virtio_balloon: transitional interface
Virtio 1.0 doesn't include a modern balloon device.
But it's not a big change to support a transitional
balloon device: this has the advantage of supporting
existing drivers, transparently.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 6a356e3..82e80e0 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -214,8 +214,8 @@
u16 tag, u64 val)
{
BUG_ON(idx >= VIRTIO_BALLOON_S_NR);
- vb->stats[idx].tag = tag;
- vb->stats[idx].val = val;
+ vb->stats[idx].tag = cpu_to_virtio16(vb->vdev, tag);
+ vb->stats[idx].val = cpu_to_virtio64(vb->vdev, val);
}
#define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT)
@@ -283,18 +283,27 @@
static inline s64 towards_target(struct virtio_balloon *vb)
{
- __le32 v;
s64 target;
+ u32 num_pages;
- virtio_cread(vb->vdev, struct virtio_balloon_config, num_pages, &v);
+ virtio_cread(vb->vdev, struct virtio_balloon_config, num_pages,
+ &num_pages);
- target = le32_to_cpu(v);
+ /* Legacy balloon config space is LE, unlike all other devices. */
+ if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1))
+ num_pages = le32_to_cpu((__force __le32)num_pages);
+
+ target = num_pages;
return target - vb->num_pages;
}
static void update_balloon_size(struct virtio_balloon *vb)
{
- __le32 actual = cpu_to_le32(vb->num_pages);
+ u32 actual = vb->num_pages;
+
+ /* Legacy balloon config space is LE, unlike all other devices. */
+ if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1))
+ actual = (__force u32)cpu_to_le32(actual);
virtio_cwrite(vb->vdev, struct virtio_balloon_config, actual,
&actual);