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

From: Jarkko Sakkinen
Date: Tue Jun 19 2018 - 09:34:43 EST


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@xxxxxxxxx>
> >
> > 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@xxxxxxxxx>
> > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > Tested-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > ---
> > 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@xxxxxxxxxxxxxxx>
> > +// Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
> > +// Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> > +
> > +#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