On 11/13/2014 01:24 PM, Jason Wang wrote:
> This patch tries to detect the possible buggy features advertised by host
> and fix them. One example is current booting virtio-net with only
> ctrl_vq disabled, qemu may still advertise many features which depends
> it. This will trigger several BUG()s in virtnet_send_command().
>
> This patch utilizes the fix_features() method, and disable all features that
> depends on ctrl_vq if it was not advertised.
>
> This fixes the crash when booting with ctrl_vq=off.
>
> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/net/virtio_net.c | 35 +++++++++++++++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index ec2a8b4..d6bb5fa 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1948,6 +1948,40 @@ static int virtnet_restore(struct virtio_device *vdev)
> }
> #endif
>
> +static void virtnet_fix_features(struct virtio_device *dev)
> +{
> + if (!virtio_has_feature(dev, VIRTIO_NET_F_CTRL_VQ)) {
> + if (virtio_has_feature(dev, VIRTIO_NET_F_CTRL_RX)) {
> + pr_warning("Disable VIRTIO_NET_F_CTRL_RX since host "
> + "does not advertise VIRTIO_NET_F_CTRL_VQ");
> + virtio_disable_feature(dev, VIRTIO_NET_F_CTRL_RX);
> + }
> + if (virtio_has_feature(dev, VIRTIO_NET_F_CTRL_VLAN)) {
> + pr_warning("Disable VIRTIO_NET_F_CTRL_VLAN since host "
> + "does not advertise VIRTIO_NET_F_CTRL_VQ");
> + virtio_disable_feature(dev, VIRTIO_NET_F_CTRL_VLAN);
> + }
> + if (virtio_has_feature(dev, VIRTIO_NET_F_GUEST_ANNOUNCE)) {
> + pr_warning("Disable VIRTIO_NET_F_GUEST_ANNOUCE since "
> + "host does not advertise "
> + "VIRTIO_NET_F_CTRL_VQ");
> + virtio_disable_feature(dev,
> + VIRTIO_NET_F_GUEST_ANNOUNCE);
> + }
> + if (virtio_has_feature(dev, VIRTIO_NET_F_MQ)) {
> + pr_warning("Disable VIRTIO_NET_F_MQ since host "
> + "does not advertise VIRTIO_NET_F_CTRL_VQ");
> + virtio_disable_feature(dev, VIRTIO_NET_F_CTRL_VLAN);
> + }
> + if (virtio_has_feature(dev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
> + pr_warning("Disable VIRTIO_NET_F_CTRL_MAC_ADDR since "
> + "host does not advertise "
> + "VIRTIO_NET_F_CTRL_VQ");
> + virtio_disable_feature(dev, VIRTIO_NET_F_CTRL_VLAN);
Oops, this looks like a cut-and-paste error. Will post V2.
> + }
> + }
> +}
> +
> static struct virtio_device_id id_table[] = {
> { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
> { 0 },
> @@ -1975,6 +2009,7 @@ static struct virtio_driver virtio_net_driver = {
> .probe = virtnet_probe,
> .remove = virtnet_remove,
> .config_changed = virtnet_config_changed,
> + .fix_features = virtnet_fix_features,
> #ifdef CONFIG_PM_SLEEP
> .freeze = virtnet_freeze,
> .restore = virtnet_restore,
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