linux-kernel - Re: [PATCH v29 00/20] Intel SGX foundations

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Message-ID: <20200514161559.GA15603@linux.intel.com>
Date:   Thu, 14 May 2020 09:15:59 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     "Dr. Greg" <greg@...ellic.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        torvalds@...ux-foundation.org, linux-kernel@...r.kernel.org,
        x86@...nel.org, linux-sgx@...r.kernel.org,
        akpm@...ux-foundation.org, dave.hansen@...el.com,
        nhorman@...hat.com, npmccallum@...hat.com, haitao.huang@...el.com,
        andriy.shevchenko@...ux.intel.com, kai.svahn@...el.com,
        bp@...en8.de, josh@...htriplett.org, luto@...nel.org,
        kai.huang@...el.com, rientjes@...gle.com, cedric.xing@...el.com,
        puiterwijk@...hat.com
Subject: Re: [PATCH v29 00/20] Intel SGX foundations

On Thu, May 14, 2020 at 04:16:37AM -0500, Dr. Greg wrote:
> What we would recommend at this point is that you and Jarkko do the
> Linux community and beyond a favor and wire up a simple kernel
> command-line parameter that controls the ability of the driver to be
> used, ie. enables/disables access to /dev/sgx/enclave.

I'm not opposed to adding a kernel param to disable SGX.  At one point
there was a proposal to extend clearcpuid to allow disabling multiple
feature bits, but it looks like that went the way of the dodo.

Note, such a param would disable SGX entirely, e.g. clear the feature bit
in /proc/cpuinfo and prevent any in-kernel SGX code from running.