Virtualization - Aug 2021 - [PATCH linux-next v3 0/6] vdpa: enable user to set mac, mtu

On Wed, Jun 16, 2021 at 10:11:49PM +0300, Parav Pandit
wrote:
> Currently user cannot set the mac address and mtu of the vdpa device.
> This patchset enables users to set the mac address and mtu of the vdpa
> device once the device is created.
> If a vendor driver supports such configuration user can set it otherwise
> user gets unsupported error.
This makes sense to me overall. People are used to
use netlink to set these parameters, and virtio does
not necessarily have a way to set all device
parameters - they can be RO in the config space.

> vdpa mac address and mtu are device configuration layout fields.
> To keep interface generic enough for multiple types of vdpa devices, mac
> address and mtu setting is implemented as configuration layout config
> knobs.
> This enables to use similar config layout for other virtio devices.
> 
> An example of query & set of config layout fields for vdpa_sim_net
> driver:
> 
> Configuration layout fields are set after device is created.
> This enables user to change such fields at later point without destroying
and
> recreating the device for new config.
> 
> $ vdpa mgmtdev show
> vdpasim_net:
>   supported_classes net
> 
> Add the device:
> $ vdpa dev add name bar mgmtdev vdpasim_net
> 
> Configure mac address and mtu:
> $ vdpa dev config set bar mac 00:11:22:33:44:55 mtu 9000
> 
> In above command only mac address or only mtu can also be set.
> 
> View the config after setting:
> $ vdpa dev config show
> bar: mac 00:11:22:33:44:55 link up link_announce false mtu 9000 speed 0
duplex 0
> 
> Patch summary:
> Patch-1 introduced and use helpers for get/set config area
> Patch-2 implement query device config layout
> Patch-3 enanble user to set mac and mtu in config space
> Patch-4 vdpa_sim_net implements get and set of config layout
> Patch-5 mlx5 vdpa driver supports user provided mac config
> Patch-6 mlx5 vdpa driver uses user provided mac during rx flow steering
> 
> changelog:
> v2->v3:
>  - dropped patches which are merged
>  - simplified code to handle non transitional devices
> 
> v1->v2:
>  - new patches to fix kdoc comment to add new kdoc section
>  - new patch to have synchronized access to features and config space
>  - read whole net config layout instead of individual fields
>  - added error extack for unmanaged vdpa device
>  - fixed several endianness issues
>  - introduced vdpa device ops for get config which is synchronized
>    with other get/set features ops and config ops
>  - fixed mtu range checking for max
>  - using NLA_POLICY_ETH_ADDR
>  - set config moved to device ops instead of mgmtdev ops
>  - merged build and set to single routine
>  - ensuring that user has NET_ADMIN capability for configuring network
>    attributes
>  - using updated interface and callbacks for get/set config
>  - following new api for config get/set for mgmt tool in mlx5 vdpa
>    driver
>  - fixes for accessing right SF dma device and bar address
>  - fix for mtu calculation
>  - fix for bit access in features
>  - fix for index restore with suspend/resume operation
> 
> 
> Eli Cohen (2):
>   vdpa/mlx5: Support configuration of MAC
>   vdpa/mlx5: Forward only packets with allowed MAC address
> 
> Parav Pandit (4):
>   vdpa: Introduce and use vdpa device get, set config helpers
>   vdpa: Introduce query of device config layout
>   vdpa: Enable user to set mac and mtu of vdpa device
>   vdpa_sim_net: Enable user to set mac address and mtu
> 
>  drivers/vdpa/mlx5/net/mlx5_vnet.c    | 101 ++++++--
>  drivers/vdpa/vdpa.c                  | 337 +++++++++++++++++++++++++++
>  drivers/vdpa/vdpa_sim/vdpa_sim.c     |  13 ++
>  drivers/vdpa/vdpa_sim/vdpa_sim.h     |   2 +
>  drivers/vdpa/vdpa_sim/vdpa_sim_net.c |  34 +--
>  drivers/vhost/vdpa.c                 |   3 +-
>  include/linux/vdpa.h                 |  38 +--
>  include/uapi/linux/vdpa.h            |  12 +
>  8 files changed, 490 insertions(+), 50 deletions(-)
> 
> -- 
> 2.26.2

> From: Michael S. Tsirkin <mst at redhat.com>
> Sent: Thursday, August 5, 2021 3:28 PM
> 
> On Wed, Jun 16, 2021 at 10:11:49PM +0300, Parav Pandit wrote:
> > Currently user cannot set the mac address and mtu of the vdpa device.
> > This patchset enables users to set the mac address and mtu of the vdpa
> > device once the device is created.
> > If a vendor driver supports such configuration user can set it
> > otherwise user gets unsupported error.
> 
> This makes sense to me overall. People are used to use netlink to set these
> parameters, and virtio does not necessarily have a way to set all device
> parameters - they can be RO in the config space.
Yes. this series enables it to RO when driver doesn't support setting it.
When driver supports it, it is RW.

Do I need to rebase + resend?
Please let me know.

? 2021/8/5 ??5:57, Michael S. Tsirkin ??:
> On Wed, Jun 16, 2021 at 10:11:49PM +0300, Parav Pandit wrote:
>> Currently user cannot set the mac address and mtu of the vdpa device.
>> This patchset enables users to set the mac address and mtu of the vdpa
>> device once the device is created.
>> If a vendor driver supports such configuration user can set it
otherwise
>> user gets unsupported error.
> This makes sense to me overall. People are used to
> use netlink to set these parameters, and virtio does
> not necessarily have a way to set all device
> parameters - they can be RO in the config space.

I don't get here, we need to care RO as well (e.g the max_virtqueue_pairs).

And do we really want netlink uAPI for virtio like:

  enum vdpa_attr {
@@ -33,6 +34,16 @@ enum vdpa_attr {
  	VDPA_ATTR_DEV_MAX_VQS,			/* u32 */
  	VDPA_ATTR_DEV_MAX_VQ_SIZE,		/* u16 */
  
+	VDPA_ATTR_DEV_NET_CFG_MACADDR,		/* binary */
+	VDPA_ATTR_DEV_NET_STATUS,		/* u8 */
+	VDPA_ATTR_DEV_NET_CFG_MAX_VQP,		/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_MTU,		/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_SPEED,		/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_DUPLEX,		/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_RSS_MAX_KEY_LEN,	/* u8 */
+	VDPA_ATTR_DEV_NET_CFG_RSS_MAX_IT_LEN,	/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_RSS_HASH_TYPES,	/* u32 */
+
  	/* new attributes must be added above here */
  	VDPA_ATTR_MAX,
  };

Or virtio uAPI and make netlink a transport?

I prefer the latter since we will meet the similar issue at the hardware 
level when we want to create and provision virtio device dynamically.

Thanks

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