On Mon, 2020-02-10 at 12:01 +0100, Christian Borntraeger wrote: > > On 10.02.20 10:47, Eugenio Perez Martin wrote: > > Hi Christian. > > > > I'm not able to reproduce the failure with eccb852f1fe6bede630e2e4f1a121a81e34354ab commit. Could you add more data? > > Your configuration (libvirt or qemu line), and host's dmesg output if any? > > > > Thanks! > > If it was not obvious, this is on s390x, a big endian system. > Hi Christian. Thank you very much for the hints. Could we add some debug traces? Something like the inline patch should give us some clues. Thanks! >From a8d65d5f0ae3d305443ee84b4842b7c712a1ac1d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@xxxxxxxxxx> Date: Tue, 11 Feb 2020 10:29:01 +0100 Subject: [PATCH] Add some traces --- 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