On Thu, Nov 20, 2014 at 02:10:35PM +0800, Jason Wang wrote:
> We currently trigger BUG when VIRTIO_NET_F_CTRL_VQ
> is not set but one of features depending on it is.
> That's not a friendly way to report errors to
> hypervisors.
> Let's check, and fail probe instead.
>
> Cc: Rusty Russell <ru...@rustcorp.com.au>
> Cc: Cornelia Huck <cornelia.h...@de.ibm.com>
> Cc: Wanlong Gao <gaowanl...@cn.fujitsu.com>
> Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> Signed-off-by: Jason Wang <jasow...@redhat.com>
Looks good, minor nits below:
> ---
> Changes from V2:
> - only check the features for ctrl vq (this fix the real bug)
> - better error message and simplify API
> ---
> drivers/net/virtio_net.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index ec2a8b4..a6bcfce 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1673,6 +1673,40 @@ static const struct attribute_group
> virtio_net_mrg_rx_group = {
> };
> #endif
>
> +static bool virtnet_fail_on_feature(struct virtio_device *vdev,
> + unsigned int fbit,
> + const char *fname, const char *dname)
> +{
> + if (!virtio_has_feature(vdev, fbit))
> + return false;
> +
> + dev_err(&vdev->dev, "Hypervisor bug: advertise feature %s but not %s",
Well we don't know it's a hypervisor. How about:
Device bug: advertises feature %s but not %s.
> + fname, dname);
> +
> + return true;
> +}
> +
> +#define VIRTNET_FAIL_ON(vdev, fbit, dbit) \
> + virtnet_fail_on_feature(vdev, fbit, #fbit, #dbit)
I would pass dbit directly, and supply a string from caller,
instead if #dbit, this way it can be any string.
> +
> +static bool virtnet_validate_features(struct virtio_device *vdev)
> +{
> + if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
> + (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
> + VIRTIO_NET_F_CTRL_VQ) ||
> + VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
> + VIRTIO_NET_F_CTRL_VQ) ||
> + VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
> + VIRTIO_NET_F_TRL_VQ) ||
Typo: VIRTIO_NET_F_CTRL_VQ.
> + VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, VIRTIO_NET_F_CTRL_VQ) ||
> + VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
> + VIRTIO_NET_F_CTRL_VQ))) {
> + return false;
> + }
> +
> + return true;
> +}
> +
> static int virtnet_probe(struct virtio_device *vdev)
> {
> int i, err;
> @@ -1680,6 +1714,9 @@ static int virtnet_probe(struct virtio_device *vdev)
> struct virtnet_info *vi;
> u16 max_queue_pairs;
>
> + if (!virtnet_validate_features(vdev))
> + return -EINVAL;
> +
> /* Find if host supports multiqueue virtio_net device */
> err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
> struct virtio_net_config,
> --
> 1.9.1
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