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From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: David Laight <David.Laight@ACULAB.COM>
Cc: "'Linus Torvalds'" <torvalds@linux-foundation.org>,
	Willy Tarreau <w@1wt.eu>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Dan Williams <dan.j.williams@intel.com>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	Andi Kleen <ak@linux.intel.com>, Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	"Network Development" <netdev@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 06/18] x86, barrier: stop speculation for failed access_ok
Date: Mon, 8 Jan 2018 12:12:45 +0000	[thread overview]
Message-ID: <20180108121245.194360d4@alans-desktop> (raw)
In-Reply-To: <138620e379794e98b606ed675da6d04d@AcuMS.aculab.com>

On Mon, 8 Jan 2018 12:00:28 +0000
David Laight <David.Laight@ACULAB.COM> wrote:

> From: Linus Torvalds
> > Sent: 07 January 2018 19:47  
> ...
> > Also, people definitely *are* noticing the performance issues with the
> > current set of patches, and they are causing real problems. Go search
> > for reports of Amazon AWS slowdowns.  
> 
> Try over 35% slowdown....
> Given that AWS instance runs known code (user and kernel) why do we
> need to worry about any of these sideband attacks?

You may not need to. Amazon themselves obviously need to worry that no
other VM steals your data (or vice versa) but above that (and with raw
hardware appliances) if you control all the code you run then the nopti
and other disables may be useful (At the end of the day as with anything
else you do your own risk assessment).

Do remember to consider if you are running untrusted but supposedly
sandboxed code (eg Java, js).

I'm not using pti etc on my minecraft VMs - no point. If anyone gets to
run arbitrary code on them except me then it's already compromised.

Alan

  reply	other threads:[~2018-01-08 12:13 UTC|newest]

Thread overview: 162+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-06  1:09 [PATCH 00/18] prevent bounds-check bypass via speculative execution Dan Williams
2018-01-06  1:09 ` [PATCH 01/18] asm-generic/barrier: add generic nospec helpers Dan Williams
2018-01-06  2:55   ` Linus Torvalds
2018-01-06  5:23     ` Dan Williams
2018-01-06 17:08       ` Mark Rutland
2018-01-06  1:10 ` [PATCH 02/18] Documentation: document " Dan Williams
2018-01-08 16:29   ` Jonathan Corbet
2018-01-08 17:09     ` Mark Rutland
2018-01-08 21:19       ` Jonathan Corbet
2018-01-06  1:10 ` [PATCH 03/18] arm64: implement nospec_ptr() Dan Williams
2018-01-06  1:10 ` [PATCH 04/18] arm: " Dan Williams
2018-01-10  2:04   ` Laura Abbott
2018-01-10  7:40     ` Hanjun Guo
2018-01-10 17:24       ` Laura Abbott
2018-01-06  1:10 ` [PATCH 05/18] x86: implement nospec_barrier() Dan Williams
2018-01-06  1:10 ` [PATCH 06/18] x86, barrier: stop speculation for failed access_ok Dan Williams
2018-01-06  2:52   ` Linus Torvalds
2018-01-06  3:09     ` Linus Torvalds
2018-01-06 23:31       ` Dan Williams
2018-01-07  1:20         ` Linus Torvalds
2018-01-08 21:09           ` Dan Williams
2018-01-08 23:44             ` Linus Torvalds
2018-01-08 23:53               ` Dan Williams
2018-01-06  5:47     ` Dan Williams
2018-01-06 12:32     ` Alan Cox
2018-01-06 17:56       ` Linus Torvalds
2018-01-06 18:13       ` Alexei Starovoitov
2018-01-06 18:29         ` Dan Williams
2018-01-06 18:39           ` Alexei Starovoitov
2018-01-06 18:54             ` Dan Williams
2018-01-06 19:25               ` Alexei Starovoitov
2018-01-06 19:36                 ` Dan Williams
2018-01-06 19:41                 ` Thomas Gleixner
2018-01-08 10:02                   ` Andrea Arcangeli
2018-01-06 18:38         ` Alan Cox
2018-01-06 18:51           ` Alexei Starovoitov
2018-01-06 19:55             ` Alan Cox
2018-01-06 20:09               ` Alexei Starovoitov
2018-01-06 20:22                 ` Alan Cox
2018-01-06 21:17                   ` Alexei Starovoitov
2018-01-06 21:21                     ` Thomas Gleixner
2018-01-06 23:05                     ` Alan Cox
2018-01-07  3:38                       ` Alexei Starovoitov
2018-01-07  6:33                         ` Willy Tarreau
2018-01-07 19:47                           ` Linus Torvalds
2018-01-07 20:12                             ` Willy Tarreau
2018-01-07 20:17                               ` Linus Torvalds
2018-01-07 20:56                                 ` Thomas Gleixner
2018-01-08  2:23                                   ` David Miller
2018-01-08  7:38                                     ` Greg KH
2018-01-07 22:15                                 ` Willy Tarreau
2018-01-07 20:15                             ` Dan Williams
2018-01-08  2:24                               ` Alexei Starovoitov
2018-01-08  9:51                                 ` Peter Zijlstra
2018-01-08 18:21                                   ` Ingo Molnar
2018-01-08 12:00                             ` David Laight
2018-01-08 12:12                               ` Alan Cox [this message]
2018-01-08 12:33                                 ` David Laight
2018-01-07 10:08                         ` Thomas Gleixner
2018-01-08  2:09                           ` Alexei Starovoitov
2018-01-07 13:59                         ` Alan Cox
2018-01-08  2:57                           ` Alexei Starovoitov
2018-01-08  9:57                             ` Peter Zijlstra
2018-01-06 20:42           ` Willy Tarreau
2018-01-07  1:36             ` David Miller
2018-01-07 17:19               ` James Bottomley
2018-01-07 18:31                 ` Thomas Gleixner
2018-01-08  2:04                   ` David Miller
2018-01-07 19:24                 ` Alan Cox
2018-01-09 21:41     ` Josh Poimboeuf
2018-01-09 21:47       ` Dan Williams
2018-01-09 21:49         ` Josh Poimboeuf
2018-01-09 21:59           ` Dan Williams
2018-01-09 22:23             ` Josh Poimboeuf
2018-01-09 22:35               ` Dan Williams
2018-01-06  1:10 ` [PATCH 07/18] [media] uvcvideo: prevent bounds-check bypass via speculative execution Dan Williams
2018-01-06  9:09   ` Greg KH
2018-01-06  9:40     ` Greg KH
2018-01-06 17:41       ` Dan Williams
2018-01-07  9:09         ` Greg KH
2018-01-07 19:37           ` Dan Williams
2018-01-09  8:40       ` Laurent Pinchart
2018-01-09 10:04         ` Greg KH
2018-01-09 14:26           ` Laurent Pinchart
2018-01-09 14:47             ` Greg KH
2018-01-08 11:23   ` Laurent Pinchart
2018-01-09  2:11     ` Dan Williams
2018-01-06  1:10 ` [PATCH 08/18] carl9170: " Dan Williams
2018-01-06 10:01   ` Sergei Shtylyov
2018-01-06 14:23   ` Christian Lamparter
2018-01-06 15:06     ` Alan Cox
2018-01-06 16:38       ` Christian Lamparter
2018-01-06 16:34     ` Dan Williams
2018-01-06  1:10 ` [PATCH 09/18] p54: " Dan Williams
2018-01-06 10:01   ` Sergei Shtylyov
2018-01-06  1:10 ` [PATCH 10/18] qla2xxx: " Dan Williams
2018-01-06  9:03   ` Greg KH
2018-01-06  9:42     ` Greg KH
2018-01-11 22:15     ` Dan Williams
2018-01-12  7:27       ` Greg KH
2018-01-12 15:25         ` James Bottomley
2018-01-06  1:10 ` [PATCH 11/18] cw1200: " Dan Williams
2018-01-06  1:10 ` [PATCH 12/18] Thermal/int340x: " Dan Williams
2018-01-06  1:53   ` Srinivas Pandruvada
2018-01-06  1:57     ` Dan Williams
2018-01-06 17:24       ` Srinivas Pandruvada
2018-01-06 10:03   ` Sergei Shtylyov
2018-01-06  1:11 ` [PATCH 13/18] ipv6: " Dan Williams
2018-01-06 10:04   ` Sergei Shtylyov
2018-01-06 14:48   ` Stephen Hemminger
2018-01-06 18:05     ` Dan Williams
2018-01-06  1:11 ` [PATCH 14/18] ipv4: " Dan Williams
2018-01-06  9:00   ` Greg KH
2018-01-06  9:01   ` Greg KH
2018-01-06 12:23     ` Alan Cox
2018-01-06 15:14       ` Greg KH
2018-01-06 16:29         ` Dan Williams
2018-01-06 18:10           ` Dan Williams
2018-01-06 10:04   ` Sergei Shtylyov
2018-01-06  1:11 ` [PATCH 15/18] vfs, fdtable: " Dan Williams
2018-01-06 10:05   ` Sergei Shtylyov
2018-01-06  1:11 ` [PATCH 16/18] net: mpls: " Dan Williams
2018-01-06 10:06   ` Sergei Shtylyov
2018-01-09  3:11   ` Eric W. Biederman
2018-01-09  3:42     ` Dan Williams
2018-01-09  4:13       ` Linus Torvalds
2018-01-09  4:21         ` Linus Torvalds
2018-01-10  0:48         ` Dan Williams
2018-01-10  1:33           ` Dan Williams
2018-01-10  1:57           ` Alexei Starovoitov
2018-01-10  2:22             ` Dan Williams
2018-01-10  3:07               ` Alexei Starovoitov
2018-01-10  3:27           ` Linus Torvalds
2018-01-09 16:17       ` Eric W. Biederman
2018-01-09 18:01         ` Dan Williams
2018-01-10  0:54           ` Eric W. Biederman
2018-01-10  1:31             ` Dan Williams
2018-01-06  1:11 ` [PATCH 17/18] udf: " Dan Williams
2018-01-08 10:20   ` Jan Kara
2018-01-06  1:11 ` [PATCH 18/18] userns: " Dan Williams
2018-01-06  2:22 ` [PATCH 00/18] " Eric W. Biederman
2018-01-06  6:30   ` Dan Williams
2018-01-08 10:08     ` Peter Zijlstra
2018-01-08 11:14       ` Laurent Pinchart
2018-01-08 11:43       ` Alan Cox
2018-01-08 11:55         ` Peter Zijlstra
2018-01-08 18:33         ` Ingo Molnar
2018-01-08 16:20     ` Bart Van Assche
2018-01-06 18:56 ` Florian Fainelli
2018-01-06 18:59   ` Arjan van de Ven
2018-01-06 19:37 ` Dan Williams
2018-01-06 20:07   ` Dan Williams
2018-01-08  4:49 ` Bart Van Assche
2018-01-08 13:33   ` Arjan van de Ven
2018-01-09 19:34 ` Jiri Kosina
2018-01-09 19:44   ` Dan Williams
2018-01-09 20:55     ` Josh Poimboeuf
2018-01-11  9:54       ` Jiri Kosina
2018-01-11 15:58         ` Dan Williams
2018-01-11 16:34           ` Daniel Borkmann
2018-01-13 11:33 ` QingFeng Hao
2018-01-09  0:12 [PATCH 06/18] x86, barrier: stop speculation for failed access_ok Linus Torvalds

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