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vdpa: Enable a user to add and delete a vdpa device
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Add the ability to add and delete a vdpa device.

Examples:
Create a vdpa device of type network named "foo2" from
the management device vdpasim:

$ vdpa dev add mgmtdev vdpasim_net name foo2

Delete the vdpa device after its use:
$ vdpa dev del foo2

Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Eli Cohen <elic@nvidia.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210105103203.82508-5-parav@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Parav Pandit authored and Michael S. Tsirkin committed Feb 23, 2021
1 parent 33b3475 commit 903f7bc
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Showing 3 changed files with 143 additions and 10 deletions.
143 changes: 133 additions & 10 deletions drivers/vdpa/vdpa.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -136,6 +136,37 @@ 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)
{
struct device *dev;

lockdep_assert_held(&vdpa_dev_mutex);
dev = bus_find_device(&vdpa_bus, NULL, dev_name(&vdev->dev), vdpa_name_match);
if (dev) {
put_device(dev);
return -EEXIST;
}
return device_add(&vdev->dev);
}

/**
* _vdpa_register_device - register a vDPA device with vdpa lock held
* Caller must have a succeed call of vdpa_alloc_device() before.
* Caller must invoke this routine in the management device dev_add()
* callback after setting up valid mgmtdev for this vdpa device.
* @vdev: the vdpa device to be registered to vDPA bus
*
* Returns an error when fail to add device to vDPA bus
*/
int _vdpa_register_device(struct vdpa_device *vdev)
{
if (!vdev->mdev)
return -EINVAL;

return __vdpa_register_device(vdev);
}
EXPORT_SYMBOL_GPL(_vdpa_register_device);

/**
* vdpa_register_device - register a vDPA device
* Callers must have a succeed call of vdpa_alloc_device() before.
Expand All @@ -145,24 +176,29 @@ static int vdpa_name_match(struct device *dev, const void *data)
*/
int vdpa_register_device(struct vdpa_device *vdev)
{
struct device *dev;
int err;

mutex_lock(&vdpa_dev_mutex);
dev = bus_find_device(&vdpa_bus, NULL, dev_name(&vdev->dev), vdpa_name_match);
if (dev) {
put_device(dev);
err = -EEXIST;
goto name_err;
}

err = device_add(&vdev->dev);
name_err:
err = __vdpa_register_device(vdev);
mutex_unlock(&vdpa_dev_mutex);
return err;
}
EXPORT_SYMBOL_GPL(vdpa_register_device);

/**
* _vdpa_unregister_device - unregister a vDPA device
* Caller must invoke this routine as part of management device dev_del()
* callback.
* @vdev: the vdpa device to be unregisted from vDPA bus
*/
void _vdpa_unregister_device(struct vdpa_device *vdev)
{
lockdep_assert_held(&vdpa_dev_mutex);
WARN_ON(!vdev->mdev);
device_unregister(&vdev->dev);
}
EXPORT_SYMBOL_GPL(_vdpa_unregister_device);

/**
* vdpa_unregister_device - unregister a vDPA device
* @vdev: the vdpa device to be unregisted from vDPA bus
Expand Down Expand Up @@ -221,10 +257,25 @@ int vdpa_mgmtdev_register(struct vdpa_mgmt_dev *mdev)
}
EXPORT_SYMBOL_GPL(vdpa_mgmtdev_register);

static int vdpa_match_remove(struct device *dev, void *data)
{
struct vdpa_device *vdev = container_of(dev, struct vdpa_device, dev);
struct vdpa_mgmt_dev *mdev = vdev->mdev;

if (mdev == data)
mdev->ops->dev_del(mdev, vdev);
return 0;
}

void vdpa_mgmtdev_unregister(struct vdpa_mgmt_dev *mdev)
{
mutex_lock(&vdpa_dev_mutex);

list_del(&mdev->list);

/* Filter out all the entries belong to this management device and delete it. */
bus_for_each_dev(&vdpa_bus, NULL, mdev, vdpa_match_remove);

mutex_unlock(&vdpa_dev_mutex);
}
EXPORT_SYMBOL_GPL(vdpa_mgmtdev_unregister);
Expand Down Expand Up @@ -368,9 +419,69 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
return msg->len;
}

static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info)
{
struct vdpa_mgmt_dev *mdev;
const char *name;
int err = 0;

if (!info->attrs[VDPA_ATTR_DEV_NAME])
return -EINVAL;

name = nla_data(info->attrs[VDPA_ATTR_DEV_NAME]);

mutex_lock(&vdpa_dev_mutex);
mdev = vdpa_mgmtdev_get_from_attr(info->attrs);
if (IS_ERR(mdev)) {
NL_SET_ERR_MSG_MOD(info->extack, "Fail to find the specified management device");
err = PTR_ERR(mdev);
goto err;
}

err = mdev->ops->dev_add(mdev, name);
err:
mutex_unlock(&vdpa_dev_mutex);
return err;
}

static int vdpa_nl_cmd_dev_del_set_doit(struct sk_buff *skb, struct genl_info *info)
{
struct vdpa_mgmt_dev *mdev;
struct vdpa_device *vdev;
struct device *dev;
const char *name;
int err = 0;

if (!info->attrs[VDPA_ATTR_DEV_NAME])
return -EINVAL;
name = nla_data(info->attrs[VDPA_ATTR_DEV_NAME]);

mutex_lock(&vdpa_dev_mutex);
dev = bus_find_device(&vdpa_bus, NULL, name, vdpa_name_match);
if (!dev) {
NL_SET_ERR_MSG_MOD(info->extack, "device not found");
err = -ENODEV;
goto dev_err;
}
vdev = container_of(dev, struct vdpa_device, dev);
if (!vdev->mdev) {
NL_SET_ERR_MSG_MOD(info->extack, "Only user created device can be deleted by user");
err = -EINVAL;
goto mdev_err;
}
mdev = vdev->mdev;
mdev->ops->dev_del(mdev, vdev);
mdev_err:
put_device(dev);
dev_err:
mutex_unlock(&vdpa_dev_mutex);
return err;
}

static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
[VDPA_ATTR_MGMTDEV_BUS_NAME] = { .type = NLA_NUL_STRING },
[VDPA_ATTR_MGMTDEV_DEV_NAME] = { .type = NLA_STRING },
[VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING },
};

static const struct genl_ops vdpa_nl_ops[] = {
Expand All @@ -380,6 +491,18 @@ static const struct genl_ops vdpa_nl_ops[] = {
.doit = vdpa_nl_cmd_mgmtdev_get_doit,
.dumpit = vdpa_nl_cmd_mgmtdev_get_dumpit,
},
{
.cmd = VDPA_CMD_DEV_NEW,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = vdpa_nl_cmd_dev_add_set_doit,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = VDPA_CMD_DEV_DEL,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = vdpa_nl_cmd_dev_del_set_doit,
.flags = GENL_ADMIN_PERM,
},
};

static struct genl_family vdpa_nl_family __ro_after_init = {
Expand Down
6 changes: 6 additions & 0 deletions include/linux/vdpa.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,8 @@ struct vdpa_mgmt_dev;
* @index: device index
* @features_valid: were features initialized? for legacy guests
* @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().
*/
struct vdpa_device {
struct device dev;
Expand All @@ -53,6 +55,7 @@ struct vdpa_device {
unsigned int index;
bool features_valid;
int nvqs;
struct vdpa_mgmt_dev *mdev;
};

/**
Expand Down Expand Up @@ -260,6 +263,9 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
int vdpa_register_device(struct vdpa_device *vdev);
void vdpa_unregister_device(struct vdpa_device *vdev);

int _vdpa_register_device(struct vdpa_device *vdev);
void _vdpa_unregister_device(struct vdpa_device *vdev);

/**
* vdpa_driver - operations for a vDPA driver
* @driver: underlying device driver
Expand Down
4 changes: 4 additions & 0 deletions include/uapi/linux/vdpa.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,8 @@ enum vdpa_command {
VDPA_CMD_UNSPEC,
VDPA_CMD_MGMTDEV_NEW,
VDPA_CMD_MGMTDEV_GET, /* can dump */
VDPA_CMD_DEV_NEW,
VDPA_CMD_DEV_DEL,
};

enum vdpa_attr {
Expand All @@ -24,6 +26,8 @@ enum vdpa_attr {
VDPA_ATTR_MGMTDEV_DEV_NAME, /* string */
VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES, /* u64 */

VDPA_ATTR_DEV_NAME, /* string */

/* new attributes must be added above here */
VDPA_ATTR_MAX,
};
Expand Down

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