[PATCH v3 0/4] vDPA: initial config export via "vdpa dev show"

[Si-Wei Liu <si-wei.liu@oracle.com>]

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 allow live migration orchestration software to export the
initial set of vdpa attributes with which the device was created, it
will be useful if the vdpa tool can report the config on demand with
simple query. This will ease the orchestration software implementation
so that it doesn't have to keep track of vdpa config change, or have
to persist vdpa attributes across failure and recovery, in fear of
being killed due to accidental software error.

In this series, the initial device config for vdpa creation will be
exported via the "vdpa dev show" command. This is unlike the "vdpa
dev config show" command that usually goes with the live value in
the device config space, and is not reliable subject to the dynamics
of feature negotiation or possible change by 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
            }
        }
    }
}

---
v2 -> v3:
  - Rename vdev_cfg to init_cfg and also related function (Jason)
  - Change "virtio_config" to "initial_config" in command example
    output (Parav)

v1 -> v2:
  - Revised example output to export all config attributes under a
    json object (Jason)

---

Si-Wei Liu (4):
  vdpa: save vdpa_dev_set_config in struct vdpa_device
  vdpa: pass initial config to _vdpa_register_device()
  vdpa: show dev config as-is in "vdpa dev show" output
  vdpa: fix improper error message when adding vdpa dev

 drivers/vdpa/ifcvf/ifcvf_main.c      |  2 +-
 drivers/vdpa/mlx5/net/mlx5_vnet.c    |  2 +-
 drivers/vdpa/vdpa.c                  | 63 +++++++++++++++++++++++++++++++++---
 drivers/vdpa/vdpa_sim/vdpa_sim_blk.c |  2 +-
 drivers/vdpa/vdpa_sim/vdpa_sim_net.c |  2 +-
 drivers/vdpa/vdpa_user/vduse_dev.c   |  2 +-
 drivers/vdpa/virtio_pci/vp_vdpa.c    |  3 +-
 include/linux/vdpa.h                 | 26 ++++++++-------
 8 files changed, 80 insertions(+), 22 deletions(-)

-- 
1.8.3.1