This patch tries to detect the possible buggy features advertised by host
and sanitize them. One example is booting virtio-net with only ctrl_vq
disabled, qemu may still advertise many features which depends on it. This
will trigger several BUG()s in virtnet_send_command().
This patch utilizes the sanitize_features() method, and disables all
features that depends on ctrl_vq if it was not advertised.
This fixes the crash when booting with ctrl_vq=off using qemu.
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Cc: Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
Changes from V1:
- fix the cut-and-paste error
Changes from V2:
- loop through an array of feature bits
- switch to use dev_warn()
---
drivers/net/virtio_net.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ec2a8b4..6fadd8c 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1948,6 +1948,31 @@ static int virtnet_restore(struct virtio_device *vdev)
}
#endif
+static void virtnet_sanitize_features(struct virtio_device *dev)
+{
+ unsigned int features_for_ctrl_vq[] = {
+ VIRTIO_NET_F_CTRL_RX,
+ VIRTIO_NET_F_CTRL_VLAN,
+ VIRTIO_NET_F_GUEST_ANNOUNCE,
+ VIRTIO_NET_F_MQ,
+ VIRTIO_NET_F_CTRL_MAC_ADDR
+ };
+ int i;
+
+ if (!virtio_has_feature(dev, VIRTIO_NET_F_CTRL_VQ)) {
+ for (i = 0; i < ARRAY_SIZE(features_for_ctrl_vq); i++) {
+ unsigned int f = features_for_ctrl_vq[i];
+ if (virtio_has_feature(dev, f)) {
+ virtio_disable_feature(dev, f);
+ dev_warn(&dev->dev,
+ "buggy hyperviser: disable feature "
+ "0x%x since VIRTIO_NET_F_CTRL_VQ was "
+ "not advertised.\n", f);
+ }
+ }
+ }
+}
+
static struct virtio_device_id id_table[] = {
{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
{ 0 },
@@ -1975,6 +2000,7 @@ static struct virtio_driver virtio_net_driver = {
.probe = virtnet_probe,
.remove = virtnet_remove,
.config_changed = virtnet_config_changed,
+ .sanitize_features = virtnet_sanitize_features,
#ifdef CONFIG_PM_SLEEP
.freeze = virtnet_freeze,
.restore = virtnet_restore,
--
1.9.1
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