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"
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"
30 #if defined(__linux__)
34 #include "hw/virtio/virtio-bus.h"
35 #include "hw/virtio/virtio-access.h"
37 #define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT)
39 static void balloon_page(void *addr
, int deflate
)
41 #if defined(__linux__)
42 if (!qemu_balloon_is_inhibited() && (!kvm_enabled() ||
43 kvm_has_sync_mmu())) {
44 qemu_madvise(addr
, BALLOON_PAGE_SIZE
,
45 deflate
? QEMU_MADV_WILLNEED
: QEMU_MADV_DONTNEED
);
50 static const char *balloon_stat_names
[] = {
51 [VIRTIO_BALLOON_S_SWAP_IN
] = "stat-swap-in",
52 [VIRTIO_BALLOON_S_SWAP_OUT
] = "stat-swap-out",
53 [VIRTIO_BALLOON_S_MAJFLT
] = "stat-major-faults",
54 [VIRTIO_BALLOON_S_MINFLT
] = "stat-minor-faults",
55 [VIRTIO_BALLOON_S_MEMFREE
] = "stat-free-memory",
56 [VIRTIO_BALLOON_S_MEMTOT
] = "stat-total-memory",
57 [VIRTIO_BALLOON_S_AVAIL
] = "stat-available-memory",
58 [VIRTIO_BALLOON_S_NR
] = NULL
62 * reset_stats - Mark all items in the stats array as unset
64 * This function needs to be called at device initialization and before
65 * updating to a set of newly-generated stats. This will ensure that no
66 * stale values stick around in case the guest reports a subset of the supported
69 static inline void reset_stats(VirtIOBalloon
*dev
)
72 for (i
= 0; i
< VIRTIO_BALLOON_S_NR
; dev
->stats
[i
++] = -1);
75 static bool balloon_stats_supported(const VirtIOBalloon
*s
)
77 VirtIODevice
*vdev
= VIRTIO_DEVICE(s
);
78 return virtio_vdev_has_feature(vdev
, VIRTIO_BALLOON_F_STATS_VQ
);
81 static bool balloon_stats_enabled(const VirtIOBalloon
*s
)
83 return s
->stats_poll_interval
> 0;
86 static void balloon_stats_destroy_timer(VirtIOBalloon
*s
)
88 if (balloon_stats_enabled(s
)) {
89 timer_del(s
->stats_timer
);
90 timer_free(s
->stats_timer
);
91 s
->stats_timer
= NULL
;
92 s
->stats_poll_interval
= 0;
96 static void balloon_stats_change_timer(VirtIOBalloon
*s
, int64_t secs
)
98 timer_mod(s
->stats_timer
, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL
) + secs
* 1000);
101 static void balloon_stats_poll_cb(void *opaque
)
103 VirtIOBalloon
*s
= opaque
;
104 VirtIODevice
*vdev
= VIRTIO_DEVICE(s
);
106 if (s
->stats_vq_elem
== NULL
|| !balloon_stats_supported(s
)) {
108 balloon_stats_change_timer(s
, s
->stats_poll_interval
);
112 virtqueue_push(s
->svq
, s
->stats_vq_elem
, s
->stats_vq_offset
);
113 virtio_notify(vdev
, s
->svq
);
114 g_free(s
->stats_vq_elem
);
115 s
->stats_vq_elem
= NULL
;
118 static void balloon_stats_get_all(Object
*obj
, Visitor
*v
, const char *name
,
119 void *opaque
, Error
**errp
)
122 VirtIOBalloon
*s
= opaque
;
125 visit_start_struct(v
, name
, NULL
, 0, &err
);
129 visit_type_int(v
, "last-update", &s
->stats_last_update
, &err
);
134 visit_start_struct(v
, "stats", NULL
, 0, &err
);
138 for (i
= 0; i
< VIRTIO_BALLOON_S_NR
; i
++) {
139 visit_type_uint64(v
, balloon_stat_names
[i
], &s
->stats
[i
], &err
);
144 visit_check_struct(v
, &err
);
149 visit_check_struct(v
, &err
);
154 error_propagate(errp
, err
);
157 static void balloon_stats_get_poll_interval(Object
*obj
, Visitor
*v
,
158 const char *name
, void *opaque
,
161 VirtIOBalloon
*s
= opaque
;
162 visit_type_int(v
, name
, &s
->stats_poll_interval
, errp
);
165 static void balloon_stats_set_poll_interval(Object
*obj
, Visitor
*v
,
166 const char *name
, void *opaque
,
169 VirtIOBalloon
*s
= opaque
;
170 Error
*local_err
= NULL
;
173 visit_type_int(v
, name
, &value
, &local_err
);
175 error_propagate(errp
, local_err
);
180 error_setg(errp
, "timer value must be greater than zero");
184 if (value
> UINT32_MAX
) {
185 error_setg(errp
, "timer value is too big");
189 if (value
== s
->stats_poll_interval
) {
194 /* timer=0 disables the timer */
195 balloon_stats_destroy_timer(s
);
199 if (balloon_stats_enabled(s
)) {
200 /* timer interval change */
201 s
->stats_poll_interval
= value
;
202 balloon_stats_change_timer(s
, value
);
206 /* create a new timer */
207 g_assert(s
->stats_timer
== NULL
);
208 s
->stats_timer
= timer_new_ms(QEMU_CLOCK_VIRTUAL
, balloon_stats_poll_cb
, s
);
209 s
->stats_poll_interval
= value
;
210 balloon_stats_change_timer(s
, 0);
213 static void virtio_balloon_handle_output(VirtIODevice
*vdev
, VirtQueue
*vq
)
215 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
216 VirtQueueElement
*elem
;
217 MemoryRegionSection section
;
222 elem
= virtqueue_pop(vq
, sizeof(VirtQueueElement
));
227 while (iov_to_buf(elem
->out_sg
, elem
->out_num
, offset
, &pfn
, 4) == 4) {
230 int p
= virtio_ldl_p(vdev
, &pfn
);
232 pa
= (ram_addr_t
) p
<< VIRTIO_BALLOON_PFN_SHIFT
;
235 /* FIXME: remove get_system_memory(), but how? */
236 section
= memory_region_find(get_system_memory(), pa
, 1);
237 if (!int128_nz(section
.size
) || !memory_region_is_ram(section
.mr
))
240 trace_virtio_balloon_handle_output(memory_region_name(section
.mr
),
242 /* Using memory_region_get_ram_ptr is bending the rules a bit, but
243 should be OK because we only want a single page. */
244 addr
= section
.offset_within_region
;
245 balloon_page(memory_region_get_ram_ptr(section
.mr
) + addr
,
247 memory_region_unref(section
.mr
);
250 virtqueue_push(vq
, elem
, offset
);
251 virtio_notify(vdev
, vq
);
256 static void virtio_balloon_receive_stats(VirtIODevice
*vdev
, VirtQueue
*vq
)
258 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
259 VirtQueueElement
*elem
;
260 VirtIOBalloonStat stat
;
264 elem
= virtqueue_pop(vq
, sizeof(VirtQueueElement
));
269 if (s
->stats_vq_elem
!= NULL
) {
270 /* This should never happen if the driver follows the spec. */
271 virtqueue_push(vq
, s
->stats_vq_elem
, 0);
272 virtio_notify(vdev
, vq
);
273 g_free(s
->stats_vq_elem
);
276 s
->stats_vq_elem
= elem
;
278 /* Initialize the stats to get rid of any stale values. This is only
279 * needed to handle the case where a guest supports fewer stats than it
280 * used to (ie. it has booted into an old kernel).
284 while (iov_to_buf(elem
->out_sg
, elem
->out_num
, offset
, &stat
, sizeof(stat
))
286 uint16_t tag
= virtio_tswap16(vdev
, stat
.tag
);
287 uint64_t val
= virtio_tswap64(vdev
, stat
.val
);
289 offset
+= sizeof(stat
);
290 if (tag
< VIRTIO_BALLOON_S_NR
)
293 s
->stats_vq_offset
= offset
;
295 if (qemu_gettimeofday(&tv
) < 0) {
296 fprintf(stderr
, "warning: %s: failed to get time of day\n", __func__
);
300 s
->stats_last_update
= tv
.tv_sec
;
303 if (balloon_stats_enabled(s
)) {
304 balloon_stats_change_timer(s
, s
->stats_poll_interval
);
308 static void virtio_balloon_get_config(VirtIODevice
*vdev
, uint8_t *config_data
)
310 VirtIOBalloon
*dev
= VIRTIO_BALLOON(vdev
);
311 struct virtio_balloon_config config
;
313 config
.num_pages
= cpu_to_le32(dev
->num_pages
);
314 config
.actual
= cpu_to_le32(dev
->actual
);
316 trace_virtio_balloon_get_config(config
.num_pages
, config
.actual
);
317 memcpy(config_data
, &config
, sizeof(struct virtio_balloon_config
));
320 static int build_dimm_list(Object
*obj
, void *opaque
)
322 GSList
**list
= opaque
;
324 if (object_dynamic_cast(obj
, TYPE_PC_DIMM
)) {
325 DeviceState
*dev
= DEVICE(obj
);
326 if (dev
->realized
) { /* only realized DIMMs matter */
327 *list
= g_slist_prepend(*list
, dev
);
331 object_child_foreach(obj
, build_dimm_list
, opaque
);
335 static ram_addr_t
get_current_ram_size(void)
337 GSList
*list
= NULL
, *item
;
338 ram_addr_t size
= ram_size
;
340 build_dimm_list(qdev_get_machine(), &list
);
341 for (item
= list
; item
; item
= g_slist_next(item
)) {
342 Object
*obj
= OBJECT(item
->data
);
343 if (!strcmp(object_get_typename(obj
), TYPE_PC_DIMM
)) {
344 size
+= object_property_get_int(obj
, PC_DIMM_SIZE_PROP
,
353 static void virtio_balloon_set_config(VirtIODevice
*vdev
,
354 const uint8_t *config_data
)
356 VirtIOBalloon
*dev
= VIRTIO_BALLOON(vdev
);
357 struct virtio_balloon_config config
;
358 uint32_t oldactual
= dev
->actual
;
359 ram_addr_t vm_ram_size
= get_current_ram_size();
361 memcpy(&config
, config_data
, sizeof(struct virtio_balloon_config
));
362 dev
->actual
= le32_to_cpu(config
.actual
);
363 if (dev
->actual
!= oldactual
) {
364 qapi_event_send_balloon_change(vm_ram_size
-
365 ((ram_addr_t
) dev
->actual
<< VIRTIO_BALLOON_PFN_SHIFT
),
368 trace_virtio_balloon_set_config(dev
->actual
, oldactual
);
371 static uint64_t virtio_balloon_get_features(VirtIODevice
*vdev
, uint64_t f
,
374 VirtIOBalloon
*dev
= VIRTIO_BALLOON(vdev
);
375 f
|= dev
->host_features
;
376 virtio_add_feature(&f
, VIRTIO_BALLOON_F_STATS_VQ
);
380 static void virtio_balloon_stat(void *opaque
, BalloonInfo
*info
)
382 VirtIOBalloon
*dev
= opaque
;
383 info
->actual
= get_current_ram_size() - ((uint64_t) dev
->actual
<<
384 VIRTIO_BALLOON_PFN_SHIFT
);
387 static void virtio_balloon_to_target(void *opaque
, ram_addr_t target
)
389 VirtIOBalloon
*dev
= VIRTIO_BALLOON(opaque
);
390 VirtIODevice
*vdev
= VIRTIO_DEVICE(dev
);
391 ram_addr_t vm_ram_size
= get_current_ram_size();
393 if (target
> vm_ram_size
) {
394 target
= vm_ram_size
;
397 dev
->num_pages
= (vm_ram_size
- target
) >> VIRTIO_BALLOON_PFN_SHIFT
;
398 virtio_notify_config(vdev
);
400 trace_virtio_balloon_to_target(target
, dev
->num_pages
);
403 static void virtio_balloon_save(QEMUFile
*f
, void *opaque
)
405 virtio_save(VIRTIO_DEVICE(opaque
), f
);
408 static void virtio_balloon_save_device(VirtIODevice
*vdev
, QEMUFile
*f
)
410 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
412 qemu_put_be32(f
, s
->num_pages
);
413 qemu_put_be32(f
, s
->actual
);
416 static int virtio_balloon_load(QEMUFile
*f
, void *opaque
, int version_id
)
421 return virtio_load(VIRTIO_DEVICE(opaque
), f
, version_id
);
424 static int virtio_balloon_load_device(VirtIODevice
*vdev
, QEMUFile
*f
,
427 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
429 s
->num_pages
= qemu_get_be32(f
);
430 s
->actual
= qemu_get_be32(f
);
432 if (balloon_stats_enabled(s
)) {
433 balloon_stats_change_timer(s
, s
->stats_poll_interval
);
438 static void virtio_balloon_device_realize(DeviceState
*dev
, Error
**errp
)
440 VirtIODevice
*vdev
= VIRTIO_DEVICE(dev
);
441 VirtIOBalloon
*s
= VIRTIO_BALLOON(dev
);
444 virtio_init(vdev
, "virtio-balloon", VIRTIO_ID_BALLOON
,
445 sizeof(struct virtio_balloon_config
));
447 ret
= qemu_add_balloon_handler(virtio_balloon_to_target
,
448 virtio_balloon_stat
, s
);
451 error_setg(errp
, "Only one balloon device is supported");
452 virtio_cleanup(vdev
);
456 s
->ivq
= virtio_add_queue(vdev
, 128, virtio_balloon_handle_output
);
457 s
->dvq
= virtio_add_queue(vdev
, 128, virtio_balloon_handle_output
);
458 s
->svq
= virtio_add_queue(vdev
, 128, virtio_balloon_receive_stats
);
462 register_savevm(dev
, "virtio-balloon", -1, 1,
463 virtio_balloon_save
, virtio_balloon_load
, s
);
466 static void virtio_balloon_device_unrealize(DeviceState
*dev
, Error
**errp
)
468 VirtIODevice
*vdev
= VIRTIO_DEVICE(dev
);
469 VirtIOBalloon
*s
= VIRTIO_BALLOON(dev
);
471 balloon_stats_destroy_timer(s
);
472 qemu_remove_balloon_handler(s
);
473 unregister_savevm(dev
, "virtio-balloon", s
);
474 virtio_cleanup(vdev
);
477 static void virtio_balloon_device_reset(VirtIODevice
*vdev
)
479 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
481 if (s
->stats_vq_elem
!= NULL
) {
482 g_free(s
->stats_vq_elem
);
483 s
->stats_vq_elem
= NULL
;
487 static void virtio_balloon_instance_init(Object
*obj
)
489 VirtIOBalloon
*s
= VIRTIO_BALLOON(obj
);
491 object_property_add(obj
, "guest-stats", "guest statistics",
492 balloon_stats_get_all
, NULL
, NULL
, s
, NULL
);
494 object_property_add(obj
, "guest-stats-polling-interval", "int",
495 balloon_stats_get_poll_interval
,
496 balloon_stats_set_poll_interval
,
500 static Property virtio_balloon_properties
[] = {
501 DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon
, host_features
,
502 VIRTIO_BALLOON_F_DEFLATE_ON_OOM
, false),
503 DEFINE_PROP_END_OF_LIST(),
506 static void virtio_balloon_class_init(ObjectClass
*klass
, void *data
)
508 DeviceClass
*dc
= DEVICE_CLASS(klass
);
509 VirtioDeviceClass
*vdc
= VIRTIO_DEVICE_CLASS(klass
);
511 dc
->props
= virtio_balloon_properties
;
512 set_bit(DEVICE_CATEGORY_MISC
, dc
->categories
);
513 vdc
->realize
= virtio_balloon_device_realize
;
514 vdc
->unrealize
= virtio_balloon_device_unrealize
;
515 vdc
->reset
= virtio_balloon_device_reset
;
516 vdc
->get_config
= virtio_balloon_get_config
;
517 vdc
->set_config
= virtio_balloon_set_config
;
518 vdc
->get_features
= virtio_balloon_get_features
;
519 vdc
->save
= virtio_balloon_save_device
;
520 vdc
->load
= virtio_balloon_load_device
;
523 static const TypeInfo virtio_balloon_info
= {
524 .name
= TYPE_VIRTIO_BALLOON
,
525 .parent
= TYPE_VIRTIO_DEVICE
,
526 .instance_size
= sizeof(VirtIOBalloon
),
527 .instance_init
= virtio_balloon_instance_init
,
528 .class_init
= virtio_balloon_class_init
,
531 static void virtio_register_types(void)
533 type_register_static(&virtio_balloon_info
);
536 type_init(virtio_register_types
)