From mboxrd@z Thu Jan  1 00:00:00 1970
From: Borislav Petkov <bp@suse.de>
Subject: Re: [PATCH v7 20/26] x86/cpufeature: Add User-Mode Instruction
 Prevention definitions
Date: Wed, 7 Jun 2017 20:24:22 +0200
Message-ID: <20170607182422.7amuhyleuzn6rjln@pd.tnic>
References: <20170505181724.55000-1-ricardo.neri-calderon@linux.intel.com>
 <20170505181724.55000-21-ricardo.neri-calderon@linux.intel.com>
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To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>, Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>, Andy Lutomirski <luto@kernel.org>, Peter Zijlstra <peterz@infradead.org>, Andrew Morton <akpm@linux-foundation.org>, Brian Gerst <brgerst@gmail.com>, Chris Metcalf <cmetcalf@mellanox.com>, Dave Hansen <dave.hansen@linux.intel.com>, Paolo Bonzini <pbonzini@redhat.com>, Masami Hiramatsu <mhiramat@kernel.org>, Huang Rui <ray.huang@amd.com>, Jiri Slaby <jslaby@suse.cz>, Jonathan Corbet <corbet@lwn.net>, "Michael S. Tsirkin" <mst@redhat.com>, Paul Gortmaker <paul.gortmaker@windriver.com>, Vlastimil Babka <vbabka@suse.cz>, Chen Yucong <slaoub@gmail.com>, Alexandre Julliard <julliard@winehq.org>, Stas Sergeev <stsp@list.ru>, Fenghua Yu <fenghua.yu>

On Fri, May 05, 2017 at 11:17:18AM -0700, Ricardo Neri wrote:
> User-Mode Instruction Prevention is a security feature present in new
> Intel processors that, when set, prevents the execution of a subset of
> instructions if such instructions are executed in user mode (CPL > 0).
> Attempting to execute such instructions causes a general protection
> exception.
> 
> The subset of instructions comprises:
> 
>  * SGDT - Store Global Descriptor Table
>  * SIDT - Store Interrupt Descriptor Table
>  * SLDT - Store Local Descriptor Table
>  * SMSW - Store Machine Status Word
>  * STR  - Store Task Register
> 
> This feature is also added to the list of disabled-features to allow
> a cleaner handling of build-time configuration.
> 
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Brian Gerst <brgerst@gmail.com>
> Cc: Chen Yucong <slaoub@gmail.com>
> Cc: Chris Metcalf <cmetcalf@mellanox.com>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: Huang Rui <ray.huang@amd.com>
> Cc: Jiri Slaby <jslaby@suse.cz>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
> Cc: Shuah Khan <shuah@kernel.org>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Liang Z. Li <liang.z.li@intel.com>
> Cc: Alexandre Julliard <julliard@winehq.org>
> Cc: Stas Sergeev <stsp@list.ru>
> Cc: x86@kernel.org
> Cc: linux-msdos@vger.kernel.org
> 
> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
> ---
>  arch/x86/include/asm/cpufeatures.h          | 1 +
>  arch/x86/include/asm/disabled-features.h    | 8 +++++++-
>  arch/x86/include/uapi/asm/processor-flags.h | 2 ++
>  3 files changed, 10 insertions(+), 1 deletion(-)

Reviewed-by: Borislav Petkov <bp@suse.de>

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--