On Tue, Jan 31, 2023 at 03:22:23PM -0800, Si-Wei Liu wrote:
> Today when device features are explicitly provisioned, the features
> user supplied may contain device class specific features that are
> not supported by the parent managment device. On the other hand,
> when parent managment device supports more than one class, the
> device features to provision may be ambiguous if none of the class
> specific attributes is provided at the same time. Validate these
> cases and prompt appropriate user errors accordingly.
> 
> Signed-off-by: Si-Wei Liu <[email protected]>
> ---
>  drivers/vdpa/vdpa.c | 51 ++++++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 42 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index 1eba978..35a72d6 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -460,12 +460,30 @@ static int vdpa_nl_mgmtdev_handle_fill(struct sk_buff 
> *msg, const struct vdpa_mg
>       return 0;
>  }
>  
> +static u64 vdpa_mgmtdev_get_classes(const struct vdpa_mgmt_dev *mdev,
> +                                 unsigned int *nclasses)

given max value is apparently 64 how important is it that it's unsigned?
Just make it an int.

Also I'd return u64 through a pointer too for consistency.

> +{
> +     u64 supported_classes = 0;
> +     unsigned int n = 0;
> +     int i = 0;
> +
> +     while (mdev->id_table[i].device) {
> +             if (mdev->id_table[i].device <= 63) {
> +                     supported_classes |= BIT_ULL(mdev->id_table[i].device);
> +                     n++;
> +             }
> +             i++;
> +     }


Better as a for loop. I know you are just moving code if you
want to make it very clear it's a refactoring split
as a separate patch, but ok anyway.

> +     if (nclasses)
> +             *nclasses = n;
> +
> +     return supported_classes;
> +}
> +
>  static int vdpa_mgmtdev_fill(const struct vdpa_mgmt_dev *mdev, struct 
> sk_buff *msg,
>                            u32 portid, u32 seq, int flags)
>  {
> -     u64 supported_classes = 0;
>       void *hdr;
> -     int i = 0;
>       int err;
>  
>       hdr = genlmsg_put(msg, portid, seq, &vdpa_nl_family, flags, 
> VDPA_CMD_MGMTDEV_NEW);
> @@ -475,14 +493,9 @@ static int vdpa_mgmtdev_fill(const struct vdpa_mgmt_dev 
> *mdev, struct sk_buff *m
>       if (err)
>               goto msg_err;
>  
> -     while (mdev->id_table[i].device) {
> -             if (mdev->id_table[i].device <= 63)
> -                     supported_classes |= BIT_ULL(mdev->id_table[i].device);
> -             i++;
> -     }
> -
>       if (nla_put_u64_64bit(msg, VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES,
> -                           supported_classes, VDPA_ATTR_UNSPEC)) {
> +                           vdpa_mgmtdev_get_classes(mdev, NULL),
> +                           VDPA_ATTR_UNSPEC)) {
>               err = -EMSGSIZE;
>               goto msg_err;
>       }
> @@ -571,8 +584,10 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff 
> *skb, struct genl_info *i
>       struct vdpa_dev_set_config config = {};
>       struct nlattr **nl_attrs = info->attrs;
>       struct vdpa_mgmt_dev *mdev;
> +     unsigned int ncls = 0;
>       const u8 *macaddr;
>       const char *name;
> +     u64 classes;
>       int err = 0;
>  
>       if (!info->attrs[VDPA_ATTR_DEV_NAME])
> @@ -649,6 +664,24 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff 
> *skb, struct genl_info *i
>               goto err;
>       }
>  
> +     classes = vdpa_mgmtdev_get_classes(mdev, &ncls);
> +     if (config.mask & VDPA_DEV_NET_ATTRS_MASK &&
> +         !(classes & BIT_ULL(VIRTIO_ID_NET))) {
> +             NL_SET_ERR_MSG_MOD(info->extack,
> +                                "Network class attributes provided on 
> unsupported management device");
> +             err = -EINVAL;
> +             goto err;
> +     }
> +     if (!(config.mask & VDPA_DEV_NET_ATTRS_MASK) &&
> +         config.mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES) &&
> +         classes & BIT_ULL(VIRTIO_ID_NET) && ncls > 1 &&
> +         config.device_features & VIRTIO_DEVICE_F_MASK) {
> +             NL_SET_ERR_MSG_MOD(info->extack,
> +                                "Management device supports multi-class 
> while device features specified are ambiguous");
> +             err = -EINVAL;
> +             goto err;
> +     }
> +
>       err = mdev->ops->dev_add(mdev, name, &config);
>  err:
>       up_write(&vdpa_dev_lock);
> -- 
> 1.8.3.1

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