From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Subject: Re: [PATCH v17 06/23] x86/cpu/intel: Detect SGX support and update
 caps appropriately
Date: Sun, 18 Nov 2018 10:37:28 +0200
Message-ID: <20181118083728.GM5897@linux.intel.com>
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To: Dave Hansen <dave.hansen@intel.com>
Cc: x86@kernel.org, platform-driver-x86@vger.kernel.org, linux-sgx@vger.kernel.org, sean.j.christopherson@intel.com, nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com, shay.katz-zamir@intel.com, haitao.huang@linux.intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, mark.shanahan@intel.com, luto@amacapital.net, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, David Woodhouse <dwmw@amazon.co.uk>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, David Wang <davidwang@zhaoxin.com>, "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com>, Jia Zhang <qianyue.zj@alibaba-inc.com>, open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)
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On Fri, Nov 16, 2018 at 03:32:36PM -0800, Dave Hansen wrote:
> On 11/15/18 5:01 PM, Jarkko Sakkinen wrote:
> > +static void detect_sgx(struct cpuinfo_x86 *c)
> > +{
> > +	unsigned long long fc;
> > +
> > +	rdmsrl(MSR_IA32_FEATURE_CONTROL, fc);
> > +	if (!(fc & FEATURE_CONTROL_LOCKED)) {
> > +		pr_err_once("sgx: IA32_FEATURE_CONTROL MSR is not locked\n");
> > +		goto out_unsupported;
> > +	}
> 
> This needs a check against the config option somewhere so the compiler
> can toss it in its entirety if SGX is config'd out.

Certainly. I'll flag it in the next version.

/Jarkko