Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) client-ip=23.128.96.35;
MIME-Version: 1.0
References: <20231212131712.1816324-1-maxime.coquelin@redhat.com> <20231212131712.1816324-3-maxime.coquelin@redhat.com>
In-Reply-To: <20231212131712.1816324-3-maxime.coquelin@redhat.com>
From:   Jason Wang <jasowang@redhat.com>
Date:   Wed, 13 Dec 2023 12:52:39 +0800
Message-ID: <CACGkMEthp13a20TGashiFNDovK+b10mgfdX8L=3Xv05g5-eo0w@mail.gmail.com>
Subject: Re: [PATCH v5 2/4] vduse: Temporarily disable control queue features
To:     Maxime Coquelin <maxime.coquelin@redhat.com>
Cc:     mst@redhat.com, xuanzhuo@linux.alibaba.com, paul@paul-moore.com,
        jmorris@namei.org, serge@hallyn.com,
        stephen.smalley.work@gmail.com, eparis@parisplace.org,
        xieyongji@bytedance.com, virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
        david.marchand@redhat.com, lulu@redhat.com, casey@schaufler-ca.com
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Tue, Dec 12, 2023 at 9:17=E2=80=AFPM Maxime Coquelin
<maxime.coquelin@redhat.com> wrote:
>
> Virtio-net driver control queue implementation is not safe
> when used with VDUSE. If the VDUSE application does not
> reply to control queue messages, it currently ends up
> hanging the kernel thread sending this command.
>
> Some work is on-going to make the control queue
> implementation robust with VDUSE. Until it is completed,
> let's disable control virtqueue and features that depend on
> it.
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>

I wonder if it's better to fail instead of a mask as a start.

Thanks

> ---
>  drivers/vdpa/vdpa_user/vduse_dev.c | 37 ++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/=
vduse_dev.c
> index 0486ff672408..fe4b5c8203fd 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -28,6 +28,7 @@
>  #include <uapi/linux/virtio_config.h>
>  #include <uapi/linux/virtio_ids.h>
>  #include <uapi/linux/virtio_blk.h>
> +#include <uapi/linux/virtio_ring.h>
>  #include <linux/mod_devicetable.h>
>
>  #include "iova_domain.h"
> @@ -46,6 +47,30 @@
>
>  #define IRQ_UNBOUND -1
>
> +#define VDUSE_NET_VALID_FEATURES_MASK           \
> +       (BIT_ULL(VIRTIO_NET_F_CSUM) |           \
> +        BIT_ULL(VIRTIO_NET_F_GUEST_CSUM) |     \
> +        BIT_ULL(VIRTIO_NET_F_MTU) |            \
> +        BIT_ULL(VIRTIO_NET_F_MAC) |            \
> +        BIT_ULL(VIRTIO_NET_F_GUEST_TSO4) |     \
> +        BIT_ULL(VIRTIO_NET_F_GUEST_TSO6) |     \
> +        BIT_ULL(VIRTIO_NET_F_GUEST_ECN) |      \
> +        BIT_ULL(VIRTIO_NET_F_GUEST_UFO) |      \
> +        BIT_ULL(VIRTIO_NET_F_HOST_TSO4) |      \
> +        BIT_ULL(VIRTIO_NET_F_HOST_TSO6) |      \
> +        BIT_ULL(VIRTIO_NET_F_HOST_ECN) |       \
> +        BIT_ULL(VIRTIO_NET_F_HOST_UFO) |       \
> +        BIT_ULL(VIRTIO_NET_F_MRG_RXBUF) |      \
> +        BIT_ULL(VIRTIO_NET_F_STATUS) |         \
> +        BIT_ULL(VIRTIO_NET_F_HOST_USO) |       \
> +        BIT_ULL(VIRTIO_F_ANY_LAYOUT) |         \
> +        BIT_ULL(VIRTIO_RING_F_INDIRECT_DESC) | \
> +        BIT_ULL(VIRTIO_RING_F_EVENT_IDX) |          \
> +        BIT_ULL(VIRTIO_F_VERSION_1) |          \
> +        BIT_ULL(VIRTIO_F_ACCESS_PLATFORM) |     \
> +        BIT_ULL(VIRTIO_F_RING_PACKED) |        \
> +        BIT_ULL(VIRTIO_F_IN_ORDER))
> +
>  struct vduse_virtqueue {
>         u16 index;
>         u16 num_max;
> @@ -1782,6 +1807,16 @@ static struct attribute *vduse_dev_attrs[] =3D {
>
>  ATTRIBUTE_GROUPS(vduse_dev);
>
> +static void vduse_dev_features_filter(struct vduse_dev_config *config)
> +{
> +       /*
> +        * Temporarily filter out virtio-net's control virtqueue and feat=
ures
> +        * that depend on it while CVQ is being made more robust for VDUS=
E.
> +        */
> +       if (config->device_id =3D=3D VIRTIO_ID_NET)
> +               config->features &=3D VDUSE_NET_VALID_FEATURES_MASK;
> +}
> +
>  static int vduse_create_dev(struct vduse_dev_config *config,
>                             void *config_buf, u64 api_version)
>  {
> @@ -1797,6 +1832,8 @@ static int vduse_create_dev(struct vduse_dev_config=
 *config,
>         if (!dev)
>                 goto err;
>
> +       vduse_dev_features_filter(config);
> +
>         dev->api_version =3D api_version;
>         dev->device_features =3D config->features;
>         dev->device_id =3D config->device_id;
> --
> 2.43.0
>