1 files changed, 465 insertions, 0 deletions

diff --git a/src/hw/virtio/virtio-balloon.c b/src/hw/virtio/virtio-balloon.c
new file mode 100644
index 0000000..9671635
--- /dev/null
+++ b/src/hw/virtio/virtio-balloon.c
@@ -0,0 +1,465 @@
+/*
+ * 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"
+#include "qapi-event.h"
+#include "trace.h"
+
+#if defined(__linux__)
+#include <sys/mman.h>
+#endif
+
+#include "hw/virtio/virtio-bus.h"
+#include "hw/virtio/virtio-access.h"
+
+static void balloon_page(void *addr, int deflate)
+{
+#if defined(__linux__)
+    if (!qemu_balloon_is_inhibited() && (!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 initialization and 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 virtio_vdev_has_feature(vdev, 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)) {
+        timer_del(s->stats_timer);
+        timer_free(s->stats_timer);
+        s->stats_timer = NULL;
+        s->stats_poll_interval = 0;
+    }
+}
+
+static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs)
+{
+    timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 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)
+{
+    Error *err = NULL;
+    VirtIOBalloon *s = opaque;
+    int i;
+
+    visit_start_struct(v, NULL, "guest-stats", name, 0, &err);
+    if (err) {
+        goto out;
+    }
+    visit_type_int(v, &s->stats_last_update, "last-update", &err);
+    if (err) {
+        goto out_end;
+    }
+
+    visit_start_struct(v, NULL, NULL, "stats", 0, &err);
+    if (err) {
+        goto out_end;
+    }
+    for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) {
+        visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
+                         &err);
+    }
+    error_propagate(errp, err);
+    err = NULL;
+    visit_end_struct(v, &err);
+
+out_end:
+    error_propagate(errp, err);
+    err = NULL;
+    visit_end_struct(v, &err);
+out:
+    error_propagate(errp, err);
+}
+
+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;
+    Error *local_err = NULL;
+    int64_t value;
+
+    visit_type_int(v, &value, name, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    if (value < 0) {
+        error_setg(errp, "timer value must be greater than zero");
+        return;
+    }
+
+    if (value > UINT32_MAX) {
+        error_setg(errp, "timer value is too big");
+        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 = timer_new_ms(QEMU_CLOCK_VIRTUAL, 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;
+            int p = virtio_ldl_p(vdev, &pfn);
+
+            pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
+            offset += 4;
+
+            /* FIXME: remove get_system_memory(), but how? */
+            section = memory_region_find(get_system_memory(), pa, 1);
+            if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
+                continue;
+
+            trace_virtio_balloon_handle_output(memory_region_name(section.mr),
+                                               pa);
+            /* 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));
+            memory_region_unref(section.mr);
+        }
+
+        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 = virtio_tswap16(vdev, stat.tag);
+        uint64_t val = virtio_tswap64(vdev, 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);
+
+    trace_virtio_balloon_get_config(config.num_pages, config.actual);
+    memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
+}
+
+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;
+    ram_addr_t vm_ram_size = get_current_ram_size();
+
+    memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
+    dev->actual = le32_to_cpu(config.actual);
+    if (dev->actual != oldactual) {
+        qapi_event_send_balloon_change(vm_ram_size -
+                        ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
+                        &error_abort);
+    }
+    trace_virtio_balloon_set_config(dev->actual, oldactual);
+}
+
+static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
+                                            Error **errp)
+{
+    VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
+    f |= dev->host_features;
+    virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
+    return f;
+}
+
+static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
+{
+    VirtIOBalloon *dev = opaque;
+    info->actual = get_current_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);
+    ram_addr_t vm_ram_size = get_current_ram_size();
+
+    if (target > vm_ram_size) {
+        target = vm_ram_size;
+    }
+    if (target) {
+        dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
+        virtio_notify_config(vdev);
+    }
+    trace_virtio_balloon_to_target(target, dev->num_pages);
+}
+
+static void virtio_balloon_save(QEMUFile *f, void *opaque)
+{
+    virtio_save(VIRTIO_DEVICE(opaque), f);
+}
+
+static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
+
+    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)
+{
+    if (version_id != 1)
+        return -EINVAL;
+
+    return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
+}
+
+static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
+                                      int version_id)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
+
+    s->num_pages = qemu_get_be32(f);
+    s->actual = qemu_get_be32(f);
+    return 0;
+}
+
+static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VirtIOBalloon *s = VIRTIO_BALLOON(dev);
+    int ret;
+
+    virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
+                sizeof(struct virtio_balloon_config));
+
+    ret = qemu_add_balloon_handler(virtio_balloon_to_target,
+                                   virtio_balloon_stat, s);
+
+    if (ret < 0) {
+        error_setg(errp, "Only one balloon device is supported");
+        virtio_cleanup(vdev);
+        return;
+    }
+
+    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);
+
+    reset_stats(s);
+
+    register_savevm(dev, "virtio-balloon", -1, 1,
+                    virtio_balloon_save, virtio_balloon_load, s);
+}
+
+static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VirtIOBalloon *s = VIRTIO_BALLOON(dev);
+
+    balloon_stats_destroy_timer(s);
+    qemu_remove_balloon_handler(s);
+    unregister_savevm(dev, "virtio-balloon", s);
+    virtio_cleanup(vdev);
+}
+
+static void virtio_balloon_instance_init(Object *obj)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(obj);
+
+    object_property_add(obj, "guest-stats", "guest statistics",
+                        balloon_stats_get_all, NULL, NULL, s, NULL);
+
+    object_property_add(obj, "guest-stats-polling-interval", "int",
+                        balloon_stats_get_poll_interval,
+                        balloon_stats_set_poll_interval,
+                        NULL, s, NULL);
+}
+
+static Property virtio_balloon_properties[] = {
+    DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
+                    VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
+    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->props = virtio_balloon_properties;
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+    vdc->realize = virtio_balloon_device_realize;
+    vdc->unrealize = virtio_balloon_device_unrealize;
+    vdc->get_config = virtio_balloon_get_config;
+    vdc->set_config = virtio_balloon_set_config;
+    vdc->get_features = virtio_balloon_get_features;
+    vdc->save = virtio_balloon_save_device;
+    vdc->load = virtio_balloon_load_device;
+}
+
+static const TypeInfo virtio_balloon_info = {
+    .name = TYPE_VIRTIO_BALLOON,
+    .parent = TYPE_VIRTIO_DEVICE,
+    .instance_size = sizeof(VirtIOBalloon),
+    .instance_init = virtio_balloon_instance_init,
+    .class_init = virtio_balloon_class_init,
+};
+
+static void virtio_register_types(void)
+{
+    type_register_static(&virtio_balloon_info);
+}
+
+type_init(virtio_register_types)