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From: Linus Torvalds <linus@torvalds.org>
To: speck@linutronix.de
Subject: [MODERATED] Re: [PATCH v2 3/8] MDSv2 5
Date: Wed, 12 Dec 2018 10:47:10 -0800	[thread overview]
Message-ID: <CAHk-=whiyhRXGrX9xh1nUeWCmPbistyVh9jmzfx6TMhR+qKPQQ@mail.gmail.com> (raw)
In-Reply-To: <20181212175803.GF25620@tassilo.jf.intel.com>

[ let's see if this comes through now ]

On Wed, Dec 12, 2018, 09:58 speck for Andi Kleen <speck@linutronix.de wrote:

>
> However there is one problem: if the guest is using
> the software sequence and the sequence gets interrupted
> by an exit,
>

So I'm at the Intel partner meeting right now, and the official statement
seems to be that the software sequence really shouldn't be used. Nobody
seems to want that to be used for anything but something really odd case.

Just the verw instruction seems to be on the order of 400 cycles. It's
probably unnoticeable on any machine that has all the other mitigations in
place, but it looks like there are machines now that have all the other
things fixed, so 400 cycles then is still quite noticeable.

But the software sequence really sounds like nobody should realistically be
using by default.

         Linus

>

  reply	other threads:[~2018-12-12 18:47 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 [this message]
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   ` [MODERATED] " Andrew Cooper
2018-12-11  0:46     ` 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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