Archipelago » qemu

typedef void (QEMUBalloonEvent)(void *opaque, ram_addr_t target,

                                MonitorCompletion cb, void *cb_data);

int qemu_balloon(ram_addr_t target, MonitorCompletion cb, void *opaque);

int qemu_balloon_status(MonitorCompletion cb, void *opaque);

#include "monitor.h"

#include "qlist.h"

#include "qint.h"

#include "qstring.h"

    VirtQueue *ivq, *dvq, *svq;

    uint64_t stats[VIRTIO_BALLOON_S_NR];

    VirtQueueElement stats_vq_elem;

    size_t stats_vq_offset;

    MonitorCompletion *stats_callback;

    void *stats_opaque_callback_data;

/*

 * 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 stat_put(QDict *dict, const char *label, uint64_t val)

{

    if (val != -1)

        qdict_put(dict, label, qint_from_int(val));

}

static QObject *get_stats_qobject(VirtIOBalloon *dev)

{

    QDict *dict = qdict_new();

    uint32_t actual = ram_size - (dev->actual << VIRTIO_BALLOON_PFN_SHIFT);

    stat_put(dict, "actual", actual);

    stat_put(dict, "mem_swapped_in", dev->stats[VIRTIO_BALLOON_S_SWAP_IN]);

    stat_put(dict, "mem_swapped_out", dev->stats[VIRTIO_BALLOON_S_SWAP_OUT]);

    stat_put(dict, "major_page_faults", dev->stats[VIRTIO_BALLOON_S_MAJFLT]);

    stat_put(dict, "minor_page_faults", dev->stats[VIRTIO_BALLOON_S_MINFLT]);

    stat_put(dict, "free_mem", dev->stats[VIRTIO_BALLOON_S_MEMFREE]);

    stat_put(dict, "total_mem", dev->stats[VIRTIO_BALLOON_S_MEMTOT]);

    return QOBJECT(dict);

}

static void complete_stats_request(VirtIOBalloon *vb)

{

    QObject *stats;

    if (!vb->stats_opaque_callback_data)

        return;

    stats = get_stats_qobject(vb);

    vb->stats_callback(vb->stats_opaque_callback_data, stats);

    qobject_decref(stats);

    vb->stats_opaque_callback_data = NULL;

    vb->stats_callback = NULL;

}

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 (memcpy_from_iovector(&stat, offset, sizeof(stat), elem->out_sg,

                                elem->out_num) == 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;

    complete_stats_request(s);

}

    f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);

static void virtio_balloon_to_target(void *opaque, ram_addr_t target,

                                     MonitorCompletion cb, void *cb_data)

    } else {

        /* For now, only allow one request at a time.  This restriction can be

         * removed later by queueing callback and data pairs.

         */

        if (dev->stats_callback != NULL) {

            return;

        }

        dev->stats_callback = cb;

        dev->stats_opaque_callback_data = cb_data; 

        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);

        } else {

            /* Stats are not supported.  Clear out any stale values that might

             * have been set by a more featureful guest kernel.

             */

            reset_stats(dev);

            complete_stats_request(dev);

        }

    qemu_put_buffer(f, (uint8_t *)&s->stats_vq_elem, sizeof(VirtQueueElement));

    qemu_put_buffer(f, (uint8_t *)&s->stats_vq_offset, sizeof(size_t));

    qemu_put_buffer(f, (uint8_t *)&s->stats_callback, sizeof(MonitorCompletion));

    qemu_put_buffer(f, (uint8_t *)&s->stats_opaque_callback_data, sizeof(void));

    qemu_get_buffer(f, (uint8_t *)&s->stats_vq_elem, sizeof(VirtQueueElement));

    qemu_get_buffer(f, (uint8_t *)&s->stats_vq_offset, sizeof(size_t));

    qemu_get_buffer(f, (uint8_t *)&s->stats_callback, sizeof(MonitorCompletion));

    qemu_get_buffer(f, (uint8_t *)&s->stats_opaque_callback_data, sizeof(void));

    s->svq = virtio_add_queue(&s->vdev, 128, virtio_balloon_receive_stats);

    reset_stats(s);

#define VIRTIO_BALLOON_F_STATS_VQ 1       /* Memory stats virtqueue */

/* Memory Statistics */

#define VIRTIO_BALLOON_S_SWAP_IN  0   /* Amount of memory swapped in */

#define VIRTIO_BALLOON_S_SWAP_OUT 1   /* Amount of memory swapped out */

#define VIRTIO_BALLOON_S_MAJFLT   2   /* Number of major faults */

#define VIRTIO_BALLOON_S_MINFLT   3   /* Number of minor faults */

#define VIRTIO_BALLOON_S_MEMFREE  4   /* Total amount of free memory */

#define VIRTIO_BALLOON_S_MEMTOT   5   /* Total amount of memory */

#define VIRTIO_BALLOON_S_NR       6

typedef struct VirtIOBalloonStat {

    uint16_t tag;

    uint64_t val;

} __attribute__((packed)) VirtIOBalloonStat;

static void print_balloon_stat(const char *key, QObject *obj, void *opaque)

    Monitor *mon = opaque;

    if (strcmp(key, "actual"))

        monitor_printf(mon, ",%s=%" PRId64, key,

                       qint_get_int(qobject_to_qint(obj)));

    if (!qdict_haskey(qdict, "actual"))

        return;

    monitor_printf(mon, "balloon: actual=%" PRId64,

                   qdict_get_int(qdict, "actual") >> 20);

    qdict_iter(qdict, print_balloon_stat, mon);

    monitor_printf(mon, "\n");

 * Make an asynchronous request for balloon info.  When the request completes

 * a QDict will be returned according to the following specification:

 * - "actual": current balloon value in bytes

 * The following fields may or may not be present:

 * - "mem_swapped_in": Amount of memory swapped in (bytes)

 * - "mem_swapped_out": Amount of memory swapped out (bytes)

 * - "major_page_faults": Number of major faults

 * - "minor_page_faults": Number of minor faults

 * - "free_mem": Total amount of free and unused memory (bytes)

 * - "total_mem": Total amount of available memory (bytes)

 * { "actual": 1073741824, "mem_swapped_in": 0, "mem_swapped_out": 0,

 *   "major_page_faults": 142, "minor_page_faults": 239245,

 *   "free_mem": 1014185984, "total_mem": 1044668416 }

 */

static int do_info_balloon(Monitor *mon, MonitorCompletion cb, void *opaque)

{

    int ret;

    if (kvm_enabled() && !kvm_has_sync_mmu()) {

        qemu_error_new(QERR_KVM_MISSING_CAP, "synchronous MMU", "balloon");

        return -1;

    }

    ret = qemu_balloon_status(cb, opaque);

    if (!ret) {

        qemu_error_new(QERR_DEVICE_NOT_ACTIVE, "balloon");

        return -1;

    }

    return 0;

}

/**

 * do_balloon(): Request VM to change its memory allocation

static int do_balloon(Monitor *mon, const QDict *params,

                       MonitorCompletion cb, void *opaque)

    int ret;

    if (kvm_enabled() && !kvm_has_sync_mmu()) {

        qemu_error_new(QERR_KVM_MISSING_CAP, "synchronous MMU", "balloon");

        return -1;

    }

    ret = qemu_balloon(qdict_get_int(params, "value"), cb, opaque);

    if (ret == 0) {

        qemu_error_new(QERR_DEVICE_NOT_ACTIVE, "balloon");

        return -1;

    return 0;

        .mhandler.info_async = do_info_balloon,

        .async      = 1,

        .mhandler.cmd_async = do_balloon,

        .async      = 1,

int qemu_balloon(ram_addr_t target, MonitorCompletion cb, void *opaque)

    if (qemu_balloon_event) {

        qemu_balloon_event(qemu_balloon_event_opaque, target, cb, opaque);

        return 1;

    } else {

        return 0;

    }

int qemu_balloon_status(MonitorCompletion cb, void *opaque)

    if (qemu_balloon_event) {

        qemu_balloon_event(qemu_balloon_event_opaque, 0, cb, opaque);

        return 1;

    } else {

        return 0;

    }