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Si-Wei Liu

2022-Oct-15 00:28 UTC

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

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, 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",
            "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

Si-Wei Liu

2022-Oct-15 00:28 UTC

head link

[PATCH 1/4] vdpa: save vdpa_dev_set_config in struct vdpa_device

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.

This commit attempts to make struct vdpa_device contain the struct
vdpa_dev_set_config, where all config attributes upon vdpa creation
are carried over. Which will be used in subsequent commits.

Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
---
 include/linux/vdpa.h | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 6d0f5e4..f1838f5 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -58,6 +58,16 @@ struct vdpa_vq_state {
 	};
 };
 
+struct vdpa_dev_set_config {
+	u64 device_features;
+	struct {
+		u8 mac[ETH_ALEN];
+		u16 mtu;
+		u16 max_vq_pairs;
+	} net;
+	u64 mask;
+};
+
 struct vdpa_mgmt_dev;
 
 /**
@@ -77,6 +87,8 @@ struct vdpa_vq_state {
  * @nvqs: maximum number of supported virtqueues
  * @mdev: management device pointer; caller must setup when registering device
as part
  *	  of dev_add() mgmtdev ops callback before invoking _vdpa_register_device().
+ * @vdev_cfg: initial device config on vdpa creation; useful when instantiate
with
+ *            the exact same config is needed.
  */
 struct vdpa_device {
 	struct device dev;
@@ -91,6 +103,7 @@ struct vdpa_device {
 	struct vdpa_mgmt_dev *mdev;
 	unsigned int ngroups;
 	unsigned int nas;
+	struct vdpa_dev_set_config vdev_cfg;
 };
 
 /**
@@ -103,16 +116,6 @@ struct vdpa_iova_range {
 	u64 last;
 };
 
-struct vdpa_dev_set_config {
-	u64 device_features;
-	struct {
-		u8 mac[ETH_ALEN];
-		u16 mtu;
-		u16 max_vq_pairs;
-	} net;
-	u64 mask;
-};
-
 /**
  * Corresponding file area for device memory mapping
  * @file: vma->vm_file for the mapping
-- 
1.8.3.1

Si-Wei Liu

2022-Oct-15 00:28 UTC

head link

[PATCH 2/4] vdpa: pass initial config to _vdpa_register_device()

Just as _vdpa_register_device taking @nvqs as the number of queues
to feed userspace inquery via vdpa_dev_fill(), we can follow the
same to stash config attributes in struct vdpa_device at the time
of vdpa registration.

Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
---
 drivers/vdpa/ifcvf/ifcvf_main.c      |  2 +-
 drivers/vdpa/mlx5/net/mlx5_vnet.c    |  2 +-
 drivers/vdpa/vdpa.c                  | 15 +++++++++++----
 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                 |  3 ++-
 8 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index f9c0044..c54ab2c 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -771,7 +771,7 @@ static int ifcvf_vdpa_dev_add(struct vdpa_mgmt_dev *mdev,
const char *name,
 	else
 		ret = dev_set_name(&vdpa_dev->dev, "vdpa%u",
vdpa_dev->index);
 
-	ret = _vdpa_register_device(&adapter->vdpa, vf->nr_vring);
+	ret = _vdpa_register_device(&adapter->vdpa, vf->nr_vring, config);
 	if (ret) {
 		put_device(&adapter->vdpa.dev);
 		IFCVF_ERR(pdev, "Failed to register to vDPA bus");
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 9091336..376082e 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -3206,7 +3206,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev,
const char *name,
 	mlx5_notifier_register(mdev, &ndev->nb);
 	ndev->nb_registered = true;
 	mvdev->vdev.mdev = &mgtdev->mgtdev;
-	err = _vdpa_register_device(&mvdev->vdev, max_vqs + 1);
+	err = _vdpa_register_device(&mvdev->vdev, max_vqs + 1, add_config);
 	if (err)
 		goto err_reg;
 
diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index febdc99..566c1c6 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -215,11 +215,16 @@ static int vdpa_name_match(struct device *dev, const void
*data)
 	return (strcmp(dev_name(&vdev->dev), data) == 0);
 }
 
-static int __vdpa_register_device(struct vdpa_device *vdev, u32 nvqs)
+static int __vdpa_register_device(struct vdpa_device *vdev, u32 nvqs,
+				  const struct vdpa_dev_set_config *cfg)
 {
 	struct device *dev;
 
 	vdev->nvqs = nvqs;
+	if (cfg)
+		vdev->vdev_cfg = *cfg;
+	else
+		vdev->vdev_cfg.mask = 0ULL;
 
 	lockdep_assert_held(&vdpa_dev_lock);
 	dev = bus_find_device(&vdpa_bus, NULL, dev_name(&vdev->dev),
vdpa_name_match);
@@ -237,15 +242,17 @@ static int __vdpa_register_device(struct vdpa_device
*vdev, u32 nvqs)
  * callback after setting up valid mgmtdev for this vdpa device.
  * @vdev: the vdpa device to be registered to vDPA bus
  * @nvqs: number of virtqueues supported by this device
+ * @cfg: initial config on vdpa device creation
  *
  * Return: Returns an error when fail to add device to vDPA bus
  */
-int _vdpa_register_device(struct vdpa_device *vdev, u32 nvqs)
+int _vdpa_register_device(struct vdpa_device *vdev, u32 nvqs,
+			  const struct vdpa_dev_set_config *cfg)
 {
 	if (!vdev->mdev)
 		return -EINVAL;
 
-	return __vdpa_register_device(vdev, nvqs);
+	return __vdpa_register_device(vdev, nvqs, cfg);
 }
 EXPORT_SYMBOL_GPL(_vdpa_register_device);
 
@@ -262,7 +269,7 @@ int vdpa_register_device(struct vdpa_device *vdev, u32 nvqs)
 	int err;
 
 	down_write(&vdpa_dev_lock);
-	err = __vdpa_register_device(vdev, nvqs);
+	err = __vdpa_register_device(vdev, nvqs, NULL);
 	up_write(&vdpa_dev_lock);
 	return err;
 }
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index c6db1a1..5e1cebc 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -387,7 +387,7 @@ static int vdpasim_blk_dev_add(struct vdpa_mgmt_dev *mdev,
const char *name,
 	if (IS_ERR(simdev))
 		return PTR_ERR(simdev);
 
-	ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_BLK_VQ_NUM);
+	ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_BLK_VQ_NUM, config);
 	if (ret)
 		goto put_dev;
 
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
index c3cb225..06ef5a0 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
@@ -260,7 +260,7 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev,
const char *name,
 
 	vdpasim_net_setup_config(simdev, config);
 
-	ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM);
+	ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_NET_VQ_NUM, config);
 	if (ret)
 		goto reg_err;
 
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c
b/drivers/vdpa/vdpa_user/vduse_dev.c
index 35dceee..6530fd2 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1713,7 +1713,7 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const
char *name,
 	if (ret)
 		return ret;
 
-	ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
+	ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num,
config);
 	if (ret) {
 		put_device(&dev->vdev->vdpa.dev);
 		return ret;
diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c
b/drivers/vdpa/virtio_pci/vp_vdpa.c
index d448db0..ffdc90e 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -538,7 +538,8 @@ static int vp_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev,
const char *name,
 	vp_vdpa->config_irq = VIRTIO_MSI_NO_VECTOR;
 
 	vp_vdpa->vdpa.mdev = &vp_vdpa_mgtdev->mgtdev;
-	ret = _vdpa_register_device(&vp_vdpa->vdpa, vp_vdpa->queues);
+	ret = _vdpa_register_device(&vp_vdpa->vdpa, vp_vdpa->queues,
+				    add_config);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to register to vdpa bus\n");
 		goto err;
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index f1838f5..b9d50e8 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -381,7 +381,8 @@ struct vdpa_device *__vdpa_alloc_device(struct device
*parent,
 int vdpa_register_device(struct vdpa_device *vdev, u32 nvqs);
 void vdpa_unregister_device(struct vdpa_device *vdev);
 
-int _vdpa_register_device(struct vdpa_device *vdev, u32 nvqs);
+int _vdpa_register_device(struct vdpa_device *vdev, u32 nvqs,
+			  const struct vdpa_dev_set_config *cfg);
 void _vdpa_unregister_device(struct vdpa_device *vdev);
 
 /**
-- 
1.8.3.1

Si-Wei Liu

2022-Oct-15 00:28 UTC

head link

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

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 from
which vdpa device was created as-is. The "vdpa dev show" command
seems to be the right vehicle for that. It is unlike the "vdpa dev
config show" command output that usually goes with the live value
in the device config space, which is not quite 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",
            "vendor_id": 5555,
            "max_vqs": 9,
            "max_vq_size": 256,
            "mac": "e4:11:c6:d3:45:f0",
            "max_vq_pairs": 4
        }
    }
}

Signed-off-by: Si-Wei Liu <si-wei.liu at 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 566c1c6..91eca6d 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_cfgattrs_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32
device_id)
+{
+	struct vdpa_dev_set_config *cfg = &vdev->vdev_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;
+
+	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_cfgattrs_fill(vdev, msg, device_id);
+	if (err)
+		goto msg_err;
+
 	genlmsg_end(msg, hdr);
 	return 0;
 
-- 
1.8.3.1

Si-Wei Liu

2022-Oct-15 00:28 UTC

head link

[PATCH 4/4] vdpa: fix improper error message when adding vdpa dev

In below example, before the fix, mtu attribute is supported
by the parent mgmtdev, but the error message showing "All
provided are not supported" is just misleading.

$ vdpa mgmtdev show
vdpasim_net:
  supported_classes net
  max_supported_vqs 3
  dev_features MTU MAC CTRL_VQ CTRL_MAC_ADDR ANY_LAYOUT VERSION_1
ACCESS_PLATFORM

$ vdpa dev add mgmtdev vdpasim_net name vdpasim0 mtu 5000 max_vqp 2
Error: vdpa: All provided attributes are not supported.
kernel answers: Operation not supported

After fix, the relevant error message will be like:

$ vdpa dev add mgmtdev vdpasim_net name vdpasim0 mtu 5000 max_vqp 2
Error: vdpa: Some provided attributes are not supported.
kernel answers: Operation not supported

$ vdpa dev add mgmtdev vdpasim_net name vdpasim0 max_vqp 2
Error: vdpa: All provided attributes are not supported.
kernel answers: Operation not supported

Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
---
 drivers/vdpa/vdpa.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 91eca6d..ff15e0a 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -629,13 +629,20 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff
*skb, struct genl_info *i
 		err = PTR_ERR(mdev);
 		goto err;
 	}
-	if ((config.mask & mdev->config_attr_mask) != config.mask) {
+	if (config.mask && (config.mask & mdev->config_attr_mask) == 0)
{
 		NL_SET_ERR_MSG_MOD(info->extack,
 				   "All provided attributes are not supported");
 		err = -EOPNOTSUPP;
 		goto err;
 	}
 
+	if ((config.mask & mdev->config_attr_mask) != config.mask) {
+		NL_SET_ERR_MSG_MOD(info->extack,
+				   "Some provided attributes are not supported");
+		err = -EOPNOTSUPP;
+		goto err;
+	}
+
 	err = mdev->ops->dev_add(mdev, name, &config);
 err:
 	up_write(&vdpa_dev_lock);
-- 
1.8.3.1

Jason Wang

2022-Oct-17 07:08 UTC

head link

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

Adding Sean and Daniel for more thoughts.

On Sat, Oct 15, 2022 at 9:33 AM Si-Wei Liu <si-wei.liu at 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 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
>

Virtualization - Oct 2022 - [PATCH 3/4] vdpa: show dev config as-is in "vdpa dev show" output

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

[PATCH 1/4] vdpa: save vdpa_dev_set_config in struct vdpa_device

[PATCH 2/4] vdpa: pass initial config to _vdpa_register_device()

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

[PATCH 4/4] vdpa: fix improper error message when adding vdpa dev

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