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

[Thomas Gleixner]

Borislav Petkov <bp@xxxxxxxxx> writes:

> On Thu, May 14, 2020 at 09:15:59AM -0700, Sean Christopherson wrote:
>> 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.

clearcpuid is a trainwreck which should have never happened.

>> 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.
>
> It is a usual practice for big features like SGX to add a
> "nosgx" cmdline param to disable it in case something goes
> south. We do this for all features - see all "no*" switches in
> Documentation/admin-guide/kernel-parameters.txt

Correct.

Thanks,

        tglx