From: Jason Wang <jasowang@redhat.com>

We only process the first in sg which may lead to the bitmap of the
pages belongs to following sgs were not cleared. This may result more
pages to be migrated. Fixing this by process all in sgs for
free_page_vq.

Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20211129030841.3611-1-jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/virtio-balloon.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index c6962fcbfe..17de2558cb 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -510,6 +510,7 @@ static bool get_free_page_hints(VirtIOBalloon *dev)
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VirtQueue *vq = dev->free_page_vq;
     bool ret = true;
+    int i;
 
     while (dev->block_iothread) {
         qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock);
@@ -544,8 +545,10 @@ static bool get_free_page_hints(VirtIOBalloon *dev)
     }
 
     if (elem->in_num && dev->free_page_hint_status == FREE_PAGE_HINT_S_START) {
-        qemu_guest_free_page_hint(elem->in_sg[0].iov_base,
-                                  elem->in_sg[0].iov_len);
+        for (i = 0; i < elem->in_num; i++) {
+            qemu_guest_free_page_hint(elem->in_sg[i].iov_base,
+                                      elem->in_sg[i].iov_len);
+        }
     }
 
 out:
-- 
MST