diff options
Diffstat (limited to 'hw/virtio')
| -rw-r--r-- | hw/virtio/virtio-balloon.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 31d3c88482..10507b2a43 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -321,6 +321,67 @@ static void balloon_stats_set_poll_interval(Object *obj, Visitor *v, 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 (qemu_balloon_is_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); @@ -835,6 +896,12 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 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); } @@ -858,6 +925,9 @@ static void virtio_balloon_device_unrealize(DeviceState *dev) 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); } @@ -945,6 +1015,8 @@ static Property virtio_balloon_properties[] = { 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. |