diff options
Diffstat (limited to 'hw/virtio/virtio-balloon.c')
| -rw-r--r-- | hw/virtio/virtio-balloon.c | 1079 |
1 files changed, 1079 insertions, 0 deletions
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c new file mode 100644 index 00000000..73ac5eb6 --- /dev/null +++ b/hw/virtio/virtio-balloon.c @@ -0,0 +1,1079 @@ +/* + * Virtio Balloon Device + * + * Copyright IBM, Corp. 2008 + * Copyright (C) 2011 Red Hat, Inc. + * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com> + * + * Authors: + * Anthony Liguori <aliguori@us.ibm.com> + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ + +#include "qemu/osdep.h" +#include "qemu/iov.h" +#include "qemu/module.h" +#include "qemu/timer.h" +#include "qemu/madvise.h" +#include "hw/virtio/virtio.h" +#include "hw/mem/pc-dimm.h" +#include "hw/qdev-properties.h" +#include "hw/boards.h" +#include "sysemu/balloon.h" +#include "hw/virtio/virtio-balloon.h" +#include "exec/address-spaces.h" +#include "qapi/error.h" +#include "qapi/qapi-events-machine.h" +#include "qapi/visitor.h" +#include "trace.h" +#include "qemu/error-report.h" +#include "migration/misc.h" +#include "migration/migration.h" + +#include "hw/virtio/virtio-bus.h" +#include "hw/virtio/virtio-access.h" + +#define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT) + +typedef struct PartiallyBalloonedPage { + ram_addr_t base_gpa; + unsigned long *bitmap; +} PartiallyBalloonedPage; + +static void virtio_balloon_pbp_free(PartiallyBalloonedPage *pbp) +{ + if (!pbp->bitmap) { + return; + } + g_free(pbp->bitmap); + pbp->bitmap = NULL; +} + +static void virtio_balloon_pbp_alloc(PartiallyBalloonedPage *pbp, + ram_addr_t base_gpa, + long subpages) +{ + pbp->base_gpa = base_gpa; + pbp->bitmap = bitmap_new(subpages); +} + +static bool virtio_balloon_pbp_matches(PartiallyBalloonedPage *pbp, + ram_addr_t base_gpa) +{ + return pbp->base_gpa == base_gpa; +} + +static bool virtio_balloon_inhibited(void) +{ + /* + * Postcopy cannot deal with concurrent discards, + * so it's special, as well as background snapshots. + */ + return ram_block_discard_is_disabled() || migration_in_incoming_postcopy() || + migration_in_bg_snapshot(); +} + +static void balloon_inflate_page(VirtIOBalloon *balloon, + MemoryRegion *mr, hwaddr mr_offset, + PartiallyBalloonedPage *pbp) +{ + void *addr = memory_region_get_ram_ptr(mr) + mr_offset; + ram_addr_t rb_offset, rb_aligned_offset, base_gpa; + RAMBlock *rb; + size_t rb_page_size; + int subpages; + + /* XXX is there a better way to get to the RAMBlock than via a + * host address? */ + rb = qemu_ram_block_from_host(addr, false, &rb_offset); + rb_page_size = qemu_ram_pagesize(rb); + + if (rb_page_size == BALLOON_PAGE_SIZE) { + /* Easy case */ + + ram_block_discard_range(rb, rb_offset, rb_page_size); + /* We ignore errors from ram_block_discard_range(), because it + * has already reported them, and failing to discard a balloon + * page is not fatal */ + return; + } + + /* Hard case + * + * We've put a piece of a larger host page into the balloon - we + * need to keep track until we have a whole host page to + * discard + */ + warn_report_once( +"Balloon used with backing page size > 4kiB, this may not be reliable"); + + rb_aligned_offset = QEMU_ALIGN_DOWN(rb_offset, rb_page_size); + subpages = rb_page_size / BALLOON_PAGE_SIZE; + base_gpa = memory_region_get_ram_addr(mr) + mr_offset - + (rb_offset - rb_aligned_offset); + + if (pbp->bitmap && !virtio_balloon_pbp_matches(pbp, base_gpa)) { + /* We've partially ballooned part of a host page, but now + * we're trying to balloon part of a different one. Too hard, + * give up on the old partial page */ + virtio_balloon_pbp_free(pbp); + } + + if (!pbp->bitmap) { + virtio_balloon_pbp_alloc(pbp, base_gpa, subpages); + } + + set_bit((rb_offset - rb_aligned_offset) / BALLOON_PAGE_SIZE, + pbp->bitmap); + + if (bitmap_full(pbp->bitmap, subpages)) { + /* We've accumulated a full host page, we can actually discard + * it now */ + + ram_block_discard_range(rb, rb_aligned_offset, rb_page_size); + /* We ignore errors from ram_block_discard_range(), because it + * has already reported them, and failing to discard a balloon + * page is not fatal */ + virtio_balloon_pbp_free(pbp); + } +} + +static void balloon_deflate_page(VirtIOBalloon *balloon, + MemoryRegion *mr, hwaddr mr_offset) +{ + void *addr = memory_region_get_ram_ptr(mr) + mr_offset; + ram_addr_t rb_offset; + RAMBlock *rb; + size_t rb_page_size; + void *host_addr; + int ret; + + /* XXX is there a better way to get to the RAMBlock than via a + * host address? */ + rb = qemu_ram_block_from_host(addr, false, &rb_offset); + rb_page_size = qemu_ram_pagesize(rb); + + host_addr = (void *)((uintptr_t)addr & ~(rb_page_size - 1)); + + /* When a page is deflated, we hint the whole host page it lives + * on, since we can't do anything smaller */ + ret = qemu_madvise(host_addr, rb_page_size, QEMU_MADV_WILLNEED); + if (ret != 0) { + warn_report("Couldn't MADV_WILLNEED on balloon deflate: %s", + strerror(errno)); + /* Otherwise ignore, failing to page hint shouldn't be fatal */ + } +} + +static const char *balloon_stat_names[] = { + [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in", + [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out", + [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults", + [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults", + [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory", + [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory", + [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory", + [VIRTIO_BALLOON_S_CACHES] = "stat-disk-caches", + [VIRTIO_BALLOON_S_HTLB_PGALLOC] = "stat-htlb-pgalloc", + [VIRTIO_BALLOON_S_HTLB_PGFAIL] = "stat-htlb-pgfail", + [VIRTIO_BALLOON_S_NR] = NULL +}; + +/* + * reset_stats - Mark all items in the stats array as unset + * + * This function needs to be called at device initialization and before + * updating to a set of newly-generated stats. This will ensure that no + * stale values stick around in case the guest reports a subset of the supported + * statistics. + */ +static inline void reset_stats(VirtIOBalloon *dev) +{ + int i; + for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1); +} + +static bool balloon_stats_supported(const VirtIOBalloon *s) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(s); + return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); +} + +static bool balloon_stats_enabled(const VirtIOBalloon *s) +{ + return s->stats_poll_interval > 0; +} + +static void balloon_stats_destroy_timer(VirtIOBalloon *s) +{ + if (balloon_stats_enabled(s)) { + timer_free(s->stats_timer); + s->stats_timer = NULL; + s->stats_poll_interval = 0; + } +} + +static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs) +{ + timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000); +} + +static void balloon_stats_poll_cb(void *opaque) +{ + VirtIOBalloon *s = opaque; + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) { + /* re-schedule */ + balloon_stats_change_timer(s, s->stats_poll_interval); + return; + } + + virtqueue_push(s->svq, s->stats_vq_elem, 0); + virtio_notify(vdev, s->svq); + g_free(s->stats_vq_elem); + s->stats_vq_elem = NULL; +} + +static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name, + void *opaque, Error **errp) +{ + Error *err = NULL; + VirtIOBalloon *s = VIRTIO_BALLOON(obj); + int i; + + if (!visit_start_struct(v, name, NULL, 0, &err)) { + goto out; + } + if (!visit_type_int(v, "last-update", &s->stats_last_update, &err)) { + goto out_end; + } + + if (!visit_start_struct(v, "stats", NULL, 0, &err)) { + goto out_end; + } + for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) { + if (!visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err)) { + goto out_nested; + } + } + visit_check_struct(v, &err); +out_nested: + visit_end_struct(v, NULL); + + if (!err) { + visit_check_struct(v, &err); + } +out_end: + visit_end_struct(v, NULL); +out: + error_propagate(errp, err); +} + +static void balloon_stats_get_poll_interval(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(obj); + visit_type_int(v, name, &s->stats_poll_interval, errp); +} + +static void balloon_stats_set_poll_interval(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(obj); + int64_t value; + + if (!visit_type_int(v, name, &value, errp)) { + return; + } + + if (value < 0) { + error_setg(errp, "timer value must be greater than zero"); + return; + } + + if (value > UINT32_MAX) { + error_setg(errp, "timer value is too big"); + return; + } + + if (value == s->stats_poll_interval) { + return; + } + + if (value == 0) { + /* timer=0 disables the timer */ + balloon_stats_destroy_timer(s); + return; + } + + if (balloon_stats_enabled(s)) { + /* timer interval change */ + s->stats_poll_interval = value; + balloon_stats_change_timer(s, value); + return; + } + + /* create a new timer */ + g_assert(s->stats_timer == NULL); + s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); + s->stats_poll_interval = value; + balloon_stats_change_timer(s, 0); +} + +static void virtio_balloon_handle_report(VirtIODevice *vdev, VirtQueue *vq) +{ + VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); + VirtQueueElement *elem; + + while ((elem = virtqueue_pop(vq, sizeof(VirtQueueElement)))) { + unsigned int i; + + /* + * When we discard the page it has the effect of removing the page + * from the hypervisor itself and causing it to be zeroed when it + * is returned to us. So we must not discard the page if it is + * accessible by another device or process, or if the guest is + * expecting it to retain a non-zero value. + */ + if (virtio_balloon_inhibited() || dev->poison_val) { + goto skip_element; + } + + for (i = 0; i < elem->in_num; i++) { + void *addr = elem->in_sg[i].iov_base; + size_t size = elem->in_sg[i].iov_len; + ram_addr_t ram_offset; + RAMBlock *rb; + + /* + * There is no need to check the memory section to see if + * it is ram/readonly/romd like there is for handle_output + * below. If the region is not meant to be written to then + * address_space_map will have allocated a bounce buffer + * and it will be freed in address_space_unmap and trigger + * and unassigned_mem_write before failing to copy over the + * buffer. If more than one bad descriptor is provided it + * will return NULL after the first bounce buffer and fail + * to map any resources. + */ + rb = qemu_ram_block_from_host(addr, false, &ram_offset); + if (!rb) { + trace_virtio_balloon_bad_addr(elem->in_addr[i]); + continue; + } + + /* + * For now we will simply ignore unaligned memory regions, or + * regions that overrun the end of the RAMBlock. + */ + if (!QEMU_IS_ALIGNED(ram_offset | size, qemu_ram_pagesize(rb)) || + (ram_offset + size) > qemu_ram_get_used_length(rb)) { + continue; + } + + ram_block_discard_range(rb, ram_offset, size); + } + +skip_element: + virtqueue_push(vq, elem, 0); + virtio_notify(vdev, vq); + g_free(elem); + } +} + +static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(vdev); + VirtQueueElement *elem; + MemoryRegionSection section; + + for (;;) { + PartiallyBalloonedPage pbp = {}; + size_t offset = 0; + uint32_t pfn; + + elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); + if (!elem) { + break; + } + + while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) { + unsigned int p = virtio_ldl_p(vdev, &pfn); + hwaddr pa; + + pa = (hwaddr) p << VIRTIO_BALLOON_PFN_SHIFT; + offset += 4; + + section = memory_region_find(get_system_memory(), pa, + BALLOON_PAGE_SIZE); + if (!section.mr) { + trace_virtio_balloon_bad_addr(pa); + continue; + } + if (!memory_region_is_ram(section.mr) || + memory_region_is_rom(section.mr) || + memory_region_is_romd(section.mr)) { + trace_virtio_balloon_bad_addr(pa); + memory_region_unref(section.mr); + continue; + } + + trace_virtio_balloon_handle_output(memory_region_name(section.mr), + pa); + if (!virtio_balloon_inhibited()) { + if (vq == s->ivq) { + balloon_inflate_page(s, section.mr, + section.offset_within_region, &pbp); + } else if (vq == s->dvq) { + balloon_deflate_page(s, section.mr, section.offset_within_region); + } else { + g_assert_not_reached(); + } + } + memory_region_unref(section.mr); + } + + virtqueue_push(vq, elem, 0); + virtio_notify(vdev, vq); + g_free(elem); + virtio_balloon_pbp_free(&pbp); + } +} + +static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(vdev); + VirtQueueElement *elem; + VirtIOBalloonStat stat; + size_t offset = 0; + + elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); + if (!elem) { + goto out; + } + + if (s->stats_vq_elem != NULL) { + /* This should never happen if the driver follows the spec. */ + virtqueue_push(vq, s->stats_vq_elem, 0); + virtio_notify(vdev, vq); + g_free(s->stats_vq_elem); + } + + s->stats_vq_elem = elem; + + /* Initialize the stats to get rid of any stale values. This is only + * needed to handle the case where a guest supports fewer stats than it + * used to (ie. it has booted into an old kernel). + */ + reset_stats(s); + + while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat)) + == sizeof(stat)) { + uint16_t tag = virtio_tswap16(vdev, stat.tag); + uint64_t val = virtio_tswap64(vdev, stat.val); + + offset += sizeof(stat); + if (tag < VIRTIO_BALLOON_S_NR) + s->stats[tag] = val; + } + s->stats_vq_offset = offset; + s->stats_last_update = g_get_real_time() / G_USEC_PER_SEC; + +out: + if (balloon_stats_enabled(s)) { + balloon_stats_change_timer(s, s->stats_poll_interval); + } +} + +static void virtio_balloon_handle_free_page_vq(VirtIODevice *vdev, + VirtQueue *vq) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(vdev); + qemu_bh_schedule(s->free_page_bh); +} + +static bool get_free_page_hints(VirtIOBalloon *dev) +{ + VirtQueueElement *elem; + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VirtQueue *vq = dev->free_page_vq; + bool ret = true; + int i; + + while (dev->block_iothread) { + qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock); + } + + elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); + if (!elem) { + return false; + } + + if (elem->out_num) { + uint32_t id; + size_t size = iov_to_buf(elem->out_sg, elem->out_num, 0, + &id, sizeof(id)); + + virtio_tswap32s(vdev, &id); + if (unlikely(size != sizeof(id))) { + virtio_error(vdev, "received an incorrect cmd id"); + ret = false; + goto out; + } + if (dev->free_page_hint_status == FREE_PAGE_HINT_S_REQUESTED && + id == dev->free_page_hint_cmd_id) { + dev->free_page_hint_status = FREE_PAGE_HINT_S_START; + } else if (dev->free_page_hint_status == FREE_PAGE_HINT_S_START) { + /* + * Stop the optimization only when it has started. This + * avoids a stale stop sign for the previous command. + */ + dev->free_page_hint_status = FREE_PAGE_HINT_S_STOP; + } + } + + if (elem->in_num && dev->free_page_hint_status == FREE_PAGE_HINT_S_START) { + for (i = 0; i < elem->in_num; i++) { + qemu_guest_free_page_hint(elem->in_sg[i].iov_base, + elem->in_sg[i].iov_len); + } + } + +out: + virtqueue_push(vq, elem, 0); + g_free(elem); + return ret; +} + +static void virtio_ballloon_get_free_page_hints(void *opaque) +{ + VirtIOBalloon *dev = opaque; + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VirtQueue *vq = dev->free_page_vq; + bool continue_to_get_hints; + + do { + qemu_mutex_lock(&dev->free_page_lock); + virtio_queue_set_notification(vq, 0); + continue_to_get_hints = get_free_page_hints(dev); + qemu_mutex_unlock(&dev->free_page_lock); + virtio_notify(vdev, vq); + /* + * Start to poll the vq once the hinting started. Otherwise, continue + * only when there are entries on the vq, which need to be given back. + */ + } while (continue_to_get_hints || + dev->free_page_hint_status == FREE_PAGE_HINT_S_START); + virtio_queue_set_notification(vq, 1); +} + +static bool virtio_balloon_free_page_support(void *opaque) +{ + VirtIOBalloon *s = opaque; + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT); +} + +static void virtio_balloon_free_page_start(VirtIOBalloon *s) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + qemu_mutex_lock(&s->free_page_lock); + + if (s->free_page_hint_cmd_id == UINT_MAX) { + s->free_page_hint_cmd_id = VIRTIO_BALLOON_FREE_PAGE_HINT_CMD_ID_MIN; + } else { + s->free_page_hint_cmd_id++; + } + + s->free_page_hint_status = FREE_PAGE_HINT_S_REQUESTED; + qemu_mutex_unlock(&s->free_page_lock); + + virtio_notify_config(vdev); +} + +static void virtio_balloon_free_page_stop(VirtIOBalloon *s) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + if (s->free_page_hint_status != FREE_PAGE_HINT_S_STOP) { + /* + * The lock also guarantees us that the + * virtio_ballloon_get_free_page_hints exits after the + * free_page_hint_status is set to S_STOP. + */ + qemu_mutex_lock(&s->free_page_lock); + /* + * The guest isn't done hinting, so send a notification + * to the guest to actively stop the hinting. + */ + s->free_page_hint_status = FREE_PAGE_HINT_S_STOP; + qemu_mutex_unlock(&s->free_page_lock); + virtio_notify_config(vdev); + } +} + +static void virtio_balloon_free_page_done(VirtIOBalloon *s) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + if (s->free_page_hint_status != FREE_PAGE_HINT_S_DONE) { + /* See virtio_balloon_free_page_stop() */ + qemu_mutex_lock(&s->free_page_lock); + s->free_page_hint_status = FREE_PAGE_HINT_S_DONE; + qemu_mutex_unlock(&s->free_page_lock); + virtio_notify_config(vdev); + } +} + +static int +virtio_balloon_free_page_hint_notify(NotifierWithReturn *n, void *data) +{ + VirtIOBalloon *dev = container_of(n, VirtIOBalloon, free_page_hint_notify); + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + PrecopyNotifyData *pnd = data; + + if (!virtio_balloon_free_page_support(dev)) { + /* + * This is an optimization provided to migration, so just return 0 to + * have the normal migration process not affected when this feature is + * not supported. + */ + return 0; + } + + /* + * Pages hinted via qemu_guest_free_page_hint() are cleared from the dirty + * bitmap and will not get migrated, especially also not when the postcopy + * destination starts using them and requests migration from the source; the + * faulting thread will stall until postcopy migration finishes and + * all threads are woken up. Let's not start free page hinting if postcopy + * is possible. + */ + if (migrate_postcopy_ram()) { + return 0; + } + + switch (pnd->reason) { + case PRECOPY_NOTIFY_BEFORE_BITMAP_SYNC: + virtio_balloon_free_page_stop(dev); + break; + case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC: + if (vdev->vm_running) { + virtio_balloon_free_page_start(dev); + break; + } + /* + * Set S_DONE before migrating the vmstate, so the guest will reuse + * all hinted pages once running on the destination. Fall through. + */ + case PRECOPY_NOTIFY_CLEANUP: + /* + * Especially, if something goes wrong during precopy or if migration + * is canceled, we have to properly communicate S_DONE to the VM. + */ + virtio_balloon_free_page_done(dev); + break; + case PRECOPY_NOTIFY_SETUP: + case PRECOPY_NOTIFY_COMPLETE: + break; + default: + virtio_error(vdev, "%s: %d reason unknown", __func__, pnd->reason); + } + + return 0; +} + +static size_t virtio_balloon_config_size(VirtIOBalloon *s) +{ + uint64_t features = s->host_features; + + if (s->qemu_4_0_config_size) { + return sizeof(struct virtio_balloon_config); + } + if (virtio_has_feature(features, VIRTIO_BALLOON_F_PAGE_POISON)) { + return sizeof(struct virtio_balloon_config); + } + if (virtio_has_feature(features, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { + return offsetof(struct virtio_balloon_config, poison_val); + } + return offsetof(struct virtio_balloon_config, free_page_hint_cmd_id); +} + +static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) +{ + VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); + struct virtio_balloon_config config = {}; + + config.num_pages = cpu_to_le32(dev->num_pages); + config.actual = cpu_to_le32(dev->actual); + config.poison_val = cpu_to_le32(dev->poison_val); + + if (dev->free_page_hint_status == FREE_PAGE_HINT_S_REQUESTED) { + config.free_page_hint_cmd_id = + cpu_to_le32(dev->free_page_hint_cmd_id); + } else if (dev->free_page_hint_status == FREE_PAGE_HINT_S_STOP) { + config.free_page_hint_cmd_id = + cpu_to_le32(VIRTIO_BALLOON_CMD_ID_STOP); + } else if (dev->free_page_hint_status == FREE_PAGE_HINT_S_DONE) { + config.free_page_hint_cmd_id = + cpu_to_le32(VIRTIO_BALLOON_CMD_ID_DONE); + } + + trace_virtio_balloon_get_config(config.num_pages, config.actual); + memcpy(config_data, &config, virtio_balloon_config_size(dev)); +} + +static int build_dimm_list(Object *obj, void *opaque) +{ + GSList **list = opaque; + + if (object_dynamic_cast(obj, TYPE_PC_DIMM)) { + DeviceState *dev = DEVICE(obj); + if (dev->realized) { /* only realized DIMMs matter */ + *list = g_slist_prepend(*list, dev); + } + } + + object_child_foreach(obj, build_dimm_list, opaque); + return 0; +} + +static ram_addr_t get_current_ram_size(void) +{ + GSList *list = NULL, *item; + ram_addr_t size = current_machine->ram_size; + + build_dimm_list(qdev_get_machine(), &list); + for (item = list; item; item = g_slist_next(item)) { + Object *obj = OBJECT(item->data); + if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) { + size += object_property_get_int(obj, PC_DIMM_SIZE_PROP, + &error_abort); + } + } + g_slist_free(list); + + return size; +} + +static bool virtio_balloon_page_poison_support(void *opaque) +{ + VirtIOBalloon *s = opaque; + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON); +} + +static void virtio_balloon_set_config(VirtIODevice *vdev, + const uint8_t *config_data) +{ + VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); + struct virtio_balloon_config config; + uint32_t oldactual = dev->actual; + ram_addr_t vm_ram_size = get_current_ram_size(); + + memcpy(&config, config_data, virtio_balloon_config_size(dev)); + dev->actual = le32_to_cpu(config.actual); + if (dev->actual != oldactual) { + qapi_event_send_balloon_change(vm_ram_size - + ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT)); + } + dev->poison_val = 0; + if (virtio_balloon_page_poison_support(dev)) { + dev->poison_val = le32_to_cpu(config.poison_val); + } + trace_virtio_balloon_set_config(dev->actual, oldactual); +} + +static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, + Error **errp) +{ + VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); + f |= dev->host_features; + virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); + + return f; +} + +static void virtio_balloon_stat(void *opaque, BalloonInfo *info) +{ + VirtIOBalloon *dev = opaque; + info->actual = get_current_ram_size() - ((uint64_t) dev->actual << + VIRTIO_BALLOON_PFN_SHIFT); +} + +static void virtio_balloon_to_target(void *opaque, ram_addr_t target) +{ + VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + ram_addr_t vm_ram_size = get_current_ram_size(); + + if (target > vm_ram_size) { + target = vm_ram_size; + } + if (target) { + dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; + virtio_notify_config(vdev); + } + trace_virtio_balloon_to_target(target, dev->num_pages); +} + +static int virtio_balloon_post_load_device(void *opaque, int version_id) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(opaque); + + if (balloon_stats_enabled(s)) { + balloon_stats_change_timer(s, s->stats_poll_interval); + } + return 0; +} + +static const VMStateDescription vmstate_virtio_balloon_free_page_hint = { + .name = "virtio-balloon-device/free-page-report", + .version_id = 1, + .minimum_version_id = 1, + .needed = virtio_balloon_free_page_support, + .fields = (VMStateField[]) { + VMSTATE_UINT32(free_page_hint_cmd_id, VirtIOBalloon), + VMSTATE_UINT32(free_page_hint_status, VirtIOBalloon), + VMSTATE_END_OF_LIST() + } +}; + +static const VMStateDescription vmstate_virtio_balloon_page_poison = { + .name = "virtio-balloon-device/page-poison", + .version_id = 1, + .minimum_version_id = 1, + .needed = virtio_balloon_page_poison_support, + .fields = (VMStateField[]) { + VMSTATE_UINT32(poison_val, VirtIOBalloon), + VMSTATE_END_OF_LIST() + } +}; + +static const VMStateDescription vmstate_virtio_balloon_device = { + .name = "virtio-balloon-device", + .version_id = 1, + .minimum_version_id = 1, + .post_load = virtio_balloon_post_load_device, + .fields = (VMStateField[]) { + VMSTATE_UINT32(num_pages, VirtIOBalloon), + VMSTATE_UINT32(actual, VirtIOBalloon), + VMSTATE_END_OF_LIST() + }, + .subsections = (const VMStateDescription * []) { + &vmstate_virtio_balloon_free_page_hint, + &vmstate_virtio_balloon_page_poison, + NULL + } +}; + +static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VirtIOBalloon *s = VIRTIO_BALLOON(dev); + int ret; + + virtio_init(vdev, VIRTIO_ID_BALLOON, virtio_balloon_config_size(s)); + + ret = qemu_add_balloon_handler(virtio_balloon_to_target, + virtio_balloon_stat, s); + + if (ret < 0) { + error_setg(errp, "Only one balloon device is supported"); + virtio_cleanup(vdev); + return; + } + + if (virtio_has_feature(s->host_features, VIRTIO_BALLOON_F_FREE_PAGE_HINT) && + !s->iothread) { + error_setg(errp, "'free-page-hint' requires 'iothread' to be set"); + virtio_cleanup(vdev); + return; + } + + s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); + s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); + s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); + + if (virtio_has_feature(s->host_features, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { + s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE, + virtio_balloon_handle_free_page_vq); + precopy_add_notifier(&s->free_page_hint_notify); + + object_ref(OBJECT(s->iothread)); + s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread), + virtio_ballloon_get_free_page_hints, s); + } + + if (virtio_has_feature(s->host_features, VIRTIO_BALLOON_F_REPORTING)) { + s->reporting_vq = virtio_add_queue(vdev, 32, + virtio_balloon_handle_report); + } + + reset_stats(s); +} + +static void virtio_balloon_device_unrealize(DeviceState *dev) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VirtIOBalloon *s = VIRTIO_BALLOON(dev); + + if (s->free_page_bh) { + qemu_bh_delete(s->free_page_bh); + object_unref(OBJECT(s->iothread)); + virtio_balloon_free_page_stop(s); + precopy_remove_notifier(&s->free_page_hint_notify); + } + balloon_stats_destroy_timer(s); + qemu_remove_balloon_handler(s); + + virtio_delete_queue(s->ivq); + virtio_delete_queue(s->dvq); + virtio_delete_queue(s->svq); + if (s->free_page_vq) { + virtio_delete_queue(s->free_page_vq); + } + if (s->reporting_vq) { + virtio_delete_queue(s->reporting_vq); + } + virtio_cleanup(vdev); +} + +static void virtio_balloon_device_reset(VirtIODevice *vdev) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(vdev); + + if (virtio_balloon_free_page_support(s)) { + virtio_balloon_free_page_stop(s); + } + + if (s->stats_vq_elem != NULL) { + virtqueue_unpop(s->svq, s->stats_vq_elem, 0); + g_free(s->stats_vq_elem); + s->stats_vq_elem = NULL; + } + + s->poison_val = 0; +} + +static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(vdev); + + if (!s->stats_vq_elem && vdev->vm_running && + (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) { + /* poll stats queue for the element we have discarded when the VM + * was stopped */ + virtio_balloon_receive_stats(vdev, s->svq); + } + + if (virtio_balloon_free_page_support(s)) { + /* + * The VM is woken up and the iothread was blocked, so signal it to + * continue. + */ + if (vdev->vm_running && s->block_iothread) { + qemu_mutex_lock(&s->free_page_lock); + s->block_iothread = false; + qemu_cond_signal(&s->free_page_cond); + qemu_mutex_unlock(&s->free_page_lock); + } + + /* The VM is stopped, block the iothread. */ + if (!vdev->vm_running) { + qemu_mutex_lock(&s->free_page_lock); + s->block_iothread = true; + qemu_mutex_unlock(&s->free_page_lock); + } + } +} + +static void virtio_balloon_instance_init(Object *obj) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(obj); + + qemu_mutex_init(&s->free_page_lock); + qemu_cond_init(&s->free_page_cond); + s->free_page_hint_cmd_id = VIRTIO_BALLOON_FREE_PAGE_HINT_CMD_ID_MIN; + s->free_page_hint_notify.notify = virtio_balloon_free_page_hint_notify; + + object_property_add(obj, "guest-stats", "guest statistics", + balloon_stats_get_all, NULL, NULL, NULL); + + object_property_add(obj, "guest-stats-polling-interval", "int", + balloon_stats_get_poll_interval, + balloon_stats_set_poll_interval, + NULL, NULL); +} + +static const VMStateDescription vmstate_virtio_balloon = { + .name = "virtio-balloon", + .minimum_version_id = 1, + .version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_VIRTIO_DEVICE, + VMSTATE_END_OF_LIST() + }, +}; + +static Property virtio_balloon_properties[] = { + DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features, + VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false), + DEFINE_PROP_BIT("free-page-hint", VirtIOBalloon, host_features, + VIRTIO_BALLOON_F_FREE_PAGE_HINT, false), + DEFINE_PROP_BIT("page-poison", VirtIOBalloon, host_features, + VIRTIO_BALLOON_F_PAGE_POISON, true), + DEFINE_PROP_BIT("free-page-reporting", VirtIOBalloon, host_features, + VIRTIO_BALLOON_F_REPORTING, false), + /* QEMU 4.0 accidentally changed the config size even when free-page-hint + * is disabled, resulting in QEMU 3.1 migration incompatibility. This + * property retains this quirk for QEMU 4.1 machine types. + */ + DEFINE_PROP_BOOL("qemu-4-0-config-size", VirtIOBalloon, + qemu_4_0_config_size, false), + DEFINE_PROP_LINK("iothread", VirtIOBalloon, iothread, TYPE_IOTHREAD, + IOThread *), + DEFINE_PROP_END_OF_LIST(), +}; + +static void virtio_balloon_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); + + device_class_set_props(dc, virtio_balloon_properties); + dc->vmsd = &vmstate_virtio_balloon; + set_bit(DEVICE_CATEGORY_MISC, dc->categories); + vdc->realize = virtio_balloon_device_realize; + vdc->unrealize = virtio_balloon_device_unrealize; + vdc->reset = virtio_balloon_device_reset; + vdc->get_config = virtio_balloon_get_config; + vdc->set_config = virtio_balloon_set_config; + vdc->get_features = virtio_balloon_get_features; + vdc->set_status = virtio_balloon_set_status; + vdc->vmsd = &vmstate_virtio_balloon_device; +} + +static const TypeInfo virtio_balloon_info = { + .name = TYPE_VIRTIO_BALLOON, + .parent = TYPE_VIRTIO_DEVICE, + .instance_size = sizeof(VirtIOBalloon), + .instance_init = virtio_balloon_instance_init, + .class_init = virtio_balloon_class_init, +}; + +static void virtio_register_types(void) +{ + type_register_static(&virtio_balloon_info); +} + +type_init(virtio_register_types) |