtIOBalloon *s) | |
91 | { | |
92 | return s->stats_poll_interval > 0; | |
93 | } | |
94 | ||
95 | static void balloon_stats_destroy_timer(VirtIOBalloon *s) | |
96 | { | |
97 | if (balloon_stats_enabled(s)) { | |
98 | qemu_del_timer(s->stats_timer); | |
99 | qemu_free_timer(s->stats_timer); | |
100 | s->stats_timer = NULL; | |
101 | s->stats_poll_interval = 0; | |
102 | } | |
103 | } | |
104 | ||
105 | static void balloon_stats_change_timer(VirtIOBalloon *s, int secs) | |
106 | { | |
107 | qemu_mod_timer(s->stats_timer, qemu_get_clock_ms(vm_clock) + secs * 1000); | |
108 | } | |
109 | ||
110 | static void balloon_stats_poll_cb(void *opaque) | |
111 | { | |
112 | VirtIOBalloon *s = opaque; | |
113 | ||
114 | if (!balloon_stats_supported(s)) { | |
115 | /* re-schedule */ | |
116 | balloon_stats_change_timer(s, s->stats_poll_interval); | |
117 | return; | |
118 | } | |
119 | ||
120 | virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset); | |
121 | virtio_notify(&s->vdev, s->svq); | |
122 | } | |
123 | ||
124 | static void balloon_stats_get_all(Object *obj, struct Visitor *v, | |
125 | void *opaque, const char *name, Error **errp) | |
126 | { | |
127 | VirtIOBalloon *s = opaque; | |
128 | int i; | |
129 | ||
130 | if (!s->stats_last_update) { | |
131 | error_setg(errp, "guest hasn't updated any stats yet"); | |
132 | return; | |
133 | } | |
134 | ||
135 | visit_start_struct(v, NULL, "guest-stats", name, 0, errp); | |
136 | visit_type_int(v, &s->stats_last_update, "last-update", errp); | |
137 | ||
138 | visit_start_struct(v, NULL, NULL, "stats", 0, errp); | |
139 | for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) { | |
140 | visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i], | |
141 | errp); | |
142 | } | |
143 | visit_end_struct(v, errp); | |
144 | ||
145 | visit_end_struct(v, errp); | |
146 | } | |
147 | ||
148 | static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v, | |
149 | void *opaque, const char *name, | |
150 | Error **errp) | |
151 | { | |
152 | VirtIOBalloon *s = opaque; | |
153 | visit_type_int(v, &s->stats_poll_interval, name, errp); | |
154 | } | |
155 | ||
156 | static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v, | |
157 | void *opaque, const char *name, | |
158 | Error **errp) | |
159 | { | |
160 | VirtIOBalloon *s = opaque; | |
161 | int64_t value; | |
162 | ||
163 | visit_type_int(v, &value, name, errp); | |
164 | if (error_is_set(errp)) { | |
165 | return; | |
166 | } | |
167 | ||
168 | if (value < 0) { | |
169 | error_setg(errp, "timer value must be greater than zero"); | |
170 | return; | |
171 | } | |
172 | ||
173 | if (value == s->stats_poll_interval) { | |
174 | return; | |
175 | } | |
176 | ||
177 | if (value == 0) { | |
178 | /* timer=0 disables the timer */ | |
179 | balloon_stats_destroy_timer(s); | |
180 | return; | |
181 | } | |
182 | ||
183 | if (balloon_stats_enabled(s)) { | |
184 | /* timer interval change */ | |
185 | s->stats_poll_interval = value; | |
186 | balloon_stats_change_timer(s, value); | |
187 | return; | |
188 | } | |
189 | ||
190 | /* create a new timer */ | |
191 | g_assert(s->stats_timer == NULL); | |
192 | s->stats_timer = qemu_new_timer_ms(vm_clock, balloon_stats_poll_cb, s); | |
193 | s->stats_poll_interval = value; | |
194 | balloon_stats_change_timer(s, 0); | |
195 | } | |
196 | ||
197 | static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) | |
198 | { | |
199 | VirtIOBalloon *s = to_virtio_balloon(vdev); | |
200 | VirtQueueElement elem; | |
201 | MemoryRegionSection section; | |
202 | ||
203 | while (virtqueue_pop(vq, &elem)) { | |
204 | size_t offset = 0; | |
205 | uint32_t pfn; | |
206 | ||
207 | while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) { | |
208 | ram_addr_t pa; | |
209 | ram_addr_t addr; | |
210 | ||
211 | pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT; | |
212 | offset += 4; | |
213 | ||
214 | /* FIXME: remove get_system_memory(), but how? */ | |
215 | section = memory_region_find(get_system_memory(), pa, 1); | |
216 | if (!section.size || !memory_region_is_ram(section.mr)) | |
217 | continue; | |
218 | ||
219 | /* Using memory_region_get_ram_ptr is bending the rules a bit, but | |
220 | should be OK because we only want a single page. */ | |
221 | addr = section.offset_within_region; | |
222 | balloon_page(memory_region_get_ram_ptr(section.mr) + addr, | |
223 | !!(vq == s->dvq)); | |
224 | } | |
225 | ||
226 | virtqueue_push(vq, &elem, offset); | |
227 | virtio_notify(vdev, vq); | |
228 | } | |
229 | } | |
230 | ||
231 | static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) | |
232 | { | |
233 | VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev); | |
234 | VirtQueueElement *elem = &s->stats_vq_elem; | |
235 | VirtIOBalloonStat stat; | |
236 | size_t offset = 0; | |
237 | qemu_timeval tv; | |
238 | ||
239 | if (!virtqueue_pop(vq, elem)) { | |
240 | goto out; | |
241 | } | |
242 | ||
243 | /* Initialize the stats to get rid of any stale values. This is only | |
244 | * needed to handle the case where a guest supports fewer stats than it | |
245 | * used to (ie. it has booted into an old kernel). | |
246 | */ | |
247 | reset_stats(s); | |
248 | ||
249 | while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat)) | |
250 | == sizeof(stat)) { | |
251 | uint16_t tag = tswap16(stat.tag); | |
252 | uint64_t val = tswap64(stat.val); | |
253 | ||
254 | offset += sizeof(stat); | |
255 | if (tag < VIRTIO_BALLOON_S_NR) | |
256 | s->stats[tag] = val; | |
257 | } | |
258 | s->stats_vq_offset = offset; | |
259 | ||
260 | if (qemu_gettimeofday(&tv) < 0) { | |
261 | fprintf(stderr, "warning: %s: failed to get time of day\n", __func__); | |
262 | goto out; | |
263 | } | |
264 | ||
265 | s->stats_last_update = tv.tv_sec; | |
266 | ||
267 | out: | |
268 | if (balloon_stats_enabled(s)) { | |
269 | balloon_stats_change_timer(s, s->stats_poll_interval); | |
270 | } | |
271 | } | |
272 | ||
273 | static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) | |
274 | { | |
275 | VirtIOBalloon *dev = to_virtio_balloon(vdev); | |
276 | struct virtio_balloon_config config; | |
277 | ||
278 | config.num_pages = cpu_to_le32(dev->num_pages); | |
279 | config.actual = cpu_to_le32(dev->actual); | |
280 | ||
281 | memcpy(config_data, &config, 8); | |
282 | } | |
283 | ||
284 | static void virtio_balloon_set_config(VirtIODevice *vdev, | |
285 | const uint8_t *config_data) | |
286 | { | |
287 | VirtIOBalloon *dev = to_virtio_balloon(vdev); | |
288 | struct virtio_balloon_config config; | |
289 | uint32_t oldactual = dev->actual; | |
290 | memcpy(&config, config_data, 8); | |
291 | dev->actual = le32_to_cpu(config.actual); | |
292 | if (dev->actual != oldactual) { | |
293 | qemu_balloon_changed(ram_size - | |
294 | (dev->actual << VIRTIO_BALLOON_PFN_SHIFT)); | |
295 | } | |
296 | } | |
297 | ||
298 | static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f) | |
299 | { | |
300 | f |= (1 << VIRTIO_BALLOON_F_STATS_VQ); | |
301 | return f; | |
302 | } | |
303 | ||
304 | static void virtio_balloon_stat(void *opaque, BalloonInfo *info) | |
305 | { | |
306 | VirtIOBalloon *dev = opaque; | |
307 | info->actual = ram_size - ((uint64_t) dev->actual << | |
308 | VIRTIO_BALLOON_PFN_SHIFT); | |
309 | } | |
310 | ||
311 | static void virtio_balloon_to_target(void *opaque, ram_addr_t target) | |
312 | { | |
313 | VirtIOBalloon *dev = opaque; | |
314 | ||
315 | if (target > ram_size) { | |
316 | target = ram_size; | |
317 | } | |
318 | if (target) { | |
319 | dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; | |
320 | virtio_notify_config(&dev->vdev); | |
321 | } | |
322 | } | |
323 | ||
324 | static void virtio_balloon_save(QEMUFile *f, void *opaque) | |
325 | { | |
326 | VirtIOBalloon *s = opaque; | |
327 | ||
328 | virtio_save(&s->vdev, f); | |
329 | ||
330 | qemu_put_be32(f, s->num_pages); | |
331 | qemu_put_be32(f, s->actual); | |
332 | } | |
333 | ||
334 | static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id) | |
335 | { | |
336 | VirtIOBalloon *s = opaque; | |
337 | int ret; | |
338 | ||
339 | if (version_id != 1) | |
340 | return -EINVAL; | |
341 | ||
342 | ret = virtio_load(&s->vdev, f); | |
343 | if (ret) { | |
344 | return ret; | |
345 | } | |
346 | ||
347 | s->num_pages = qemu_get_be32(f); | |
348 | s->actual = qemu_get_be32(f); | |
349 | return 0; | |
350 | } | |
351 | ||
352 | VirtIODevice *virtio_balloon_init(DeviceState *dev) | |
353 | { | |
354 | VirtIOBalloon *s; | |
355 | int ret; | |
356 | ||
357 | s = (VirtIOBalloon *)virtio_common_init("virtio-balloon", | |
358 | VIRTIO_ID_BALLOON, | |
359 | 8, sizeof(VirtIOBalloon)); | |
360 | ||
361 | s->vdev.get_config = virtio_balloon_get_config; | |
362 | s->vdev.set_config = virtio_balloon_set_config; | |
363 | s->vdev.get_features = virtio_balloon_get_features; | |
364 | ||
365 | ret = qemu_add_balloon_handler(virtio_balloon_to_target, | |
366 | virtio_balloon_stat, s); | |
367 | if (ret < 0) { | |
368 | virtio_cleanup(&s->vdev); | |
369 | return NULL; | |
370 | } | |
371 | ||
372 | s->ivq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output); | |
373 | s->dvq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output); | |
374 | s->svq = virtio_add_queue(&s->vdev, 128, virtio_balloon_receive_stats); | |
375 | ||
376 | s->qdev = dev; | |
377 | register_savevm(dev, "virtio-balloon", -1, 1, | |
378 | virtio_balloon_save, virtio_balloon_load, s); | |
379 | ||
380 | object_property_add(OBJECT(dev), "guest-stats", "guest statistics", | |
381 | balloon_stats_get_all, NULL, NULL, s, NULL); | |
382 | ||
383 | object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int", | |
384 | balloon_stats_get_poll_interval, | |
385 | balloon_stats_set_poll_interval, | |
386 | NULL, s, NULL); | |
387 | ||
388 | return &s->vdev; | |
389 | } | |
390 | ||
391 | void virtio_balloon_exit(VirtIODevice *vdev) | |
392 | { | |
393 | VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev); | |
394 | ||
395 | balloon_stats_destroy_timer(s); | |
396 | qemu_remove_balloon_handler(s); | |
397 | unregister_savevm(s->qdev, "virtio-balloon", s); | |
398 | virtio_cleanup(vdev); | |
399 | } |