[PATCH net] vhost_net: remove VHOST_NET_F_VIRTIO_NET_HDR support

Jason Wang
2018-06-08T03:50:42Z

This feature bit is duplicated with VIRTIO_F_ANY_LAYOUT, this means if
a userpsace want to enable VRITIO_F_ANY_LAYOUT,
VHOST_NET_F_VIRTIO_NET_HDR will be implied too. This is wrong and will
break networking. Fixing this by safely removing
VHOST_NET_F_VIRTIO_NET_HDR support. There should be very few or even
no userspace can use this. Further cleanups could be done for
-net-next for safety.

In the future, we need a vhost dedicated feature set/get ioctl()
instead of reusing virtio ones.

Fixes: 4e9fa50c6ccbe ("vhost: move features to core")
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/net.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 986058a..83eef52 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -69,7 +69,6 @@ MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"

enum {
VHOST_NET_FEATURES = VHOST_FEATURES |
- (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
(1ULL << VIRTIO_NET_F_MRG_RXBUF) |
(1ULL << VIRTIO_F_IOMMU_PLATFORM)
};
@@ -1255,15 +1254,11 @@ static int vhost_net_set_features(struct vhost_net *n, u64 features)
(1ULL << VIRTIO_F_VERSION_1))) ?
sizeof(struct virtio_net_hdr_mrg_rxbuf) :
sizeof(struct virtio_net_hdr);
- if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
- /* vhost provides vnet_hdr */
- vhost_hlen = hdr_len;
- sock_hlen = 0;
- } else {
- /* socket provides vnet_hdr */
- vhost_hlen = 0;
- sock_hlen = hdr_len;
- }
+
+ /* socket provides vnet_hdr */
+ vhost_hlen = 0;
+ sock_hlen = hdr_len;
+
mutex_lock(&n->dev.mutex);
if ((features & (1 << VHOST_F_LOG_ALL)) &&
!vhost_log_access_ok(&n->dev))
--
2.7.4