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Subject: Re: [PATCH v17 18/23] platform/x86: Intel SGX driver
To:     Andy Lutomirski <luto@kernel.org>
Cc:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        X86 ML <x86@kernel.org>,
        Platform Driver <platform-driver-x86@vger.kernel.org>,
        linux-sgx@vger.kernel.org, nhorman@redhat.com,
        npmccallum@redhat.com, "Ayoun, Serge" <serge.ayoun@intel.com>,
        shay.katz-zamir@intel.com,
        Haitao Huang <haitao.huang@linux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        "Svahn, Kai" <kai.svahn@intel.com>, mark.shanahan@intel.com,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
        <linux-kernel@vger.kernel.org>
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From:   Dave Hansen <dave.hansen@intel.com>
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Message-ID: <beea8ad3-a607-5478-ad87-b8dd33e86146@intel.com>
Date:   Mon, 17 Dec 2018 11:17:49 -0800
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On 12/17/18 11:12 AM, Andy Lutomirski wrote:
> So I'm not saying that you shouldn't do it the way you are now, but I
> do think that the changelog or at least some emails should explain
> *why* the enclave needs to keep a pointer to the creating process's
> mm.  And, if you do keep the current model, it would be nice to
> understand what happens if you do something awful like mremap()ing an
> enclave, or calling madvise on it, or otherwise abusing the vma.  Or
> doing fork(), for that matter.

Yeah, the code is built to have one VMA and only one VMA per enclave.
You need to go over the origin of this restriction and what enforces this.