From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Stas Sergeev <stsp@list.ru>
Cc: Andy Lutomirski <luto@amacapital.net>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@suse.de>,
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>,
Liang Z Li <liang.z.li@intel.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>,
Fenghua Yu <fenghua.yu@intel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Shuah Khan <shuah@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
X86 ML <x86@kernel.org>,
linux-msdos@vger.kernel.org, wine-devel@winehq.org
Subject: Re: [v6 PATCH 00/21] x86: Enable User-Mode Instruction Prevention
Date: Tue, 28 Mar 2017 21:38:04 -0700 [thread overview]
Message-ID: <1490762284.2647.24.camel@ranerica-desktop> (raw)
In-Reply-To: <cc490254-9c0b-e55e-6228-ad5e1f365123@list.ru>
On Tue, 2017-03-28 at 12:38 +0300, Stas Sergeev wrote:
> 28.03.2017 02:46, Ricardo Neri пишет:
> > On Tue, 2017-03-14 at 00:25 +0300, Stas Sergeev wrote:
> >> 11.03.2017 02:59, Ricardo Neri пишет:
> >>> On Fri, 2017-03-10 at 14:33 +0300, Stas Sergeev wrote:
> >>>
> >>>> Why would you need one?
> >>>> Or do you really want to allow these instructions
> >>>> in v86 by the means of emulation? If so - this wasn't
> >>>> clearly stated in the patch description, neither it was
> >>>> properly discussed, it seems.
> >>> It str and sldt can be emulated in vm86 but as Andy mention, the
> >>> behavior sould be the same with and without emulation.
> >> Why would you do that?
> >> I looked up the dosemu2 CPU simulator code that
> >> is used under x86-64. It says this:
> > Stas, I apologize for the delayed reply; I missed your e-mail.
> >> It only implements smsw.
> >> So maybe you can make your code much
> >> simpler and remove the unneeded emulation?
> >> Same is for prot mode.
> > Do you mean the unneeded emulation for SLDT and STR?
> Not quite, I meant also sgdt and sidt in vm86.
> Yes that it will be a somewhat "incompatible" change,
> but if there is nothing to stay compatible with,
> then why to worry?
My idea of compatibility was to have the emulation code behave exactly
as a processor without UMIP :)
> Probably you could also remove
> the sldt and str emulation for protected mode, because,
> as I understand from this thread, wine does not
> need those.
I see. I would lean on keeping the emulation because I already
implemented it :), for completeness, and because it is performed in a
single switch. The bulk of the emulation code deals with operands.
>
> Note that these days dosemu2 uses v86 mode set
> up under kvm rather than vm86(). Your patches
> affect that the same way as they do for vm86()
> syscall, or can there be some differences?
My code does not touch kvm at all. I would need to assess how kvm will
behave.
> Or should
> the UMIP be enabled under kvm by hands?
There was an attempt to emulate UMIP that was submitted a while ago:
https://lkml.org/lkml/2016/7/12/644
>
> >> You know the wine's
> >> requirements now - they are very small. And
> >> dosemu doesn't need anything at all but smsw.
> >> And even smsw is very rare.
> > But emulation is still needed for SMSW, right?
> Likely so.
> If you want, I can enable the logging of this command
> and see if it is used by some of the DOS programs I have.
It would be great if you could do that, if you don't mind.
> But at least dosemu implements it, so probably it is needed.
Right.
> Of course if it is used by one of 100 DOS progs, then there
> is an option to just add its support to dosemu2 and pretend
> the compatibility problems did not exist. :)
Do you mean relaying the GP fault to dosemu instead of trapping it and
emulating it in the kernel?
Thanks and BR,
Ricardo
next prev parent reply other threads:[~2017-03-29 4:38 UTC|newest]
Thread overview: 112+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-08 0:32 [v6 PATCH 00/21] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 01/21] x86/mpx: Use signed variables to compute effective addresses Ricardo Neri
2017-04-11 21:56 ` Borislav Petkov
2017-04-26 1:40 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 02/21] x86/mpx: Do not use SIB index if index points to R/ESP Ricardo Neri
2017-04-11 11:31 ` Borislav Petkov
2017-04-26 1:39 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 03/21] x86/mpx: Do not use R/EBP as base in the SIB byte with Mod = 0 Ricardo Neri
2017-04-11 22:08 ` Borislav Petkov
2017-04-26 2:04 ` Ricardo Neri
2017-04-26 8:05 ` Borislav Petkov
2017-04-27 22:49 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 04/21] x86/mpx, x86/insn: Relocate insn util functions to a new insn-kernel Ricardo Neri
2017-04-12 10:03 ` Borislav Petkov
2017-04-26 2:05 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 05/21] x86/insn-eval: Add utility functions to get register offsets Ricardo Neri
2017-04-12 16:28 ` Borislav Petkov
2017-04-26 18:13 ` Ricardo Neri
2017-04-28 10:40 ` Borislav Petkov
2017-03-08 0:32 ` [v6 PATCH 06/21] x86/insn-eval: Add utility functions to get segment selector Ricardo Neri
2017-04-18 9:42 ` Borislav Petkov
2017-04-26 20:44 ` Ricardo Neri
2017-04-26 20:47 ` Ricardo Neri
2017-04-30 17:15 ` Borislav Petkov
2017-05-05 18:31 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 07/21] x86/insn-eval: Add utility function to get segment descriptor Ricardo Neri
2017-04-19 10:26 ` Borislav Petkov
2017-04-26 21:51 ` Ricardo Neri
2017-05-04 11:02 ` Borislav Petkov
2017-05-12 2:13 ` Ricardo Neri
2017-05-15 17:27 ` Borislav Petkov
2017-03-08 0:32 ` [v6 PATCH 08/21] x86/insn-eval: Add utility function to get segment descriptor base address Ricardo Neri
2017-04-20 8:25 ` Borislav Petkov
2017-04-26 22:37 ` Ricardo Neri
2017-05-05 17:19 ` Borislav Petkov
2017-05-12 2:09 ` Ricardo Neri
2017-04-26 22:52 ` Ricardo Neri
2017-05-05 17:28 ` Borislav Petkov
2017-05-12 2:06 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 09/21] x86/insn-eval: Add functions to get default operand and address sizes Ricardo Neri
2017-04-20 13:06 ` Borislav Petkov
2017-04-27 1:07 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 10/21] x86/insn-eval: Do not use R/EBP as base if mod in ModRM is zero Ricardo Neri
2017-04-21 10:52 ` Borislav Petkov
2017-04-27 1:29 ` Ricardo Neri
2017-05-07 17:20 ` Borislav Petkov
2017-05-12 1:57 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 11/21] insn/eval: Incorporate segment base in address computation Ricardo Neri
2017-04-21 14:55 ` Borislav Petkov
2017-04-27 1:31 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 12/21] x86/insn: Support both signed 32-bit and 64-bit effective addresses Ricardo Neri
2017-04-25 13:51 ` Borislav Petkov
2017-04-27 3:33 ` Ricardo Neri
2017-05-08 11:42 ` Borislav Petkov
2017-05-12 1:55 ` Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 13/21] x86/insn-eval: Add support to resolve 16-bit addressing encodings Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 14/21] x86/insn-eval: Add wrapper function for 16-bit and 32-bit address encodings Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 15/21] x86/mm: Relocate page fault error codes to traps.h Ricardo Neri
2017-03-08 16:08 ` Andy Lutomirski
2017-03-08 0:32 ` [v6 PATCH 16/21] x86/cpufeature: Add User-Mode Instruction Prevention definitions Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 17/21] x86: Add emulation code for UMIP instructions Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 18/21] x86/umip: Force a page fault when unable to copy emulated result to user Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 19/21] x86/traps: Fixup general protection faults caused by UMIP Ricardo Neri
2017-03-08 15:54 ` Andy Lutomirski
2017-03-08 0:32 ` [v6 PATCH 20/21] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-03-08 0:32 ` [v6 PATCH 21/21] selftests/x86: Add tests for " Ricardo Neri
2017-03-08 15:56 ` Andy Lutomirski
2017-03-10 23:38 ` Ricardo Neri
2017-03-08 14:08 ` [v6 PATCH 00/21] x86: Enable " Stas Sergeev
2017-03-08 16:06 ` Andy Lutomirski
2017-03-08 16:29 ` Stas Sergeev
2017-03-08 16:46 ` Andy Lutomirski
2017-03-08 16:53 ` Stas Sergeev
2017-03-09 1:11 ` Ricardo Neri
2017-03-09 22:05 ` Stas Sergeev
2017-03-10 2:41 ` Andy Lutomirski
2017-03-10 10:30 ` Stas Sergeev
2017-03-10 21:04 ` Andy Lutomirski
2017-03-10 21:37 ` Stas Sergeev
2017-03-09 1:15 ` Ricardo Neri
2017-03-09 22:10 ` Stas Sergeev
2017-03-10 2:39 ` Andy Lutomirski
2017-03-10 11:33 ` Stas Sergeev
2017-03-10 14:17 ` Andy Lutomirski
2017-03-11 1:22 ` Ricardo Neri
2017-03-10 23:59 ` Ricardo Neri
2017-03-13 21:25 ` Stas Sergeev
2017-03-27 23:46 ` Ricardo Neri
2017-03-28 9:38 ` Stas Sergeev
2017-03-29 4:38 ` Ricardo Neri [this message]
2017-03-29 20:55 ` Stas Sergeev
2017-03-30 5:14 ` Ricardo Neri
2017-03-30 10:10 ` Stas Sergeev
2017-03-31 1:33 ` Ricardo Neri
2017-03-31 14:11 ` Alexandre Julliard
2017-03-31 21:26 ` Stas Sergeev
2017-04-01 2:18 ` Andy Lutomirski
2017-04-04 2:02 ` Ricardo Neri
2017-04-04 6:08 ` Alexandre Julliard
2017-04-01 13:08 ` Stas Sergeev
2017-04-01 17:49 ` H. Peter Anvin
2017-04-02 15:52 ` Andy Lutomirski
2017-04-04 9:59 ` Stas Sergeev
2017-04-04 2:05 ` Ricardo Neri
2017-04-04 8:03 ` Stas Sergeev
2017-03-10 23:58 ` Ricardo Neri
2017-03-09 0:46 ` Ricardo Neri
2017-03-09 22:01 ` Stas Sergeev
2017-03-10 23:47 ` Ricardo Neri
2017-03-10 23:58 ` Stas Sergeev
2017-03-11 0:13 ` Ricardo Neri
2017-03-08 16:07 ` Andy Lutomirski
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