Si-Wei Liu
2023-Feb-06 04:53 UTC
[PATCH v3 5/6] vdpa/mlx5: conditionally show MTU and STATUS in config space
On 2/5/2023 1:36 AM, Eli Cohen wrote:> > On 03/02/2023 7:02, Si-Wei Liu wrote: >> The spec says: >> ???? mtu only exists if VIRTIO_NET_F_MTU is set >> ???? status only exists if VIRTIO_NET_F_STATUS is set >> >> We should only show MTU and STATUS conditionally depending on >> the feature bits. >> >> Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com> >> --- >> ? drivers/vdpa/mlx5/net/mlx5_vnet.c | 22 ++++++++++++++-------- >> ? 1 file changed, 14 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c >> b/drivers/vdpa/mlx5/net/mlx5_vnet.c >> index 3a6dbbc6..867ac18 100644 >> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c >> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c >> @@ -3009,6 +3009,8 @@ static int event_handler(struct notifier_block >> *nb, unsigned long event, void *p >> ????? struct mlx5_vdpa_wq_ent *wqent; >> ? ????? if (event == MLX5_EVENT_TYPE_PORT_CHANGE) { >> +??????? if (!(ndev->mvdev.actual_features & >> BIT_ULL(VIRTIO_NET_F_STATUS))) >> +??????????? return NOTIFY_DONE; >> ????????? switch (eqe->sub_type) { >> ????????? case MLX5_PORT_CHANGE_SUBTYPE_DOWN: >> ????????? case MLX5_PORT_CHANGE_SUBTYPE_ACTIVE: >> @@ -3118,16 +3120,20 @@ static int mlx5_vdpa_dev_add(struct >> vdpa_mgmt_dev *v_mdev, const char *name, >> ????????????? goto err_alloc; >> ????? } >> ? -??? err = query_mtu(mdev, &mtu); >> -??? if (err) >> -??????? goto err_alloc; >> +??? if (ndev->mvdev.mlx_features & BIT_ULL(VIRTIO_NET_F_MTU)) { > > VIRTIO_NET_F_MTU is offered by the device. So conditional is always true.With the next patch in series that selectively provisions device features to mlx5_vdpa, this conditional will not be always true. That was the reason why I made patch 5 and 6 in a single commit, as this conditional will only be needed until feature provisioning is supported. Basically patch 5 and 6 are logically connected and technically should be separated out. I'm now puzzled, what was your thought then the change in patch 5 shouldn't be part of patch 6?> We are not done with feature negotiation at this stage so you'You' are who? device, driver or guest user?> may still set a value to device mtu if MTU won't be negotiated > eventually. But that is not a problem because the spec says: > > ?VIRTIO_NET_F_MTU(3) Device maximum MTU reporting is supported. If > offered by the device, device > advises driver about the value of its maximum MTU. If negotiated, the > driver uses mtu as the maximum > > MTU value. > > So the driver will use whatever value is there only if negotiated.My understanding is that 'vdpa dev config' now displays user provisioned config, or default config value advertised by the device, rather than what config driver will actually use.> >> +??????? err = query_mtu(mdev, &mtu); >> +??????? if (err) >> +??????????? goto err_alloc; >> ? -??? ndev->config.mtu = cpu_to_mlx5vdpa16(mvdev, mtu); >> +??????? ndev->config.mtu = cpu_to_mlx5vdpa16(mvdev, mtu); >> +??? } >> ? -??? if (get_link_state(mvdev)) >> -??????? ndev->config.status |= cpu_to_mlx5vdpa16(mvdev, >> VIRTIO_NET_S_LINK_UP); >> -??? else >> -??????? ndev->config.status &= cpu_to_mlx5vdpa16(mvdev, >> ~VIRTIO_NET_S_LINK_UP); >> +??? if (ndev->mvdev.mlx_features & BIT_ULL(VIRTIO_NET_F_STATUS)) { >> +??????? if (get_link_state(mvdev)) >> +??????????? ndev->config.status |= cpu_to_mlx5vdpa16(mvdev, >> VIRTIO_NET_S_LINK_UP); >> +??????? else >> +??????????? ndev->config.status &= cpu_to_mlx5vdpa16(mvdev, >> ~VIRTIO_NET_S_LINK_UP); >> +??? } > Same thing here. Feature negotiation is not complete yet and if > > VIRTIO_NET_F_STATUS ends up not being negotiated, the driver will > ignore this value.See above. With feature provisioning, whether the VIRTIO_NET_F_STATUS feature is advertised by device is subject to the device_features value provisioned by the host admin users. -Siwei> >> ? ????? if (add_config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR)) { >> ????????? memcpy(ndev->config.mac, add_config->net.mac, ETH_ALEN);