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From: Ingo Molnar <mingo@kernel.org>
To: Jan Beulich <JBeulich@suse.com>
Cc: mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com,
	linux-kernel@vger.kernel.org,
	Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
	Stas Sergeev <stsp@list.ru>
Subject: Re: [PATCH] x86: add UMIP support
Date: Thu, 17 Nov 2016 07:52:13 +0100	[thread overview]
Message-ID: <20161117065213.GA10358@gmail.com> (raw)
In-Reply-To: <582C8CE3020000780011F475@prv-mh.provo.novell.com>


* Jan Beulich <JBeulich@suse.com> wrote:

> This is a small aid to security, hiding in particular the kernel address
> information otherwise available through SGDT/SIDT.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> ---
> Main question here is whether to limit this to 64-bit (or at least
> !CONFIG_VM86) for the time being, or to disable it while running VM86
> mode code: Such code isn't unlikely to use SMSW (and one of SGDT/SIDT)
> to figure out whether it's running on an i286 or i386, as the EFLAGS
> based method recommended by Intel's SDM can't be relied upon there.
> ---
>  Documentation/kernel-parameters.txt         |    4 ++++
>  arch/x86/include/asm/cpufeatures.h          |    1 +
>  arch/x86/include/uapi/asm/processor-flags.h |    2 ++
>  arch/x86/kernel/cpu/common.c                |   16 +++++++++++++++-
>  4 files changed, 22 insertions(+), 1 deletion(-)

Note that similar patches have been submitted a week ago:

  https://lkml.org/lkml/2016/11/8/68

Thanks,

	Ingo

  reply	other threads:[~2016-11-17  6:52 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-16 15:44 [PATCH] x86: add UMIP support Jan Beulich
2016-11-17  6:52 ` Ingo Molnar [this message]
2016-11-17 23:27   ` Ricardo Neri

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