Adding Sean and Daniel for more thoughts.
On Sat, Oct 15, 2022 at 9:33 AM Si-Wei Liu <si-wei.liu@xxxxxxxxxx> 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 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.
For live migration, I think the management layer should have this
knowledge and they can communicate directly without bothering the vdpa
tool on the source. If I was not wrong this is the way libvirt is
doing now.
> 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, which is not reliable subject to the dynamics
> of feature negotiation and possible change in device 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
> 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",
So "mgmtdev" looks not necessary for live migration.
Thanks
> "vendor_id": 5555,
> "max_vqs": 9,
> "max_vq_size": 256,
> "mac": "e4:11:c6:d3:45:f0",
> "max_vq_pairs": 4
> }
> }
> }
>
> ---
>
> 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
>
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