Messages in this thread | | | Subject | Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not mapkernel in user mode | From | Rik van Riel <> | Date | Tue, 09 May 2017 11:30:57 -0400 |
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On Tue, 2017-05-09 at 16:57 +0200, Richard Weinberger wrote: > 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.
Well, if it is a compile time switch, and the overhead is unacceptable on everything but the very latest Intel chips, chances are the code will not be enabled in any distribution kernel.
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