Question: How are AES-XTS tests with small IVs intended to be used?

The [aes_xts_test.json](https://github.com/C2SP/wycheproof/blob/main/testvectors_v1/aes_xts_test.json) file provides test vectors for different sizes of key and IV. I haven't been able to find an implementation of AES-XTS which allows an AES IV which isn't block size of the cipher.

I was hoping someone could provide a link to either a standard which defines how to use the IV, or at least provide some hints on how to handle this case. Is it as simple as just padding with zero bytes at the beginning or end to fill it to 8 bytes? If there is an easy way to deal with this, it would be useful to add it to the header of that file.