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From: "Jan Beulich" <JBeulich@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>, Feng Wu <feng.wu@intel.com>
Cc: kevin.tian@intel.com, eddie.dong@intel.com,
	ian.campbell@citrix.com, jun.nakajima@intel.com,
	xen-devel@lists.xen.org
Subject: Re: [PATCH v6 05/10] Clear AC bit in RFLAGS to protect Xen itself by SMAP
Date: Wed, 07 May 2014 12:40:45 +0100	[thread overview]
Message-ID: <536A37DD020000780000FE3D@mail.emea.novell.com> (raw)
In-Reply-To: <536A009B.20802@citrix.com>

>>> On 07.05.14 at 11:44, <andrew.cooper3@citrix.com> wrote:
> On 07/05/14 09:19, Feng Wu wrote:
>> @@ -673,6 +675,7 @@ ENTRY(nmi_crash)
>>          ud2
>>  
>>  ENTRY(machine_check)
>> +        ASM_CLAC
> 
> This is not needed.  the start of handle_ist_exception has a SAVE_ALL,
> which also covers the nmi entry point.
> 
> On the subject of IST exceptions, perhaps the double fault explicitly
> wants a STAC to reduce the likelihood of taking a further fault while
> trying to dump state. ?

I agree. And perhaps along with do_double_fault(), fatal_trap()
should then also get a stac() added?

Jan

  reply	other threads:[~2014-05-07 11:40 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-07  8:19 [PATCH v6 00/10] x86: Enable Supervisor Mode Access Prevention (SMAP) Feng Wu
2014-05-07  8:19 ` [PATCH v6 01/10] x86: define macros CPUINFO_features and CPUINFO_FEATURE_OFFSET Feng Wu
2014-05-07  8:19 ` [PATCH v6 02/10] x86: move common_interrupt to entry.S Feng Wu
2014-05-07  8:19 ` [PATCH v6 03/10] x86: merge stuff from asm-x86/x86_64/asm_defns.h to asm-x86/asm_defns.h Feng Wu
2014-05-07  8:19 ` [PATCH v6 04/10] x86: Add support for STAC/CLAC instructions Feng Wu
2014-05-07  9:36   ` Andrew Cooper
2014-05-07  8:19 ` [PATCH v6 05/10] Clear AC bit in RFLAGS to protect Xen itself by SMAP Feng Wu
2014-05-07  9:44   ` Andrew Cooper
2014-05-07 11:40     ` Jan Beulich [this message]
2014-05-07 11:53       ` Andrew Cooper
2014-05-08  1:41         ` Wu, Feng
2014-05-08  1:57           ` Andrew Cooper
2014-05-08  2:02             ` Wu, Feng
2014-05-08  6:40               ` Jan Beulich
2014-05-08  6:49                 ` Wu, Feng
2014-05-08  6:54                   ` Jan Beulich
2014-05-08  6:58                     ` Wu, Feng
2014-05-08  7:08                       ` Jan Beulich
2014-05-08  7:13                         ` Wu, Feng
2014-05-08  9:48               ` Andrew Cooper
2014-05-07  8:19 ` [PATCH v6 06/10] x86: Temporary disable SMAP to legally access user pages in kernel mode Feng Wu
2014-05-07  9:49   ` Andrew Cooper
2014-05-08  1:14   ` Tian, Kevin
2014-05-07  8:19 ` [PATCH v6 07/10] VMX: Disable SMAP feature when guest is in non-paging mode Feng Wu
2014-05-08  1:16   ` Tian, Kevin
2014-05-07  8:19 ` [PATCH v6 08/10] x86: Enable Supervisor Mode Access Prevention (SMAP) for Xen Feng Wu
2014-05-07 10:26   ` Andrew Cooper
2014-05-07 11:44     ` Jan Beulich
2014-05-07 11:47       ` Andrew Cooper
2014-05-08  2:32     ` Wu, Feng
2014-05-08  1:20   ` Tian, Kevin
2014-05-08  6:25     ` Wu, Feng
2014-05-08  7:06       ` Jan Beulich
2014-05-07  8:19 ` [PATCH v6 09/10] x86/hvm: Add SMAP support to HVM guest Feng Wu
2014-05-07 10:46   ` Andrew Cooper
2014-05-07 11:47     ` Jan Beulich
2014-05-08  1:22   ` Tian, Kevin
2014-05-07  8:19 ` [PATCH v6 10/10] x86/tools: Expose SMAP to HVM guests Feng Wu
2014-05-07  8:35 ` [PATCH v6 00/10] x86: Enable Supervisor Mode Access Prevention (SMAP) Jan Beulich
2014-05-07  9:00   ` Wu, Feng
2014-05-07  9:33     ` Jan Beulich
2014-05-07  8:57 ` Ian Campbell
2014-05-07  8:59   ` Wu, Feng

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