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-rw-r--r--drivers/vhost/vhost.c18
-rw-r--r--drivers/vhost/vhost.h8
2 files changed, 19 insertions, 7 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 1f80eac5d6ae..60c9ebd629dd 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1600,17 +1600,25 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
r = -EFAULT;
break;
}
- if (s.num > 0xffff) {
- r = -EINVAL;
- break;
+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
+ vq->last_avail_idx = s.num & 0xffff;
+ vq->last_used_idx = (s.num >> 16) & 0xffff;
+ } else {
+ if (s.num > 0xffff) {
+ r = -EINVAL;
+ break;
+ }
+ vq->last_avail_idx = s.num;
}
- vq->last_avail_idx = s.num;
/* Forget the cached index value. */
vq->avail_idx = vq->last_avail_idx;
break;
case VHOST_GET_VRING_BASE:
s.index = idx;
- s.num = vq->last_avail_idx;
+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+ s.num = (u32)vq->last_avail_idx | ((u32)vq->last_used_idx << 16);
+ else
+ s.num = vq->last_avail_idx;
if (copy_to_user(argp, &s, sizeof s))
r = -EFAULT;
break;
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 305ec8593d46..fc900be504b3 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -92,13 +92,17 @@ struct vhost_virtqueue {
/* The routine to call when the Guest pings us, or timeout. */
vhost_work_fn_t handle_kick;
- /* Last available index we saw. */
+ /* Last available index we saw.
+ * Values are limited to 0x7fff, and the high bit is used as
+ * a wrap counter when using VIRTIO_F_RING_PACKED. */
u16 last_avail_idx;
/* Caches available index value from user. */
u16 avail_idx;
- /* Last index we used. */
+ /* Last index we used.
+ * Values are limited to 0x7fff, and the high bit is used as
+ * a wrap counter when using VIRTIO_F_RING_PACKED. */
u16 last_used_idx;
/* Used flags */