Re: [PATCH v13 07/13] x86/sgx: Add data structures for tracking the EPC pages

[Andy Shevchenko]

On Tue, Sep 4, 2018 a> +/**

> > > +       va = ioremap_cache(addr, size);
> > > +       if (!va)
> > > +               return -ENOMEM;
> >
> > I'm not sure this is a right API. Do we operate with memory? Does it
> > have I/O side effects?
> > If no, memremap() would be better to use.
>
> Preserving __iomem is desirable.  There aren't side effects per se,
> but direct non-enclave accesses to the EPC get abort page semantics so
> the kernel shouldn't be directly dereferencing a pointer to the EPC.
> Though by that argument, sgx_epc_bank.va, sgx_epc_addr's return and
> all ENCLS helpers should be tagged __iomem.

Why?
Does it related to *any* I/O?

-- 
With Best Regards,
Andy Shevchenko