After live migration, 'guest-stats' can't get the expected memory
status in the guest. This issue is caused by commit 4eae2a657d.
The value of 's->stats_vq_elem' will be NULL after live migration,
and the check in the function 'balloon_stats_poll_cb()' will
prevent the 'virtio_notify()' from executing. So guest will not
update the memory status.
Commit 4eae2a657d is doing the right thing, but 's->stats_vq_elem'
should be treated as part of balloon device state and migrated to
destination if it's not NULL to make everything works well.
Signed-off-by: Liang Li <liang.z...@intel.com>
Suggested-by: Paolo Bonzini <pbonz...@redhat.com>
Cc: Michael S. Tsirkin <m...@redhat.com>
Cc: Ladi Prosek <lpro...@redhat.com>
Cc: Paolo Bonzini <pbonz...@redhat.com>
---
hw/virtio/virtio-balloon.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 557d3f9..64e80c6 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -31,6 +31,7 @@
#include "hw/virtio/virtio-access.h"
#define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT)
+#define BALLOON_VERSION 2
static void balloon_page(void *addr, int deflate)
{
@@ -404,15 +405,24 @@ static void virtio_balloon_save(QEMUFile *f, void *opaque)
static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
{
VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
+ uint16_t elem_num = 0;
qemu_put_be32(f, s->num_pages);
qemu_put_be32(f, s->actual);
+ if (s->stats_vq_elem != NULL) {
+ elem_num = 1;
+ }
+ qemu_put_be16(f, elem_num);
+ if (elem_num) {
+ qemu_put_virtqueue_element(f, s->stats_vq_elem);
+ }
}
static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
{
- if (version_id != 1)
+ if (version_id < 1 || version_id > BALLOON_VERSION) {
return -EINVAL;
+ }
return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
}
@@ -421,9 +431,17 @@ static int virtio_balloon_load_device(VirtIODevice *vdev,
QEMUFile *f,
int version_id)
{
VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
+ uint16_t elem_num = 0;
s->num_pages = qemu_get_be32(f);
s->actual = qemu_get_be32(f);
+ if (version_id == BALLOON_VERSION) {
+ elem_num = qemu_get_be16(f);
+ if (elem_num == 1) {
+ s->stats_vq_elem =
+ qemu_get_virtqueue_element(f, sizeof(VirtQueueElement));
+ }
+ }
if (balloon_stats_enabled(s)) {
balloon_stats_change_timer(s, s->stats_poll_interval);
@@ -455,7 +473,7 @@ static void virtio_balloon_device_realize(DeviceState *dev,
Error **errp)
reset_stats(s);
- register_savevm(dev, "virtio-balloon", -1, 1,
+ register_savevm(dev, "virtio-balloon", -1, BALLOON_VERSION,
virtio_balloon_save, virtio_balloon_load, s);
}
--
1.8.3.1
