#include "qemu/osdep.h"
#include "qemu/iov.h"
+#include "qemu/module.h"
#include "qemu/timer.h"
-#include "qemu-common.h"
#include "hw/virtio/virtio.h"
#include "hw/mem/pc-dimm.h"
+#include "hw/qdev-properties.h"
#include "sysemu/balloon.h"
#include "hw/virtio/virtio-balloon.h"
#include "exec/address-spaces.h"
#include "qapi/visitor.h"
#include "trace.h"
#include "qemu/error-report.h"
+#include "migration/misc.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/virtio/virtio-access.h"
#define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT)
-static void balloon_page(void *addr, int deflate)
+typedef struct PartiallyBalloonedPage {
+ ram_addr_t base_gpa;
+ unsigned long *bitmap;
+} PartiallyBalloonedPage;
+
+static void virtio_balloon_pbp_free(PartiallyBalloonedPage *pbp)
{
- if (!qemu_balloon_is_inhibited()) {
- qemu_madvise(addr, BALLOON_PAGE_SIZE,
- deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
+ if (!pbp->bitmap) {
+ return;
+ }
+ g_free(pbp->bitmap);
+ pbp->bitmap = NULL;
+}
+
+static void virtio_balloon_pbp_alloc(PartiallyBalloonedPage *pbp,
+ ram_addr_t base_gpa,
+ long subpages)
+{
+ pbp->base_gpa = base_gpa;
+ pbp->bitmap = bitmap_new(subpages);
+}
+
+static bool virtio_balloon_pbp_matches(PartiallyBalloonedPage *pbp,
+ ram_addr_t base_gpa)
+{
+ return pbp->base_gpa == base_gpa;
+}
+
+static void balloon_inflate_page(VirtIOBalloon *balloon,
+ MemoryRegion *mr, hwaddr mr_offset,
+ PartiallyBalloonedPage *pbp)
+{
+ void *addr = memory_region_get_ram_ptr(mr) + mr_offset;
+ ram_addr_t rb_offset, rb_aligned_offset, base_gpa;
+ RAMBlock *rb;
+ size_t rb_page_size;
+ int subpages;
+
+ /* XXX is there a better way to get to the RAMBlock than via a
+ * host address? */
+ rb = qemu_ram_block_from_host(addr, false, &rb_offset);
+ rb_page_size = qemu_ram_pagesize(rb);
+
+ if (rb_page_size == BALLOON_PAGE_SIZE) {
+ /* Easy case */
+
+ ram_block_discard_range(rb, rb_offset, rb_page_size);
+ /* We ignore errors from ram_block_discard_range(), because it
+ * has already reported them, and failing to discard a balloon
+ * page is not fatal */
+ return;
+ }
+
+ /* Hard case
+ *
+ * We've put a piece of a larger host page into the balloon - we
+ * need to keep track until we have a whole host page to
+ * discard
+ */
+ warn_report_once(
+"Balloon used with backing page size > 4kiB, this may not be reliable");
+
+ rb_aligned_offset = QEMU_ALIGN_DOWN(rb_offset, rb_page_size);
+ subpages = rb_page_size / BALLOON_PAGE_SIZE;
+ base_gpa = memory_region_get_ram_addr(mr) + mr_offset -
+ (rb_offset - rb_aligned_offset);
+
+ if (pbp->bitmap && !virtio_balloon_pbp_matches(pbp, base_gpa)) {
+ /* We've partially ballooned part of a host page, but now
+ * we're trying to balloon part of a different one. Too hard,
+ * give up on the old partial page */
+ virtio_balloon_pbp_free(pbp);
+ }
+
+ if (!pbp->bitmap) {
+ virtio_balloon_pbp_alloc(pbp, base_gpa, subpages);
+ }
+
+ set_bit((rb_offset - rb_aligned_offset) / BALLOON_PAGE_SIZE,
+ pbp->bitmap);
+
+ if (bitmap_full(pbp->bitmap, subpages)) {
+ /* We've accumulated a full host page, we can actually discard
+ * it now */
+
+ ram_block_discard_range(rb, rb_aligned_offset, rb_page_size);
+ /* We ignore errors from ram_block_discard_range(), because it
+ * has already reported them, and failing to discard a balloon
+ * page is not fatal */
+ virtio_balloon_pbp_free(pbp);
+ }
+}
+
+static void balloon_deflate_page(VirtIOBalloon *balloon,
+ MemoryRegion *mr, hwaddr mr_offset)
+{
+ void *addr = memory_region_get_ram_ptr(mr) + mr_offset;
+ ram_addr_t rb_offset;
+ RAMBlock *rb;
+ size_t rb_page_size;
+ void *host_addr;
+ int ret;
+
+ /* XXX is there a better way to get to the RAMBlock than via a
+ * host address? */
+ rb = qemu_ram_block_from_host(addr, false, &rb_offset);
+ rb_page_size = qemu_ram_pagesize(rb);
+
+ host_addr = (void *)((uintptr_t)addr & ~(rb_page_size - 1));
+
+ /* When a page is deflated, we hint the whole host page it lives
+ * on, since we can't do anything smaller */
+ ret = qemu_madvise(host_addr, rb_page_size, QEMU_MADV_WILLNEED);
+ if (ret != 0) {
+ warn_report("Couldn't MADV_WILLNEED on balloon deflate: %s",
+ strerror(errno));
+ /* Otherwise ignore, failing to page hint shouldn't be fatal */
}
}
MemoryRegionSection section;
for (;;) {
+ PartiallyBalloonedPage pbp = {};
size_t offset = 0;
uint32_t pfn;
+
elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
if (!elem) {
- return;
+ break;
}
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);
+ unsigned int p = virtio_ldl_p(vdev, &pfn);
+ hwaddr pa;
- pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
+ pa = (hwaddr) 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) ||
+ section = memory_region_find(get_system_memory(), pa,
+ BALLOON_PAGE_SIZE);
+ if (!section.mr) {
+ trace_virtio_balloon_bad_addr(pa);
+ continue;
+ }
+ if (!memory_region_is_ram(section.mr) ||
memory_region_is_rom(section.mr) ||
memory_region_is_romd(section.mr)) {
trace_virtio_balloon_bad_addr(pa);
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));
+ if (!qemu_balloon_is_inhibited()) {
+ if (vq == s->ivq) {
+ balloon_inflate_page(s, section.mr,
+ section.offset_within_region, &pbp);
+ } else if (vq == s->dvq) {
+ balloon_deflate_page(s, section.mr, section.offset_within_region);
+ } else {
+ g_assert_not_reached();
+ }
+ }
memory_region_unref(section.mr);
}
virtqueue_push(vq, elem, offset);
virtio_notify(vdev, vq);
g_free(elem);
+ virtio_balloon_pbp_free(&pbp);
}
}
}
}
+static void virtio_balloon_handle_free_page_vq(VirtIODevice *vdev,
+ VirtQueue *vq)
+{
+ VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
+ qemu_bh_schedule(s->free_page_bh);
+}
+
+static bool get_free_page_hints(VirtIOBalloon *dev)
+{
+ VirtQueueElement *elem;
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VirtQueue *vq = dev->free_page_vq;
+ bool ret = true;
+
+ while (dev->block_iothread) {
+ qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock);
+ }
+
+ elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
+ if (!elem) {
+ return false;
+ }
+
+ if (elem->out_num) {
+ uint32_t id;
+ size_t size = iov_to_buf(elem->out_sg, elem->out_num, 0,
+ &id, sizeof(id));
+
+ virtio_tswap32s(vdev, &id);
+ if (unlikely(size != sizeof(id))) {
+ virtio_error(vdev, "received an incorrect cmd id");
+ ret = false;
+ goto out;
+ }
+ if (id == dev->free_page_report_cmd_id) {
+ dev->free_page_report_status = FREE_PAGE_REPORT_S_START;
+ } else {
+ /*
+ * Stop the optimization only when it has started. This
+ * avoids a stale stop sign for the previous command.
+ */
+ if (dev->free_page_report_status == FREE_PAGE_REPORT_S_START) {
+ dev->free_page_report_status = FREE_PAGE_REPORT_S_STOP;
+ }
+ }
+ }
+
+ if (elem->in_num) {
+ if (dev->free_page_report_status == FREE_PAGE_REPORT_S_START) {
+ qemu_guest_free_page_hint(elem->in_sg[0].iov_base,
+ elem->in_sg[0].iov_len);
+ }
+ }
+
+out:
+ virtqueue_push(vq, elem, 1);
+ g_free(elem);
+ return ret;
+}
+
+static void virtio_ballloon_get_free_page_hints(void *opaque)
+{
+ VirtIOBalloon *dev = opaque;
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ VirtQueue *vq = dev->free_page_vq;
+ bool continue_to_get_hints;
+
+ do {
+ qemu_mutex_lock(&dev->free_page_lock);
+ virtio_queue_set_notification(vq, 0);
+ continue_to_get_hints = get_free_page_hints(dev);
+ qemu_mutex_unlock(&dev->free_page_lock);
+ virtio_notify(vdev, vq);
+ /*
+ * Start to poll the vq once the reporting started. Otherwise, continue
+ * only when there are entries on the vq, which need to be given back.
+ */
+ } while (continue_to_get_hints ||
+ dev->free_page_report_status == FREE_PAGE_REPORT_S_START);
+ virtio_queue_set_notification(vq, 1);
+}
+
+static bool virtio_balloon_free_page_support(void *opaque)
+{
+ VirtIOBalloon *s = opaque;
+ VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+ return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT);
+}
+
+static void virtio_balloon_free_page_start(VirtIOBalloon *s)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+ /* For the stop and copy phase, we don't need to start the optimization */
+ if (!vdev->vm_running) {
+ return;
+ }
+
+ if (s->free_page_report_cmd_id == UINT_MAX) {
+ s->free_page_report_cmd_id =
+ VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN;
+ } else {
+ s->free_page_report_cmd_id++;
+ }
+
+ s->free_page_report_status = FREE_PAGE_REPORT_S_REQUESTED;
+ virtio_notify_config(vdev);
+}
+
+static void virtio_balloon_free_page_stop(VirtIOBalloon *s)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+ if (s->free_page_report_status != FREE_PAGE_REPORT_S_STOP) {
+ /*
+ * The lock also guarantees us that the
+ * virtio_ballloon_get_free_page_hints exits after the
+ * free_page_report_status is set to S_STOP.
+ */
+ qemu_mutex_lock(&s->free_page_lock);
+ /*
+ * The guest hasn't done the reporting, so host sends a notification
+ * to the guest to actively stop the reporting.
+ */
+ s->free_page_report_status = FREE_PAGE_REPORT_S_STOP;
+ qemu_mutex_unlock(&s->free_page_lock);
+ virtio_notify_config(vdev);
+ }
+}
+
+static void virtio_balloon_free_page_done(VirtIOBalloon *s)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+ s->free_page_report_status = FREE_PAGE_REPORT_S_DONE;
+ virtio_notify_config(vdev);
+}
+
+static int
+virtio_balloon_free_page_report_notify(NotifierWithReturn *n, void *data)
+{
+ VirtIOBalloon *dev = container_of(n, VirtIOBalloon,
+ free_page_report_notify);
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+ PrecopyNotifyData *pnd = data;
+
+ if (!virtio_balloon_free_page_support(dev)) {
+ /*
+ * This is an optimization provided to migration, so just return 0 to
+ * have the normal migration process not affected when this feature is
+ * not supported.
+ */
+ return 0;
+ }
+
+ switch (pnd->reason) {
+ case PRECOPY_NOTIFY_SETUP:
+ precopy_enable_free_page_optimization();
+ break;
+ case PRECOPY_NOTIFY_COMPLETE:
+ case PRECOPY_NOTIFY_CLEANUP:
+ case PRECOPY_NOTIFY_BEFORE_BITMAP_SYNC:
+ virtio_balloon_free_page_stop(dev);
+ break;
+ case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC:
+ if (vdev->vm_running) {
+ virtio_balloon_free_page_start(dev);
+ } else {
+ virtio_balloon_free_page_done(dev);
+ }
+ break;
+ default:
+ virtio_error(vdev, "%s: %d reason unknown", __func__, pnd->reason);
+ }
+
+ return 0;
+}
+
+static size_t virtio_balloon_config_size(VirtIOBalloon *s)
+{
+ uint64_t features = s->host_features;
+
+ if (s->qemu_4_0_config_size) {
+ return sizeof(struct virtio_balloon_config);
+ }
+ if (virtio_has_feature(features, VIRTIO_BALLOON_F_PAGE_POISON)) {
+ return sizeof(struct virtio_balloon_config);
+ }
+ if (virtio_has_feature(features, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
+ return offsetof(struct virtio_balloon_config, poison_val);
+ }
+ return offsetof(struct virtio_balloon_config, free_page_report_cmd_id);
+}
+
static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
{
VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
- struct virtio_balloon_config config;
+ struct virtio_balloon_config config = {};
config.num_pages = cpu_to_le32(dev->num_pages);
config.actual = cpu_to_le32(dev->actual);
+ if (dev->free_page_report_status == FREE_PAGE_REPORT_S_REQUESTED) {
+ config.free_page_report_cmd_id =
+ cpu_to_le32(dev->free_page_report_cmd_id);
+ } else if (dev->free_page_report_status == FREE_PAGE_REPORT_S_STOP) {
+ config.free_page_report_cmd_id =
+ cpu_to_le32(VIRTIO_BALLOON_CMD_ID_STOP);
+ } else if (dev->free_page_report_status == FREE_PAGE_REPORT_S_DONE) {
+ config.free_page_report_cmd_id =
+ cpu_to_le32(VIRTIO_BALLOON_CMD_ID_DONE);
+ }
+
trace_virtio_balloon_get_config(config.num_pages, config.actual);
- memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
+ memcpy(config_data, &config, virtio_balloon_config_size(dev));
}
static int build_dimm_list(Object *obj, void *opaque)
uint32_t oldactual = dev->actual;
ram_addr_t vm_ram_size = get_current_ram_size();
- memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
+ memcpy(&config, config_data, virtio_balloon_config_size(dev));
dev->actual = le32_to_cpu(config.actual);
if (dev->actual != oldactual) {
qapi_event_send_balloon_change(vm_ram_size -
VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
f |= dev->host_features;
virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
+
return f;
}
return 0;
}
+static const VMStateDescription vmstate_virtio_balloon_free_page_report = {
+ .name = "virtio-balloon-device/free-page-report",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = virtio_balloon_free_page_support,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT32(free_page_report_cmd_id, VirtIOBalloon),
+ VMSTATE_UINT32(free_page_report_status, VirtIOBalloon),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
static const VMStateDescription vmstate_virtio_balloon_device = {
.name = "virtio-balloon-device",
.version_id = 1,
VMSTATE_UINT32(actual, VirtIOBalloon),
VMSTATE_END_OF_LIST()
},
+ .subsections = (const VMStateDescription * []) {
+ &vmstate_virtio_balloon_free_page_report,
+ NULL
+ }
};
static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
int ret;
virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
- sizeof(struct virtio_balloon_config));
+ virtio_balloon_config_size(s));
ret = qemu_add_balloon_handler(virtio_balloon_to_target,
virtio_balloon_stat, s);
s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
+ if (virtio_has_feature(s->host_features,
+ VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
+ s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE,
+ virtio_balloon_handle_free_page_vq);
+ s->free_page_report_status = FREE_PAGE_REPORT_S_STOP;
+ s->free_page_report_cmd_id =
+ VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN;
+ s->free_page_report_notify.notify =
+ virtio_balloon_free_page_report_notify;
+ precopy_add_notifier(&s->free_page_report_notify);
+ if (s->iothread) {
+ object_ref(OBJECT(s->iothread));
+ s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread),
+ virtio_ballloon_get_free_page_hints, s);
+ qemu_mutex_init(&s->free_page_lock);
+ qemu_cond_init(&s->free_page_cond);
+ s->block_iothread = false;
+ } else {
+ /* Simply disable this feature if the iothread wasn't created. */
+ s->host_features &= ~(1 << VIRTIO_BALLOON_F_FREE_PAGE_HINT);
+ virtio_error(vdev, "iothread is missing");
+ }
+ }
reset_stats(s);
}
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtIOBalloon *s = VIRTIO_BALLOON(dev);
+ if (virtio_balloon_free_page_support(s)) {
+ qemu_bh_delete(s->free_page_bh);
+ virtio_balloon_free_page_stop(s);
+ precopy_remove_notifier(&s->free_page_report_notify);
+ }
balloon_stats_destroy_timer(s);
qemu_remove_balloon_handler(s);
+
+ virtio_delete_queue(s->ivq);
+ virtio_delete_queue(s->dvq);
+ virtio_delete_queue(s->svq);
+ if (s->free_page_vq) {
+ virtio_delete_queue(s->free_page_vq);
+ }
virtio_cleanup(vdev);
}
{
VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
+ if (virtio_balloon_free_page_support(s)) {
+ virtio_balloon_free_page_stop(s);
+ }
+
if (s->stats_vq_elem != NULL) {
virtqueue_unpop(s->svq, s->stats_vq_elem, 0);
g_free(s->stats_vq_elem);
* was stopped */
virtio_balloon_receive_stats(vdev, s->svq);
}
+
+ if (virtio_balloon_free_page_support(s)) {
+ /*
+ * The VM is woken up and the iothread was blocked, so signal it to
+ * continue.
+ */
+ if (vdev->vm_running && s->block_iothread) {
+ qemu_mutex_lock(&s->free_page_lock);
+ s->block_iothread = false;
+ qemu_cond_signal(&s->free_page_cond);
+ qemu_mutex_unlock(&s->free_page_lock);
+ }
+
+ /* The VM is stopped, block the iothread. */
+ if (!vdev->vm_running) {
+ qemu_mutex_lock(&s->free_page_lock);
+ s->block_iothread = true;
+ qemu_mutex_unlock(&s->free_page_lock);
+ }
+ }
}
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);
+ balloon_stats_get_all, NULL, NULL, s);
object_property_add(obj, "guest-stats-polling-interval", "int",
balloon_stats_get_poll_interval,
balloon_stats_set_poll_interval,
- NULL, s, NULL);
+ NULL, s);
}
static const VMStateDescription vmstate_virtio_balloon = {
static Property virtio_balloon_properties[] = {
DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
+ DEFINE_PROP_BIT("free-page-hint", VirtIOBalloon, host_features,
+ VIRTIO_BALLOON_F_FREE_PAGE_HINT, false),
+ /* QEMU 4.0 accidentally changed the config size even when free-page-hint
+ * is disabled, resulting in QEMU 3.1 migration incompatibility. This
+ * property retains this quirk for QEMU 4.1 machine types.
+ */
+ DEFINE_PROP_BOOL("qemu-4-0-config-size", VirtIOBalloon,
+ qemu_4_0_config_size, false),
+ DEFINE_PROP_LINK("iothread", VirtIOBalloon, iothread, TYPE_IOTHREAD,
+ IOThread *),
DEFINE_PROP_END_OF_LIST(),
};
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
- dc->props = virtio_balloon_properties;
+ device_class_set_props(dc, virtio_balloon_properties);
dc->vmsd = &vmstate_virtio_balloon;
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
vdc->realize = virtio_balloon_device_realize;
projects / mirror_qemu.git / blobdiff