From: Borislav Petkov <bp@alien8.de>
To: KP Singh <kpsingh@kernel.org>
Cc: linux-kernel@vger.kernel.org, pjt@google.com, evn@google.com,
jpoimboe@kernel.org, tglx@linutronix.de, x86@kernel.org,
hpa@zytor.com, peterz@infradead.org,
pawan.kumar.gupta@linux.intel.com, kim.phillips@amd.com,
alexandre.chartre@oracle.com, daniel.sneddon@linux.intel.com,
corbet@lwn.net, bp@suse.de, linyujun809@huawei.com,
jmattson@google.com
Subject: Re: [PATCH v2 2/2] Documentation/hw-vuln: Document the interaction between IBRS and STIBP
Date: Thu, 23 Feb 2023 15:52:25 +0100 [thread overview]
Message-ID: <Y/d9qajJnR/ZcHvB@zn.tnic> (raw)
In-Reply-To: <20230221184908.2349578-2-kpsingh@kernel.org>
On Tue, Feb 21, 2023 at 07:49:08PM +0100, KP Singh wrote:
> ... Consequently, STIBP needs to be explicitly
> + enabled to guard against cross-thread attacks in userspace.
needs?
That sounds like something the user needs to do. But we do it by
default. Let's rephrase:
"Systems which support enhanced IBRS (eIBRS) enable IBRS protections once at
boot and they're automatically protected against Spectre v2 variant
attacks, including cross-thread branch target injections on SMT systems
(STIBP). IOW, eIBRS enables STIBP too.
Legacy IBRS systems clear the IBRS bit on exit to userspace and
therefore explicitly enable STIBP for that."
Simple.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2023-02-23 14:52 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-21 18:49 [PATCH v2 1/2] x86/speculation: Allow enabling STIBP with legacy IBRS KP Singh
2023-02-21 18:49 ` [PATCH v2 2/2] Documentation/hw-vuln: Document the interaction between IBRS and STIBP KP Singh
2023-02-23 14:52 ` Borislav Petkov [this message]
2023-02-24 3:30 ` KP Singh
2023-02-26 1:42 ` KP Singh
2023-02-21 19:29 ` [PATCH v2 1/2] x86/speculation: Allow enabling STIBP with legacy IBRS Greg KH
2023-02-21 19:29 ` Greg KH
2023-02-21 19:35 ` KP Singh
2023-02-21 19:47 ` Greg KH
2023-02-21 19:57 ` Borislav Petkov
2023-02-21 20:09 ` Greg KH
2023-02-21 20:23 ` Borislav Petkov
2023-02-22 3:07 ` Pawan Gupta
2023-02-22 5:49 ` KP Singh
2023-02-22 8:25 ` Pawan Gupta
2023-02-22 12:32 ` Borislav Petkov
2023-02-22 13:56 ` David Laight
2023-02-22 12:24 ` Borislav Petkov
2023-02-22 17:16 ` KP Singh
2023-02-22 17:48 ` Borislav Petkov
2023-02-22 19:41 ` KP Singh
2023-02-23 12:44 ` Borislav Petkov
2023-02-26 1:50 ` KP Singh
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