@@ -4,9 +4,13 @@
#ifndef __MLX5_VDPA_H__
#define __MLX5_VDPA_H__
+#include <linux/etherdevice.h>
+#include <linux/if_vlan.h>
#include <linux/vdpa.h>
#include <linux/mlx5/driver.h>
+#define MLX5V_ETH_HARD_MTU (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN)
+
struct mlx5_vdpa_direct_mr {
u64 start;
u64 end;
@@ -1907,6 +1907,19 @@ static int mlx5_get_vq_irq(struct vdpa_device *vdv, u16 idx)
.free = mlx5_vdpa_free,
};
+static int query_mtu(struct mlx5_core_dev *mdev, u16 *mtu)
+{
+ u16 hw_mtu;
+ int err;
+
+ err = mlx5_query_nic_vport_mtu(mdev, &hw_mtu);
+ if (err)
+ return err;
+
+ *mtu = hw_mtu - MLX5V_ETH_HARD_MTU;
+ return 0;
+}
+
static int alloc_resources(struct mlx5_vdpa_net *ndev)
{
struct mlx5_vdpa_net_resources *res = &ndev->res;
@@ -1992,7 +2005,7 @@ static int mlx5v_probe(struct auxiliary_device *adev,
init_mvqs(ndev);
mutex_init(&ndev->reslock);
config = &ndev->config;
- err = mlx5_query_nic_vport_mtu(mdev, &ndev->mtu);
+ err = query_mtu(mdev, &ndev->mtu);
if (err)
goto err_mtu;
When feature VIRTIO_NET_F_MTU is negotiated on mlx5_vdpa, 22 extra bytes worth of MTU length is shown in guest. This is because the mlx5_query_port_max_mtu API returns the "hardware" MTU value, which does not just contain the Ethernet payload, but includes extra lengths starting from the Ethernet header up to the FCS altogether. Fix the MTU so packets won't get dropped silently. Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices") Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com> Acked-by: Jason Wang <jasowang@redhat.com> Acked-by: Eli Cohen <elic@nvidia.com> --- drivers/vdpa/mlx5/core/mlx5_vdpa.h | 4 ++++ drivers/vdpa/mlx5/net/mlx5_vnet.c | 15 ++++++++++++++- 2 files changed, 18 insertions(+), 1 deletion(-)