From: Thomas Gleixner <tglx@linutronix.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
X86 ML <x86@kernel.org>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Borislav Petkov <bp@suse.de>, Brian Gerst <brgerst@gmail.com>,
Chen Yucong <slaoub@gmail.com>,
Chris Metcalf <cmetcalf@mellanox.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Fenghua Yu <fenghua.yu@intel.com>, 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>,
"Ravi V . Shankar" <ravi.v.shankar@intel.com>,
Vlastimil Babka <vbabka@suse.cz>, Shuah Khan <shuah@kernel.org>
Subject: Re: [PATCH 0/4] x86: enable User-Mode Instruction Prevention
Date: Tue, 8 Nov 2016 17:52:25 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.20.1611081750360.3501@nanos> (raw)
In-Reply-To: <CALCETrV+c4Rw9zbB3=Jc2F6jtxib3prxNqMXgnUSyMc5QnU9fA@mail.gmail.com>
On Tue, 8 Nov 2016, Andy Lutomirski wrote:
> On Tue, Nov 8, 2016 at 5:16 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Mon, Nov 07, 2016 at 10:12:09PM -0800, Ricardo Neri wrote:
> >> There is a caveat, however. Certain applications running in virtual-8086
> >> mode, such as DOSEMU[1] and Wine[2], want to utilize the SGDT, SIDT and
> >> SLDT instructions for legitimate reasons. In order to keep such
> >> applications working, UMIP must be disabled/enabled when entering/exiting
> >> virtual-8086 mode.
> >
> > Would it not be better to emulate these instructions for them? What way
> > we can verify they're not malicious.
>
> Forget malice -- if they are really needed for some silly vm86-using
> program, let's trap them and emulate them so they return dummy values.
handle_vm86_fault() already does instruction emulation, so adding the few
bits there is the right thing to do. Then we just can enable UMIP
unconditionally and be done with it.
Thanks,
tglx
next prev parent reply other threads:[~2016-11-08 16:55 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-08 6:12 [PATCH 0/4] x86: enable User-Mode Instruction Prevention Ricardo Neri
2016-11-08 6:12 ` [PATCH 1/4] x86/cpufeature: Add User-Mode Instruction Prevention definitions Ricardo Neri
2016-11-08 15:32 ` Andy Lutomirski
2016-11-09 4:25 ` Ricardo Neri
2016-11-09 11:02 ` Andy Lutomirski
2016-11-10 3:24 ` Ricardo Neri
2016-11-10 8:58 ` Borislav Petkov
2016-11-11 4:08 ` Ricardo Neri
2016-11-11 10:22 ` Borislav Petkov
2016-11-12 1:24 ` Ricardo Neri
2016-11-11 18:06 ` Dave Hansen
2016-11-10 17:09 ` Dave Hansen
2016-11-08 6:12 ` [PATCH 2/4] x86: Prepare vm86 tasks to handle User-Mode Instruction Prevention Ricardo Neri
2016-11-08 16:01 ` Andy Lutomirski
2016-11-08 17:00 ` Peter Zijlstra
2016-11-09 4:26 ` Ricardo Neri
2016-11-08 6:12 ` [PATCH 3/4] x86: Enable " Ricardo Neri
2016-11-08 6:12 ` [PATCH 4/4] selftests/x86: Add tests for " Ricardo Neri
2016-11-08 13:16 ` [PATCH 0/4] x86: enable " Peter Zijlstra
2016-11-08 15:34 ` Andy Lutomirski
2016-11-08 16:52 ` Thomas Gleixner [this message]
2016-11-09 4:26 ` Ricardo Neri
2016-11-09 4:31 ` Ricardo Neri
2016-11-09 11:05 ` Andy Lutomirski
2016-11-10 6:46 ` Ricardo Neri
2016-11-10 8:52 ` Stas Sergeev
2016-11-11 4:14 ` Ricardo Neri
2016-11-11 20:51 ` Stas Sergeev
2016-11-12 1:29 ` Ricardo Neri
2016-11-14 10:59 ` One Thousand Gnomes
2016-11-14 18:36 ` Harald Arnesen
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