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);
+ }
+ }
+}
+
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,
--
1.9.1
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