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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: [PATCH v2 6/8] MDSv2 3
Date: Tue, 11 Dec 2018 00:37:49 +0000	[thread overview]
Message-ID: <fa1f5b14-1f23-a762-b508-072b09b68fff@citrix.com> (raw)
In-Reply-To: <4c82eebb25381317499b1a92b7c6d516df265536.1544464266.git.ak@linux.intel.com>

[-- Attachment #1: Type: text/plain, Size: 839 bytes --]

On 10/12/2018 17:53, speck for Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> Subject:  x86/speculation/mds: Force MDS_EXIT on paranoid exit
>  for sw sequence
>
> When we use a software sequence for clearing CPU buffers an NMI
> or similar interrupt could interrupt the clearing sequence.
> In this case make sure we really flush by always doing the extra
> clearing on paranoid interrupt exit.
>
> This is only needed for the software sequence because VERW
> is an instruction that cannot be interrupted.

Interrupting the middle of the software sequence is only one half of the
problem.

The other half is when an NMI/#MC/etc hits on the return to guest path
after executing VERW, at which point you've just refilled all the
buffers between trying to clear them, and returning to userspace.

~Andrew


  reply	other threads:[~2018-12-11  0:37 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-10 17:53 [MODERATED] [PATCH v2 0/8] MDSv2 8 Andi Kleen
2018-12-10 17:53 ` [MODERATED] [PATCH v2 1/8] MDSv2 4 Andi Kleen
2018-12-11 14:14   ` [MODERATED] " Paolo Bonzini
2018-12-12 21:22   ` Konrad Rzeszutek Wilk
2018-12-12 21:28     ` Andi Kleen
2018-12-12 21:25   ` Konrad Rzeszutek Wilk
2018-12-10 17:53 ` [MODERATED] [PATCH v2 2/8] MDSv2 1 Andi Kleen
2018-12-10 22:49   ` [MODERATED] " Jiri Kosina
2018-12-11  0:03     ` Andi Kleen
2018-12-11  0:13     ` Kanth Ghatraju
2018-12-11  2:00       ` Andi Kleen
2018-12-11  5:36       ` Jiri Kosina
2018-12-11 10:03       ` Borislav Petkov
2018-12-12 21:31         ` Konrad Rzeszutek Wilk
2018-12-12 21:43           ` Andi Kleen
2018-12-12 22:17           ` Borislav Petkov
2018-12-12 22:40             ` Konrad Rzeszutek Wilk
2018-12-12 22:45               ` Borislav Petkov
2018-12-13 15:15                 ` Andrew Cooper
2018-12-13 16:52                   ` Borislav Petkov
2018-12-10 17:53 ` [MODERATED] [PATCH v2 3/8] MDSv2 5 Andi Kleen
2018-12-10 23:00   ` [MODERATED] " Linus Torvalds
2018-12-11  0:03     ` Andi Kleen
2018-12-11  0:43       ` Linus Torvalds
2018-12-11  1:33         ` Linus Torvalds
2018-12-11  2:12           ` Andi Kleen
2018-12-11  2:20           ` Linus Torvalds
2018-12-11  3:25             ` Andi Kleen
2018-12-11 17:55               ` Linus Torvalds
2018-12-11 18:10                 ` Borislav Petkov
2018-12-11 18:21                 ` Linus Torvalds
2018-12-11 18:26                   ` Borislav Petkov
2018-12-11 19:47                   ` Andi Kleen
2018-12-11 21:22                   ` Thomas Gleixner
2018-12-12 14:02               ` [MODERATED] " Paolo Bonzini
2018-12-12 17:58                 ` Andi Kleen
2018-12-12 18:47                   ` Linus Torvalds
2018-12-13 19:44                     ` Linus Torvalds
2018-12-13 20:48                       ` Andi Kleen
2018-12-13 20:56                         ` Linus Torvalds
2018-12-15  0:30                         ` Andi Kleen
2018-12-11  2:10         ` Andi Kleen
2018-12-11  0:09     ` Andrew Cooper
2018-12-10 17:53 ` [MODERATED] [PATCH v2 4/8] MDSv2 0 Andi Kleen
2018-12-12 21:45   ` [MODERATED] " Konrad Rzeszutek Wilk
2018-12-12 22:09     ` Andi Kleen
2018-12-12 22:36       ` Konrad Rzeszutek Wilk
2018-12-10 17:53 ` [MODERATED] [PATCH v2 5/8] MDSv2 7 Andi Kleen
2018-12-11  0:33   ` [MODERATED] " Andrew Cooper
2018-12-12 18:05     ` Andrew Cooper
2018-12-12 21:41   ` Konrad Rzeszutek Wilk
2018-12-12 22:12     ` Andi Kleen
2018-12-10 17:53 ` [MODERATED] [PATCH v2 6/8] MDSv2 3 Andi Kleen
2018-12-11  0:37   ` Andrew Cooper [this message]
2018-12-11  0:46     ` [MODERATED] " Luck, Tony
2018-12-11  1:02       ` Andrew Cooper
2018-12-11  1:53       ` Andi Kleen
2018-12-10 17:53 ` [MODERATED] [PATCH v2 7/8] MDSv2 6 Andi Kleen
2018-12-10 17:53 ` [MODERATED] [PATCH v2 8/8] MDSv2 2 Andi Kleen

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