Re: [PATCH v3 3/4] vdpa: show dev config as-is in "vdpa dev show" output

Jason Wang
2022-10-24T08:40:28Z

On Sat, Oct 22, 2022 at 7:49 AM Si-Wei Liu <si-wei.liu@oracle.com> wrote:
>
> Live migration of vdpa would typically require re-instate vdpa
> device with an idential set of configs on the destination node,
> same way as how source node created the device in the first
> place. In order to save orchestration software from memorizing
> and keeping track of vdpa config, it will be helpful if the vdpa
> tool provides the aids for exporting the initial configs as-is,
> the way how vdpa device was created. The "vdpa dev show" command
> seems to be the right vehicle for that. It is unlike the "vdpa dev
> config show" command output which usually goes with the live value
> in the device config space, and is not quite reliable subject to
> the dynamics of feature negotiation or possible change by the
> driver to the config space.
>
> Examples:
>
> 1) Create vDPA by default without any config attribute
>
> $ vdpa dev add mgmtdev pci/0000:41:04.2 name vdpa0
> $ vdpa dev show vdpa0
> vdpa0: type network mgmtdev pci/0000:41:04.2 vendor_id 5555 max_vqs 9 max_vq_size 256
> $ vdpa dev -jp show vdpa0
> {
> "dev": {
> "vdpa0": {
> "type": "network",
> "mgmtdev": "pci/0000:41:04.2",
> "vendor_id": 5555,
> "max_vqs": 9,
> "max_vq_size": 256,
> }
> }
> }
>
> 2) Create vDPA with config attribute(s) specified
>
> $ vdpa dev add mgmtdev pci/0000:41:04.2 name vdpa0 \
> mac e4:11:c6:d3:45:f0 max_vq_pairs 4
> $ vdpa dev show
> vdpa0: type network mgmtdev pci/0000:41:04.2 vendor_id 5555 max_vqs 9 max_vq_size 256
> initial_config: mac e4:11:c6:d3:45:f0 max_vq_pairs 4
> $ vdpa dev -jp show
> {
> "dev": {
> "vdpa0": {
> "type": "network",
> "mgmtdev": "pci/0000:41:04.2",
> "vendor_id": 5555,
> "max_vqs": 9,
> "max_vq_size": 256,
> "initial_config": {
> "mac": "e4:11:c6:d3:45:f0",
> "max_vq_pairs": 4
> }
> }
> }
> }
>
> Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
> ---
> drivers/vdpa/vdpa.c | 39 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index bebded6..bfb8f54 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -677,6 +677,41 @@ static int vdpa_nl_cmd_dev_del_set_doit(struct sk_buff *skb, struct genl_info *i
> }
>
> static int
> +vdpa_dev_initcfg_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 device_id)
> +{
> + struct vdpa_dev_set_config *cfg = &vdev->init_cfg;
> + int err = -EMSGSIZE;
> +
> + if (!cfg->mask)
> + return 0;
> +
> + switch (device_id) {
> + case VIRTIO_ID_NET:
> + if ((cfg->mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MACADDR)) != 0 &&
> + nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR,
> + sizeof(cfg->net.mac), cfg->net.mac))
> + return err;
> + if ((cfg->mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU)) != 0 &&
> + nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, cfg->net.mtu))
> + return err;
> + if ((cfg->mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP)) != 0 &&
> + nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP,
> + cfg->net.max_vq_pairs))
> + return err;
> + break;
> + default:
> + break;
> + }
> +
> + if ((cfg->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) != 0 &&
> + nla_put_u64_64bit(msg, VDPA_ATTR_DEV_FEATURES,
> + cfg->device_features, VDPA_ATTR_PAD))
> + return err;

A question: If any of those above attributes were not provisioned,
should we show the ones that are inherited from the parent?

Thanks

> +
> + return 0;
> +}
> +
> +static int
> vdpa_dev_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq,
> int flags, struct netlink_ext_ack *extack)
> {
> @@ -715,6 +750,10 @@ static int vdpa_nl_cmd_dev_del_set_doit(struct sk_buff *skb, struct genl_info *i
> if (nla_put_u16(msg, VDPA_ATTR_DEV_MIN_VQ_SIZE, min_vq_size))
> goto msg_err;
>
> + err = vdpa_dev_initcfg_fill(vdev, msg, device_id);
> + if (err)
> + goto msg_err;
> +
> genlmsg_end(msg, hdr);
> return 0;
>
> --
> 1.8.3.1
>