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 #define VMSTATE_VIRTIO_DEVICE_USE_NEW
18 #include "qemu/osdep.h"
20 #include "qemu/timer.h"
21 #include "qemu-common.h"
22 #include "hw/virtio/virtio.h"
23 #include "hw/i386/pc.h"
24 #include "sysemu/balloon.h"
25 #include "hw/virtio/virtio-balloon.h"
26 #include "sysemu/kvm.h"
27 #include "exec/address-spaces.h"
28 #include "qapi/visitor.h"
29 #include "qapi-event.h"
32 #include "hw/virtio/virtio-bus.h"
33 #include "hw/virtio/virtio-access.h"
35 #define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT)
37 static void balloon_page(void *addr
, int deflate
)
39 if (!qemu_balloon_is_inhibited() && (!kvm_enabled() ||
40 kvm_has_sync_mmu())) {
41 qemu_madvise(addr
, BALLOON_PAGE_SIZE
,
42 deflate
? QEMU_MADV_WILLNEED
: QEMU_MADV_DONTNEED
);
46 static const char *balloon_stat_names
[] = {
47 [VIRTIO_BALLOON_S_SWAP_IN
] = "stat-swap-in",
48 [VIRTIO_BALLOON_S_SWAP_OUT
] = "stat-swap-out",
49 [VIRTIO_BALLOON_S_MAJFLT
] = "stat-major-faults",
50 [VIRTIO_BALLOON_S_MINFLT
] = "stat-minor-faults",
51 [VIRTIO_BALLOON_S_MEMFREE
] = "stat-free-memory",
52 [VIRTIO_BALLOON_S_MEMTOT
] = "stat-total-memory",
53 [VIRTIO_BALLOON_S_AVAIL
] = "stat-available-memory",
54 [VIRTIO_BALLOON_S_NR
] = NULL
58 * reset_stats - Mark all items in the stats array as unset
60 * This function needs to be called at device initialization and before
61 * updating to a set of newly-generated stats. This will ensure that no
62 * stale values stick around in case the guest reports a subset of the supported
65 static inline void reset_stats(VirtIOBalloon
*dev
)
68 for (i
= 0; i
< VIRTIO_BALLOON_S_NR
; dev
->stats
[i
++] = -1);
71 static bool balloon_stats_supported(const VirtIOBalloon
*s
)
73 VirtIODevice
*vdev
= VIRTIO_DEVICE(s
);
74 return virtio_vdev_has_feature(vdev
, VIRTIO_BALLOON_F_STATS_VQ
);
77 static bool balloon_stats_enabled(const VirtIOBalloon
*s
)
79 return s
->stats_poll_interval
> 0;
82 static void balloon_stats_destroy_timer(VirtIOBalloon
*s
)
84 if (balloon_stats_enabled(s
)) {
85 timer_del(s
->stats_timer
);
86 timer_free(s
->stats_timer
);
87 s
->stats_timer
= NULL
;
88 s
->stats_poll_interval
= 0;
92 static void balloon_stats_change_timer(VirtIOBalloon
*s
, int64_t secs
)
94 timer_mod(s
->stats_timer
, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL
) + secs
* 1000);
97 static void balloon_stats_poll_cb(void *opaque
)
99 VirtIOBalloon
*s
= opaque
;
100 VirtIODevice
*vdev
= VIRTIO_DEVICE(s
);
102 if (s
->stats_vq_elem
== NULL
|| !balloon_stats_supported(s
)) {
104 balloon_stats_change_timer(s
, s
->stats_poll_interval
);
108 virtqueue_push(s
->svq
, s
->stats_vq_elem
, s
->stats_vq_offset
);
109 virtio_notify(vdev
, s
->svq
);
110 g_free(s
->stats_vq_elem
);
111 s
->stats_vq_elem
= NULL
;
114 static void balloon_stats_get_all(Object
*obj
, Visitor
*v
, const char *name
,
115 void *opaque
, Error
**errp
)
118 VirtIOBalloon
*s
= opaque
;
121 visit_start_struct(v
, name
, NULL
, 0, &err
);
125 visit_type_int(v
, "last-update", &s
->stats_last_update
, &err
);
130 visit_start_struct(v
, "stats", NULL
, 0, &err
);
134 for (i
= 0; i
< VIRTIO_BALLOON_S_NR
; i
++) {
135 visit_type_uint64(v
, balloon_stat_names
[i
], &s
->stats
[i
], &err
);
140 visit_check_struct(v
, &err
);
142 visit_end_struct(v
, NULL
);
145 visit_check_struct(v
, &err
);
148 visit_end_struct(v
, NULL
);
150 error_propagate(errp
, err
);
153 static void balloon_stats_get_poll_interval(Object
*obj
, Visitor
*v
,
154 const char *name
, void *opaque
,
157 VirtIOBalloon
*s
= opaque
;
158 visit_type_int(v
, name
, &s
->stats_poll_interval
, errp
);
161 static void balloon_stats_set_poll_interval(Object
*obj
, Visitor
*v
,
162 const char *name
, void *opaque
,
165 VirtIOBalloon
*s
= opaque
;
166 Error
*local_err
= NULL
;
169 visit_type_int(v
, name
, &value
, &local_err
);
171 error_propagate(errp
, local_err
);
176 error_setg(errp
, "timer value must be greater than zero");
180 if (value
> UINT32_MAX
) {
181 error_setg(errp
, "timer value is too big");
185 if (value
== s
->stats_poll_interval
) {
190 /* timer=0 disables the timer */
191 balloon_stats_destroy_timer(s
);
195 if (balloon_stats_enabled(s
)) {
196 /* timer interval change */
197 s
->stats_poll_interval
= value
;
198 balloon_stats_change_timer(s
, value
);
202 /* create a new timer */
203 g_assert(s
->stats_timer
== NULL
);
204 s
->stats_timer
= timer_new_ms(QEMU_CLOCK_VIRTUAL
, balloon_stats_poll_cb
, s
);
205 s
->stats_poll_interval
= value
;
206 balloon_stats_change_timer(s
, 0);
209 static void virtio_balloon_handle_output(VirtIODevice
*vdev
, VirtQueue
*vq
)
211 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
212 VirtQueueElement
*elem
;
213 MemoryRegionSection section
;
218 elem
= virtqueue_pop(vq
, sizeof(VirtQueueElement
));
223 while (iov_to_buf(elem
->out_sg
, elem
->out_num
, offset
, &pfn
, 4) == 4) {
226 int p
= virtio_ldl_p(vdev
, &pfn
);
228 pa
= (ram_addr_t
) p
<< VIRTIO_BALLOON_PFN_SHIFT
;
231 /* FIXME: remove get_system_memory(), but how? */
232 section
= memory_region_find(get_system_memory(), pa
, 1);
233 if (!int128_nz(section
.size
) || !memory_region_is_ram(section
.mr
))
236 trace_virtio_balloon_handle_output(memory_region_name(section
.mr
),
238 /* Using memory_region_get_ram_ptr is bending the rules a bit, but
239 should be OK because we only want a single page. */
240 addr
= section
.offset_within_region
;
241 balloon_page(memory_region_get_ram_ptr(section
.mr
) + addr
,
243 memory_region_unref(section
.mr
);
246 virtqueue_push(vq
, elem
, offset
);
247 virtio_notify(vdev
, vq
);
252 static void virtio_balloon_receive_stats(VirtIODevice
*vdev
, VirtQueue
*vq
)
254 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
255 VirtQueueElement
*elem
;
256 VirtIOBalloonStat stat
;
260 elem
= virtqueue_pop(vq
, sizeof(VirtQueueElement
));
265 if (s
->stats_vq_elem
!= NULL
) {
266 /* This should never happen if the driver follows the spec. */
267 virtqueue_push(vq
, s
->stats_vq_elem
, 0);
268 virtio_notify(vdev
, vq
);
269 g_free(s
->stats_vq_elem
);
272 s
->stats_vq_elem
= elem
;
274 /* Initialize the stats to get rid of any stale values. This is only
275 * needed to handle the case where a guest supports fewer stats than it
276 * used to (ie. it has booted into an old kernel).
280 while (iov_to_buf(elem
->out_sg
, elem
->out_num
, offset
, &stat
, sizeof(stat
))
282 uint16_t tag
= virtio_tswap16(vdev
, stat
.tag
);
283 uint64_t val
= virtio_tswap64(vdev
, stat
.val
);
285 offset
+= sizeof(stat
);
286 if (tag
< VIRTIO_BALLOON_S_NR
)
289 s
->stats_vq_offset
= offset
;
291 if (qemu_gettimeofday(&tv
) < 0) {
292 fprintf(stderr
, "warning: %s: failed to get time of day\n", __func__
);
296 s
->stats_last_update
= tv
.tv_sec
;
299 if (balloon_stats_enabled(s
)) {
300 balloon_stats_change_timer(s
, s
->stats_poll_interval
);
304 static void virtio_balloon_get_config(VirtIODevice
*vdev
, uint8_t *config_data
)
306 VirtIOBalloon
*dev
= VIRTIO_BALLOON(vdev
);
307 struct virtio_balloon_config config
;
309 config
.num_pages
= cpu_to_le32(dev
->num_pages
);
310 config
.actual
= cpu_to_le32(dev
->actual
);
312 trace_virtio_balloon_get_config(config
.num_pages
, config
.actual
);
313 memcpy(config_data
, &config
, sizeof(struct virtio_balloon_config
));
316 static int build_dimm_list(Object
*obj
, void *opaque
)
318 GSList
**list
= opaque
;
320 if (object_dynamic_cast(obj
, TYPE_PC_DIMM
)) {
321 DeviceState
*dev
= DEVICE(obj
);
322 if (dev
->realized
) { /* only realized DIMMs matter */
323 *list
= g_slist_prepend(*list
, dev
);
327 object_child_foreach(obj
, build_dimm_list
, opaque
);
331 static ram_addr_t
get_current_ram_size(void)
333 GSList
*list
= NULL
, *item
;
334 ram_addr_t size
= ram_size
;
336 build_dimm_list(qdev_get_machine(), &list
);
337 for (item
= list
; item
; item
= g_slist_next(item
)) {
338 Object
*obj
= OBJECT(item
->data
);
339 if (!strcmp(object_get_typename(obj
), TYPE_PC_DIMM
)) {
340 size
+= object_property_get_int(obj
, PC_DIMM_SIZE_PROP
,
349 static void virtio_balloon_set_config(VirtIODevice
*vdev
,
350 const uint8_t *config_data
)
352 VirtIOBalloon
*dev
= VIRTIO_BALLOON(vdev
);
353 struct virtio_balloon_config config
;
354 uint32_t oldactual
= dev
->actual
;
355 ram_addr_t vm_ram_size
= get_current_ram_size();
357 memcpy(&config
, config_data
, sizeof(struct virtio_balloon_config
));
358 dev
->actual
= le32_to_cpu(config
.actual
);
359 if (dev
->actual
!= oldactual
) {
360 qapi_event_send_balloon_change(vm_ram_size
-
361 ((ram_addr_t
) dev
->actual
<< VIRTIO_BALLOON_PFN_SHIFT
),
364 trace_virtio_balloon_set_config(dev
->actual
, oldactual
);
367 static uint64_t virtio_balloon_get_features(VirtIODevice
*vdev
, uint64_t f
,
370 VirtIOBalloon
*dev
= VIRTIO_BALLOON(vdev
);
371 f
|= dev
->host_features
;
372 virtio_add_feature(&f
, VIRTIO_BALLOON_F_STATS_VQ
);
376 static void virtio_balloon_stat(void *opaque
, BalloonInfo
*info
)
378 VirtIOBalloon
*dev
= opaque
;
379 info
->actual
= get_current_ram_size() - ((uint64_t) dev
->actual
<<
380 VIRTIO_BALLOON_PFN_SHIFT
);
383 static void virtio_balloon_to_target(void *opaque
, ram_addr_t target
)
385 VirtIOBalloon
*dev
= VIRTIO_BALLOON(opaque
);
386 VirtIODevice
*vdev
= VIRTIO_DEVICE(dev
);
387 ram_addr_t vm_ram_size
= get_current_ram_size();
389 if (target
> vm_ram_size
) {
390 target
= vm_ram_size
;
393 dev
->num_pages
= (vm_ram_size
- target
) >> VIRTIO_BALLOON_PFN_SHIFT
;
394 virtio_notify_config(vdev
);
396 trace_virtio_balloon_to_target(target
, dev
->num_pages
);
399 static void virtio_balloon_save_device(VirtIODevice
*vdev
, QEMUFile
*f
)
401 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
403 qemu_put_be32(f
, s
->num_pages
);
404 qemu_put_be32(f
, s
->actual
);
407 static int virtio_balloon_load_device(VirtIODevice
*vdev
, QEMUFile
*f
,
410 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
412 s
->num_pages
= qemu_get_be32(f
);
413 s
->actual
= qemu_get_be32(f
);
415 if (balloon_stats_enabled(s
)) {
416 balloon_stats_change_timer(s
, s
->stats_poll_interval
);
421 static void virtio_balloon_device_realize(DeviceState
*dev
, Error
**errp
)
423 VirtIODevice
*vdev
= VIRTIO_DEVICE(dev
);
424 VirtIOBalloon
*s
= VIRTIO_BALLOON(dev
);
427 virtio_init(vdev
, "virtio-balloon", VIRTIO_ID_BALLOON
,
428 sizeof(struct virtio_balloon_config
));
430 ret
= qemu_add_balloon_handler(virtio_balloon_to_target
,
431 virtio_balloon_stat
, s
);
434 error_setg(errp
, "Only one balloon device is supported");
435 virtio_cleanup(vdev
);
439 s
->ivq
= virtio_add_queue(vdev
, 128, virtio_balloon_handle_output
);
440 s
->dvq
= virtio_add_queue(vdev
, 128, virtio_balloon_handle_output
);
441 s
->svq
= virtio_add_queue(vdev
, 128, virtio_balloon_receive_stats
);
446 static void virtio_balloon_device_unrealize(DeviceState
*dev
, Error
**errp
)
448 VirtIODevice
*vdev
= VIRTIO_DEVICE(dev
);
449 VirtIOBalloon
*s
= VIRTIO_BALLOON(dev
);
451 balloon_stats_destroy_timer(s
);
452 qemu_remove_balloon_handler(s
);
453 virtio_cleanup(vdev
);
456 static void virtio_balloon_device_reset(VirtIODevice
*vdev
)
458 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
460 if (s
->stats_vq_elem
!= NULL
) {
461 virtqueue_discard(s
->svq
, s
->stats_vq_elem
, 0);
462 g_free(s
->stats_vq_elem
);
463 s
->stats_vq_elem
= NULL
;
467 static void virtio_balloon_set_status(VirtIODevice
*vdev
, uint8_t status
)
469 VirtIOBalloon
*s
= VIRTIO_BALLOON(vdev
);
471 if (!s
->stats_vq_elem
&& vdev
->vm_running
&&
472 (status
& VIRTIO_CONFIG_S_DRIVER_OK
) && virtqueue_rewind(s
->svq
, 1)) {
473 /* poll stats queue for the element we have discarded when the VM
475 virtio_balloon_receive_stats(vdev
, s
->svq
);
479 static void virtio_balloon_instance_init(Object
*obj
)
481 VirtIOBalloon
*s
= VIRTIO_BALLOON(obj
);
483 object_property_add(obj
, "guest-stats", "guest statistics",
484 balloon_stats_get_all
, NULL
, NULL
, s
, NULL
);
486 object_property_add(obj
, "guest-stats-polling-interval", "int",
487 balloon_stats_get_poll_interval
,
488 balloon_stats_set_poll_interval
,
492 static const VMStateDescription vmstate_virtio_balloon
= {
493 .name
= "virtio-balloon",
494 .minimum_version_id
= 1,
496 .fields
= (VMStateField
[]) {
497 VMSTATE_VIRTIO_DEVICE
,
498 VMSTATE_END_OF_LIST()
502 static Property virtio_balloon_properties
[] = {
503 DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon
, host_features
,
504 VIRTIO_BALLOON_F_DEFLATE_ON_OOM
, false),
505 DEFINE_PROP_END_OF_LIST(),
508 static void virtio_balloon_class_init(ObjectClass
*klass
, void *data
)
510 DeviceClass
*dc
= DEVICE_CLASS(klass
);
511 VirtioDeviceClass
*vdc
= VIRTIO_DEVICE_CLASS(klass
);
513 dc
->props
= virtio_balloon_properties
;
514 dc
->vmsd
= &vmstate_virtio_balloon
;
515 set_bit(DEVICE_CATEGORY_MISC
, dc
->categories
);
516 vdc
->realize
= virtio_balloon_device_realize
;
517 vdc
->unrealize
= virtio_balloon_device_unrealize
;
518 vdc
->reset
= virtio_balloon_device_reset
;
519 vdc
->get_config
= virtio_balloon_get_config
;
520 vdc
->set_config
= virtio_balloon_set_config
;
521 vdc
->get_features
= virtio_balloon_get_features
;
522 vdc
->save
= virtio_balloon_save_device
;
523 vdc
->load
= virtio_balloon_load_device
;
524 vdc
->set_status
= virtio_balloon_set_status
;
527 static const TypeInfo virtio_balloon_info
= {
528 .name
= TYPE_VIRTIO_BALLOON
,
529 .parent
= TYPE_VIRTIO_DEVICE
,
530 .instance_size
= sizeof(VirtIOBalloon
),
531 .instance_init
= virtio_balloon_instance_init
,
532 .class_init
= virtio_balloon_class_init
,
535 static void virtio_register_types(void)
537 type_register_static(&virtio_balloon_info
);
540 type_init(virtio_register_types
)