From: Pavel Machek <pavel@ucw.cz>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Andy Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@suse.de>
Subject: Re: [PATCH] x86/cpu, x86/pti: Do not enable PTI on AMD processors
Date: Mon, 12 Feb 2018 16:26:30 +0100 [thread overview]
Message-ID: <20180212152630.GD13962@amd> (raw)
In-Reply-To: <20171227054354.20369.94587.stgit@tlendack-t1.amdoffice.net>
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On Tue 2017-12-26 23:43:54, Tom Lendacky wrote:
> AMD processors are not subject to the types of attacks that the kernel
> page table isolation feature protects against. The AMD microarchitecture
> does not allow memory references, including speculative references, that
> access higher privileged data when running in a lesser privileged mode
> when that access would result in a page fault.
>
> Disable page table isolation by default on AMD processors by not setting
> the X86_BUG_CPU_INSECURE feature, which controls whether X86_FEATURE_PTI
> is set.
PTI was originally meant to protect KASLR from memory leaks, before
Spectre was public. I guess that's still valid use on AMD cpus?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2018-02-12 15:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-27 5:43 [PATCH] x86/cpu, x86/pti: Do not enable PTI on AMD processors Tom Lendacky
2017-12-27 8:48 ` Dave Hansen
2017-12-27 14:47 ` Tom Lendacky
2017-12-28 0:20 ` Borislav Petkov
2018-01-03 16:21 ` [tip:x86/pti] " tip-bot for Tom Lendacky
2018-02-12 15:26 ` Pavel Machek [this message]
2018-02-12 15:37 ` [PATCH] " Brian Gerst
2018-02-13 13:21 ` Thomas Gleixner
2018-01-03 11:07 Ivan Ivanov
2018-01-03 19:38 Tim Mouraveiko
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