Re: [PATCH v5 1/7] x86/sgx: Provide indication of life-cycle of EPC pages

[Dave Hansen]

On 9/21/21 2:28 PM, Jarkko Sakkinen wrote:
>> Since there are multiple uses of the "owner" field with different types
>> change the sgx_epc_page structure to define an anonymous union with
>> each of the uses explicitly called out.
> But it's still always a pointer.
> 
> And not only that, but two alternative fields in that union have *exactly* the
> same type, so it's kind of artifically representing the problem more complex
> than it really is.
> 
> I'm not just getting, why all this complexity, and not a few casts instead?

I suggested this.  It makes the structure more self-describing because
it explicitly lists the possibles uses of the space in the structure.

Maybe I stare at 'struct page' and its 4 unions too much and I'm
enamored by their shininess.  But, in the end, I prefer unions to casting.