From: Alexander Duyck <>
It can be confusing to have multiple features within the same driver that
are using the same verbage. As such this patch is creating a union of
free_page_report_cmd_id with free_page_hint_cmd_id so that we can clean-up
the userspace code a bit in terms of readability while maintaining the
functionality of legacy code.
Signed-off-by: Alexander Duyck <>
---
drivers/virtio/virtio_balloon.c | 2 +-
include/uapi/linux/virtio_balloon.h | 13 ++++++++++---
2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 0ef16566c3f3..95d9c2f0a7be 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -580,7 +580,7 @@ static u32 virtio_balloon_cmd_id_received(struct virtio_balloon *vb)
if (test_and_clear_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID,
&vb->config_read_bitmap))
virtio_cread(vb->vdev, struct virtio_balloon_config,
- free_page_report_cmd_id,
+ free_page_hint_cmd_id,
&vb->cmd_id_received_cache);
return vb->cmd_id_received_cache;
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index 19974392d324..3ce64f72bd09 100644
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -34,7 +34,7 @@
#define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */
#define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */
#define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */
-#define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */
+#define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* Free page hinting VQ and config */
#define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */
#define VIRTIO_BALLOON_F_REPORTING 5 /* Page reporting virtqueue */
@@ -48,8 +48,15 @@ struct virtio_balloon_config {
__u32 num_pages;
/* Number of pages we've actually got in balloon. */
__u32 actual;
- /* Free page report command id, readonly by guest */
- __u32 free_page_report_cmd_id;
+ /*
+ * Free page hint command id, readonly by guest.
+ * Was previously named free_page_report_cmd_id so we
+ * need to carry that name for legacy support.
+ */
+ union {
+ __u32 free_page_hint_cmd_id;
+ __u32 free_page_report_cmd_id; /* deprecated */
+ };
/* Stores PAGE_POISON if page poisoning is in use */
__u32 poison_val;
};
