Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230419134329.346825-1-maxime.coquelin@redhat.com> <20230419134329.346825-2-maxime.coquelin@redhat.com>
In-Reply-To: <20230419134329.346825-2-maxime.coquelin@redhat.com>
From:   Jason Wang <jasowang@redhat.com>
Date:   Thu, 20 Apr 2023 12:06:18 +0800
Message-ID: <CACGkMEtooodqB9pSGTQJx4x55-+RqPhNhT5_4zSDMiCSJXyjVg@mail.gmail.com>
Subject: Re: [RFC 1/2] vduse: validate block features only with block devices
To:     Maxime Coquelin <maxime.coquelin@redhat.com>
Cc:     xieyongji@bytedance.com, mst@redhat.com, david.marchand@redhat.com,
        linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        xuanzhuo@linux.alibaba.com, eperezma@redhat.com
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Wed, Apr 19, 2023 at 9:43=E2=80=AFPM Maxime Coquelin
<maxime.coquelin@redhat.com> wrote:
>
> This patch is preliminary work to enable network device
> type support to VDUSE.
>
> As VIRTIO_BLK_F_CONFIG_WCE shares the same value as
> VIRTIO_NET_F_HOST_TSO4, we need to restrict its check
> to Virtio-blk device type.
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  drivers/vdpa/vdpa_user/vduse_dev.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/=
vduse_dev.c
> index 0c3b48616a9f..6fa598a03d8e 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -1416,13 +1416,14 @@ static bool device_is_allowed(u32 device_id)
>         return false;
>  }
>
> -static bool features_is_valid(u64 features)
> +static bool features_is_valid(struct vduse_dev_config *config)
>  {
> -       if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
> +       if (!(config->features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
>                 return false;
>
>         /* Now we only support read-only configuration space */
> -       if (features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE))
> +       if ((config->device_id =3D=3D VIRTIO_ID_BLOCK) &&
> +                       (config->features & (1ULL << VIRTIO_BLK_F_CONFIG_=
WCE)))

The reason we filter WCE out is to avoid writable config space which
might block the driver with a buggy userspace.

For networking, I guess we should fail if VERSION_1 is not negotiated,
then we can avoid setting mac addresses via the config space.

Thanks

>                 return false;
>
>         return true;
> @@ -1446,7 +1447,7 @@ static bool vduse_validate_config(struct vduse_dev_=
config *config)
>         if (!device_is_allowed(config->device_id))
>                 return false;
>
> -       if (!features_is_valid(config->features))
> +       if (!features_is_valid(config))
>                 return false;
>
>         return true;
> --
> 2.39.2
>