2 * Virtio Balloon Device
4 * Copyright IBM, Corp. 2008
5 * Copyright (C) 2011 Red Hat, Inc.
6 * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
9 * Anthony Liguori <aliguori@us.ibm.com>
11 * This work is licensed under the terms of the GNU GPL, version 2. See
12 * the COPYING file in the top-level directory.
16 #include "qemu/osdep.h"
18 #include "qemu/timer.h"
19 #include "qemu-common.h"
20 #include "hw/virtio/virtio.h"
21 #include "hw/i386/pc.h"
23 #include "sysemu/balloon.h"
24 #include "hw/virtio/virtio-balloon.h"
25 #include "sysemu/kvm.h"
26 #include "exec/address-spaces.h"
27 #include "qapi/visitor.h"
28 #include "qapi-event.h"
31 #if defined(__linux__)
35 #include "hw/virtio/virtio-bus.h"
36 #include "hw/virtio/virtio-access.h"
38 static void balloon_page(void *addr
, int deflate
)
40 #if defined(__linux__)
41 if (!qemu_balloon_is_inhibited() && (!kvm_enabled() ||
42 kvm_has_sync_mmu())) {
43 qemu_madvise(addr
, TARGET_PAGE_SIZE
,
44 deflate
? QEMU_MADV_WILLNEED
: QEMU_MADV_DONTNEED
);
49 static const char *balloon_stat_names
[] = {
50 [VIRTIO_BALLOON_S_SWAP_IN
] = "stat-swap-in",
51 [VIRTIO_BALLOON_S_SWAP_OUT
] = "stat-swap-out",
52 [VIRTIO_BALLOON_S_MAJFLT
] = "stat-major-faults",
53 [VIRTIO_BALLOON_S_MINFLT
] = "stat-minor-faults",
54 [VIRTIO_BALLOON_S_MEMFREE
] = "stat-free-memory",
55 [VIRTIO_BALLOON_S_MEMTOT
] = "stat-total-memory",
56 [VIRTIO_BALLOON_S_NR
] = NULL
60 * reset_stats - Mark all items in the stats array as unset
62 * This function needs to be called at device initialization and before
63 * updating to a set of newly-generated stats. This will ensure that no
64 * stale values stick around in case the guest reports a subset of the supported
67 static inline void reset_stats(VirtIOBalloon
*dev
)
70 for (i
= 0; i
< VIRTIO_BALLOON_S_NR
; dev
->stats
[i
++] = -1);
73 static bool balloon_stats_supported(const VirtIOBalloon
*s
)
75 VirtIODevice
*vdev
= VIRTIO_DEVICE(s
);
76 return virtio_vdev_has_feature(vdev
, VIRTIO_BALLOON_F_STATS_VQ
);
79 static bool balloon_stats_enabled(const VirtIOBalloon
*s
)
81 return s
->stats_poll_interval
> 0;
84 static void balloon_stats_destroy_timer(VirtIOBalloon
*s
)
86 if (balloon_stats_enabled(s
)) {
87 timer_del(s
->stats_timer
);
88 timer_free(s
->stats_timer
);
89 s
->stats_timer
= NULL
;
90 s
->stats_poll_interval
= 0;
94 static void balloon_stats_change_timer(VirtIOBalloon
*s
, int64_t secs
)
96 timer_mod(s
->stats_timer
, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL
) + secs
* 1000);
99 static void balloon_stats_poll_cb(void *opaque
)
101 VirtIOBalloon
*s
= opaque
;
102 VirtIODevice
*vdev
= VIRTIO_DEVICE(s
);
104 if (!balloon_stats_supported(s
)) {
106 balloon_stats_change_timer(s
, s
->stats_poll_interval
);
110 virtqueue_push(s
->svq
, &s
->stats_vq_elem
, s
->stats_vq_offset
);
111 virtio_notify(vdev
, s
->svq
);
114 static void balloon_stats_get_all(Object
*obj
, struct Visitor
*v
,
115 void *opaque
, const char *name
, Error
**errp
)
118 VirtIOBalloon
*s
= opaque
;
121 visit_start_struct(v
, NULL
, "guest-stats", name
, 0, &err
);
125 visit_type_int(v
, &s
->stats_last_update
, "last-update", &err
);
130 visit_start_struct(v
, NULL
, NULL
, "stats", 0, &err
);
134 for (i
= 0; !err
&& i
< VIRTIO_BALLOON_S_NR
; i
++) {
135 visit_type_int64(v
, (int64_t *) &s
->stats
[i
], balloon_stat_names
[i
],
138 error_propagate(errp
, err
);
140 visit_end_struct(v
, &err
);
143 error_propagate(errp
, err
);
145 visit_end_struct(v
, &err
);
147 error_propagate(errp
, err
);
150 static void balloon_stats_get_poll_interval(Object
*obj
, struct Visitor
*v
,
151 void *opaque
, const char *name
,
154 VirtIOBalloon
*s
= opaque
;
155 visit_type_int(v
, &s
->stats_poll_interval
, name
, errp
);
158 static void balloon_stats_set_poll_interval(Object
*obj
, struct Visitor
*v
,
159 void *opaque
, const char *name
,
162 VirtIOBalloon
*s
= opaque
;
163 Error
*local_err
= NULL
;
166 visit_type_int(v
, &value
, name
, &local_err
);
168 error_propagate(errp
, local_err
);
173 error_setg(errp
, "timer value must be greater than zero");
177 if (value
> UINT32_MAX
) {
178 error_setg(errp
, "timer value is too big");
182 if (value
== s
->stats_poll_interval
) {
187 /* timer=0 disables the timer */
188 balloon_stats_destroy_timer(s
);
192 if (balloon_stats_enabled(s
)) {
193 /* timer interval change */
194 s
->stats_poll_interval
= value
;
195 balloon_stats_change_timer(s
, value
);
199 /* create a new timer */
200 g_assert(s
->stats_timer
== NULL
);
201 s
->stats_timer
= timer_new_ms(QEMU_CLOCK_VIRTUAL
, balloon_stats_poll_cb
, s
);
202 s
->stats_poll_interval
= value
;
203 balloon_stats_change_timer(s
, 0);
206 static void virtio_balloon_handle_output(VirtIODevice
*vdev
, VirtQueue
*vq
)
208 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
209 VirtQueueElement elem
;
210 MemoryRegionSection section
;
212 while (virtqueue_pop(vq
, &elem
)) {
216 while (iov_to_buf(elem
.out_sg
, elem
.out_num
, offset
, &pfn
, 4) == 4) {
219 int p
= virtio_ldl_p(vdev
, &pfn
);
221 pa
= (ram_addr_t
) p
<< VIRTIO_BALLOON_PFN_SHIFT
;
224 /* FIXME: remove get_system_memory(), but how? */
225 section
= memory_region_find(get_system_memory(), pa
, 1);
226 if (!int128_nz(section
.size
) || !memory_region_is_ram(section
.mr
))
229 trace_virtio_balloon_handle_output(memory_region_name(section
.mr
),
231 /* Using memory_region_get_ram_ptr is bending the rules a bit, but
232 should be OK because we only want a single page. */
233 addr
= section
.offset_within_region
;
234 balloon_page(memory_region_get_ram_ptr(section
.mr
) + addr
,
236 memory_region_unref(section
.mr
);
239 virtqueue_push(vq
, &elem
, offset
);
240 virtio_notify(vdev
, vq
);
244 static void virtio_balloon_receive_stats(VirtIODevice
*vdev
, VirtQueue
*vq
)
246 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
247 VirtQueueElement
*elem
= &s
->stats_vq_elem
;
248 VirtIOBalloonStat stat
;
252 if (!virtqueue_pop(vq
, elem
)) {
256 /* Initialize the stats to get rid of any stale values. This is only
257 * needed to handle the case where a guest supports fewer stats than it
258 * used to (ie. it has booted into an old kernel).
262 while (iov_to_buf(elem
->out_sg
, elem
->out_num
, offset
, &stat
, sizeof(stat
))
264 uint16_t tag
= virtio_tswap16(vdev
, stat
.tag
);
265 uint64_t val
= virtio_tswap64(vdev
, stat
.val
);
267 offset
+= sizeof(stat
);
268 if (tag
< VIRTIO_BALLOON_S_NR
)
271 s
->stats_vq_offset
= offset
;
273 if (qemu_gettimeofday(&tv
) < 0) {
274 fprintf(stderr
, "warning: %s: failed to get time of day\n", __func__
);
278 s
->stats_last_update
= tv
.tv_sec
;
281 if (balloon_stats_enabled(s
)) {
282 balloon_stats_change_timer(s
, s
->stats_poll_interval
);
286 static void virtio_balloon_get_config(VirtIODevice
*vdev
, uint8_t *config_data
)
288 VirtIOBalloon
*dev
= VIRTIO_BALLOON(vdev
);
289 struct virtio_balloon_config config
;
291 config
.num_pages
= cpu_to_le32(dev
->num_pages
);
292 config
.actual
= cpu_to_le32(dev
->actual
);
294 trace_virtio_balloon_get_config(config
.num_pages
, config
.actual
);
295 memcpy(config_data
, &config
, sizeof(struct virtio_balloon_config
));
298 static void virtio_balloon_set_config(VirtIODevice
*vdev
,
299 const uint8_t *config_data
)
301 VirtIOBalloon
*dev
= VIRTIO_BALLOON(vdev
);
302 struct virtio_balloon_config config
;
303 uint32_t oldactual
= dev
->actual
;
304 ram_addr_t vm_ram_size
= get_current_ram_size();
306 memcpy(&config
, config_data
, sizeof(struct virtio_balloon_config
));
307 dev
->actual
= le32_to_cpu(config
.actual
);
308 if (dev
->actual
!= oldactual
) {
309 qapi_event_send_balloon_change(vm_ram_size
-
310 ((ram_addr_t
) dev
->actual
<< VIRTIO_BALLOON_PFN_SHIFT
),
313 trace_virtio_balloon_set_config(dev
->actual
, oldactual
);
316 static uint64_t virtio_balloon_get_features(VirtIODevice
*vdev
, uint64_t f
,
319 VirtIOBalloon
*dev
= VIRTIO_BALLOON(vdev
);
320 f
|= dev
->host_features
;
321 virtio_add_feature(&f
, VIRTIO_BALLOON_F_STATS_VQ
);
325 static void virtio_balloon_stat(void *opaque
, BalloonInfo
*info
)
327 VirtIOBalloon
*dev
= opaque
;
328 info
->actual
= get_current_ram_size() - ((uint64_t) dev
->actual
<<
329 VIRTIO_BALLOON_PFN_SHIFT
);
332 static void virtio_balloon_to_target(void *opaque
, ram_addr_t target
)
334 VirtIOBalloon
*dev
= VIRTIO_BALLOON(opaque
);
335 VirtIODevice
*vdev
= VIRTIO_DEVICE(dev
);
336 ram_addr_t vm_ram_size
= get_current_ram_size();
338 if (target
> vm_ram_size
) {
339 target
= vm_ram_size
;
342 dev
->num_pages
= (vm_ram_size
- target
) >> VIRTIO_BALLOON_PFN_SHIFT
;
343 virtio_notify_config(vdev
);
345 trace_virtio_balloon_to_target(target
, dev
->num_pages
);
348 static void virtio_balloon_save(QEMUFile
*f
, void *opaque
)
350 virtio_save(VIRTIO_DEVICE(opaque
), f
);
353 static void virtio_balloon_save_device(VirtIODevice
*vdev
, QEMUFile
*f
)
355 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
357 qemu_put_be32(f
, s
->num_pages
);
358 qemu_put_be32(f
, s
->actual
);
361 static int virtio_balloon_load(QEMUFile
*f
, void *opaque
, int version_id
)
366 return virtio_load(VIRTIO_DEVICE(opaque
), f
, version_id
);
369 static int virtio_balloon_load_device(VirtIODevice
*vdev
, QEMUFile
*f
,
372 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
374 s
->num_pages
= qemu_get_be32(f
);
375 s
->actual
= qemu_get_be32(f
);
379 static void virtio_balloon_device_realize(DeviceState
*dev
, Error
**errp
)
381 VirtIODevice
*vdev
= VIRTIO_DEVICE(dev
);
382 VirtIOBalloon
*s
= VIRTIO_BALLOON(dev
);
385 virtio_init(vdev
, "virtio-balloon", VIRTIO_ID_BALLOON
,
386 sizeof(struct virtio_balloon_config
));
388 ret
= qemu_add_balloon_handler(virtio_balloon_to_target
,
389 virtio_balloon_stat
, s
);
392 error_setg(errp
, "Only one balloon device is supported");
393 virtio_cleanup(vdev
);
397 s
->ivq
= virtio_add_queue(vdev
, 128, virtio_balloon_handle_output
);
398 s
->dvq
= virtio_add_queue(vdev
, 128, virtio_balloon_handle_output
);
399 s
->svq
= virtio_add_queue(vdev
, 128, virtio_balloon_receive_stats
);
403 register_savevm(dev
, "virtio-balloon", -1, 1,
404 virtio_balloon_save
, virtio_balloon_load
, s
);
407 static void virtio_balloon_device_unrealize(DeviceState
*dev
, Error
**errp
)
409 VirtIODevice
*vdev
= VIRTIO_DEVICE(dev
);
410 VirtIOBalloon
*s
= VIRTIO_BALLOON(dev
);
412 balloon_stats_destroy_timer(s
);
413 qemu_remove_balloon_handler(s
);
414 unregister_savevm(dev
, "virtio-balloon", s
);
415 virtio_cleanup(vdev
);
418 static void virtio_balloon_instance_init(Object
*obj
)
420 VirtIOBalloon
*s
= VIRTIO_BALLOON(obj
);
422 object_property_add(obj
, "guest-stats", "guest statistics",
423 balloon_stats_get_all
, NULL
, NULL
, s
, NULL
);
425 object_property_add(obj
, "guest-stats-polling-interval", "int",
426 balloon_stats_get_poll_interval
,
427 balloon_stats_set_poll_interval
,
431 static Property virtio_balloon_properties
[] = {
432 DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon
, host_features
,
433 VIRTIO_BALLOON_F_DEFLATE_ON_OOM
, false),
434 DEFINE_PROP_END_OF_LIST(),
437 static void virtio_balloon_class_init(ObjectClass
*klass
, void *data
)
439 DeviceClass
*dc
= DEVICE_CLASS(klass
);
440 VirtioDeviceClass
*vdc
= VIRTIO_DEVICE_CLASS(klass
);
442 dc
->props
= virtio_balloon_properties
;
443 set_bit(DEVICE_CATEGORY_MISC
, dc
->categories
);
444 vdc
->realize
= virtio_balloon_device_realize
;
445 vdc
->unrealize
= virtio_balloon_device_unrealize
;
446 vdc
->get_config
= virtio_balloon_get_config
;
447 vdc
->set_config
= virtio_balloon_set_config
;
448 vdc
->get_features
= virtio_balloon_get_features
;
449 vdc
->save
= virtio_balloon_save_device
;
450 vdc
->load
= virtio_balloon_load_device
;
453 static const TypeInfo virtio_balloon_info
= {
454 .name
= TYPE_VIRTIO_BALLOON
,
455 .parent
= TYPE_VIRTIO_DEVICE
,
456 .instance_size
= sizeof(VirtIOBalloon
),
457 .instance_init
= virtio_balloon_instance_init
,
458 .class_init
= virtio_balloon_class_init
,
461 static void virtio_register_types(void)
463 type_register_static(&virtio_balloon_info
);
466 type_init(virtio_register_types
)