linux-kernel - Re: [Patch v5 11/16] x86/speculation: Add Spectre v2 app to app protection modes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <49d27ed3-dc44-042c-4941-31dedb2a56d2@linux.intel.com>
Date:   Mon, 19 Nov 2018 14:48:21 -0800
From:   Tim Chen <tim.c.chen@...ux.intel.com>
To:     Jiri Kosina <jikos@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Tom Lendacky <thomas.lendacky@....com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Andi Kleen <ak@...ux.intel.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Casey Schaufler <casey.schaufler@...el.com>,
        Asit Mallick <asit.k.mallick@...el.com>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Jon Masters <jcm@...hat.com>,
        Waiman Long <longman9394@...il.com>,
        linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [Patch v5 11/16] x86/speculation: Add Spectre v2 app to app
 protection modes

On 11/19/2018 12:55 PM, Jiri Kosina wrote:
> On Mon, 19 Nov 2018, Thomas Gleixner wrote:
> 
>>
>> So before that change IBPB was usable without STIBP, now not longer. What's
>> the rationale?
>>
>> This patch changes a gazillion things at once and is completely
>> unreviewable.
> 
> The patchset actually ties together IBPB and STIBP pretty closely, which 
> is IMO a good thing; there is no good reason why anone would want just one 
> of those (or each in a different mode), at least before this magical 
> coscheduling exists.
> 
> But I guess this fact should be documented somewhere.
> 

Yes, it wouldn't make sense for having just one of those if a task
is worried about attack from user space.

I'll document it.

Tim