On Tue, Feb 11, 2020 at 02:04:54PM +0100, Eugenio Pérez wrote:
> 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 your fast responses.
>
> Could you try this patch on top of eccb852f1fe6bede630e2e4f1a121a81e34354ab?
>
> Thanks!
>
> >From 71d0f9108a18aa894cc0c0c1c7efbad39f465a27 Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <
> eperezma@xxxxxxxxxx>
> Date: Tue, 11 Feb 2020 13:19:10 +0100
> Subject: [PATCH] vhost: fix return value of vhost_get_vq_desc
>
> Before of the batch change, it was the chain's head. Need to keep that
> way or we will not be able to free a chain of descriptors.
I think it's cleaner to have all descriptors in the chain
have the same id.
> Fixes: eccb852f1fe6 ("vhost: batching fetches")
> ---
> drivers/vhost/vhost.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index b5a51b1f2e79..fc422c3e5c08 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -2409,12 +2409,11 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
> *out_num += ret;
> }
>
> - ret = desc->id;
> -
> if (!(desc->flags & VRING_DESC_F_NEXT))
> break;
> }
>
> + ret = vq->descs[vq->first_desc].id;
> vq->first_desc = i + 1;
>
> return ret;
> --
> 2.18.1
