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From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>, 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>,
	"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>, "Neri, Ricardo" <ricardo.neri@intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Tony Luck <tony.luck@intel.com>
Subject: Re: [PATCH v9 25/29] x86/umip: Force a page fault when unable to copy emulated result to user
Date: Fri, 27 Oct 2017 14:46:58 -0700	[thread overview]
Message-ID: <20171027214658.GA14203@voyager> (raw)
In-Reply-To: <CALCETrU22Y_=MZyXT2YtFzjKf3DabhPKyt1eoDTtY0g8W=ggeg@mail.gmail.com>

On Thu, Oct 26, 2017 at 12:59:55AM -0700, Andy Lutomirski wrote:
> On Tue, Oct 3, 2017 at 8:54 PM, Ricardo Neri
> <ricardo.neri-calderon@linux.intel.com> wrote:
> > fixup_umip_exception() will be called from do_general_protection(). If the
> > former returns false, the latter will issue a SIGSEGV with SEND_SIG_PRIV.
> > However, when emulation is successful but the emulated result cannot be
> > copied to user space memory, it is more accurate to issue a SIGSEGV with
> > SEGV_MAPERR with the offending address. A new function, inspired in
> > force_sig_info_fault(), is introduced to model the page fault.
> 
> This code is slightly buggy (with, for example, PKRU, although the
> chance that anyone ever notices is about nil).  For an alternative
> approach, see current->thread.sig_on_uaccess_err, used in
> arch/x86/entry/vsyscall/vsyscall_64.c.  But I'm fine with this patch
> as is, too.

Thanks Andy, I will study the alternative you mention. Since you are OK
with this patch, I will submit v10 of this series to allow the review
of the series to continue.

BR,
Ricardo

  reply	other threads:[~2017-10-27 21:48 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-04  3:54 [PATCH v9 00/29] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 01/29] x86/mm: Relocate page fault error codes to traps.h Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 02/29] x86/boot: Relocate definition of the initial state of CR0 Ricardo Neri
2017-10-04  3:54   ` Ricardo Neri
2017-10-04  3:54   ` Ricardo Neri
2017-10-26  7:51   ` Andy Lutomirski
2017-10-26  7:51     ` Andy Lutomirski
2017-10-26  7:51     ` Andy Lutomirski
2017-10-26  9:00     ` Borislav Petkov
2017-10-26  9:00       ` Borislav Petkov
2017-10-26  9:00       ` Borislav Petkov
2017-10-26  9:02       ` Andy Lutomirski
2017-10-26  9:02         ` Andy Lutomirski
2017-10-26  9:02         ` Andy Lutomirski
2017-10-26 12:55         ` Borislav Petkov
2017-10-26 12:55           ` Borislav Petkov
2017-10-26 12:55           ` Borislav Petkov
2017-10-27 19:02           ` Ricardo Neri
2017-10-27 19:02             ` Ricardo Neri
2017-10-27 19:02             ` Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 03/29] ptrace,x86: Make user_64bit_mode() available to 32-bit builds Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 04/29] uprobes/x86: Use existing definitions for segment override prefixes Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 05/29] x86/mpx: Simplify handling of errors when computing linear addresses Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 06/29] x86/mpx: Use signed variables to compute effective addresses Ricardo Neri
2017-10-05  9:41   ` Borislav Petkov
2017-10-05 17:38     ` Neri, Ricardo
2017-10-04  3:54 ` [PATCH v9 07/29] x86/mpx: Do not use SIB.index if its value is 100b and ModRM.mod is not 11b Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 08/29] x86/mpx: Do not use SIB.base if its value is 101b and ModRM.mod = 0 Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 09/29] x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 10/29] x86/insn-eval: Do not BUG on invalid register type Ricardo Neri
2017-10-07 16:22   ` Borislav Petkov
2017-10-09 23:56     ` Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 11/29] x86/insn-eval: Add a utility function to get register offsets Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 12/29] x86/insn-eval: Add utility function to identify string instructions Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 13/29] x86/insn-eval: Add utility functions to get segment selector Ricardo Neri
2017-10-10 22:41   ` Borislav Petkov
2017-10-12  1:12     ` Ricardo Neri
2017-10-12  9:48       ` Borislav Petkov
2017-10-13  1:08         ` Ricardo Neri
2017-10-13 11:37           ` Borislav Petkov
2017-10-13 18:43             ` Ricardo Neri
2017-10-17  9:35               ` Borislav Petkov
2017-10-17 20:31                 ` Ricardo Neri
2017-10-18 20:29                   ` Borislav Petkov
2017-10-19  6:30                     ` Ricardo Neri
2017-10-20  7:55                       ` Borislav Petkov
2017-10-20 18:05                         ` Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 14/29] x86/insn-eval: Add utility function to get segment descriptor Ricardo Neri
2017-10-11 14:57   ` Borislav Petkov
2017-10-12  0:45     ` Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 15/29] x86/insn-eval: Add utility functions to get segment descriptor base address and limit Ricardo Neri
2017-10-11 15:15   ` Borislav Petkov
2017-10-11 19:57     ` Ricardo Neri
2017-10-11 20:16       ` Borislav Petkov
2017-10-12  1:24         ` Ricardo Neri
2017-10-12 16:02           ` Borislav Petkov
2017-10-04  3:54 ` [PATCH v9 16/29] x86/insn-eval: Add function to get default params of code segment Ricardo Neri
2017-10-12 16:31   ` Borislav Petkov
2017-10-12 18:27     ` Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 17/29] x86/insn-eval: Indicate a 32-bit displacement if ModRM.mod is 0 and ModRM.rm is 101b Ricardo Neri
2017-10-20 15:44   ` Borislav Petkov
2017-10-20 18:07     ` Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 18/29] x86/insn-eval: Incorporate segment base in linear address computation Ricardo Neri
2017-10-20 16:08   ` Borislav Petkov
2017-10-20 18:10     ` Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 19/29] x86/insn-eval: Add support to resolve 32-bit address encodings Ricardo Neri
2017-10-20 17:12   ` Borislav Petkov
2017-10-20 18:24     ` Ricardo Neri
2017-10-20 18:38       ` Borislav Petkov
2017-10-20 19:16         ` Ricardo Neri
2017-10-20 22:04           ` Borislav Petkov
2017-10-04  3:54 ` [PATCH v9 20/29] x86/insn-eval: Add wrapper function for 32 and 64-bit addresses Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 21/29] x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 22/29] x86/insn-eval: Add support to resolve 16-bit addressing encodings Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 23/29] x86/cpufeature: Add User-Mode Instruction Prevention definitions Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 24/29] x86: Add emulation code for UMIP instructions Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 25/29] x86/umip: Force a page fault when unable to copy emulated result to user Ricardo Neri
2017-10-26  7:59   ` Andy Lutomirski
2017-10-27 21:46     ` Ricardo Neri [this message]
2017-10-04  3:54 ` [PATCH v9 26/29] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 27/29] x86/traps: Fixup general protection faults caused by UMIP Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 28/29] selftests/x86: Add tests for User-Mode Instruction Prevention Ricardo Neri
2017-10-04  3:54 ` [PATCH v9 29/29] selftests/x86: Add tests for instruction str and sldt Ricardo Neri

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