After the introduction of vhost MTU, VIRTIO_NET_F_MTU is enabled
by default. However, virtio-user vtpci does not support to get
MTU from device yet, i.e., vtpci_read_dev_config(MTU) fails.
Plus, struct virtio_net_config is defined as a uninitialized
variable, and could be different values in
virtio_negotiate_features() and virtio_init_device().
In some cases, it passes the check in virtio_negotiate_features()
but fails the check in virtio_init_device(). As a result,
virtio-user canno be initialized.
To fix it, (1) accessing uninitialized variable is not a good
practice, so initialize it as zero; (2) explicitly disable MTU
feature in virtio-user.
Fixes: 49d26d9e3f47 ("net/virtio: support MTU feature")
Cc: Maxime Coquelin <maxime.coque...@redhat.com>
Cc: Yuanhan Liu <yuanhan....@linux.intel.com>
Signed-off-by: Jianfeng Tan <jianfeng....@intel.com>
---
drivers/net/virtio/virtio_ethdev.c | 4 ++--
drivers/net/virtio/virtio_user/virtio_user_dev.c | 6 ++++++
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/net/virtio/virtio_ethdev.c
b/drivers/net/virtio/virtio_ethdev.c
index 78cb3e8..4c43784 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1163,7 +1163,7 @@ virtio_negotiate_features(struct virtio_hw *hw, uint64_t
req_features)
/* If supported, ensure MTU value is valid before acknowledging it. */
if (host_features & req_features & (1ULL << VIRTIO_NET_F_MTU)) {
- struct virtio_net_config config;
+ struct virtio_net_config config = {0};
vtpci_read_dev_config(hw,
offsetof(struct virtio_net_config, mtu),
@@ -1332,7 +1332,7 @@ virtio_init_device(struct rte_eth_dev *eth_dev, uint64_t
req_features)
{
struct virtio_hw *hw = eth_dev->data->dev_private;
struct virtio_net_config *config;
- struct virtio_net_config local_config;
+ struct virtio_net_config local_config = {0};
struct rte_pci_device *pci_dev = NULL;
int ret;
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c
b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index 6871cd4..529b3d7 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -362,6 +362,12 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char
*path, int queues,
/* The backend will not report this feature, we add it explicitly */
dev->device_features |= (1ull << VIRTIO_NET_F_STATUS);
+ /* TODO: VIRTIO_NET_F_MTU is for QEMU to advertise MTU to both frontend
+ * and backend driver. For virtio-user, disable it for now, until we
+ * have a parameter to specify the MTU.
+ */
+ dev->device_features &= ~(1ull << VIRTIO_NET_F_MTU);
+
return 0;
}
--
2.7.4
