On Tue, Jul 04, 2023 at 06:40:45PM +0200, Maxime Coquelin 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@xxxxxxxxxx>
> ---
> drivers/vdpa/vdpa_user/vduse_dev.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index 1271c9796517..04367a53802b 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -1778,6 +1778,25 @@ static struct attribute *vduse_dev_attrs[] = {
>
> ATTRIBUTE_GROUPS(vduse_dev);
>
> +static void vduse_dev_features_fixup(struct vduse_dev_config *config)
> +{
> + if (config->device_id == VIRTIO_ID_NET) {
> + /*
> + * Temporarily disable control virtqueue and features that
> + * depend on it while CVQ is being made more robust for VDUSE.
> + */
> + config->features &= ~((1ULL << VIRTIO_NET_F_CTRL_VQ) |
> + (1ULL << VIRTIO_NET_F_CTRL_RX) |
> + (1ULL << VIRTIO_NET_F_CTRL_VLAN) |
> + (1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE) |
> + (1ULL << VIRTIO_NET_F_MQ) |
> + (1ULL << VIRTIO_NET_F_CTRL_MAC_ADDR) |
> + (1ULL << VIRTIO_NET_F_RSS) |
> + (1ULL << VIRTIO_NET_F_HASH_REPORT) |
> + (1ULL << VIRTIO_NET_F_NOTF_COAL));
> + }
> +}
> +
This will never be exhaustive, we are adding new features.
Please add an allowlist with just legal ones instead.
> static int vduse_create_dev(struct vduse_dev_config *config,
> void *config_buf, u64 api_version)
> {
> @@ -1793,6 +1812,8 @@ static int vduse_create_dev(struct vduse_dev_config *config,
> if (!dev)
> goto err;
>
> + vduse_dev_features_fixup(config);
> +
> dev->api_version = api_version;
> dev->device_features = config->features;
> dev->device_id = config->device_id;
> --
> 2.41.0
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