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    SubjectRE: [PATCH 1/4] x86/sgx: Track phase and type of SGX EPC pages
    Date
    > Could this tracking be done at the enclave page (struct sgx_encl_page) 
    > instead?

    In principle yes. Though Sean has some issues with me tracking types
    at all.

    > The enclave page's EPC page information is not available when
    > the page is in swap and it would be useful to know the page type without
    > loading the page from swap. The information would continue to be
    > accessible from struct epc_page via the owner pointer that may make some
    > of the changes easier since it would not be needed to pass the page type
    > around so much and thus possibly address the SECS page issue that Sean
    > pointed out in
    > https://lore.kernel.org/lkml/YO3FuBupQTKYaKBf@google.com/

    I think I noticed that the "owner" pointer in sgx_encl_page doesn't point
    back to the epc_page for all types of SGX pages. So some additional
    changes would be needed. I'm not at all sure why this is different (or
    what use the non-REG pages use "owner" for.

    >> struct sgx_epc_page {
    >> unsigned int section;
    >> - unsigned int flags;
    >> + u16 flags;
    >> + u16 type;
    >
    > Could this be "enum sgx_page_type type" ?

    Maybe. I thought I needed extra types (like FREE and DIRTY). But
    Sean pointed out how to avoid some of them.

    -Tony
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