From: Jiri Kosina <jkosina@suse.cz>
To: speck@linutronix.de
Subject: [MODERATED] Re: ***UNCHECKED*** Re: [PATCH v5 08/11] TAAv5 8
Date: Tue, 15 Oct 2019 17:32:08 +0200 (CEST) [thread overview]
Message-ID: <nycvar.YFH.7.76.1910151728110.13160@cbobk.fhfr.pm> (raw)
In-Reply-To: <20191015152649.yim4krwuttrh6xgi@treble>
On Tue, 15 Oct 2019, speck for Josh Poimboeuf wrote:
> > > Since all (or most?) modern Intel CPUs are vulnerable to TAA,
> > > defaulting to tsx=auto would effectively be the same as defaulting
> > > to tsx=off, right? How does this help with regressions?
> >
> > The mitigation is only needed on CPUs where verw doesn't have the buffer
> > clearing semantics.
>
> Can you elaborate? I have no idea what you're trying to say and how it
> relates to my question :-)
Only those CPUs with TSX *and* with MDS_NO need TSX disabled in order to
protect from this issues.
The CPUs that don't enumarate MDS_NO (and therefore got ucode update with
verw buffer-clearing semantics) are fully mitigated against TAA by MDS
mitigations already.
Therefore the set of CPUs where we *really* need to turn of TSX in order
to protect from TAA is currently rather minimal (CascadeLake-B,
WhiskeyLake-V, CommitLake, CoffeeLake-R), so force-disabling on all CPUs
covers way bigger set of platforms than actually needed.
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2019-10-15 15:32 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-05 6:17 [MODERATED] [PATCH v5 00/11] TAAv5 0 Pawan Gupta
2019-10-05 6:26 ` [MODERATED] [PATCH v5 01/11] TAAv5 1 Pawan Gupta
2019-10-05 6:27 ` [MODERATED] [PATCH v5 02/11] TAAv5 2 Pawan Gupta
2019-10-05 6:28 ` [MODERATED] [PATCH v5 03/11] TAAv5 3 Pawan Gupta
2019-10-05 6:29 ` [MODERATED] [PATCH v5 04/11] TAAv5 4 Pawan Gupta
2019-10-05 6:30 ` [MODERATED] [PATCH v5 05/11] TAAv5 5 Pawan Gupta
2019-10-05 6:31 ` [MODERATED] [PATCH v5 06/11] TAAv5 6 Pawan Gupta
2019-10-05 6:32 ` [MODERATED] [PATCH v5 07/11] TAAv5 7 Pawan Gupta
2019-10-05 6:33 ` [MODERATED] [PATCH v5 08/11] TAAv5 8 Pawan Gupta
2019-10-05 6:34 ` [MODERATED] [PATCH v5 09/11] TAAv5 9 Pawan Gupta
2019-10-05 6:35 ` [MODERATED] [PATCH v5 10/11] TAAv5 10 Pawan Gupta
2019-10-05 6:36 ` [MODERATED] [PATCH v5 11/11] TAAv5 11 Pawan Gupta
2019-10-05 10:54 ` [MODERATED] Re: [PATCH v5 02/11] TAAv5 2 Borislav Petkov
2019-10-07 17:48 ` Pawan Gupta
[not found] ` <5d98396a.1c69fb81.6c7a8.23b1SMTPIN_ADDED_BROKEN@mx.google.com>
2019-10-05 21:43 ` [MODERATED] Re: [PATCH v5 03/11] TAAv5 3 Andy Lutomirski
2019-10-07 17:50 ` Pawan Gupta
[not found] ` <5d9839a4.1c69fb81.238e9.8312SMTPIN_ADDED_BROKEN@mx.google.com>
2019-10-05 21:45 ` [MODERATED] Re: [PATCH v5 04/11] TAAv5 4 Andy Lutomirski
[not found] ` <5d983ad2.1c69fb81.63edd.6575SMTPIN_ADDED_BROKEN@mx.google.com>
2019-10-05 21:49 ` [MODERATED] Re: [PATCH v5 09/11] TAAv5 9 Andy Lutomirski
2019-10-07 18:35 ` Pawan Gupta
[not found] ` <5d9838f1.1c69fb81.f1bab.d886SMTPIN_ADDED_BROKEN@mx.google.com>
2019-10-05 21:49 ` [MODERATED] Re: [PATCH v5 01/11] TAAv5 1 Andy Lutomirski
2019-10-06 17:40 ` Andrew Cooper
[not found] ` <5d983ad2.1c69fb81.e6640.8f51SMTPIN_ADDED_BROKEN@mx.google.com>
2019-10-06 17:06 ` [MODERATED] Re: [PATCH v5 09/11] TAAv5 9 Greg KH
2019-10-08 6:01 ` Pawan Gupta
2019-10-10 21:31 ` Pawan Gupta
2019-10-11 8:45 ` Greg KH
2019-10-21 8:00 ` Thomas Gleixner
2019-10-08 2:46 ` [MODERATED] Re: [PATCH v5 05/11] TAAv5 5 Josh Poimboeuf
2019-10-09 1:45 ` Pawan Gupta
2019-10-08 2:57 ` [MODERATED] Re: [PATCH v5 09/11] TAAv5 9 Josh Poimboeuf
2019-10-08 6:10 ` Pawan Gupta
2019-10-08 10:49 ` Jiri Kosina
2019-10-09 13:12 ` [MODERATED] Re: ***UNCHECKED*** [PATCH v5 08/11] TAAv5 8 Michal Hocko
2019-10-14 19:41 ` Thomas Gleixner
2019-10-14 19:51 ` [MODERATED] " Jiri Kosina
2019-10-14 21:04 ` [MODERATED] " Borislav Petkov
2019-10-14 21:31 ` Jiri Kosina
2019-10-15 8:01 ` Thomas Gleixner
2019-10-15 10:34 ` [MODERATED] Re: ***UNCHECKED*** " Michal Hocko
2019-10-15 13:06 ` Josh Poimboeuf
2019-10-15 13:10 ` Jiri Kosina
2019-10-15 15:26 ` Josh Poimboeuf
2019-10-15 15:32 ` Jiri Kosina [this message]
2019-10-15 19:34 ` Tyler Hicks
2019-10-15 20:00 ` Josh Poimboeuf
2019-10-15 20:15 ` Jiri Kosina
2019-10-15 20:35 ` Jiri Kosina
2019-10-15 20:54 ` Josh Poimboeuf
2019-10-15 20:56 ` [MODERATED] " Pawan Gupta
2019-10-15 21:14 ` Jiri Kosina
2019-10-15 23:12 ` Josh Poimboeuf
2019-10-15 23:13 ` [MODERATED] [AUTOREPLY] [MODERATED] [AUTOREPLY] Automatic reply: " James, Hengameh M
2019-10-16 4:52 ` [MODERATED] " Jiri Kosina
2019-10-16 5:05 ` Jiri Kosina
2019-10-21 21:15 ` Luck, Tony
2019-10-16 7:14 ` Josh Poimboeuf
2019-10-16 7:20 ` Jiri Kosina
2019-10-18 1:17 ` Ben Hutchings
2019-10-18 4:04 ` Pawan Gupta
2019-10-15 17:47 ` Borislav Petkov
2019-10-16 7:26 ` [MODERATED] Re: ***UNCHECKED*** " Jiri Kosina
2019-10-16 7:54 ` [MODERATED] Re: ***UNCHECKED*** " Michal Hocko
2019-10-16 9:23 ` [MODERATED] Re: ***UNCHECKED*** " Michal Hocko
2019-10-16 12:15 ` Thomas Gleixner
2019-10-16 18:34 ` [MODERATED] " Pawan Gupta
2019-10-18 0:14 ` Pawan Gupta
2019-10-21 8:09 ` Thomas Gleixner
2019-10-21 12:54 ` [MODERATED] Re: ***UNCHECKED*** " Michal Hocko
2019-10-21 20:01 ` [MODERATED] " Pawan Gupta
2019-10-21 20:33 ` Josh Poimboeuf
2019-10-21 20:34 ` Josh Poimboeuf
2019-10-21 20:33 ` Pawan Gupta
2019-10-21 23:01 ` Andrew Cooper
2019-10-21 23:37 ` Luck, Tony
2019-10-21 23:39 ` Andrew Cooper
2019-10-14 21:05 ` [MODERATED] Re: ***UNCHECKED*** " Michal Hocko
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