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    SubjectRe: [PATCH v13 07/13] x86/sgx: Add data structures for tracking the EPC pages
    On Mon, Sep 03, 2018 at 05:41:53PM +0300, Andy Shevchenko wrote:
    > On Mon, Aug 27, 2018 at 9:58 PM Jarkko Sakkinen
    > <jarkko.sakkinen@linux.intel.com> wrote:
    >
    > > + 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.

    For documentation purposes, maybe it would be better to use __private
    or "#define __sgx_epc __iomem" and use that?

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