xref: /openbmc/qemu/hw/virtio/virtio-balloon.c (revision bfb27e60) 
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 "hw/virtio/virtio.h"
20 #include "hw/i386/pc.h"
21 #include "cpu.h"
22 #include "sysemu/balloon.h"
23 #include "hw/virtio/virtio-balloon.h"
24 #include "sysemu/kvm.h"
25 #include "exec/address-spaces.h"
26 #include "qapi/visitor.h"
27 #include "qapi-event.h"
28 
29 #if defined(__linux__)
30 #include <sys/mman.h>
31 #endif
32 
33 #include "hw/virtio/virtio-bus.h"
34 #include "hw/virtio/virtio-access.h"
35 
36 static void balloon_page(void *addr, int deflate)
37 {
38 #if defined(__linux__)
39     if (!kvm_enabled() || kvm_has_sync_mmu())
40         qemu_madvise(addr, TARGET_PAGE_SIZE,
41                 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
42 #endif
43 }
44 
45 static const char *balloon_stat_names[] = {
46    [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
47    [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
48    [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
49    [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
50    [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
51    [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
52    [VIRTIO_BALLOON_S_NR] = NULL
53 };
54 
55 /*
56  * reset_stats - Mark all items in the stats array as unset
57  *
58  * This function needs to be called at device initialization and before
59  * updating to a set of newly-generated stats.  This will ensure that no
60  * stale values stick around in case the guest reports a subset of the supported
61  * statistics.
62  */
63 static inline void reset_stats(VirtIOBalloon *dev)
64 {
65     int i;
66     for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
67 }
68 
69 static bool balloon_stats_supported(const VirtIOBalloon *s)
70 {
71     VirtIODevice *vdev = VIRTIO_DEVICE(s);
72     return vdev->guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ);
73 }
74 
75 static bool balloon_stats_enabled(const VirtIOBalloon *s)
76 {
77     return s->stats_poll_interval > 0;
78 }
79 
80 static void balloon_stats_destroy_timer(VirtIOBalloon *s)
81 {
82     if (balloon_stats_enabled(s)) {
83         timer_del(s->stats_timer);
84         timer_free(s->stats_timer);
85         s->stats_timer = NULL;
86         s->stats_poll_interval = 0;
87     }
88 }
89 
90 static void balloon_stats_change_timer(VirtIOBalloon *s, int secs)
91 {
92     timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000);
93 }
94 
95 static void balloon_stats_poll_cb(void *opaque)
96 {
97     VirtIOBalloon *s = opaque;
98     VirtIODevice *vdev = VIRTIO_DEVICE(s);
99 
100     if (!balloon_stats_supported(s)) {
101         /* re-schedule */
102         balloon_stats_change_timer(s, s->stats_poll_interval);
103         return;
104     }
105 
106     virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset);
107     virtio_notify(vdev, s->svq);
108 }
109 
110 static void balloon_stats_get_all(Object *obj, struct Visitor *v,
111                                   void *opaque, const char *name, Error **errp)
112 {
113     Error *err = NULL;
114     VirtIOBalloon *s = opaque;
115     int i;
116 
117     visit_start_struct(v, NULL, "guest-stats", name, 0, &err);
118     if (err) {
119         goto out;
120     }
121     visit_type_int(v, &s->stats_last_update, "last-update", &err);
122     if (err) {
123         goto out_end;
124     }
125 
126     visit_start_struct(v, NULL, NULL, "stats", 0, &err);
127     if (err) {
128         goto out_end;
129     }
130     for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) {
131         visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
132                          &err);
133     }
134     error_propagate(errp, err);
135     err = NULL;
136     visit_end_struct(v, &err);
137 
138 out_end:
139     error_propagate(errp, err);
140     err = NULL;
141     visit_end_struct(v, &err);
142 out:
143     error_propagate(errp, err);
144 }
145 
146 static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,
147                                             void *opaque, const char *name,
148                                             Error **errp)
149 {
150     VirtIOBalloon *s = opaque;
151     visit_type_int(v, &s->stats_poll_interval, name, errp);
152 }
153 
154 static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
155                                             void *opaque, const char *name,
156                                             Error **errp)
157 {
158     VirtIOBalloon *s = opaque;
159     Error *local_err = NULL;
160     int64_t value;
161 
162     visit_type_int(v, &value, name, &local_err);
163     if (local_err) {
164         error_propagate(errp, local_err);
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 = timer_new_ms(QEMU_CLOCK_VIRTUAL, 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 = 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             int p = virtio_ldl_p(vdev, &pfn);
211 
212             pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
213             offset += 4;
214 
215             /* FIXME: remove get_system_memory(), but how? */
216             section = memory_region_find(get_system_memory(), pa, 1);
217             if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
218                 continue;
219 
220             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
221                should be OK because we only want a single page.  */
222             addr = section.offset_within_region;
223             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
224                          !!(vq == s->dvq));
225             memory_region_unref(section.mr);
226         }
227 
228         virtqueue_push(vq, &elem, offset);
229         virtio_notify(vdev, vq);
230     }
231 }
232 
233 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
234 {
235     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
236     VirtQueueElement *elem = &s->stats_vq_elem;
237     VirtIOBalloonStat stat;
238     size_t offset = 0;
239     qemu_timeval tv;
240 
241     if (!virtqueue_pop(vq, elem)) {
242         goto out;
243     }
244 
245     /* Initialize the stats to get rid of any stale values.  This is only
246      * needed to handle the case where a guest supports fewer stats than it
247      * used to (ie. it has booted into an old kernel).
248      */
249     reset_stats(s);
250 
251     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
252            == sizeof(stat)) {
253         uint16_t tag = virtio_tswap16(vdev, stat.tag);
254         uint64_t val = virtio_tswap64(vdev, stat.val);
255 
256         offset += sizeof(stat);
257         if (tag < VIRTIO_BALLOON_S_NR)
258             s->stats[tag] = val;
259     }
260     s->stats_vq_offset = offset;
261 
262     if (qemu_gettimeofday(&tv) < 0) {
263         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
264         goto out;
265     }
266 
267     s->stats_last_update = tv.tv_sec;
268 
269 out:
270     if (balloon_stats_enabled(s)) {
271         balloon_stats_change_timer(s, s->stats_poll_interval);
272     }
273 }
274 
275 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
276 {
277     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
278     struct virtio_balloon_config config;
279 
280     config.num_pages = cpu_to_le32(dev->num_pages);
281     config.actual = cpu_to_le32(dev->actual);
282 
283     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
284 }
285 
286 static void virtio_balloon_set_config(VirtIODevice *vdev,
287                                       const uint8_t *config_data)
288 {
289     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
290     struct virtio_balloon_config config;
291     uint32_t oldactual = dev->actual;
292     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
293     dev->actual = le32_to_cpu(config.actual);
294     if (dev->actual != oldactual) {
295         qapi_event_send_balloon_change(ram_size -
296                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
297                         &error_abort);
298     }
299 }
300 
301 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
302 {
303     f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
304     return f;
305 }
306 
307 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
308 {
309     VirtIOBalloon *dev = opaque;
310     info->actual = ram_size - ((uint64_t) dev->actual <<
311                                VIRTIO_BALLOON_PFN_SHIFT);
312 }
313 
314 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
315 {
316     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
317     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
318 
319     if (target > ram_size) {
320         target = ram_size;
321     }
322     if (target) {
323         dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
324         virtio_notify_config(vdev);
325     }
326 }
327 
328 static void virtio_balloon_save(QEMUFile *f, void *opaque)
329 {
330     virtio_save(VIRTIO_DEVICE(opaque), f);
331 }
332 
333 static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
334 {
335     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
336 
337     qemu_put_be32(f, s->num_pages);
338     qemu_put_be32(f, s->actual);
339 }
340 
341 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
342 {
343     if (version_id != 1)
344         return -EINVAL;
345 
346     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
347 }
348 
349 static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
350                                       int version_id)
351 {
352     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
353 
354     s->num_pages = qemu_get_be32(f);
355     s->actual = qemu_get_be32(f);
356     return 0;
357 }
358 
359 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
360 {
361     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
362     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
363     int ret;
364 
365     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
366                 sizeof(struct virtio_balloon_config));
367 
368     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
369                                    virtio_balloon_stat, s);
370 
371     if (ret < 0) {
372         error_setg(errp, "Adding balloon handler failed");
373         virtio_cleanup(vdev);
374         return;
375     }
376 
377     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
378     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
379     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
380 
381     reset_stats(s);
382 
383     register_savevm(dev, "virtio-balloon", -1, 1,
384                     virtio_balloon_save, virtio_balloon_load, s);
385 
386     object_property_add(OBJECT(dev), "guest-stats", "guest statistics",
387                         balloon_stats_get_all, NULL, NULL, s, NULL);
388 
389     object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int",
390                         balloon_stats_get_poll_interval,
391                         balloon_stats_set_poll_interval,
392                         NULL, s, NULL);
393 }
394 
395 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
396 {
397     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
398     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
399 
400     balloon_stats_destroy_timer(s);
401     qemu_remove_balloon_handler(s);
402     unregister_savevm(dev, "virtio-balloon", s);
403     virtio_cleanup(vdev);
404 }
405 
406 static Property virtio_balloon_properties[] = {
407     DEFINE_PROP_END_OF_LIST(),
408 };
409 
410 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
411 {
412     DeviceClass *dc = DEVICE_CLASS(klass);
413     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
414 
415     dc->props = virtio_balloon_properties;
416     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
417     vdc->realize = virtio_balloon_device_realize;
418     vdc->unrealize = virtio_balloon_device_unrealize;
419     vdc->get_config = virtio_balloon_get_config;
420     vdc->set_config = virtio_balloon_set_config;
421     vdc->get_features = virtio_balloon_get_features;
422     vdc->save = virtio_balloon_save_device;
423     vdc->load = virtio_balloon_load_device;
424 }
425 
426 static const TypeInfo virtio_balloon_info = {
427     .name = TYPE_VIRTIO_BALLOON,
428     .parent = TYPE_VIRTIO_DEVICE,
429     .instance_size = sizeof(VirtIOBalloon),
430     .class_init = virtio_balloon_class_init,
431 };
432 
433 static void virtio_register_types(void)
434 {
435     type_register_static(&virtio_balloon_info);
436 }
437 
438 type_init(virtio_register_types)
439