| /* |
| * 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 "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, s->stats_vq_offset); |
| 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 = opaque; |
| 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 = opaque; |
| 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 = opaque; |
| 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, offset); |
| 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; |
| qemu_timeval tv; |
| |
| 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; |
| |
| if (qemu_gettimeofday(&tv) < 0) { |
| warn_report("%s: failed to get time of day", __func__); |
| goto out; |
| } |
| |
| s->stats_last_update = tv.tv_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; |
| |
| 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) { |
| qemu_guest_free_page_hint(elem->in_sg[0].iov_base, |
| elem->in_sg[0].iov_len); |
| } |
| |
| out: |
| virtqueue_push(vq, elem, 1); |
| 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-balloon", 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, s); |
| |
| object_property_add(obj, "guest-stats-polling-interval", "int", |
| balloon_stats_get_poll_interval, |
| balloon_stats_set_poll_interval, |
| NULL, s); |
| } |
| |
| 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) |