From: Jon Masters <jcm@redhat.com>
To: Tim Chen <tim.c.chen@linux.intel.com>,
Jiri Kosina <jikos@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Cc: 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>,
linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH 2/2] x86/speculation: Provide application property based STIBP protection
Date: Tue, 2 Oct 2018 11:41:28 -0400 [thread overview]
Message-ID: <1a501628-a232-a126-166e-814c26243f2d@redhat.com> (raw)
In-Reply-To: <0c55c162a077aadbfd57878e2694e35292c1a29c.1537392876.git.tim.c.chen@linux.intel.com>
On 9/19/18 5:35 PM, Tim Chen wrote:
> This patch provides an application property based spectre_v2
> protection with STIBP against attack from another app from
> a sibling hyper-thread. For security sensitive non-dumpable
> app, STIBP will be turned on before switching to it for Intel
> processors vulnerable to spectre_v2.
A general comment. I think in practice this will be similar to the
speculative store buffer bypass (aka "variant 4") issue in terms of
opt-in mitigation. Many users won't want to take the performance hit of
having STIBP by default for peer threads. We should make sure that we
don't force users into a mitigation but retain an option. Whether it's
default-on or not can be debated, though I think the vendors lean toward
having default-off with an opt-in, and customers will probably agree. So
anyway, I encourage a pragmatic approach similar to that for SSBD.
Jon.
--
Computer Architect | Sent with my Fedora powered laptop
next prev parent reply other threads:[~2018-10-02 15:41 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-19 21:35 [PATCH 0/2] Provide options to enable spectre_v2 userspace-userspace protection Tim Chen
2018-09-19 21:35 ` [PATCH 1/2] x86/speculation: Option to select app to app mitigation for spectre_v2 Tim Chen
2018-09-19 21:35 ` [PATCH 2/2] x86/speculation: Provide application property based STIBP protection Tim Chen
2018-09-20 7:57 ` Peter Zijlstra
2018-09-20 17:17 ` Tim Chen
2018-09-20 8:00 ` Peter Zijlstra
2018-09-20 17:32 ` Tim Chen
2018-10-02 15:41 ` Jon Masters [this message]
2018-10-02 15:43 ` Jiri Kosina
2018-10-02 15:44 ` Jon Masters
2018-09-20 21:38 ` [PATCH 0/2] Provide options to enable spectre_v2 userspace-userspace protection Lendacky, Thomas
2018-09-21 15:44 ` Lendacky, Thomas
2018-09-21 17:14 ` Tim Chen
2018-09-21 17:44 ` Lendacky, Thomas
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