[PATCH] Add some traces

[Eugenio PÃrez]

---
 drivers/vhost/vhost.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b5a51b1f2e79..60c048eebe4d 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2239,8 +2239,8 @@ static int fetch_buf(struct vhost_virtqueue *vq)
 		vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
 
 		if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
-			vq_err(vq, "Guest moved used index from %u to %u",
-				last_avail_idx, vq->avail_idx);
+			vq_err(vq, "Guest moved vq %p used index from %u to %u",
+				vq, last_avail_idx, vq->avail_idx);
 			return -EFAULT;
 		}
 
@@ -2336,6 +2336,8 @@ static int fetch_descs(struct vhost_virtqueue *vq)
 	while (!ret && vq->ndescs <= vq->batch_descs)
 		ret = fetch_buf(vq);
 
+	pr_debug("[vq=%p][vq->ndescs=%d]", vq, vq->ndescs);
+
 	return vq->ndescs ? 0 : ret;
 }
 
@@ -2416,6 +2418,8 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 	}
 
 	vq->first_desc = i + 1;
+	pr_debug("[vq=%p][vq->ndescs=%d][vq->first_desc=%d]", vq, vq->ndescs,
+		 vq->first_desc);
 
 	return ret;
 
@@ -2459,6 +2463,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq,
 
 	start = vq->last_used_idx & (vq->num - 1);
 	used = vq->used->ring + start;
+	pr_debug("[vq=%p][start=%d][count=%u]", vq, start, count);
 	if (vhost_put_used(vq, heads, start, count)) {
 		vq_err(vq, "Failed to write used");
 		return -EFAULT;
-- 
2.18.1