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References: <20221110141335.62171-1-sgarzare@redhat.com>
In-Reply-To: <20221110141335.62171-1-sgarzare@redhat.com>
From:   Jason Wang <jasowang@redhat.com>
Date:   Fri, 11 Nov 2022 14:34:22 +0800
Message-ID: <CACGkMEvmumcokt4UpazGKWfOeLDrh+kaLEWywQtPF0dJfW-kUw@mail.gmail.com>
Subject: Re: [PATCH] vdpa_sim: fix vringh initialization in vdpasim_queue_ready()
To:     Stefano Garzarella <sgarzare@redhat.com>
Cc:     virtualization@lists.linux-foundation.org,
        "Michael S. Tsirkin" <mst@redhat.com>,
        linux-kernel@vger.kernel.org,
        Eugenio Perez Martin <eperezma@redhat.com>
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On Thu, Nov 10, 2022 at 10:13 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> When we initialize vringh, we should pass the features and the
> number of elements in the virtqueue negotiated with the driver,
> otherwise operations with vringh may fail.
>
> This was discovered in a case where the driver sets a number of
> elements in the virtqueue different from the value returned by
> .get_vq_num_max().
>
> In vdpasim_vq_reset() is safe to initialize the vringh with
> default values, since the virtqueue will not be used until
> vdpasim_queue_ready() is called again.
>
> Fixes: 2c53d0f64c06 ("vdpasim: vDPA device simulator")
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

> ---
>  drivers/vdpa/vdpa_sim/vdpa_sim.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index b071f0d842fb..b20689f8fe89 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -67,8 +67,7 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
>  {
>         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
>
> -       vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features,
> -                         VDPASIM_QUEUE_MAX, false,
> +       vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, false,
>                           (struct vring_desc *)(uintptr_t)vq->desc_addr,
>                           (struct vring_avail *)
>                           (uintptr_t)vq->driver_addr,
> --
> 2.38.1
>