/* * 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 "iov.h" #include "qemu-common.h" #include "virtio.h" #include "pc.h" #include "cpu.h" #include "balloon.h" #include "virtio-balloon.h" #include "kvm.h" #include "exec-memory.h" #if defined(__linux__) #include <sys/mman.h> #endif typedef struct VirtIOBalloon { VirtIODevice vdev; VirtQueue *ivq, *dvq, *svq; uint32_t num_pages; uint32_t actual; uint64_t stats[VIRTIO_BALLOON_S_NR]; VirtQueueElement stats_vq_elem; size_t stats_vq_offset; DeviceState *qdev; } VirtIOBalloon; static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev) { return (VirtIOBalloon *)vdev; } static void balloon_page(void *addr, int deflate) { #if defined(__linux__) if (!kvm_enabled() || kvm_has_sync_mmu()) qemu_madvise(addr, TARGET_PAGE_SIZE, deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED); #endif } /* * reset_stats - Mark all items in the stats array as unset * * This function needs to be called at device intialization and before * 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 void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) { VirtIOBalloon *s = to_virtio_balloon(vdev); VirtQueueElement elem; MemoryRegionSection section; while (virtqueue_pop(vq, &elem)) { size_t offset = 0; uint32_t pfn; while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) { ram_addr_t pa; ram_addr_t addr; pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT; offset += 4; /* FIXME: remove get_system_memory(), but how? */ section = memory_region_find(get_system_memory(), pa, 1); if (!section.size || !memory_region_is_ram(section.mr)) continue; /* Using memory_region_get_ram_ptr is bending the rules a bit, but should be OK because we only want a single page. */ addr = section.offset_within_region; balloon_page(memory_region_get_ram_ptr(section.mr) + addr, !!(vq == s->dvq)); } virtqueue_push(vq, &elem, offset); virtio_notify(vdev, vq); } } static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) { VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev); VirtQueueElement *elem = &s->stats_vq_elem; VirtIOBalloonStat stat; size_t offset = 0; if (!virtqueue_pop(vq, elem)) { return; } /* 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 = tswap16(stat.tag); uint64_t val = tswap64(stat.val); offset += sizeof(stat); if (tag < VIRTIO_BALLOON_S_NR) s->stats[tag] = val; } s->stats_vq_offset = offset; } static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) { VirtIOBalloon *dev = to_virtio_balloon(vdev); struct virtio_balloon_config config; config.num_pages = cpu_to_le32(dev->num_pages); config.actual = cpu_to_le32(dev->actual); memcpy(config_data, &config, 8); } static void virtio_balloon_set_config(VirtIODevice *vdev, const uint8_t *config_data) { VirtIOBalloon *dev = to_virtio_balloon(vdev); struct virtio_balloon_config config; uint32_t oldactual = dev->actual; memcpy(&config, config_data, 8); dev->actual = le32_to_cpu(config.actual); if (dev->actual != oldactual) { qemu_balloon_changed(ram_size - (dev->actual << VIRTIO_BALLOON_PFN_SHIFT)); } } static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f) { f |= (1 << VIRTIO_BALLOON_F_STATS_VQ); return f; } static void virtio_balloon_stat(void *opaque, BalloonInfo *info) { VirtIOBalloon *dev = opaque; #if 0 /* Disable guest-provided stats for now. For more details please check: * https://bugzilla.redhat.com/show_bug.cgi?id=623903 * * If you do enable it (which is probably not going to happen as we * need a new command for it), remember that you also need to fill the * appropriate members of the BalloonInfo structure so that the stats * are returned to the client. */ if (dev->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ)) { virtqueue_push(dev->svq, &dev->stats_vq_elem, dev->stats_vq_offset); virtio_notify(&dev->vdev, dev->svq); return; } #endif /* Stats are not supported. Clear out any stale values that might * have been set by a more featureful guest kernel. */ reset_stats(dev); info->actual = ram_size - ((uint64_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT); } static void virtio_balloon_to_target(void *opaque, ram_addr_t target) { VirtIOBalloon *dev = opaque; if (target > ram_size) { target = ram_size; } if (target) { dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; virtio_notify_config(&dev->vdev); } } static void virtio_balloon_save(QEMUFile *f, void *opaque) { VirtIOBalloon *s = opaque; virtio_save(&s->vdev, f); qemu_put_be32(f, s->num_pages); qemu_put_be32(f, s->actual); } static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id) { VirtIOBalloon *s = opaque; int ret; if (version_id != 1) return -EINVAL; ret = virtio_load(&s->vdev, f); if (ret) { return ret; } s->num_pages = qemu_get_be32(f); s->actual = qemu_get_be32(f); return 0; } VirtIODevice *virtio_balloon_init(DeviceState *dev) { VirtIOBalloon *s; int ret; s = (VirtIOBalloon *)virtio_common_init("virtio-balloon", VIRTIO_ID_BALLOON, 8, sizeof(VirtIOBalloon)); s->vdev.get_config = virtio_balloon_get_config; s->vdev.set_config = virtio_balloon_set_config; s->vdev.get_features = virtio_balloon_get_features; ret = qemu_add_balloon_handler(virtio_balloon_to_target, virtio_balloon_stat, s); if (ret < 0) { virtio_cleanup(&s->vdev); return NULL; } s->ivq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output); s->dvq = virtio_add_queue(&s->vdev, 128, virtio_balloon_handle_output); s->svq = virtio_add_queue(&s->vdev, 128, virtio_balloon_receive_stats); reset_stats(s); s->qdev = dev; register_savevm(dev, "virtio-balloon", -1, 1, virtio_balloon_save, virtio_balloon_load, s); return &s->vdev; } void virtio_balloon_exit(VirtIODevice *vdev) { VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev); qemu_remove_balloon_handler(s); unregister_savevm(s->qdev, "virtio-balloon", s); virtio_cleanup(vdev); }