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From: Linus Torvalds <torvalds@linux-foundation.org>
To: speck@linutronix.de
Subject: [MODERATED] Re: L1D-Fault KVM mitigation
Date: Thu, 24 May 2018 10:30:10 -0700 (PDT)	[thread overview]
Message-ID: <alpine.LFD.2.21.999.1805241026440.32557@i7.lan> (raw)
In-Reply-To: <47bca42e-656b-4918-14de-1f26ad932df1@linux.intel.com>



On Thu, 24 May 2018, speck for Dave Hansen wrote:
> 
> The most straightforward thing is to do trigger the same behavior as
> "noht" as part of our arch/x86/kernel/cpu/bugs.c code whenever KVM is
> compile-time enabled.

Absolutely not.

The whole HT issue is only for people who run untrusted loads. 

Lots of people use kvm for testing, but also for just running qemu etc. 
They have absolutely zero reason to disable HT in general.

The only people who worry are Amazon etc.

We should document the hell out of it, and happily the tech press will be 
very happy to inform everybody about the issue. But most people won't care 
one whit, and will run only "good" loads (ie operating systems that have 
been fixed) in their vm's and not random garbage.

Don't try to make this HT workaround be anything but what it is: an issue 
for the Amazons and googles of the world.

               Linus

  reply	other threads:[~2018-05-24 17:30 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-24  9:06 [MODERATED] L1D-Fault KVM mitigation Joerg Roedel
2018-04-24  9:35 ` [MODERATED] " Peter Zijlstra
2018-04-24  9:48   ` David Woodhouse
2018-04-24 11:04     ` Peter Zijlstra
2018-04-24 11:16       ` David Woodhouse
2018-04-24 15:10         ` Jon Masters
2018-05-23  9:45       ` David Woodhouse
2018-05-24  9:45         ` Peter Zijlstra
2018-05-24 14:14           ` Jon Masters
2018-05-24 15:04           ` Thomas Gleixner
2018-05-24 15:33             ` Thomas Gleixner
2018-05-24 15:38               ` [MODERATED] " Jiri Kosina
2018-05-24 17:22                 ` Dave Hansen
2018-05-24 17:30                   ` Linus Torvalds [this message]
2018-05-24 23:18               ` [MODERATED] Encrypted Message Tim Chen
2018-05-24 23:28                 ` [MODERATED] Re: L1D-Fault KVM mitigation Linus Torvalds
2018-05-25  8:31                   ` Thomas Gleixner
2018-05-28 14:43                     ` [MODERATED] " Paolo Bonzini
2018-05-25 18:22                 ` [MODERATED] Encrypted Message Tim Chen
2018-05-26 19:14                 ` L1D-Fault KVM mitigation Thomas Gleixner
2018-05-26 20:43                   ` [MODERATED] " Andi Kleen
2018-05-26 20:48                     ` Linus Torvalds
2018-05-27 18:25                       ` Andi Kleen
2018-05-27 18:49                         ` Linus Torvalds
2018-05-27 18:57                           ` Thomas Gleixner
2018-05-27 19:13                           ` [MODERATED] " Andrew Cooper
2018-05-27 19:26                             ` Linus Torvalds
2018-05-27 19:41                               ` Thomas Gleixner
2018-05-27 22:26                                 ` [MODERATED] " Andrew Cooper
2018-05-28  6:47                                   ` Thomas Gleixner
2018-05-28 12:26                                     ` [MODERATED] " Andrew Cooper
2018-05-28 14:40                           ` Paolo Bonzini
2018-05-28 15:56                             ` Thomas Gleixner
2018-05-28 17:15                               ` [MODERATED] " Paolo Bonzini
2018-05-27 15:42                     ` Thomas Gleixner
2018-05-27 16:26                       ` [MODERATED] " Linus Torvalds
2018-05-27 18:31                       ` Andi Kleen
2018-05-29 19:29                   ` [MODERATED] Encrypted Message Tim Chen
2018-05-29 21:14                     ` L1D-Fault KVM mitigation Thomas Gleixner
2018-05-30 16:38                       ` [MODERATED] Encrypted Message Tim Chen
2018-05-24 15:44             ` [MODERATED] Re: L1D-Fault KVM mitigation Andi Kleen
2018-05-24 15:38           ` Linus Torvalds
2018-05-24 15:59             ` David Woodhouse
2018-05-24 16:35               ` Linus Torvalds
2018-05-24 16:51                 ` David Woodhouse
2018-05-24 16:57                   ` Linus Torvalds
2018-05-25 11:29                     ` David Woodhouse
2018-04-24 10:30   ` [MODERATED] Re: ***UNCHECKED*** " Joerg Roedel
2018-04-24 11:09     ` Thomas Gleixner
2018-04-24 16:06       ` [MODERATED] " Andi Kleen
2018-04-24 12:53   ` Paolo Bonzini
2018-05-03 16:20     ` Konrad Rzeszutek Wilk
2018-05-07 17:11       ` Paolo Bonzini
2018-05-16  8:51         ` Jiri Kosina
2018-05-16  8:53           ` Paolo Bonzini
2018-05-21 10:06             ` David Woodhouse
2018-05-21 13:40               ` Thomas Gleixner

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