From: Andy Lutomirski <luto@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
X86 ML <x86@kernel.org>,
Platform Driver <platform-driver-x86@vger.kernel.org>,
Andi Kleen <ak@linux.intel.com>,
Greg KH <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
npmccallum@redhat.com, LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
intel-sgx-kernel-dev@lists.01.org,
"H. Peter Anvin" <hpa@zytor.com>,
Vikas Shivappa <vikas.shivappa@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [intel-sgx-kernel-dev] [PATCH v11 07/13] x86, sgx: detect Intel SGX
Date: Mon, 18 Jun 2018 14:36:35 -0700 [thread overview]
Message-ID: <CALCETrU+s97soHtiC3p3hkdwqZhEMdjPyJByskb99a+Z8PZjpA@mail.gmail.com> (raw)
In-Reply-To: <4fc3b6b0-6e4b-3d5f-4d54-2bf7539c7a17@intel.com>
On Mon, Jun 18, 2018 at 8:11 AM Dave Hansen <dave.hansen@intel.com> wrote:
>
> > +config INTEL_SGX_CORE
> > + prompt "Intel SGX core functionality
> > + 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.
>
> That semicolon needs to be a colon. The second half of that sentence is
> not a stand-alone statement.
>
> > + 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@linux.intel.com>
> > +// Suresh Siddha <suresh.b.siddha@intel.com>
> > +// Sean Christopherson <sean.j.christopherson@intel.com>
> > +
> > +#ifndef _ASM_X86_SGX_H
> > +#define _ASM_X86_SGX_H
> > +
> > +#include <linux/types.h>
> > +
> > +#define SGX_CPUID 0x12
>
> Hey, I just saw 0x12 as a magic, hard-coded number earlier in these
> patches. It seems cruel to hard-code it, and then also have a #define
> that isn't used.
>
> > +enum sgx_cpuid {
> > + SGX_CPUID_CAPABILITIES = 0,
> > + SGX_CPUID_ATTRIBUTES = 1,
> > + SGX_CPUID_EPC_BANKS = 2,
> > +};
>
> These are cpuid *leaves*, right? Please make this clear that these are
> hardware-defined values and not some kind of software construct.
>
> > +bool sgx_enabled __ro_after_init = false;
> > +EXPORT_SYMBOL(sgx_enabled);
> > +
> > +static __init bool sgx_is_enabled(void)
> > +{
> > + unsigned long fc;
> > +
> > + if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
> > + return false;
>
> Not necessary. CPUID does this part for you.
More to the point, if a non-Intel vendor chooses to support SGX, then
the driver should allow it.
>
> > + if (!boot_cpu_has(X86_FEATURE_SGX))
> > + return false;
> > +
> > + if (!boot_cpu_has(X86_FEATURE_SGX1))
> > + return false;
> > +
> > + rdmsrl(MSR_IA32_FEATURE_CONTROL, fc);
> > + if (!(fc & FEATURE_CONTROL_LOCKED))
> > + return false;
> > +
> > + if (!(fc & FEATURE_CONTROL_SGX_ENABLE))
> > + return false;
>
> Comments, please. Why would this happen? What would it mean?
Let's add actual pr_info() statements to document this, like:
SGX: disabled by firmware
SGX: disabled because CPU does not support flexible launch control
SGX: disabled because firmware does not support flexible launch control
SGX: disabled because the phase of the moon is wrong
SGX: enabled; using SGX1
SGX: enabled, using SGX2
If the CPU doesn't support SGX at all, then I see no reason to print anything.
etc.
(Is the feature actually called flexible launch control? I may have
made that up.)
next prev parent reply other threads:[~2018-06-18 21:36 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-08 17:09 [PATCH v11 00/13] Intel SGX1 support Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 01/13] compiler.h, kasan: add __SANITIZE_ADDRESS__ check for __no_kasan_or_inline Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 02/13] x86, sgx: updated MAINTAINERS Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 03/13] x86, sgx: add SGX definitions to cpufeature Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 04/13] x86, sgx: add SGX definitions to msr-index.h Jarkko Sakkinen
2018-06-08 17:25 ` Dave Hansen
2018-06-19 13:18 ` Jarkko Sakkinen
2018-06-19 14:01 ` Dave Hansen
2018-06-21 17:22 ` Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 05/13] x86, cpufeatures: add Intel-defined SGX leaf CPUID_12_EAX Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 06/13] crypto: aesni: add minimal build option for SGX LE Jarkko Sakkinen
2018-06-08 17:27 ` Dave Hansen
2018-06-11 15:24 ` Sean Christopherson
2018-06-08 17:09 ` [PATCH v11 07/13] x86, sgx: detect Intel SGX Jarkko Sakkinen
2018-06-08 17:36 ` Dave Hansen
2018-06-18 21:36 ` Andy Lutomirski [this message]
2018-06-25 7:39 ` [intel-sgx-kernel-dev] " Jarkko Sakkinen
2018-06-19 13:33 ` Jarkko Sakkinen
2018-06-11 11:35 ` Neil Horman
2018-06-19 13:34 ` Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 08/13] x86, sgx: added ENCLS wrappers Jarkko Sakkinen
2018-06-08 17:43 ` Dave Hansen
2018-06-19 13:25 ` Jarkko Sakkinen
2018-06-20 13:12 ` Sean Christopherson
2018-06-25 9:16 ` Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 09/13] x86, sgx: basic routines for enclave page cache Jarkko Sakkinen
2018-06-08 18:21 ` Jethro Beekman
2018-06-18 21:33 ` [intel-sgx-kernel-dev] " Andy Lutomirski
2018-06-25 7:36 ` Jarkko Sakkinen
2018-06-19 14:08 ` Jarkko Sakkinen
2018-06-19 15:44 ` Jethro Beekman
2018-06-08 18:24 ` Dave Hansen
2018-06-19 14:57 ` Jarkko Sakkinen
2018-06-19 15:19 ` Neil Horman
2018-06-19 15:32 ` Dave Hansen
2018-06-25 9:01 ` Jarkko Sakkinen
2018-06-19 15:59 ` Sean Christopherson
2018-06-25 9:14 ` Jarkko Sakkinen
2018-06-10 5:32 ` [intel-sgx-kernel-dev] " Andy Lutomirski
2018-06-11 15:12 ` Sean Christopherson
2018-06-20 13:21 ` Sean Christopherson
2018-06-25 9:21 ` Jarkko Sakkinen
2018-06-25 16:14 ` Neil Horman
2018-06-20 15:26 ` Sean Christopherson
2018-06-25 9:21 ` Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 10/13] intel_sgx: driver for Intel Software Guard Extensions Jarkko Sakkinen
2018-06-08 19:35 ` Dave Hansen
2018-06-19 13:29 ` Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 11/13] intel_sgx: ptrace() support Jarkko Sakkinen
2018-06-08 18:34 ` Dave Hansen
2018-06-11 15:02 ` Sean Christopherson
2018-06-19 13:38 ` Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 12/13] intel_sgx: driver documentation Jarkko Sakkinen
2018-06-08 18:32 ` Jethro Beekman
2018-06-19 13:30 ` Jarkko Sakkinen
2018-06-08 21:41 ` Randy Dunlap
2018-06-19 13:31 ` Jarkko Sakkinen
2018-06-08 17:09 ` [PATCH v11 13/13] intel_sgx: in-kernel launch enclave Jarkko Sakkinen
2018-06-08 18:50 ` [intel-sgx-kernel-dev] " Andy Lutomirski
2018-06-19 15:05 ` Jarkko Sakkinen
2018-06-10 5:39 ` Andy Lutomirski
2018-06-11 5:17 ` Andy Lutomirski
2018-06-11 11:52 ` Neil Horman
2018-06-12 4:55 ` Andy Lutomirski
2018-06-12 17:45 ` Neil Horman
2018-06-18 21:58 ` Andy Lutomirski
2018-06-19 13:17 ` Neil Horman
2018-06-20 16:28 ` Nathaniel McCallum
2018-06-20 18:16 ` Jethro Beekman
2018-06-20 18:39 ` Jethro Beekman
2018-06-20 21:01 ` Sean Christopherson
2018-06-21 12:32 ` Nathaniel McCallum
2018-06-21 15:29 ` Neil Horman
2018-06-21 19:11 ` Nathaniel McCallum
2018-06-21 21:20 ` Sean Christopherson
2018-06-25 21:00 ` Nathaniel McCallum
2018-06-25 22:35 ` Sean Christopherson
2018-06-21 22:48 ` Andy Lutomirski
2018-06-25 21:06 ` Nathaniel McCallum
2018-06-25 23:40 ` Andy Lutomirski
2018-06-25 9:41 ` Jarkko Sakkinen
2018-06-25 15:45 ` Andy Lutomirski
2018-06-25 21:28 ` Nathaniel McCallum
2018-06-26 8:43 ` Jarkko Sakkinen
2018-06-26 15:01 ` Nathaniel McCallum
2018-06-27 15:31 ` Jarkko Sakkinen
2018-06-21 12:12 ` Nathaniel McCallum
2018-06-25 9:27 ` Jarkko Sakkinen
2018-06-25 21:26 ` Nathaniel McCallum
2018-06-20 7:23 ` Jarkko Sakkinen
2018-06-12 10:50 ` [PATCH v11 00/13] Intel SGX1 support Pavel Machek
2018-06-19 14:59 ` Jarkko Sakkinen
2018-06-19 20:04 ` Pavel Machek
2018-06-19 20:23 ` Peter Zijlstra
2018-06-19 21:48 ` Josh Triplett
2018-12-09 20:06 ` Pavel Machek
2018-12-10 7:47 ` Josh Triplett
2018-12-10 8:27 ` Pavel Machek
2018-12-10 23:12 ` Josh Triplett
2018-12-11 18:10 ` Dave Hansen
2018-12-11 18:31 ` Sean Christopherson
2018-06-19 20:36 ` Peter Zijlstra
2018-06-21 12:55 ` Ingo Molnar
2018-06-25 9:44 ` Jarkko Sakkinen
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