On Mon, Apr 12, 2021 at 3:16 PM Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > 在 2021/4/9 下午4:02, Yongji Xie 写道: > >>>>> +}; > >>>>> + > >>>>> +struct vduse_dev_config_data { > >>>>> + __u32 offset; /* offset from the beginning of config space */ > >>>>> + __u32 len; /* the length to read/write */ > >>>>> + __u8 data[VDUSE_CONFIG_DATA_LEN]; /* data buffer used to read/write */ > >>>> Note that since VDUSE_CONFIG_DATA_LEN is part of uAPI it means we can > >>>> not change it in the future. > >>>> > >>>> So this might suffcient for future features or all type of virtio devices. > >>>> > >>> Do you mean 256 is no enough here? > >> Yes. > >> > > But this request will be submitted multiple times if config lengh is > > larger than 256. So do you think whether we need to extent the size to > > 512 or larger? > > > So I think you'd better either: > > 1) document the limitation (256) in somewhere, (better both uapi and doc) > But the VDUSE_CONFIG_DATA_LEN doesn't mean the limitation of configuration space. It only means the maximum size of one data transfer for configuration space. Do you mean document this? Thanks, Yongji