Re: [Xen-devel] [PATCH v14] This is the ABI for the two halves of a para-virtualized sound driver to communicate with each to other.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 29.11.16 at 17:55, <andr2000@xxxxxxxxx> wrote:
> On 11/29/2016 06:09 PM, Jan Beulich wrote:
>>>>> On 29.11.16 at 16:24, <andr2000@xxxxxxxxx> wrote:
>>> +struct xensnd_req {
>>> +    uint16_t id;
>>> +    uint8_t operation;
>>> +    uint8_t stream_idx;
>>> +    uint32_t reserved;
>>> +    union {
>>> +        struct xensnd_open_req open;
>>> +        struct xensnd_rw_req rw;
>>> +        uint8_t padding[24];
>>> +    } op;
>>> +};
>>> +
>>> +struct xensnd_resp {
>>> +    uint16_t id;
>>> +    uint8_t operation;
>>> +    uint8_t stream_idx;
>>> +    int8_t status;
>>> +    uint8_t padding[27];
>> Other than in _req, this ought to be "reserved" imo.
> IMO, this is a classic padding, why reserved?

If you document it as padding, you can't easily use it later on for
some extension. But you know possible extension routes of this
protocol better than me...

Jan


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