From: Pavel Machek <pavel@ucw.cz>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>, Kees Cook <keescook@chromium.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
kernel list <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>
Subject: [kernel-hardening] Re: rowhammer protection [was Re: Getting interrupt every million cache misses]
Date: Fri, 28 Oct 2016 13:27:08 +0200 [thread overview]
Message-ID: <20161028112707.GB5635@amd> (raw)
In-Reply-To: <20161028090423.GY3102@twins.programming.kicks-ass.net>
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Hi!
> > I agree this needs to be tunable (and with the other suggestions). But
> > this is actually not the most important tunable: the detection
> > threshold (rh_attr.sample_period) should be way more important.
>
> So being totally ignorant of the detail of how rowhammer abuses the DDR
> thing, would it make sense to trigger more often and delay shorter? Or
> is there some minimal delay required for things to settle or
> something.
We can trigger more often and delay shorter, but it will mean that
protection will trigger with more false positives. I guess I'll play
with constants too see how big the effect is.
BTW...
[ 6267.180092] INFO: NMI handler (perf_event_nmi_handler) took too
long to run: 63.501 msecs
but I'm doing mdelay(64). .5 msec is not big difference, but...
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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WARNING: multiple messages have this Message-ID (diff)
From: Pavel Machek <pavel@ucw.cz>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>, Kees Cook <keescook@chromium.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
kernel list <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>
Subject: Re: rowhammer protection [was Re: Getting interrupt every million cache misses]
Date: Fri, 28 Oct 2016 13:27:08 +0200 [thread overview]
Message-ID: <20161028112707.GB5635@amd> (raw)
In-Reply-To: <20161028090423.GY3102@twins.programming.kicks-ass.net>
[-- Attachment #1: Type: text/plain, Size: 987 bytes --]
Hi!
> > I agree this needs to be tunable (and with the other suggestions). But
> > this is actually not the most important tunable: the detection
> > threshold (rh_attr.sample_period) should be way more important.
>
> So being totally ignorant of the detail of how rowhammer abuses the DDR
> thing, would it make sense to trigger more often and delay shorter? Or
> is there some minimal delay required for things to settle or
> something.
We can trigger more often and delay shorter, but it will mean that
protection will trigger with more false positives. I guess I'll play
with constants too see how big the effect is.
BTW...
[ 6267.180092] INFO: NMI handler (perf_event_nmi_handler) took too
long to run: 63.501 msecs
but I'm doing mdelay(64). .5 msec is not big difference, but...
Best regards,
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:[~2016-10-28 11:27 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-26 20:54 Getting interrupt every million cache misses Pavel Machek
2016-10-27 8:28 ` Peter Zijlstra
2016-10-27 8:46 ` Pavel Machek
2016-10-27 9:15 ` Peter Zijlstra
2016-10-27 9:11 ` Pavel Machek
2016-10-27 9:33 ` Peter Zijlstra
2016-10-27 20:40 ` [kernel-hardening] " Kees Cook
2016-10-27 20:40 ` Kees Cook
2016-10-27 21:27 ` [kernel-hardening] rowhammer protection [was Re: Getting interrupt every million cache misses] Pavel Machek
2016-10-27 21:27 ` Pavel Machek
2016-10-28 7:07 ` [kernel-hardening] " Ingo Molnar
2016-10-28 7:07 ` Ingo Molnar
2016-10-28 8:50 ` [kernel-hardening] " Pavel Machek
2016-10-28 8:50 ` Pavel Machek
2016-10-28 8:59 ` [kernel-hardening] " Ingo Molnar
2016-10-28 8:59 ` Ingo Molnar
2016-10-28 11:55 ` [kernel-hardening] " Pavel Machek
2016-10-28 11:55 ` Pavel Machek
2016-10-28 9:04 ` [kernel-hardening] " Peter Zijlstra
2016-10-28 9:04 ` Peter Zijlstra
2016-10-28 9:27 ` [kernel-hardening] " Vegard Nossum
2016-10-28 9:27 ` Vegard Nossum
2016-10-28 9:35 ` [kernel-hardening] " Ingo Molnar
2016-10-28 9:35 ` Ingo Molnar
2016-10-28 9:47 ` [kernel-hardening] " Vegard Nossum
2016-10-28 9:47 ` Vegard Nossum
2016-10-28 9:53 ` [kernel-hardening] " Mark Rutland
2016-10-28 11:27 ` Pavel Machek [this message]
2016-10-28 11:27 ` Pavel Machek
2016-10-28 9:51 ` [kernel-hardening] " Mark Rutland
2016-10-28 11:21 ` Pavel Machek
2016-10-28 14:05 ` Mark Rutland
2016-10-28 14:18 ` Peter Zijlstra
2016-10-28 18:30 ` Pavel Machek
2016-10-28 18:48 ` Peter Zijlstra
2016-11-02 18:13 ` Pavel Machek
2016-10-28 17:27 ` Pavel Machek
2016-10-29 13:06 ` Daniel Gruss
2016-10-29 19:42 ` Pavel Machek
2016-10-29 20:05 ` Daniel Gruss
2016-10-29 20:14 ` Daniel Gruss
2016-10-29 21:05 ` Pavel Machek
2016-10-29 21:07 ` Daniel Gruss
2016-10-29 21:45 ` Pavel Machek
2016-10-29 21:49 ` Daniel Gruss
2016-10-29 22:01 ` Pavel Machek
2016-10-29 22:02 ` Daniel Gruss
2016-10-31 8:27 ` Pavel Machek
2016-10-31 14:47 ` Mark Rutland
2016-10-31 21:13 ` Pavel Machek
2016-10-31 22:09 ` Mark Rutland
2016-11-01 6:33 ` Ingo Molnar
2016-11-01 7:20 ` Daniel Micay
2016-11-01 7:53 ` Daniel Gruss
2016-11-01 8:10 ` Pavel Machek
2016-11-01 8:13 ` Daniel Gruss
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