linux-kernel - Re: [PATCH v11 07/13] x86, sgx: detect Intel SGX

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Date:   Tue, 19 Jun 2018 16:34:22 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Neil Horman <nhorman@...hat.com>
Cc:     x86@...nel.org, platform-driver-x86@...r.kernel.org,
        dave.hansen@...el.com, sean.j.christopherson@...el.com,
        npmccallum@...hat.com, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Vikas Shivappa <vikas.shivappa@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andi Kleen <ak@...ux.intel.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
        <linux-kernel@...r.kernel.org>,
        "open list:INTEL SGX" <intel-sgx-kernel-dev@...ts.01.org>
Subject: Re: [PATCH v11 07/13] x86, sgx: detect Intel SGX

On Mon, Jun 11, 2018 at 07:35:21AM -0400, Neil Horman wrote:
> On Fri, Jun 08, 2018 at 07:09:42PM +0200, Jarkko Sakkinen wrote:
> > From: Sean Christopherson <sean.j.christopherson@...el.com>
> > 
> > Intel(R) SGX is a set of CPU instructions that can be used by applications
> > to set aside private regions of code and data. The code outside the enclave
> > is disallowed to access the memory inside the enclave by the CPU access
> > control.
> > 
> > This commit adds the check for SGX to arch/x86 and a new config option,
> > INTEL_SGX_CORE. Exposes a boolean variable 'sgx_enabled' to query whether
> > or not the SGX support is available.
> > 
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
> > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> > Tested-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> > ---
> >  arch/x86/Kconfig                | 19 ++++++++++++
> >  arch/x86/include/asm/sgx.h      | 25 ++++++++++++++++
> >  arch/x86/include/asm/sgx_pr.h   | 20 +++++++++++++
> >  arch/x86/kernel/cpu/Makefile    |  1 +
> >  arch/x86/kernel/cpu/intel_sgx.c | 53 +++++++++++++++++++++++++++++++++
> >  5 files changed, 118 insertions(+)
> >  create mode 100644 arch/x86/include/asm/sgx.h
> >  create mode 100644 arch/x86/include/asm/sgx_pr.h
> >  create mode 100644 arch/x86/kernel/cpu/intel_sgx.c
> > 
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index c07f492b871a..42015d5366ef 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -1925,6 +1925,25 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS
> >  
> >  	  If unsure, say y.
> >  
> > +config INTEL_SGX_CORE
> > +	prompt "Intel SGX core functionality"
> > +	def_bool n
> > +	depends on X86_64 && CPU_SUP_INTEL
> > +	help
> > +	Intel Software Guard eXtensions (SGX) is a set of CPU instructions
> > +	that allows ring 3 applications to create enclaves; private regions
> > +	of memory that are protected, by hardware, from unauthorized access
> > +	and/or modification.
> > +
> > +	This option enables kernel recognition of SGX, high-level management
> > +	of the Enclave Page Cache (EPC), tracking and writing of SGX Launch
> > +	Enclave Hash MSRs, and allows for virtualization of SGX via KVM. By
> > +	iteslf, this option does not provide SGX support to userspace.
> > +
> > +	For details, see Documentation/x86/intel_sgx.rst
> > +
> > +	If unsure, say N.
> > +
> >  config EFI
> >  	bool "EFI runtime service support"
> >  	depends on ACPI
> > diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
> > new file mode 100644
> > index 000000000000..fa3e6e0eb8af
> > --- /dev/null
> > +++ b/arch/x86/include/asm/sgx.h
> > @@ -0,0 +1,25 @@
> > +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> > +// Copyright(c) 2016-18 Intel Corporation.
> > +//
> > +// Authors:
> > +//
> > +// Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> > +// Suresh Siddha <suresh.b.siddha@...el.com>
> > +// Sean Christopherson <sean.j.christopherson@...el.com>
> > +
> > +#ifndef _ASM_X86_SGX_H
> > +#define _ASM_X86_SGX_H
> > +
> > +#include <linux/types.h>
> > +
> > +#define SGX_CPUID 0x12
> > +
> Agree with Dave, this can just be remoed and you can use the feature macro from
> cpuid.h instead
> 
> Neil

Will do, thanks.

/Jarkko