Archipelago » qemu

/*

 * 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/iov.h"

#include "qemu/timer.h"

#include "qemu-common.h"

#include "hw/virtio/virtio.h"

#include "hw/i386/pc.h"

#include "cpu.h"

#include "sysemu/balloon.h"

#include "hw/virtio/virtio-balloon.h"

#include "sysemu/kvm.h"

#include "exec/address-spaces.h"

#include "qapi/visitor.h"

#if defined(__linux__)

#include <sys/mman.h>

#endif

#include "hw/virtio/virtio-bus.h"

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

}

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_NR] = NULL

};

/*

 * 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 bool balloon_stats_supported(const VirtIOBalloon *s)

{

    VirtIODevice *vdev = VIRTIO_DEVICE(s);

    return vdev->guest_features & (1 << 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)) {

        qemu_del_timer(s->stats_timer);

        qemu_free_timer(s->stats_timer);

        s->stats_timer = NULL;

        s->stats_poll_interval = 0;

    }

}

static void balloon_stats_change_timer(VirtIOBalloon *s, int secs)

{

    qemu_mod_timer(s->stats_timer, qemu_get_clock_ms(vm_clock) + secs * 1000);

}

static void balloon_stats_poll_cb(void *opaque)

{

    VirtIOBalloon *s = opaque;

    VirtIODevice *vdev = VIRTIO_DEVICE(s);

    if (!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);

}

static void balloon_stats_get_all(Object *obj, struct Visitor *v,

                                  void *opaque, const char *name, Error **errp)

{

    VirtIOBalloon *s = opaque;

    int i;

    if (!s->stats_last_update) {

        error_setg(errp, "guest hasn't updated any stats yet");

        return;

    }

    visit_start_struct(v, NULL, "guest-stats", name, 0, errp);

    visit_type_int(v, &s->stats_last_update, "last-update", errp);

    visit_start_struct(v, NULL, NULL, "stats", 0, errp);

    for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {

        visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],

                         errp);

    }

    visit_end_struct(v, errp);

    visit_end_struct(v, errp);

}

static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,

                                            void *opaque, const char *name,

                                            Error **errp)

{

    VirtIOBalloon *s = opaque;

    visit_type_int(v, &s->stats_poll_interval, name, errp);

}

static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,

                                            void *opaque, const char *name,

                                            Error **errp)

{

    VirtIOBalloon *s = opaque;

    int64_t value;

    visit_type_int(v, &value, name, errp);

    if (error_is_set(errp)) {

        return;

    }

    if (value < 0) {

        error_setg(errp, "timer value must be greater than zero");

        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 = qemu_new_timer_ms(vm_clock, balloon_stats_poll_cb, s);

    s->stats_poll_interval = value;

    balloon_stats_change_timer(s, 0);

}

static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)

{

    VirtIOBalloon *s = 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 = VIRTIO_BALLOON(vdev);

    VirtQueueElement *elem = &s->stats_vq_elem;

    VirtIOBalloonStat stat;

    size_t offset = 0;

    qemu_timeval tv;

    if (!virtqueue_pop(vq, elem)) {

        goto out;

    }

    /* 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;

    if (qemu_gettimeofday(&tv) < 0) {

        fprintf(stderr, "warning: %s: failed to get time of day\n", __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_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);

    memcpy(config_data, &config, 8);

}

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;

    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;

    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 = VIRTIO_BALLOON(opaque);

    VirtIODevice *vdev = VIRTIO_DEVICE(dev);

    if (target > ram_size) {

        target = ram_size;

    }

    if (target) {

        dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;

        virtio_notify_config(vdev);

    }

}

static void virtio_balloon_save(QEMUFile *f, void *opaque)

{

    VirtIOBalloon *s = VIRTIO_BALLOON(opaque);

    VirtIODevice *vdev = VIRTIO_DEVICE(s);

    virtio_save(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 = VIRTIO_BALLOON(opaque);

    VirtIODevice *vdev = VIRTIO_DEVICE(s);

    int ret;

    if (version_id != 1)

        return -EINVAL;

    ret = virtio_load(vdev, f);

    if (ret) {

        return ret;

    }

    s->num_pages = qemu_get_be32(f);

    s->actual = qemu_get_be32(f);

    return 0;

}

static int virtio_balloon_device_init(VirtIODevice *vdev)

{

    DeviceState *qdev = DEVICE(vdev);

    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);

    int ret;

    virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 8);

    vdev->get_config = virtio_balloon_get_config;

    vdev->set_config = virtio_balloon_set_config;

    vdev->get_features = virtio_balloon_get_features;

    ret = qemu_add_balloon_handler(virtio_balloon_to_target,

                                   virtio_balloon_stat, s);

    if (ret < 0) {

        virtio_common_cleanup(VIRTIO_DEVICE(s));

        return -1;

    }

    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);

    register_savevm(qdev, "virtio-balloon", -1, 1,

                    virtio_balloon_save, virtio_balloon_load, s);

    object_property_add(OBJECT(qdev), "guest-stats", "guest statistics",

                        balloon_stats_get_all, NULL, NULL, s, NULL);

    object_property_add(OBJECT(qdev), "guest-stats-polling-interval", "int",

                        balloon_stats_get_poll_interval,

                        balloon_stats_set_poll_interval,

                        NULL, s, NULL);

    return 0;

}

static int virtio_balloon_device_exit(DeviceState *qdev)

{

    VirtIOBalloon *s = VIRTIO_BALLOON(qdev);

    VirtIODevice *vdev = VIRTIO_DEVICE(qdev);

    balloon_stats_destroy_timer(s);

    qemu_remove_balloon_handler(s);

    unregister_savevm(qdev, "virtio-balloon", s);

    virtio_common_cleanup(vdev);

    return 0;

}

static Property virtio_balloon_properties[] = {

    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);

    dc->exit = virtio_balloon_device_exit;

    dc->props = virtio_balloon_properties;

    vdc->init = virtio_balloon_device_init;

    vdc->get_config = virtio_balloon_get_config;

    vdc->set_config = virtio_balloon_set_config;

    vdc->get_features = virtio_balloon_get_features;

}

static const TypeInfo virtio_balloon_info = {

    .name = TYPE_VIRTIO_BALLOON,

    .parent = TYPE_VIRTIO_DEVICE,

    .instance_size = sizeof(VirtIOBalloon),

    .class_init = virtio_balloon_class_init,

};

static void virtio_register_types(void)

{

    type_register_static(&virtio_balloon_info);

}

type_init(virtio_register_types)