root / hw / virtio-balloon.c @ 8294a64d
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/*
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* Virtio Balloon Device
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*
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* Copyright IBM, Corp. 2008
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* Copyright (C) 2011 Red Hat, Inc.
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* Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "iov.h" |
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#include "qemu-common.h" |
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#include "virtio.h" |
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#include "pc.h" |
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#include "cpu.h" |
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#include "balloon.h" |
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#include "virtio-balloon.h" |
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#include "kvm.h" |
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#include "exec-memory.h" |
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#if defined(__linux__)
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#include <sys/mman.h> |
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#endif
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typedef struct VirtIOBalloon |
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{ |
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VirtIODevice vdev; |
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VirtQueue *ivq, *dvq, *svq; |
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uint32_t num_pages; |
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uint32_t actual; |
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uint64_t stats[VIRTIO_BALLOON_S_NR]; |
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VirtQueueElement stats_vq_elem; |
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size_t stats_vq_offset; |
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DeviceState *qdev; |
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} VirtIOBalloon; |
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static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev)
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{ |
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return (VirtIOBalloon *)vdev;
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} |
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static void balloon_page(void *addr, int deflate) |
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{ |
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#if defined(__linux__)
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if (!kvm_enabled() || kvm_has_sync_mmu())
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qemu_madvise(addr, TARGET_PAGE_SIZE, |
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deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED); |
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#endif
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} |
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/*
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* reset_stats - Mark all items in the stats array as unset
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*
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* This function needs to be called at device intialization and before
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* before updating to a set of newly-generated stats. This will ensure that no
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* stale values stick around in case the guest reports a subset of the supported
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* statistics.
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*/
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static inline void reset_stats(VirtIOBalloon *dev) |
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{ |
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int i;
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for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1); |
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} |
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static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) |
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{ |
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VirtIOBalloon *s = to_virtio_balloon(vdev); |
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VirtQueueElement elem; |
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MemoryRegionSection section; |
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while (virtqueue_pop(vq, &elem)) {
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size_t offset = 0;
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uint32_t pfn; |
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while (iov_to_buf(elem.out_sg, elem.out_num, &pfn, offset, 4) == 4) { |
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ram_addr_t pa; |
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ram_addr_t addr; |
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pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT; |
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offset += 4;
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/* FIXME: remove get_system_memory(), but how? */
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section = memory_region_find(get_system_memory(), pa, 1);
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if (!section.size || !memory_region_is_ram(section.mr))
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continue;
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/* Using memory_region_get_ram_ptr is bending the rules a bit, but
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should be OK because we only want a single page. */
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addr = section.offset_within_region; |
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balloon_page(memory_region_get_ram_ptr(section.mr) + addr, |
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!!(vq == s->dvq)); |
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} |
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virtqueue_push(vq, &elem, offset); |
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virtio_notify(vdev, vq); |
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} |
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} |
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static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) |
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{ |
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VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev); |
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VirtQueueElement *elem = &s->stats_vq_elem; |
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VirtIOBalloonStat stat; |
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size_t offset = 0;
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if (!virtqueue_pop(vq, elem)) {
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return;
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} |
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/* Initialize the stats to get rid of any stale values. This is only
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* needed to handle the case where a guest supports fewer stats than it
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* used to (ie. it has booted into an old kernel).
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*/
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reset_stats(s); |
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while (iov_to_buf(elem->out_sg, elem->out_num, &stat, offset, sizeof(stat)) |
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== sizeof(stat)) {
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uint16_t tag = tswap16(stat.tag); |
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uint64_t val = tswap64(stat.val); |
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offset += sizeof(stat);
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if (tag < VIRTIO_BALLOON_S_NR)
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s->stats[tag] = val; |
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} |
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s->stats_vq_offset = offset; |
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} |
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static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) |
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{ |
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VirtIOBalloon *dev = to_virtio_balloon(vdev); |
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struct virtio_balloon_config config;
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config.num_pages = cpu_to_le32(dev->num_pages); |
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config.actual = cpu_to_le32(dev->actual); |
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memcpy(config_data, &config, 8);
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} |
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static void virtio_balloon_set_config(VirtIODevice *vdev, |
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const uint8_t *config_data)
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{ |
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VirtIOBalloon *dev = to_virtio_balloon(vdev); |
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struct virtio_balloon_config config;
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memcpy(&config, config_data, 8);
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dev->actual = le32_to_cpu(config.actual); |
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} |
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static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
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{ |
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f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
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return f;
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} |
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static void virtio_balloon_stat(void *opaque, BalloonInfo *info) |
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{ |
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VirtIOBalloon *dev = opaque; |
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#if 0
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/* Disable guest-provided stats for now. For more details please check:
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* https://bugzilla.redhat.com/show_bug.cgi?id=623903
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*
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* If you do enable it (which is probably not going to happen as we
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* need a new command for it), remember that you also need to fill the
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* appropriate members of the BalloonInfo structure so that the stats
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* are returned to the client.
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*/
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if (dev->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ)) {
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virtqueue_push(dev->svq, &dev->stats_vq_elem, dev->stats_vq_offset);
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virtio_notify(&dev->vdev, dev->svq);
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return;
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}
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#endif
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/* Stats are not supported. Clear out any stale values that might
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* have been set by a more featureful guest kernel.
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*/
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reset_stats(dev); |
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info->actual = ram_size - ((uint64_t) dev->actual << |
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VIRTIO_BALLOON_PFN_SHIFT); |
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} |
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static void virtio_balloon_to_target(void *opaque, ram_addr_t target) |
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{ |
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VirtIOBalloon *dev = opaque; |
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if (target > ram_size) {
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target = ram_size; |
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} |
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if (target) {
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dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; |
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virtio_notify_config(&dev->vdev); |
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} |
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} |
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static void virtio_balloon_save(QEMUFile *f, void *opaque) |
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{ |
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VirtIOBalloon *s = opaque; |
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virtio_save(&s->vdev, f); |
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qemu_put_be32(f, s->num_pages); |
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qemu_put_be32(f, s->actual); |
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} |
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static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id) |
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{ |
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VirtIOBalloon *s = opaque; |
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int ret;
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if (version_id != 1) |
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return -EINVAL;
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ret = virtio_load(&s->vdev, f); |
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if (ret) {
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return ret;
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} |
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s->num_pages = qemu_get_be32(f); |
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s->actual = qemu_get_be32(f); |
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return 0; |
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} |
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VirtIODevice *virtio_balloon_init(DeviceState *dev) |
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{ |
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VirtIOBalloon *s; |
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int ret;
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s = (VirtIOBalloon *)virtio_common_init("virtio-balloon",
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VIRTIO_ID_BALLOON, |
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8, sizeof(VirtIOBalloon)); |
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s->vdev.get_config = virtio_balloon_get_config; |
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s->vdev.set_config = virtio_balloon_set_config; |
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s->vdev.get_features = virtio_balloon_get_features; |
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ret = qemu_add_balloon_handler(virtio_balloon_to_target, |
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virtio_balloon_stat, s); |
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if (ret < 0) { |
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virtio_cleanup(&s->vdev); |
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return NULL; |
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} |
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s->ivq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
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s->dvq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output);
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s->svq = virtio_add_queue(&s->vdev, 128, virtio_balloon_receive_stats);
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reset_stats(s); |
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s->qdev = dev; |
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register_savevm(dev, "virtio-balloon", -1, 1, |
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virtio_balloon_save, virtio_balloon_load, s); |
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return &s->vdev;
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} |
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void virtio_balloon_exit(VirtIODevice *vdev)
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{ |
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VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev); |
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qemu_remove_balloon_handler(s); |
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unregister_savevm(s->qdev, "virtio-balloon", s);
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virtio_cleanup(vdev); |
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} |