Re: [PATCH 1/2] vDPA: allow userspace to query features of a vDPA device

Zhu, Lingshan
2022-08-16T06:47:31Z

On 8/16/2022 2:15 AM, Si-Wei Liu wrote:
>
>
> On 8/15/2022 2:26 AM, Zhu Lingshan wrote:
>> This commit adds a new vDPA netlink attribution
>> VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES. Userspace can query
>> features of vDPA devices through this new attr.
>>
>> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
>> ---
>>   drivers/vdpa/vdpa.c       | 17 +++++++++++++----
>>   include/uapi/linux/vdpa.h |  3 +++
>>   2 files changed, 16 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
>> index c06c02704461..efb55a06e961 100644
>> --- a/drivers/vdpa/vdpa.c
>> +++ b/drivers/vdpa/vdpa.c
>> @@ -491,6 +491,8 @@ static int vdpa_mgmtdev_fill(const struct
>> vdpa_mgmt_dev *mdev, struct sk_buff *m
>>           err = -EMSGSIZE;
>>           goto msg_err;
>>       }
>> +
>> +    /* report features of a vDPA management device through
>> VDPA_ATTR_DEV_SUPPORTED_FEATURES */
>>       if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_SUPPORTED_FEATURES,
>>                     mdev->supported_features, VDPA_ATTR_PAD)) {
>>           err = -EMSGSIZE;
>> @@ -815,7 +817,7 @@ static int vdpa_dev_net_mq_config_fill(struct
>> vdpa_device *vdev,
>>   static int vdpa_dev_net_config_fill(struct vdpa_device *vdev,
>> struct sk_buff *msg)
>>   {
>>       struct virtio_net_config config = {};
>> -    u64 features;
>> +    u64 features_device, features_driver;
>>       u16 val_u16;
>>         vdpa_get_config_unlocked(vdev, 0, &config, sizeof(config));
>> @@ -832,12 +834,19 @@ static int vdpa_dev_net_config_fill(struct
>> vdpa_device *vdev, struct sk_buff *ms
>>       if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16))
>>           return -EMSGSIZE;
>>   -    features = vdev->config->get_driver_features(vdev);
>> -    if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES,
>> features,
>> +    features_driver = vdev->config->get_driver_features(vdev);
>> +    if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES,
>> features_driver,
>> +                  VDPA_ATTR_PAD))
>> +        return -EMSGSIZE;
>> +
>> +    features_device = vdev->config->get_device_features(vdev);
>> +
>> +    /* report features of a vDPA device through
>> VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES */
>> +    if (nla_put_u64_64bit(msg,
>> VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES, features_device,
>>                     VDPA_ATTR_PAD))
>>           return -EMSGSIZE;
>>   -    return vdpa_dev_net_mq_config_fill(vdev, msg, features, &config);
>> +    return vdpa_dev_net_mq_config_fill(vdev, msg, features_driver,
>> &config);
>>   }
>>     static int
>> diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
>> index 25c55cab3d7c..d171b92ef522 100644
>> --- a/include/uapi/linux/vdpa.h
>> +++ b/include/uapi/linux/vdpa.h
>> @@ -46,7 +46,10 @@ enum vdpa_attr {
>>         VDPA_ATTR_DEV_NEGOTIATED_FEATURES,    /* u64 */
>>       VDPA_ATTR_DEV_MGMTDEV_MAX_VQS,        /* u32 */
>> +    /* features of a vDPA management device */
>>       VDPA_ATTR_DEV_SUPPORTED_FEATURES,    /* u64 */
>> +    /* features of a vDPA device, e.g., /dev/vhost-vdpa0 */
>> +    VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES,    /* u64 */
> Append to the end, please. Otherwise it breaks userspace ABI.
OK, will fix it in V2
>
> -Siwei
>
>> VDPA_ATTR_DEV_QUEUE_INDEX,              /* u32 */
>>       VDPA_ATTR_DEV_VENDOR_ATTR_NAME,        /* string */
>