On Tue, Jul 19, 2022 at 01:25:42PM +0000, Eli Cohen
wrote:> Hi,
>
>
>
> mlx5_vdpa is offering VIRTIO_NET_F_MTU. However the driver (is it qemu
> responsibility?) does not accept and it ends up not negotiated.
qemu is responsible for passing features to driver.
>
>
> I don't see how can the driver refuse to negotiate this. What if the
hardware
> has a limitation with respect to mtu?
Then it can fail FEATURES_OK
>
>
> I noticed this when I created the device with mtu of 1000. I expected the
> netdev at the vm to have mtu of 1000 and any attempt to go beyond should
fail
> but that's not the case.
>
>
>
> Comments?
Any chance mtu is too small?
if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) {
int mtu = virtio_cread16(vdev,
offsetof(struct virtio_net_config,
mtu));
if (mtu < MIN_MTU)
__virtio_clear_bit(vdev, VIRTIO_NET_F_MTU);
}
any chance it's on power or another BE system?
--
MST