在 2021/4/9 下午4:02, Yongji Xie 写道:

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+};
+
+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)

or

2) make it variable

Thanks