From: Andi Kleen <ak@linux.intel.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: L1D-Fault KVM mitigation
Date: Sun, 27 May 2018 11:25:50 -0700 [thread overview]
Message-ID: <20180527182550.GC4486@tassilo.jf.intel.com> (raw)
In-Reply-To: <alpine.LFD.2.21.999.1805261345410.7864@i7.lan>
On Sat, May 26, 2018 at 01:48:01PM -0700, speck for Linus Torvalds wrote:
>
>
> On Sat, 26 May 2018, speck for Andi Kleen wrote:
> >
> > Keep in mind that we don't need to synchronize when the other CPU is idle
> > in the guest, so it's only a problem when all the CPUs are busy.
>
> What? No.
>
> Maybe you mean "idle in the _host_"?
It's both actually. Either idle in the host, or idle in the guest.
When it's idle in the host we don't need to synchronize, unless
there is an interrupt (which does its own synchronization) because
the idle loop has nothing valuable to leak.
And if it's idle in the guest then the vcpu is blocked and
also obviously doesn't need to be synchronized.
Both cases can be reasonably common.
-Andi
next prev parent reply other threads:[~2018-05-27 18:25 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
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 [this message]
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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