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Message-ID: <fa1465e6fc3e8f40330673b28137e92755bf1fa7.camel@linux.intel.com>
Subject: Re: [PATCH v29 00/20] Intel SGX foundations
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Sean Christopherson <sean.j.christopherson@intel.com>,
        "Dr. Greg" <greg@enjellic.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
        x86@kernel.org, linux-sgx@vger.kernel.org,
        akpm@linux-foundation.org, dave.hansen@intel.com,
        nhorman@redhat.com, npmccallum@redhat.com, haitao.huang@intel.com,
        andriy.shevchenko@linux.intel.com, kai.svahn@intel.com,
        bp@alien8.de, josh@joshtriplett.org, luto@kernel.org,
        kai.huang@intel.com, rientjes@google.com, cedric.xing@intel.com,
        puiterwijk@redhat.com
Date:   Fri, 15 May 2020 03:09:42 +0300
In-Reply-To: <20200514161559.GA15603@linux.intel.com>
References: <20200421215316.56503-1-jarkko.sakkinen@linux.intel.com>
         <20200426165753.GA11046@wind.enjellic.com>
         <87d07gk24l.fsf@nanos.tec.linutronix.de>
         <20200508190226.GA31465@wind.enjellic.com>
         <20200508195635.GR27052@linux.intel.com>
         <20200514091637.GA25156@wind.enjellic.com>
         <20200514161559.GA15603@linux.intel.com>
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On Thu, 2020-05-14 at 09:15 -0700, Sean Christopherson wrote:
> 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.

Greg, you are free to submit a patch for review that adds any possible
kernel command line parameter SGX and beyond. SGX support does not "wire
up" anything that would prevent reviewing such patches.

/Jarkko