Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not mapkernel in user mode

From: Richard Weinberger <richard@nod.at>
To: "Fogh, Anders" <anders.fogh@gdata-adan.de>,
	Daniel Gruss <daniel.gruss@iaik.tugraz.at>
Cc: Christoph Hellwig <hch@infradead.org>,
	kernel list <linux-kernel@vger.kernel.org>,
	"kernel-hardening@lists.openwall.com" 
	<kernel-hardening@lists.openwall.com>,
	"clementine.maurice@iaik.tugraz.at" 
	<clementine.maurice@iaik.tugraz.at>,
	"moritz.lipp@iaik.tugraz.at" <moritz.lipp@iaik.tugraz.at>,
	Michael Schwarz <michael.schwarz@iaik.tugraz.at>,
	Richard Fellner <richard.fellner@student.tugraz.at>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not mapkernel in user mode
Date: Tue, 9 May 2017 16:57:28 +0200	[thread overview]
Message-ID: <22a14b06-9489-3494-bbb7-428d4e5fa186@nod.at> (raw)
In-Reply-To: <07322e2c-e95f-ea35-bc1f-7b05c082e287@gdata-adan.de>

Am 09.05.2017 um 16:44 schrieb Fogh, Anders:
>>> i.e. how does it perform on recent AMD systems?
> 
> Sorry for the latency. Recent AMD is reported by Enrique Nissem to not
> be vulnerable to the prefetch attack. TSX attack doesn't apply to AMD.
> Hund, Willems & Holz wrote in 2013 that AMD was vulnerable to that
> attack. The BTB is almost surely working in a different manner of
> fashion if at all. So AMD may or may not be vulnerable to the DPF
> attack, but none of the modern attacks should work - at least out of the
> box.

But the promoted patch will also run on AMD systems, that's why I asked
for the overhead.

Thanks,
//richard