Re: Re: [PATCH v6 09/10] vduse: Introduce VDUSE - vDPA Device in Userspace

[Yongji Xie <xieyongji@bytedance.com>]

On Mon, Apr 12, 2021 at 3:16 PM Jason Wang <jasowang@redhat.com> 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