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From: Tim Chen <tim.c.chen@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jikos@kernel.org>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	David Woodhouse <dwmw@amazon.co.uk>,
	Andi Kleen <ak@linux.intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Casey Schaufler <casey.schaufler@intel.com>,
	Asit Mallick <asit.k.mallick@intel.com>,
	Arjan van de Ven <arjan@linux.intel.com>,
	Jon Masters <jcm@redhat.com>, Waiman Long <longman9394@gmail.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: [Patch v5 11/16] x86/speculation: Add Spectre v2 app to app protection modes
Date: Mon, 19 Nov 2018 10:27:38 -0800	[thread overview]
Message-ID: <d4b538ba-ce4f-978c-8ccf-cf89187f265a@linux.intel.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1811191556350.1537@nanos.tec.linutronix.de>

On 11/19/2018 07:00 AM, Thomas Gleixner wrote:
> On Fri, 16 Nov 2018, Tim Chen wrote:
>> +DEFINE_STATIC_KEY_FALSE(spectre_v2_app_lite);
>> +EXPORT_SYMBOL_GPL(spectre_v2_app_lite);
> 
> Why would this be exported? The only usage site outside of this code is in
> tlb.c which is hardly modular.

That was my initial thought too.  Ingo suggested to export it in
review of v2.  Wonder Ingo has some reason?

https://lore.kernel.org/patchwork/patch/991759/

> 
>> @@ -328,14 +411,19 @@ static bool stibp_needed(void)
>>  	/*
>>  	 * Determine if STIBP should be always on.
>>  	 * Using enhanced IBRS makes using STIBP unnecessary.
>> +	 * For lite option, STIBP is used only for task with
>> +	 * TIF_STIBP flag. STIBP is not always on for that case.
> 
> Having the comment detached from the code is really not helpful.
> 

Sorry, would have the comment moved.

Tim


  reply	other threads:[~2018-11-19 18:27 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-17  1:53 [Patch v5 00/16] Provide task property based options to enable Spectre v2 userspace-userspace protection Tim Chen
2018-11-17  1:53 ` [Patch v5 01/16] x86/speculation: Clean up spectre_v2_parse_cmdline() Tim Chen
2018-11-17  1:53 ` [Patch v5 02/16] x86/speculation: Remove unnecessary ret variable in cpu_show_common() Tim Chen
2018-11-17  1:53 ` [Patch v5 03/16] x86/speculation: Reorganize cpu_show_common() Tim Chen
2018-11-17  1:53 ` [Patch v5 04/16] x86/speculation: Add X86_FEATURE_USE_IBRS_ENHANCED Tim Chen
2018-11-17  1:53 ` [Patch v5 05/16] x86/speculation: Disable STIBP when enhanced IBRS is in use Tim Chen
2018-11-17  1:53 ` [Patch v5 06/16] x86/speculation: Rename SSBD update functions Tim Chen
2018-11-17  1:53 ` [Patch v5 07/16] x86/speculation: Reorganize speculation control MSRs update Tim Chen
2018-11-17  1:53 ` [Patch v5 08/16] smt: Create cpu_smt_enabled static key for SMT specific code Tim Chen
2018-11-19 12:58   ` Thomas Gleixner
2018-11-19 20:50     ` Tim Chen
2018-11-19 14:57   ` Peter Zijlstra
2018-11-19 18:08     ` Tim Chen
2018-11-19 19:03       ` Thomas Gleixner
2018-11-19 19:25         ` Tim Chen
2018-11-17  1:53 ` [Patch v5 09/16] x86/smt: Convert cpu_smt_control check to cpu_smt_enabled static key Tim Chen
2018-11-19 12:48   ` Thomas Gleixner
2018-11-19 12:59     ` Thomas Gleixner
2018-11-17  1:53 ` [Patch v5 10/16] x86/speculation: Turn on or off STIBP according to a task's TIF_STIBP Tim Chen
2018-11-17  1:53 ` [Patch v5 11/16] x86/speculation: Add Spectre v2 app to app protection modes Tim Chen
2018-11-17  9:47   ` Jiri Kosina
2018-11-18 22:59     ` Jiri Kosina
2018-11-19 13:36       ` Thomas Gleixner
2018-11-19 13:49         ` Jiri Kosina
2018-11-19 13:51           ` Thomas Gleixner
2018-11-19 14:00             ` Jiri Kosina
2018-11-19 18:31               ` Tim Chen
2018-11-19 19:32           ` Andrea Arcangeli
2018-11-19 19:39             ` Jiri Kosina
2018-11-19 21:40               ` Andrea Arcangeli
2018-11-19 21:33             ` Dave Hansen
2018-11-19 23:16               ` Andrea Arcangeli
2018-11-19 23:25                 ` Dave Hansen
2018-11-19 23:45                   ` Andrea Arcangeli
2018-11-20  0:22                 ` Thomas Gleixner
2018-11-19 13:32   ` Thomas Gleixner
2018-11-20  0:08     ` Tim Chen
2018-11-20  0:30       ` Thomas Gleixner
2018-11-20  1:14         ` Tim Chen
2018-11-20  1:17         ` Andi Kleen
2018-11-19 15:00   ` Thomas Gleixner
2018-11-19 18:27     ` Tim Chen [this message]
2018-11-19 18:31       ` Jiri Kosina
2018-11-19 20:21   ` Thomas Gleixner
2018-11-19 22:44     ` Tim Chen
2018-11-19 20:46   ` Thomas Gleixner
2018-11-19 20:55     ` Jiri Kosina
2018-11-19 21:12       ` Thomas Gleixner
2018-11-19 22:48       ` Tim Chen
2018-11-19 23:01         ` Thomas Gleixner
2018-11-19 23:23           ` Jiri Kosina
2018-11-20  0:00             ` Thomas Gleixner
2018-11-20  0:24               ` Tim Chen
2018-11-19 23:39           ` Dave Hansen
2018-11-19 23:49             ` Jiri Kosina
2018-11-20  0:02               ` Thomas Gleixner
2018-11-17  1:53 ` [Patch v5 12/16] x86/speculation: Create PRCTL interface to restrict indirect branch speculation Tim Chen
2018-11-17  9:53   ` Jiri Kosina
2018-11-19 18:29     ` Tim Chen
2018-11-17  1:53 ` [Patch v5 13/16] security: Update speculation restriction of a process when modifying its dumpability Tim Chen
2018-11-17  1:53 ` [Patch v5 14/16] x86/speculation: Use STIBP to restrict speculation on non-dumpable task Tim Chen
2018-11-17  1:53 ` [Patch v5 15/16] x86/speculation: Update comment on TIF_SSBD Tim Chen
2018-11-17  1:53 ` [Patch v5 16/16] x86: Group thread info flags by functionality Tim Chen
2018-11-17  9:34 ` [Patch v5 00/16] Provide task property based options to enable Spectre v2 userspace-userspace protection Jiri Kosina

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